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Phenotypic plasticity in plants: A case study in ecological development
... Even when these effects catastrophically impacted a laborious multi-year experiment, these authors did not recognize that developmental plasticity had transformed a wild phenotype into a domesticated one over the course of a single growing season. We believe that this blind spot stems from a bias in domestication studies towards viewing plasticity as noise, which is getting in the way of explaining evolutionary change through fixation of genetic variants [26]. ...
... Adaptive plasticity shapes the relative ecological breadth of closely related species, with species that are cosmopolitan weeds exhibiting a greater capacity to respond to the environment than their less widespread relatives [26]. For example, the common weed Persicaria maculosa Gray is able to allocate more energy to leaf biomass in shady conditions than its less common cousin P. hydropiper L. Opiz, which grows only in sunny locations. ...
... P. maculosa is also more able to allocate energy to root biomass in drought conditions than its cousin Polygonum cespitosum Blume, which grows only in moist soils. These studies and many others within the Persicaria/Polygonum study system [30][31][32][33][34] fall under the umbrella of ecological development, which is "the study of development as it occurs in nature, and its ecological consequences" [26]. Our research draws from this perspective and its methodologies: we are interested in development as it occurs in agroecosystems, and its evolutionary consequences. ...
Our experiments with crop progenitors have demonstrated that these species exhibit dramatic plasticity in key traits that are affected by domestication, including seed and fruit morphology. These traits can be altered by cultivating crop progenitors for a single season, in the absence of any selection for domesticated phenotypes. We hypothesize that cultivation caused environmental shifts that led to immediate phenotypic changes in crop progenitors via developmental plasticity, similar to tameness in animals. Here we focus on the loss or reduction of germination inhibitors in an annual seed crop because seeds with high dormancy are undesirable in crops, and also present a serious barrier to selective pressures that arise from seed-saving and planting by humans. Data from four seasons of observation of the crop progenitor Polygonum erectum L. suggest that the low plant density conditions of an agroecosystem trigger a phenotypic response that reduces germination inhibitors, eliminating a key barrier to further selection. The timing of the harvest can also be used to manipulate the germinability of seed stock. These observations suggest that genetic assimilation may have played a role in the domestication of this plant. More experimental work with crop progenitors is needed to understand whether or not this phenomenon played a part in the domestication of other plants, and to accurately interpret the significance of ancient plant phenotypes in the archaeological record.
... During the experiment reported here number of reproductive traits known as fitness-related traits (Sultan, 2003) were assessed. In addition, achenes of the invasive and non invasive Tagetes ...
... Allocation pattern of plant species to distinct tissues such as roots, leaves, stems and reproductive structures is considered as an environmental and ecological important aspect of plant development (Sultan, 2003) which influence plant fitness (Annapurna and Singh, 2003 b). As part of both plasticity experiments the allocation patterns of invasive and non invasive Tagetes species were assessed. ...
This thesis deals with the invasive traits of an invasive plant species (Tagetes minuta) from the Asteraceae family by comparing with the non-invasive species (Tagetes erecta). The comparison was made at the most two critical stages in a plant life cycle, germination and early seedling growth stages. The results, in general, showed the superiority of the invasive species over the non-invasive one in almost all the tested traits.
... Root development has been identified as a key factor in drought stress tolerance for sunflowers [30,33], as well as Arabidopsis [34], maize [35], common bean [36], soybean [37], wheat [38], cotton [39], and rice [40]. Plants frequently exhibit plasticity in resource allocation in such ways as to increase the capture of scarce resources [41]. Plants that allocate proportionally greater resources to the development of organs that maximize acquisition of limiting environmental resources greatly increase biomass [42]. ...
... We observed that late stressed plants unexpectedly exhibited higher yield, which we speculate was due to more rapid seed filling. Plants may allocate greater proportions of their resources to reproduction, so as to mitigate the loss of reproductive output [41]. Though drought stress generally inhibits seed filling by inducing a shorter seed filling period [43,[90][91][92][93][94], drought stress may result in more rapid seed development in the short term [94] (though not all studies bear this out [92]). ...
Cultivated sunflower (Helianthus annuus L.) exhibits numerous phenotypic and transcriptomic responses to drought. However, the ways in which these responses vary with differences in drought timing and severity are insufficiently understood. We used phenotypic and transcriptomic data to evaluate the response of sunflower to drought scenarios of different timing and severity in a common garden experiment. Using a semi-automated outdoor high-throughput phenotyping platform, we grew six oilseed sunflower lines under control and drought conditions. Our results reveal that similar transcriptomic responses can have disparate phenotypic effects when triggered at different developmental time points. Leaf transcriptomic responses, however, share similarities despite timing and severity differences (e.g., 523 differentially expressed genes (DEGs) were shared across all treatments), though increased severity elicited greater differences in expression, particularly during vegetative growth. Across treatments, DEGs were highly enriched for genes related to photosynthesis and plastid maintenance. A co-expression analysis identified a single module (M8) enriched in all drought stress treatments. Genes related to drought, temperature, proline biosynthesis, and other stress responses were overrepresented in this module. In contrast to transcriptomic responses, phenotypic responses were largely divergent between early and late drought. Early-stressed sunflowers responded to drought with reduced overall growth, but became highly water-acquisitive during recovery irrigation, resulting in overcompensation (higher aboveground biomass and leaf area) and a greater overall shift in phenotypic correlations, whereas late-stressed sunflowers were smaller and more water use-efficient. Taken together, these results suggest that drought stress at an earlier growth stage elicits a change in development that enables greater uptake and transpiration of water during recovery, resulting in higher growth rates despite similar initial transcriptomic responses.
... Фенотипічна пластичність, тобто здатність генотипу змінювати свою експресію та реалізуватися у різних фенотипах у відповідь на різноманітні зовнішні впливи, зумовлює пристосування організмів до часових та просторових варіацій зовнішнього середовища Фенотипічний прояв змін в експресії генів визначається вже на рівні транскрипції, а також процесингу РНК і трансляції та охоплює надзвичайно широке коло екологічно важливих ознак -мікроморфологічних, фізіолого-біохімічних, особливості біології розвитку, час переходу до репродуктивної фази, системи розмноження та розвиток нащадків (Bradshow, 1965;Singer, Berg, 1991;Sultan, 2000Sultan, , 2003Schlichting, Smith, 2002;Kordyum et al., 2003;Pigliucci, 2005;Kelly et al., 2012). Висунута модулярна концепція фенотипічної пластичності, за якою зміни в експресії ознак, що виникають під час росту й розвитку, а також під впливом зовнішнього середовища, відбуваються на рівні модулів (Kroon et al., 2005). ...
... Наголошується, що уявлення про пластичність як загальне біологічне явище потребує особливої уваги до її екологічних аспектів, оскільки припускається істотний вплив пластичності організмів на стабільність і локальне різноманіття популяцій та угруповань шляхом впливу на перенос енергії, вуглецеві цикли, число трофічних рівнів, кругообіг поживних речовин та первинну продуктивність. Підкреслюється перспективність досліджень пластичності в екологічному аспекті для подальшого розуміння як механізмів відповідей організмів на дію чинників абіотичного та біотичного оточення, так і впливу цих відповідей на взаємовідношення організмів між собою та довкіллям (Sultan, 2003;Miner et al., 2005;Aubin-North, Renn, 2009;Dubyna, Kordyum, 2015;Kordyum, Dubyna, 2019;Eriksson et al., 2020). ...
In recent decades, knowledge about the role of epigenetic regulation of gene expression in plant responses to external stimuli and in adaptation of plants to adverse environmental fluctuations have extended significantly. DNA methylation is considered as the main molecular mechanism that provides genomic information and contributes to the understanding of the molecular basis of phenotypic variations based on epigenetic modifications. Unfortunately, the vast majority of research in this area has been performed on the model species Arabidopsis thaliana. The development of the methylation-sensitive amplified polymorphism (MSAP) method has made it possible to implement the large-scale detection of DNA methylation alterations in wild non-model and agricultural plants with large and highly repetitive genomes in natural and manipulated habitats. The article presents current information on DNA methylation in species of natural communities and crops and its importance in plant development and adaptive phenotypic plasticity, along with brief reviews of current ideas about adaptive phenotypic plasticity and epigenetic regulation of gene expression. The great potential of further studies of the epigenetic role in phenotypic plasticity of a wide range of non-model species in natural populations and agrocenoses for understanding the molecular mechanisms of plant existence in the changing environment in onto- and phylogeny, directly related to the key tasks of forecasting the effects of global warming and crop selection, is emphasized. Specific taxa of the Ukrainian flora, which, in authors’ opinion, are promising and interesting for this type of research, are recommended.
... The ability that the same species has to develop in nonflooded (or exclusively terrestrial) and flooded (i.e., aquatic) environments is an inherent strategy of its survival and colonization in floodplains (Scremin-Dias 2000a). The occurrence of aquatic plants in non-flooded environments -which usually occurs when ponds and riverbeds dry out in the Pantanal -depends on their ability to respond (e.g., structurally and physiologically) hydric fluctuations.This ability is an environment-dependent phenotypic expression, generally referred to as phenotypic plasticity (Coleman et al. 1994;Sultan 2003). Our focus in this paper is not to address the intricate, genetic-based field of phenotypic plasticity. ...
... Instead, we focus on phenotypic responses to investigate qualitative and quantitative morpho-anatomical changes and strategies of aquatic species associated with seasonally dry environments in the Pantanal. This kind of approach is one of the first steps in providing relevant findings on phenotypic plasticity and understanding the evolutionary patterns and processes in plants (Sultan 1995;2003). ...
[OPEN ACCESS] Hydric fluctuations in the Pantanal comprise annual dry and wet seasons that modify local diversity and plant morphology and anatomy. Widespread in this wetland are the sympatric Pontederia azurea and P. crassipes, which, although primarily aquatic, can also develop in non-flooded environments. This study undertook a comparative investigation of the qualitative and quantitative phenotypic responses and strategies of these two species (regarding life-form and leaf morpho-anatomy) in moderately dry and aquatic environments in the Pantanal. Field observations, conventional methods in plant anatomy, and leaf biometry were performed, followed by statistical analyses. Phenotypic responses, such as the decreased size of lacunae, increased lignification of vessel elements, and storage of starch granules, are the most prominent responses associated with moderately dry environments. The ability of petioles to elongate and inflate seems to be closely related to specific morphological patterns of each species. In contrast, petiole length, leaf blade dimensions, size of lacunae, and lignification rates seem to be somewhat associated with water level fluctuations. Our results provide evidence of how plant structure can simultaneously reflect phylogeny and ecology, thus supporting further investigations into phenotypic plasticity.
... Selecting pot size involves balancing soil volume, growing period, resource requirement and imaging capabilities for noninvasive analysis. An important question is whether pot size influences experimental outcomes, especially regarding phenotypic plasticity, i.e., the ability of organisms to modify their phenotypes in response to environmental changes (Sultan 2003). Pot size variation alters the environment, affecting physiology, morphology, resource allocation or mutualistic interactions with other organisms. ...
Pot size is a critical factor in plant growth experiments, influencing root architecture, nutrient uptake, and overall plant development as well as sensing of stress. In controlled environments, variation in pot size can impact phenotypic and molecular outcomes and may bias experimental results. Here, we investigated how pot size affects the root system architecture and molecular responses of two barley genotypes, the landrace BERE and the modern elite CONCERTO, through assessment of shoot and root traits and by using X-ray computed tomography complemented by transcriptomic and metabolomic analyses. The two genotypes showed distinctly different adaptations to changes in pot size. The landrace showed greater stability and adaptability with consistent root traits and enhanced accumulation of osmoprotectant metabolites across different pot sizes with respect to CONCERTO. Conversely, the elite line was more sensitive to pot size variations, particularly showing altered root architecture and transcriptomic responses. Overall, this study highlights the importance of selecting an appropriate pot size for plant growth experiments, particularly when focused on root traits, and highlights the importance of considering the physiological and molecular changes due to growth environment choice in experimental design in barley.
... Observations and analyses under diverse environmental and temporal conditions have revealed key insights into plant growth and adaptability. Systematic analyses in different ecological settings demonstrate significant plasticity in plant growth under varying environmental factors [5]. The impact of light on the apical growth of poplar trees reveals a direct correlation between daylight duration and growth [6]. ...
Observing plants across time and diverse scenes is critical in uncovering plant growth patterns. Classic methods often struggle to observe or measure plants against complex backgrounds and at different growth stages. This highlights the need for a universal approach capable of providing realistic plant visualizations across time and scene. Here, we introduce PlantGaussian, an approach for generating realistic three-dimensional (3D) visualization for plants across time and scenes. It marks one of the first applications of 3D Gaussian splatting techniques in plant science, achieving high-quality visualization across species and growth stages. By integrating the Segment Anything Model (SAM) and tracking algorithms, PlantGaussian overcomes the limitations of classic Gaussian reconstruction techniques in complex planting environments. A new mesh partitioning technique is employed to convert Gaussian rendering results into measurable plant meshes, offering a methodology for accurate 3D plant morphology phenotyping. To support this approach, PlantGaussian dataset is developed, which includes images of four crop species captured under multiple conditions and growth stages. Using only plant image sequences as input, it computes high-fidelity plant visualization models and 3D meshes for 3D plant morphological phenotyping. Visualization results indicate that most plant models achieve a Peak Signal-to-Noise Ratio (PSNR) exceeding 25, outperforming all models including the original 3D Gaussian Splatting and enhanced NeRF. The mesh results indicate an average relative error of 4% between the calculated values and the true measurements. As a generic 3D digital plant model, PlantGaussian will support expansion of plant phenotype databases, ecological research, and remote expert consultations.
... The morphometric and genetic analyses revealed clear differences among the five species that compose the Stigmatodon goniorachis complex, including a new species described here, Stigmatodon carioca. The differences among populations are probably influenced by microclimatic factors at the location of each species (Sultan 2003;Valladares et al. 2006;Kelly et al. 2009). The differences among plants growing on the different faces of the inselbergs seem to be directly influenced by sunlight intensity. ...
... As plantas são capazes de responder e se adaptar a diferentes condições ambientais. Tais respostas são impulsionadas pela variação de seus atributos funcionais, o que pode permitir que as espécies superassem filtros ecológicos (SULTAN, 2003;OLIVEIRA et al.,2021). Cássia-Silva et al. (2017) estudaram como ocorre variação intraespecífica de estratégias ecológicas em habitats distintos de savana neotropical no centro-oeste do Brasil. ...
The savannahs of the state of Amapá have tree species with great economic potential, widely distributed in a mosaic formed by different phytophysiognomies. In this study, differences in functional strategies among individuals of the species Byrsonima crassifolia (L.) Kunth were analyzed in order to understand the different combinations of functional traits exhibited by tree-shrub individuals across the environmental gradient present in a savannah of the state of Amapá. Four leaf functional traits and the maximum height were measured in each individual with diameter above the ground ≥ 5 cm within 24 500-m² plots distributed in three phytophysiognomies: savannah sensu stricto, ‘campo sujo’ (shrub-savannah), and rupestrian savannah. Functional traits of 198 individuals were sampled. Significant differences in the set of functional traits were found among the three phytophysiognomies. Individuals from the rupestrian savannah exhibited a strategy of greater leaf productivity, while those in savannah sensu stricto and ‘campo sujo’ exhibited a strategy of greater conservation of resources. Furthermore, there was a secondary strategy related to leaf size, with more conservative individuals with larger leaves predominating in ‘campo sujo’, and more photosynthetically productive individuals with larger leaves predominating in the rupestrian savannah. It is concluded that the rupestrian savannah can be considered a strategic area for the sustainable management of the studied species.
... The negative correlation between photosynthetic capacity and the concentration of phenolics at the interspecific level concerns adaptive characteristics (inherent fixed traits) of each species, in the absence of any stress factor. On the other hand, in the presence of stress factors in the environment, acquired modulations (acclimation) take place in order to adjust growth and defense to the harmful conditions and provide additional protection [10,11]. For example, using meta-analyses, Wallis and Galarneau [12] observed that phenolic concentration was increased upon insect feeding or pathogen colonization, irrespective of plant life form (see also [13]). ...
Phenolics are multifunctional secondary metabolites taking part in both the defence against biotic and the protection against abiotic stress factors. At the interspecific level the concentration of leaf phenolics is negatively correlated with net photosynthesis: Plant species with inherently high photosynthetic rates (mainly annuals) are characterized by low phenolic pool, whereas slow growing species (mainly perennials) show the opposite trend. Crop plants represent a special case of the first group because they have been bred to maximize photosynthesis at the expense of defence and protection. We conducted meta-analyses in four selected crop plants (tomato, pepper, cucumber and olive) in order to test if the trade-off between photosynthesis and phenolics is valid at the intraspecific level as well. We observed that all plants are able to accumulate phenolics under conditions that reduce photosynthesis. However this negative correlation shows different characteristics, pending on the individual species. Moreover, both the basic and maximum level of phenolics in olive leaves is higher than the corresponding ones of the other species. The present investigation indicates that the trade-off between photosynthesis and phenolics at the intraspecific level reflects the answer given by each plant species against the growth–defense/protection dilemma.
... Light is a crucial external factor affecting the biosynthesis and accumulation of secondary metabolites in plants. Photosynthesis, a distinctive physiological process in plants, is subject to a range of factors than can be categorized as either internal or external [3,4]. The intensity of light is an important external factor affecting plant growth [5]. ...
Polygonum cuspidatum, an important medicinal plant, often experiences shading from surrounding vegetation during its growth phase, raising questions about the impact of such conditions on the functionality of arbuscular mycorrhizal fungi. This study investigated the effects of an arbuscular mycorrhizal fungus (Funneliformis mosseae) on the growth, leaf gas exchange, and concentrations of active ingredient concentrations in leaves and roots of P. cuspidatum under shading (with a 72% shading rate) conditions. A nine-week shading intervention significantly suppressed root colonization by F. mosseae and the formation of soil mycorrhizal mycelium. Shading significantly inhibited the above-ground growth performance, biomass production, leaf photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO2 concentration, while F. mosseae significantly increased these variables in the absence of shading. Plant height, leaf biomass, stem biomass, leaf photosynthetic rate, transpiration rate, and stomatal conductance were all decreased by F. mosseae when the plants were shaded. The shading treatment also significantly diminished the concentrations of active components measured in both leaves and roots. Under no-shading conditions, F. mosseae significantly boosted the concentrations of polydatin, resveratrol, aloe-emodin, emodin, chrysophanol, and physcion in roots, as well as the concentrations of polydatin and chrysophanol in leaves. Conversely, in the presence of shading, F. mosseae distinctly reduced these active ingredient levels in roots, followed by an increase in leaf polydatin and chrysophanol concentrations. In summary, shading substantially impaired the mycorrhizal benefits on plant growth, leaf gas exchange, and root active ingredients in P. cuspidatum, highlighting the importance of sufficient light to maximize mycorrhizal contributions.
... Ultimately, while we can conceive of an animal as standing in contrast to (even in opposition to) its environment, this is impossible in the case of trees. 9 This is because the "environment" is realized in and through the activities of the trees, while trees -in their morphology, in adjustments they make to tissue allocation and root deployment, and in the ways successive generations are affected by factors in parent environments ("crossgenerational plasticity" [Sultan 2003])are expressions of this environment. The one does not precede and effect the other (the environment does not preexist the tree, nor vice versa). ...
This article develops the notion of the "embodied history of trees" and articulates its conceptual and ethical implications. It demonstrates how trees literally embody their environment in their very structure and argues that trees express their environments in the deepest, most responsive, and most immediate way. The article then moves to consider how trees fundamentally shape their environment, showing that just as trees are expressions of their contexts, so their contexts are expressions of the trees. By highlighting the deep reciprocity between trees and their environments, the article raises crucial questions about the usual modes of conceptualizing the relation between organism and environment, and points to the ways in which environmental ethics remains largely wedded to these problematic conceptualizations. It concludes by developing environmental ethical concepts in light of the embodied history of trees, noting how these concepts challenge assumptions within mainstream environmental ethics, while extending the insights of deep ecology, ecofeminism, and Indigenous relational ethics in illuminating ways. Kia ora e te Rimu-Hello Rimu My Friend I 'm standing at your base, and my outstretched arms reach less than halfway around you. I give you a half-hug as I look upward to your moss-furred, sky-reaching branches, hoping that my feet aren't hurting too many of your delicate surface
... We created a trait space using 11 functional traits that captured unique patterns of interspecific and intraspecific variability for three species of tropical marine macroalgae and identified critical traits that represent trade-offs. Interspecific patterns show that individuals of the same species cluster together and are distinct from one another, implying fundamental differences between species that represent different ecological strategies (Sultan, 2003). We also found considerable intraspecific variability for two species, but little for the third, demonstrating a wide range in their ability to respond to environmental drivers that may vary across spatial scales (Clausing F I G U R E 4 Spatial and species-specific patterns in the distribution of selected traits with different coloured outlines indicating functions: (a-c) resource acquisition, (d) resistance to herbivory, and (e) resistance to physical disturbance. ...
The development of trait‐based approaches has accelerated our understanding of how communities assemble, respond to environmental change and may best be managed in the Anthropocene. Understanding the magnitude and pattern of interspecific variability forms a critical underpinning of trait‐based approaches while exploring intraspecific variability can identify the potential of species to adapt to changing environmental drivers. Our work is motivated by the critical need for a novel conceptual framework for understanding the functional ecology of macroalgae, as the current paradigm is still mired in functional group models developed in the 1980s.
Our objective was to quantify interspecific and intraspecific functional trait variability in three common and morphologically diverse species of tropical marine macroalgae by exploring traits relating to the ecological functions of resource acquisition, resistance to herbivory, and resistance to physical disturbance and the trade‐offs between them.
We quantified intraspecific and interspecific variability of 11 functional traits for three common and morphologically diverse species of tropical macroalgae from five fringing reefs of Mo'orea, French Polynesia that were likely to capture a wide range of environmental variability. Differences in traits among species and sites were determined with PERMANOVA, visualised with non‐metric multidimensional scaling, and trade‐offs between pairs of traits explored with correlation. Finally, spatial patterns among select traits across all species were quantified.
Species clustered together in distinctly different trait spaces driven by trade‐offs among suites of functional traits. Two of three species had considerable intraspecific variability, though this variability occurred at different scales, while one clustered tightly. Exploration of individual traits across species and sites revealed trade‐offs between two strategies for resource acquisition, growing tall and strong versus investing in large surface area.
Synthesis. We captured novel patterns of interspecific and intraspecific variability for tropical marine macroalgae. We found fundamental differences in traits between species that may represent ecological strategies while considerable intraspecific variability demonstrates a wide range in abilities to respond to environmental drivers. Overall, our work provides novel insights into intra and interspecific trait variation that form an essential underpinning for using a trait‐based framework in a taxon that is increasingly dominant on tropical reefs.
... The increased size of the submersed leaves in P. gramineus, caused by the dense stands of E. nuttallii, is a response to decreased light availability. The reduction in the total number of leaves while maximizing surface area for light capture is also observed in shade-inhabiting species such as Polygonum caespitosum Blume [52]. On the other hand, dense macrophyte growth of E. nuttallii can decrease oxygen levels due to the accumulation of organic detritus and fine sediment, as stated by Kaenel et al. [53]. ...
Elodea nuttallii represents non-native and highly invasive species in Europe that significantly
influence freshwater plant communities by decreasing the diversity of native species. This study
aimed to determine whether the morphological and anatomical features of Potamogeton gramineus,
a native species in Vlasina Lake, differ between sites where it coexists with E. nuttallii and those
where E. nuttallii is not present. Environmental variables such as water depth, temperature, pH,
conductivity, saturation, and O2 concentration were included in the analysis. Analyses were conducted on 32 morphological and anatomical features of P. gramineus collected from six sites within
Vlasina Lake, comprising three sites where E. nuttallii was present and three sites where it was
absent. The datasets containing morphometric and environmental variables underwent analysis
using standard univariate techniques (Descriptive, ANOVA), Tukey’s Honest Significant Difference
(HSD) test, Student’s t-test, and the Mann–Whitney U test, as well as multivariate statistical methods
such as Canonical Discriminant Analysis (CDA). The results show the presence of morphological
differentiation among P. gramineus individuals across the analyzed sites. These findings suggest that
morphological and anatomical features, such as epidermis, mesophyll, palisade, and aerenchyma
tissue thickness in floating leaves, number, length, width, and the surface area of stomata, as well
as the width of submersed leaves and stem aerenchyma tissue thickness, effectively differentiate
individuals that coexist with E. nuttallii and individuals that growth without its presence. Moreover,
they indicate that P. gramineus exhibits a notable ability to modify its morphological traits in response
to invasion.
... The functional and structural characteristics of plants changes in response to environmental factors to which they are exposed refer to phenotypic plasticity, and this plasticity is important for the organism to survive in heterogeneous environments or under variable environmental conditions (Valladares et al. 1997, Sultan 2003, Corrêa 2003. ...
Chrysophyllum rufum leaves collected under different light conditions provide information on how this fact can influence the morphology of the species. The anatomy techniques applied to the samples showed that there were discreet differences in the characters considered diagnostic. This indicates that the plant is capable of adapting, despite its prevalence in both dry and humid environments. The pollen grains were acetolyzed, measured, described qualitatively, analyzed quantitatively, and illustrated using light microscopy (LM).
... The negative correlation between photosynthetic capacity and the concentration of phenolics at the interspeci c level concerns adaptive characteristics (inherent xed traits) of each species, in the absence of any stress factor. On the other hand, in the presence of stress factors in the environment, acquired modulations (acclimation) take place in order to adjust growth and defense to the harmful conditions and provide additional protection [10,11]. For example, using meta-analyses, Wallis and Galarneau [12] observed that phenolic concentration was increased upon insect feeding or pathogen colonization, irrespective of plant life form (see also [13]). ...
Phenolics are multifunctional secondary metabolites taking part in both the defence against biotic and the protection against abiotic stress factors. At the interspecific level the concentration of leaf phenolics is negatively correlated with net photosynthesis: Plant species with inherently high photosynthetic rates (mainly annuals) are characterized by low phenolic pool, whereas slow growing species (mainly perennials) show the opposite trend. Crop plants represent a special case of the first group because they have been bred to maximize photosynthesis at the expense of defence and protection. We conducted meta-analyses in four selected crop plants (tomato, pepper, cucumber and olive) in order to test if the trade-off between photosynthesis and phenolics is valid at the intraspecific level as well. We observed that all plants are able to accumulate phenolics under conditions that reduce photosynthesis. However this negative correlation shows different characteristics, pending on the individual species. Moreover, both the basic and maximum level of phenolics in olive leaves is higher than the corresponding ones of the other species. The present investigation indicates that the trade-off between photosynthesis and phenolics at the intraspecific level reflects the answer given by each plant species against the growth–defense/protection dilemma.
... In addition, several sources of variation are not based on genetic changes, such as phenotypic plasticity, self-organization, or niche construction (see West-Eberhard, 2003;Gilbert & Epel, 2015;Müller & Newman, 2003;Wagner, 2014). Polygonum, for example, is a plant in which plasticity has been well studied (Sultan, 2003). It exhibits allometric plasticity-the biomass produced in each tissue and organ is relative to the amount of energy in the environment that each tissue and organ can access-morphological plasticity-the shape and size of roots and leaves varies according to the environmental resources available-and reproductive plasticity-reproductive timing is relative to favorable or stressful environmental conditions. ...
This paper argues that a central explanatory role for the concept of Umwelt in theoretical biology is to be found in developmental biology, in particular in the effort to understand development as a goal-directed and adaptive process that is controlled by the organism itself. I will reach this conclusion in two (interrelated) ways. The first is purely theoretical and relates to the current scenario in the philosophy of biology. Challenging neo-Darwinism requires a new understanding of the various components involved in natural selection processes. An important prerequisite is to understand developmental change in a teleological way. Here, the concept of Umwelt plays a crucial role: if organisms are responsible for generating adaptive variation in specific environments, we need a theory that explains the context-dependent nature of adaptively oriented processes. The Umwelt is thus a central element in determining the goal that an adaptive process pursues. The second path in my analysis also has a historical dimension. I will present Karl Ernst von Baer’s reflections on teleological development and his influence on Jacob von Uexküll’s thinking. I will present various ideas developed by Baer, such as the distinction between Ziel and Zweck and the use of musical metaphors, which can help to understand development teleologically and give Uexküll’s theory a central place in this framework.
... close to genetically identical) seeds sown in different environments will give rise to phenotypically distinct plants. This developmental plasticity can be adaptive, involving the plant sensing environmental cues and modulating its development accordingly, such that its resulting phenotype promotes reproductive success in the conditions it finds itself in [1,2]. Phenotypic plasticity works well when the future environment can be predicted from current environmental cues [3,4]. ...
When future conditions are unpredictable, bet-hedging strategies can be advantageous. This can involve isogenic individuals producing different phenotypes, under the same environmental conditions. Ecological studies provide evidence that variability in seed germination time has been selected for as a bet-hedging strategy. We demonstrate how variability in germination time found in Arabidopsis could function as a bet-hedging strategy in the face of unpredictable lethal stresses. Despite a body of knowledge on how the degree of seed dormancy versus germination is controlled, relatively little is known about how differences between isogenic seeds in a batch are generated. We review proposed mechanisms for generating variability in germination time and the current limitations and new possibilities for testing the model predictions. We then look beyond germination to the role of variability in seedling and adult plant growth and review new technologies for quantification of noisy gene expression dynamics. We discuss evidence for phenotypic variability in plant traits beyond germination being under genetic control and propose that variability in stress response gene expression could function as a bet-hedging strategy. We discuss open questions about how noisy gene expression could lead to between-plant heterogeneity in gene expression and phenotypes.
This article is part of a discussion meeting issue ‘Causes and consequences of stochastic processes in development and disease’.
... As indicated by leaf morphology, plants generally exhibit phenotypic plasticity (Sultan 2003, Stotz et al. 2021, which is the ability of genotypes to express different phenotypes in response to the environment. However, this is likely to be trait-dependent (Stotz et al. 2021). ...
Karyomorphological evaluations of the amphidiploid species Drosera tokaiensis (2n=60) and its parent species D. rotundifolia (2n=20) and D. spatulate (2n=40) were followed by an investigation of monochromatic light responses among these three species. The biseriate glandular trichome (BGT) maintained the characteristic cell morphology of each species, regardless of the differences in monochromatic light. The plant morphologies of all three Drosera species showed that petiole and stem growths were stimulated by blue light and inhibited by red light. In contrast, inflorescences of D. spatulata formed regardless of light conditions, but not D. rotundifolia. All Drosera species showed increased fresh weights when cultured under blue light, although the dry weight was not significantly different from that under red or white light, except for that of D. rotundifolia. The results of seven phenolic compounds of the three Drosera species revealed that milicitrin and quercimelin, lacking in D. rotundifolia, and ellagic acid low-detecting in D. spatulata, were present in D. tokaiensis. The contents of myricitrin and quercimelin in the Drosera extracts were higher under red light than under blue light for D. spatulata and D. tokaiensis. In contrast, the content of ellagic acid in the extracts was slightly higher under red light conditions than under blue light for D. tokaiensis. However, it was higher under blue light than under red light in D. rotundifolia, and other phenolic compounds also increased under blue light.
... In addition, several sources of variation are not based on genetic changes, such as phenotypic plasticity, self-organization, or niche construction (see West-Eberhard, 2003;Gilbert and Epel, 2015;Müller and Newman, 2003;Wagner, 2014). Polygonum, for example, is a plant in which plasticity has been well studied (Sultan, 2003). It exhibits allometric plasticity -the biomass produced in each tissue and organ is relative to the amount of energy in the environment that each tissue and organ can access-morphological plasticity -the shape and size of roots and leaves varies according to the environmental resources available-and reproductive plasticity -reproductive timing is relative to favorable or stressful environmental conditions. ...
This paper argues that a central explanatory role for the concept of Umwelt in theoretical biology is to be found in developmental biology, in particular in the effort to understand development as a goal-directed and adaptive process that is controlled by the organism itself. I will reach this conclusion in two (interrelated) ways. The first is purely theoretical and relates to the current scenario in the philosophy of biology. Challenging neo-Darwinism requires a new understanding of the various components involved in natural selection processes. An important prerequisite for the explanation is the ability to understand development in a teleological way. Here, the concept of Umwelt plays a crucial role: if organisms are responsible for generating adaptive variation in specific environments, we need a theory that explains the context-dependent nature of adaptively oriented processes. The Umwelt is thus a central element in determining the goal that an adaptive process pursues. The second path in my analysis also has a historical dimension. I will present Karl Ernst von Baer's reflections on teleological development and his influence on von Uexküll's thinking. I will present various ideas developed by von Baer, such as the distinction between Ziel and Zweck and the use of musical metaphors, which can help to understand development teleologically and give von Uexküll's theory a central place in this framework.
... The high plasticity value of NPQ for C. cucullans indicates a high adaptive capacity to survive under light-stress conditions. It is important to note that both plants and animals have integrated development, in which environmental change can generate changes in a wide variety of physiological and morphological characters, which go hand in hand with developmental processes since they are not isolated characters [52]. ...
The study of the causes and expressions of physiological and phenotypic plasticity in plants is crucial to understanding the responses of plants to environmental heterogeneity, which may reflect central aspects of plant strategies. In this work, we analyze whether closely related species distributed in the same environment present similar strategies when faced with changes in light intensity. We evaluated the physiological and phenotypic plasticity in two species of ferns under different light intensities and constant irrigation. We assessed physiological and morphological characters and evaluated the index of plasticity (RPDI). We found significant differences in RDPI between the two species in the physiological traits, particularly in the high light intensity treatments, and for the morphological variables, the RDPI of the leaf area and the trichome area. The physiology of Notholaena aschenborniana acclimates more quickly to high amounts of light than that of Cheilanthes cucullans but is less plastic in the long term. C. cucullans presents a higher phenotypic plasticity at the morphological level. We found that both fern species have the capacity to adapt to contrasting light environment conditions by adjusting their physiology and morphology in a short period of time using different strategies.
Keywords: Chlorophyll Concentration; ETR; Morphological; NPQ; RDPI; Yield
... These mechanisms are manifested through phenotypic plasticity (PP), the capacity of a genotype to present different phenotypes in response to changes in its environment (Bradshaw, 1965;DeWitt and Scheiner, 2004). There are different approaches and methods to estimate the degree of PP in specific functional traits of interest (Sultań, 2003;Valladares et al., 2006;Escobar-Sandoval et al., 2021). One of these approaches is the estimation of reaction norms (RN), which quantify PP as the regression of an individual's phenotypic trait in response to changes in a given environmental variable (Valladares et al., 2006;Sultań, 2007;Arnold et al., 2019). ...
Introduction
Phenotypic plasticity (PP) could be an important short-term mechanism to modify physiological and morphological traits in response to climate change and global warming, particularly for high-mountain tree species. The objective was to evaluate PP response of growth ring traits to temperature and precipitation in Pinus hartwegii Lindl. populations located at the ends of its elevational gradient on two volcanic mountains in central Mexico (La Malinche and Nevado de Toluca).
Methods
Increment cores collected from 274 P. hartwegii trees were used to estimate their PP through reaction norms (RN), which relate the ring width and density traits with climate variables (temperature and precipitation). We estimated the trees’ sensitivity (significant RN) to climatic variables, as well as the relative proportion of RN with positive and negative slope. We also estimated the relationship between the PP of ring width and density traits using correlation and Principal Component (PC) analyses.
Results
Over 70% of all trees showed significant RN to growing season and winter temperatures for at least one growth ring trait, with a similar proportion of significant RN at both ends of the gradient on both mountains. Ring width traits had mostly negative RN, while ring density traits tended to have positive RN. Frequency of negative RN decreased from lower to higher elevation for most traits. Average PP was higher at the lower end of the gradient, especially on LM, both for ring width and ring density traits, although high intrapopulation variation in PP was found on both mountains.
Discussion
Results indicate that P. hartwegii presents spatially differentiated plastic responses in width and density components of radial growth. PP was particularly strong at the lower elevation, which has higher temperature and water stress conditions, putting these populations at risk from the continuing global warming driven by climate change.
... One of the main ways to obtain a representative data set on plant individuals and the state of specific populations growing in different parts of the ecocoenotic range and experiencing various degrees of anthropogenic load is through the use of morphometric techniques [11]. Relying on them, one can obtain valuable information about the state of rare plant species and assess the bioecological characteristics of individuals and populations in a comparative aspect on an objective basis [12][13][14][15][16][17][18][19]. ...
When working with rare plant species, applying morphometric techniques is one of the main ways to obtain a representative data set on plant individuals and the state of particular populations growing in different ecological conditions and experiencing different degrees of anthropogenic load. Zygophyllum pinnatum, an understudied species growing on the territory of the Republic of Bashkortostan, the Orenburg region, and the Republic of Kazakhstan, is referred as a rare species. The purpose of the work is to study morphometric parameters and reveal the vitality structure of the Z. pinnatum coenopopulations in two regions of the Russian Federation (the Republic of Bashkortostan and Orenburg region) and in the north-west of the Republic of Kazakhstan (the Aktobe Region). Applying standard morphometric techniques, we analyzed the state of 16 coenopopulations of the species. Judging by most morphometric parameters, the leadership belongs to the individuals from the “Troitsk Cretaceous Mountains” coenopopulation located in the Sol-Iletsky District of Orenburg oblast, where, apparently, the most optimal plant conditions are formed (the absence of human impact and low projective cover of the grass stand to have a favorable effect). The minimum values for most parameters are recorded in the coenopopulations located on the territory of the Republic of Kazakhstan, resulting from arid growing conditions. The variability of most characters is within the normal range of the species response (Cv—5.0–44.6%). The discriminant function analysis revealed the morphostructural similarity of individuals from most coenopopulations. Regarding vitality, eight coenopopulations are prosperous, and another eight are depressed. The condition of the species coenopopulations is stable; however, the species is not provided with proper protection measures. Therefore, further monitoring of its habitats and improvement of environmental measures are necessary.
... Plants construct themselves through the process of morphogenesis, driven by the interactions between plant components and processes, their environment, and their genetic code (Zahadat et al., 2018). Additionally, plant growth and development take place in dynamic and often harsh environments, where plants exhibit remarkable adaptability in response to external factors such as resource competition, stress from pathogens, herbivores, and weather (Sultan, 2003). This raises questions about the balance between a plant's predetermined genetic code and its development through interactions with its surroundings. ...
Plants are complex systems made up of many interacting components, ranging from architectural elements such as branches and roots, to entities comprising cellular processes such as metabolic pathways and gene regulatory networks. The collective behaviour of these components, along with the plant's response to the environment, give rise to the plant as a whole. Properties that result from these interactions and cannot be attributed to individual parts alone are called emergent properties, occurring at different time and spatial scales. Deepening our understanding of plant growth and development requires computational tools capable of handling a large number of interactions and a multiscale approach connecting properties across scales. There currently exist few methods able to integrate models across scales, or models capable of predicting new emergent plant properties. This perspective explores current approaches to modelling emergent behaviour in plants, with a focus on how current and future tools can handle multiscale plant systems.
... Plant phenotypic variation refers to the ability of a plant to change its phenotype in response to environmental factors, including the type of substrate in which it grows [1][2][3][4]. Variation in the phenotypic expression of traits of a given organism under the influence of environmental factors affects its development and ecology [5][6][7]. This includes a variety of biotic and abiotic factors, which can influence phenotypic changes that are important for survival and reproduction in heterogeneous environments [1,2,8]. ...
The shape–environment relationship in plants refers to the ways in which the physical characteristics and structures of plants are influenced by their environment. Plants have evolved a remarkable ability to adapt to their specific habitats, and their shape and form play a crucial role in determining their survival and reproductive success. This study aimed to examine differences in size and shape between morphological traits in mountain germander (Teucrium montanum L.) from different geological substrates (calcareous and serpentinite). For this study, 400 individuals of T. montanum from 20 populations (ten populations from the serpentinite and ten from the calcareous substrate) were selected. Using the geometric morphometrics approach, it was shown that the degree of phenotypic variation in the size and shape of the corolla, leaf, and stem of T. montanum depends on the type of substrate. The main differences between the populations are the narrower part of the lower lip of the corolla, the narrower leaf, and the wider central part of the vascular system stem from serpentinite populations. The results of this study will contribute to a better understanding of the morphological variability of T. montanum in relation to edaphic conditions. In addition, the results confirm that certain morphological differences play an important role in the adaptive response in relation to substrate composition, especially for substrates with increased metal content, such as serpentinite. The shape–environment relationship in plants could define diversity and complexity in plant life, and underscores the importance of shape as a key factor in their survival and success in different habitats.
... The control group of 50 Norway spruce trees, at a distance of 100 m from the selected "plus trees", was chosen from a culture (1490 trees) that had been established in the 1970s. Considering that phenotypic plasticity is the ability of one genotype to form alternative phenotypes in heterogeneous environmental conditions and that changes in development, morphology, and growth dynamics, potentially enable individuals to match their phenotypes with temporal and spatial variations in their immediate environment (Bradshaw, 1965;Sultan, 2003) according to Petrov and Ocokoljić (2022) the selective parameters are shown in Table 1. Individual characteristics are shown for "plus trees" and the mean value for the control group. ...
... In this study, we found that fruit weight varied from 2.23 to 3.90 g. Low fruit weight in semiarid stations (Sefrou and Fez) could be related to phenotypic plasticity due to resource limitation (Sultan 2003).Our obtained results are in agreement with other studies that indicated that fruit size seemed to be larger in areas without water stress (Stauffer & al. 2017). ...
Fruit phenotypic diversity in Chamaerops humilis (Arecaceae), in semi-arid and sub-humid regions of Morocco Abstract Nekhla, H., El Ghadraoui, L., lahrizi, L., El Hanafi, L., Zahri, A., Harrach, A. & Saouab, F.-E.: Fruit phenotypic diversity in Chamaerops humilis (Arecaceae), in semi-arid and sub-humid regions of Morocco.-Fl. Medit. 33: 67-81. 2023.-ISSN: 1120-4052 printed, 2240-4538 online. The aim of this work is to determine the phenotypic variability of fruits of Chamaerops humilis (Arecaceae) according to the climatic conditions. Three hundred accessions were sampled from three climatically different regions of Northern Morocco: Sefrou, Fez, and El Hajeb. They were examined, in order to evaluate the morphological variability of C. humilis fruits and identify its morphotypes, in order to ensure a better valuation of the species and to maintain its sustainable development. Nine characters have been examined, including five quantitative characters and four qualitative. Comparison of means tests and principal component analysis were used to assess the variation in the morphological characters of dwarf palm fruits based on the regions. Hierarchical clustering was performed to identify C. humilis morphotypes. There was variability in dwarf palm fruit morphological characters in the three regions studied. The results revealed a great variation between individuals for the majority of the studied populations. The data collected from the field showed that the population originating from El hajeb presents fruits of large size, weight and shape that varied between oval and round-oblong, with an orange-brown color at maturity. On the other hand, the populations originating from the regions of Fez and Sefrou are characterized by less developed fruits, with smaller size, and a color generally red-brown and sometimes brown concerning the mature fruits.
... Although steeper slopes can lead to reduced reproduction in some plants, we observed no relationship between slope gradient and number of reproductive culms per P. ciliare plant (Nicole et al. 2011). Some plants allocate more resources to reproduction in stressful conditions to maintain reproductive output (Sultan 2003). It is possible that P. ciliare plants on steeper slopes increased resource allocation to reproduction due to stressful conditions on steeper slopes. ...
Buffelgrass [ Pennisetum ciliare (L.) Link] is an invasive C 4 perennial bunchgrass that is a threat to biodiversity in aridlands in the Americas and Australia. Topography influences P. ciliare occurrence at large spatial scales, but further investigation into the relationship between local-scale topography and P. ciliare growth and reproduction would be beneficial. Further, density dependent effects on P. ciliare growth and reproduction have been demonstrated in greenhouse experiments, but the extent to which density dependence influences P. ciliare in natural populations warrants further investigation. Here we present a study on the relationships between local-scale topography (aspect and slope gradient) and vegetation characteristics (shrub cover, P. ciliare cover, and P. ciliare density) and their interactions on individual P. ciliare plant size and reproduction. We measured slope gradient, aspect, shrub cover, P. ciliare cover, P. ciliare density and the total number of live culms and reproductive culms of ten P. ciliare plants in 33 4x4 m plots located in 11 transects at the Desert Laboratory at Tumamoc Hill, Tucson, AZ, USA. We modeled the relationships at the local-scale of 1) P. ciliare cover and density with aspect and slope gradient and 2) P. ciliare size and reproduction with abiotic (slope gradient and aspect) and biotic ( P. ciliare cover and density and native shrub and cacti cover) characteristics. Aspect and slope gradient were poor predictors of P. ciliare cover and density in already invaded sites at the scale of our plots. However, aspect had a significant relationship with P. ciliare plant size and reproduction. P . ciliare plants on south-facing aspects were larger and produced more reproductive culms than on other aspects. Further, we found no relationship between P. ciliare density and P. ciliare plant size and reproduction. Shrub cover was positively correlated with P. ciliare reproduction. South-facing aspects are likely most vulnerable to fast spread and infilling by new P. ciliare introductions.
... Although plants are immobile, they have developed a unique mechanism termed phenotypic plasticity, to survive their stressful environments. The plant characteristics can be maintained by repairing the damage and the alteration in the genetic composition brought about by the stress factors 23 . According to Goh, et al. 24 , acute and chronic exposure to gamma radiation (at 200 Gy) reduced the height, silique number, and silique length of Arabidopsis plants, coupled with a decrease in antioxidant enzyme levels such as catalase (CAT) and peroxidase (POD). ...
Due to their sessile nature, plants are exposed to various environmental stressors such as exposure to high levels of harmful ultraviolet (UV), ionizing, and non-ionizing radiations. This exposure may result in various damages, ranging from DNA and chromosomal aberrations to phenotypic abnormalities. As an adaptation, plants have evolved efficient DNA repair mechanisms to detect and repair any damage caused by exposure to these harmful stressors to ensure their survival. In this study, the effects of gamma radiation (as a source of ionizing radiation) on clonal Ananas comosus var. MD2 was evaluated. The morphology and physiology of the clonal plantlets before and after exposure to gamma radiation were monitored at specific time intervals. The degree of genetic variation between the samples pre- and post-irradiation was also analyzed by using inter-simple sequence repeat (ISSR) markers. The resulting data revealed that the heights of the irradiated plantlets were significantly reduced (compared to control), but improved with the recovery period. Irradiated samples also exhibited relatively good photosynthetic efficiency that further improved as the plantlets recover. These observations were supported by the ISSR analysis, where the genetic dissimilarities between the irradiated samples and control were reduced by 0.1017, after 4 weeks of recovery. Overall, our findings suggested that the phenotype recovery of the clonal A. comosus var. MD2 plantlets was contributed by their ability to detect and repair the DNA lesions (as exemplified by the reduction in genetic dissimilarity after 4 weeks) and hence allow the plantlets to undergo phenotype reversion to normal plant stature.
... Because developments of sexual reproductive organs are restricted to flowering time, phenotypes on leaves are often used to identify plant species. However, plants generally express plasticity for several morphological traits produced in different environmental conditions, especially leaf sizes and shapes (Sultan 2003, Li et al. 2019. In the previous reevaluation of the taxonomic treatment of the D. spatulata complex, multiple analyses of the Drosera leaf properties (including stipule shape and leaf area covered emergencies) statistically revealed a characteristic histogram pattern to clearly distinguish between D. spatulata and D. tokaiensis (Nakamura and Ueda 1991), at the same time certain proportions of the leaves in the histogram made continuity or overlap between them, even between D. rotundifolia and D. tokaiensis. ...
To discriminate allopolyploid species from their parental species in Drosera, a comparative analysis of biseriate glandular trichomes (BGTs) of D. tokaiensis and its parental species was carried out. Because accurate identification of allopolyploid species D. tokaiensis is difficult due to showing intermediate morphologies between the parental species D. rotundifolia and D. spatulata, the species confirmation of 11 strains of four Drosera species including D. anglica were performed by determining the somatic chromosome numbers first, and then, cytomorphological details of the BGTs were characterized. Except for D. anglica, the typical form of the BGT was a biseriate structure made up of three cell pairs (consisted of six cells): head part (two apical cells), stalk part (two stalk cells), and foot part (two basal cells). In D. tokaiensis and its parental species, the BGTs stained with DAPI exhibited a single nucleus in each cell. Among 16 cytomorphological BGT characters of the three species, the maximum value of the BGT width of D. spatulata was shorter than those of the minimum values of D. rotundifolia and D. tokaiensis. A canonical discriminant analysis showed that the BGTs gave a clear separation to distinguish D. tokaiensis from its parental species. In cross-validated discriminant analysis, the individual variation of BGTs robustly predicted the species of each BGT, demonstrating species specificity for simple and accurate species identification by the cytomorphological characters.
... Fortunately, winter wheat has one of the fastest growing and prolific root systems of all arable crops [15]. The size of a root system as well as its architecture is known to exhibit a very high phenotypic plasticity in response to environmental factors [16][17][18][19], particularly with respect to nitrogen availability and distribution [20]. However, in addition to environmental effects, there is also genotypic variation in the development of the root system architecture (RSA) of wheat [21], providing the baseline for later adaptation to the environmental conditions. ...
An ever-growing world population demands to be fed in the future and environmental protection and climate change need to be taken into account. An important factor here is nitrogen uptake efficiency (NUpE), which is influenced by the root system (the interface between plant and soil). To understand the natural variation of root system architecture (RSA) as a function of nitrogen (N) availability, a subset of the multiparent advanced generation intercross (MAGIC) winter wheat population WM-800 was phenotyped under two contrasting N treatments in a high-throughput phenotyping system at the seedling stage. Fourteen root and shoot traits were measured. Subsequently, these traits were genetically analyzed using 13,060 polymorphic haplotypes and SNPs in a genome-wide association study (GWAS). In total, 64 quantitative trait loci (QTL) were detected; 60 of them were N treatment specific. Candidate genes for the detected QTL included NRT1.1 and genes involved in stress signaling under N−, whereas candidate genes under N+ were more associated with general growth, such as mei2 and TaWOX11b. This finding may indicate (i) a disparity of the genetic control of root development under low and high N supply and, furthermore, (ii) the need for an N specific selection of genes and genotypes in breeding new wheat cultivars with improved NUpE.
... Here we report that after 20 years of judicious natural adaption towards OCS and CCS, barley populations segregated in root phenotypes. Variation of root system architecture is regarded as a significant aspect of plants' adaptability in response to fluctuating growing conditions 5,12,36,37 . These differences are critical parameters that could influence plants' competitive ability in searching for unevenly distributed soil resources and hence a predictor of plants' adaptation to various growing conditions 9,10,38 . ...
A beneficial root system is crucial for efficient nutrient uptake and stress tolerance. Therefore, evaluating the root system variation for breeding crop plants towards stress adaptation is critically important. Here, we phenotyped root architectural traits of naturally adapted populations from organic and conventional cropping systems under hydroponic and field trails. Long-term natural selection under these two cropping systems resulted in a microevolution of root morphological and anatomical traits. Barley lines developed under an organic system possessed longer roots with narrow root angle, larger surface area, increased root mass density, and a thinner root diameter with an increased number of metaxylem vessels. In contrast, lines adapted to the conventional system tend to have a shorter and wider root system with a larger root volume with a thicker diameter but fewer metaxylem vessels. Allometry analysis established a relationship between root traits and plant size among barley genotypes, which specifies that root angle could be a good candidate among studied root traits to determine root-borne shoot architecture. Further, multivariate analyses showed a strong tendency towards increased variability of the organically adapted population's root morphological and anatomical traits. The genotyping of ancestor populations validated the observations made in these experiments. Collectively, this results indicate significant differences in root phenotypes between conventional and organic populations, which could be useful in comparative genomics and breeding.
... Algunas investigaciones han señalado el hecho de que en los seres vivos el crecimiento y desarrollo depende de las características de su entorno. En las plantas, los individuos que se encuentran sobre sustratos que presentan limitaciones en la disponibilidad de algún recurso, inevitablemente crecen menos (Sultan, 2003). De esta forma cuando una planta está sometida a condiciones diferentes de las óptimas para su desarrollo, se dice que esta se encuentra bajo estrés. ...
La contaminación ocasionada por las actividades humanas representa un problema para la homeostasis ambiental. Por esta razón la necesidad de aplicar tecnologías que permitan solucionar esta problemática se ha convertido en una prioridad. En este sentido la fitorremediación se presenta como una opción viable para llevar a cabo la estabilización y extracción de uno de los contaminantes más persistentes en el suelo; los metales pesados. Así lo dejan de manifiesto varias investigaciones que han demostrado el potencial de algunas especies de plantas para tratar este tipo de contaminantes. Las especies a utilizar en fitorremediación deben contar con la capacidad de tolerar altas concentraciones de elementos como el As, Cd, Cr, Co, Mn, Ni, Pb, Se, Ta y Zn, esto al emplear eficientemente estrategias basadas en la exclusión o la acumulación. Aunque la tolerancia a estos últimos es fundamental, varios autores han señalado que existe la necesidad de utilizar especies con la capacidad de resistir los factores abióticos de los sitios a tratar, tales como un alto contenido de sales, temperaturas extremas y una baja disponibilidad de agua. Esto es importante puesto que los factores antes mencionados condicionan el crecimiento y desarrollo de las plantas al limitar la cantidad de nutrientes que son absorbidos por las raíces, inhibir la actividad fotosintética u ocasionar marchitez por deshidratación, situaciones que, dificultan la continuidad y el éxito de los procesos de fitorremediación.
... Here we report that after 20 years of judicious natural adaption towards OCS and CCS, barley populations segregated in root phenotypes. Variation of root system architecture is regarded as a signi cant aspect of plants' adaptability in response to uctuating growing conditions 5,12,34,35 . These differences are critical parameters that could in uence plants' competitive ability in searching for unevenly distributed soil resources and hence a predictor of plant's adaptation to various growing conditions 9, 10, 36 . ...
A beneficial root system is crucial for efficient nutrient uptake and stress tolerance. Therefore, it is critically important to evaluate the root system variation for breeding crop plants towards stress adaptation. We phenotyped root architectural traits of naturally adapted populations from organic and conventional cropping systems under hydroponic and field trails. Long-term natural selection under these two cropping systems resulted a microevolution in root morphological and anatomical traits. Barley lines developed under organic system possessed longer roots with narrow root angle, larger surface area, increased root mass density, and a thinner root diameter with an increased number of metaxylem vessels. In contrast, lines adapted to the conventional system tend to have a shorter and wider root system which possess a larger root volume with thicker diameter, but has fewer metaxylem vessels. Allometry analysis established a relationship between root traits and plant size among barley genotypes, which specify that root angle could be a good candidate among studied root traits to determine root-borne shoot architecture. Further, multivariate analyses showed a strong tendency towards an increased variability of the root morphological and anatomical traits in the organically adapted population. Our data indicates a significant differences in root phenotypes between conventional and organic populations, which could be useful in comparative genomics and breeding.
... phenotypic plasticity that enables these strategies (Sultan, 2003) is crucial in determining the fate of plants in a rapidly changing 25 climate. In this paper, we provide a conceptual and mathematical basis for a proposed mechanism that allows plants to exploit nutrient-rich but dry shallow soils by transferring water from wetter deep layers. ...
The rhizosphere is an exclusive passage for water and nutrients from the bulk soil to the whole plant. As such, its importance significantly outweighs the limited volume it represents. Numerous recent experimental and modeling studies have shown that plants invest considerable resources in modifying this region. However, roots must also balance the significant differences in resource availability in the vast soil volume they inhabit. Studies suggest that hydraulic redistribution by roots helps counterbalance the large differences in water status experienced by roots. In addition, experimental evidence suggests that hydraulic redistribution plays a role in mitigating drought effects and aiding nutrient uptake. However, whether hydraulic redistribution is a passive happy accident or a process controlled by plants remains unclear. Here, we present a novel mathematical model that integrates rhizosphere-scale modification of soil hydraulic properties by root exudation with long-distance interaction between roots that occupy disparately resourced soil regions. The model reproduces several known phenomena. First, hydraulic redistribution is proportional to the hydraulic gradient between wet and dry regions. Its magnitude substantially increases with the accumulation of hydrophilic rhizodeposits in the rhizosphere of the dry region. However, its effect on net water uptake by the whole root system is meager, negating the current hypotheses that hydraulic redistribution helps mitigate drought. Second, hydraulic redistribution facilitates nutrient uptake. We observed that periodic rewetting of nutrient-rich but dry soil layers significantly increases the active uptake of soluble nutrients. Moreover, cyclic rewetting of the rhizosphere increases the mineralization of the organic matter, thereby releasing nutrients locked in soil organic matter. The latter is another mechanism that supports the well-known phenomenon of priming of organic matter mineralization by root exudation. Overall, our model supports a hypothesis that roots faced with nutrient and organic matter accumulation in unfavorably dry soil regions facilitate hydraulic redistribution via exudation and benefit from the increased nutrient uptake and mineralization rate. These mechanisms could crucial role in determining whether plants can adapt to shifts in resource distributions under a changing climate.
... Plants change their phenotypes in response to their environment. Although formerly thought to be ambient noise, it is now apparent that (adaptive) phenotypic plasticity involves modifications to exhibit functionally relevant phenotypes under different situations [54]. Consequently, the significance of phenotypic plasticity in crop plant adaptation to environmental variation is yet to be determined. ...
Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre, though it plays a key role in crop improvement programs of cultivated rice (Oryza sativa L.). The present study was carried out to identify the morphological variation pattern of the wild populations of O. nivara in Sri Lanka. Seven populations (P1 to P7) collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits. The findings revealed a high level of phenotypic variation between populations when compared to within a population. The most variable traits were the flag leaf panicle neck length (FLPNL) and flag leaf angle (FLA), whereas the least variable trait was the flag leaf length (FLL). Box plots clearly illustrated the large differentiation of phenotypic traits in the entire distribution of wild rice populations. The cumulative values of the two principal components, i.e., FLPNL and FLA, explained 58.7% of the total variance. Populations from similar natural habitats clustered together. The P7 was adapted to intercept more sunlight by increasing flag leaf width (FLW) and FLA to compete with weeds and other shrubs. P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone. The P3 population from the intermediate zone showed a vigorous plant growth with the highest plant height, culm girth and awn length (P < 0.05). Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for the proper utilization of wild resources in rice genetic improvement.
... Different environmental factors are decisive for the development of adaptive strategies by tree individuals and are represented by morphological, anatomical, and physiological characteristics, also known as functional traits (Sultan 2003, Violle et al. 2007). Thus, species coexistence in tree communities may be explained by functional trait diversity since these traits reflect the plant ecological strategies (Adler et al. 2014, McGill et al. 2006). ...
Solar radiation is one of the aspects which most influence species composition, so light is a limiting factor to tree growth in forests. This study aimed to evaluate the leaf morphological variations between individuals of the Myrcia splendens (Sw.) DC. species under different light conditions in an urban forest. The fragment is characterized by having an open canopy area and an advanced regeneration stage in which branches of five individuals were collected, totaling 100 leaves. The traits
evaluated were leaf area, fresh biomass, dry biomass, water content, specific leaf area and leaf dry matter content. An analysis of variance showed that most of the morphological traits (dry biomass, specific leaf area, leaf dry matter content) varied significantly. Furthermore, variables such as dry biomass, water content and leaf area showed a high correlation with fresh biomass in both areas. The morphological variation found in M. splendens allows for creating growth and establishment strategies according to the environmental conditions.
... We suggest that the studied V. anagallis-aquatica populations are characterized by adaptation to local conditions and phenotypic plasticity, which does not form along previously determined taxonomic limits but is not independent of these. The existence of some level of differentiation among the studied populations must be due to different environmental effects including geographical, hydrographical connection, soil, climate, and biotic factors from different districts (Shafie & al. 2011) or natural selection (Sultan 2003). ...
Water speedwells (Veronica anagallis-aquatica L.) mostly occur in damp freshwater places. They show a high level of phenotypic plasticity in response to variations in environmental factors, a characteristic that allows them to occur over a wide range of conditions. Populations of V. anagallis-aquatica are scattered in many parts of Iran and often have a wide variation in the same region while having a similar appearance in different regions. We attempt to provide an accurate estimate of diversity within and among populations. Also, using the analysis of habitat characteristics and morphological traits, we aim to determine the distribution pattern of specific morphotypes. Here, we present a morphometric study based on 39 morphological and four ecological characters for 576 individuals from the north, northwest, and center of Iran. The analyses of habitat factors and morphological traits showed that morphotypes were distributed in a specific habitat with a cline of diversity from the northeastern to the northwest, west, and center of Iran. Morphometric results showed a high level of intraspecific variability and diversity among populations. Seed weight, number of seeds per capsule, the length and width of the capsule, number of lateral racemes, number of pollen per flower, length of sepals, and peduncle position were the most important characters to predict the overall variation and diversity of the individuals and populations. Electrical conductivity and pH were important characters influencing the distribution of morphotypes.
... Katsura et al. (2008) and Liu et al. (2019) stated that the efficient use of light intensity through a wide canopy can increase biomass production. Sultan (2003) explained that phenotypic plasticity, such as allocation of assimilate is altered, stem elongation and branching are suppressed, and reproduction is accelerated, modulated by the response to environmental stress. Burgess et al. (2017) stated that cultivars with elongated and erect flag leaf can penetrate more light throughout the canopy, which causes a high leaf area index and photosynthetic assimilate. ...
Breeding rice (Oryza sativa L.) for the multi‐canopy (MC) cropping system is one of the novel ideas for increasing production. This system involves combining rice genotypes with different plant heights to form stratified panicles and flag leaves. This study aimed to elucidate the effects of different characteristics of flag leaves of tall plant genotypes on yield and agronomic traits in MC cultivation. The study was conducted from May 2020 to January 2021 at the IPB University Experimental Station at Babakan, Bogor, West Java, Indonesia. The genetic materials were seven rice inbred lines of F9 from an ongoing breeding program at IPB University, consisting of four tall genotypes with different flag leaf characters, namely IPB187‐F‐90‐1‐1 (ordinary, short flag leaf); IPB189‐F‐19‐2‐1 (V‐shaped, medium‐length flag leaf); IPB187‐F‐40‐1‐2 (V‐shape, narrow, half rolled, and long flag leaf); IPB189‐F‐8‐1‐1 (wide, long flag leaf), and three short genotypes, namely IPB193‐F‐19‐1‐3, IPB187‐F‐69‐2‐3, and IPB189‐F‐13‐1‐1. The experiment was carried out in four environmental conditions, namely: (a) monoculture and (b) MC, 2020 dry season, (c) monoculture, and (d) MC, 2020/2021 wet season, using a randomized complete block design with three replications. The results showed that the genotype × cropping system interaction significantly affected total yield (p < .05). The MC cropping system produced a higher average yield (6.65 t ha–1) than the monoculture (6.01 t ha–1) across the two seasons. The genotype with V‐shape and medium‐length flag leaf gave the highest yield in MC. This study substantiated the potential of breeding rice varieties suitable for the MC system.
... The production of aerenchyma is stimulated by ethylene accumulation and facilitates oxygen conduction from aerial to submerged organs (Armstrong et al. 2000;Jung et al. 2008). Accordingly, aerenchyma is commonly found in hygrophytic species subjected to hypoxic or anoxic conditions (Chen et al. 2002;Sultan 2003;Leite et al. 2012), including the emergent macrophyte Typha angustifolia L. (Typhaceae), found throughout Brazil (Corrêa et al. 2015). Likewise, Maricle & Lee (2002) reported that the highly invasive intertidal grass Spartina alterniflora Loisel (Poaceae) produced more aerenchyma in underground organs under flooding than in well-drained soils on the west coast of North America. ...
The ability to maintain high competitiveness under a wide range of conditions is common among successful invasive species. The performance of rhizomatous macrophytes in different habitats is closely related to morphological and physiological adaptations in the rhizome system. We investigated the effects of soil moisture conditions on the microstructure of rhizomes of Hedychium coronarium (Zingiberaceae), an aggressive invader of Neotropical riparian sites. We collected rhizome fragments of H. coronarium and soil samples in wet and dry regions of riparian areas dominated by this species in southeastern Brazil. We measured soil moisture content gravimetrically and rhizome fragments were fixed, sectioned, and stained for histological analysis. Only rhizomes from wet regions exhibited aerenchyma, whereas amyloplasts were much more abundant and larger in rhizomes from dry regions than in rhizomes from wet regions. Even though low starch content in wet soils indicates the occurrence of anaerobic metabolism, the presence of aerenchyma may contribute to the typically high performance of H. coronarium in waterlogged soils. Although further studies are needed to assess how responses at the rhizome level affect the competitive ability of H. coronarium, our findings show that they may play a role in the dominance of this species in Neotropical riparian sites.
Keywords:
aerenchyma; amyloplasts; invasive macrophytes; riparian floodplains; soil hypoxia
... Evidence for this concept was provided by Twilley and Barko (1990), who reported that plants subjected to salt stress have different growth responses (i.e., increasing root or shoot growth), which results in changes in the root to shoot ratio with increasing salinity levels. Such biomass allocation strategies may lead to phenotypic plasticity by which a plant adjusts the proportions of leaves (light-harvesting tissue) versus water and mineral-collecting root tissue, which may allow the plant to access a specific resource and to adapt or avoid stresses (Sultan 2003). ...
Increased salinity can significantly impact plant population and species assemblages in aquatic ecosystems. Salinity level increases when road salt is applied to melt snow or by natural processes such as saltwater intrusion and storm surges. In a series of experiments, I studied saltwater chemistry and compared various salts to provide a simple method for producing saline solutions that mimic ocean water. Creating a realistic saline solution was possible with artificial aquarium salts that induced similar stress responses in plants and enabled us to study salinity stress indoors under controlled conditions. In the next step, I studied the response to salinity stress of 24 ecotypes of vallisneria (Vallisneria americana) that were collected from various regions within Florida. I used a nonlinear regression model to fit the growth and decay of ecotypes under a salinity gradient and utilized LC50 – the concentration of salt lethal to 50% of plant population – estimation to compare salt tolerance thresholds among ecotypes. Results from visual quality rating, growth rate and LC50 estimations demonstrated that ecotypes differ significantly in their response to salinity stress. In another experiment, three ecotypes of vallisneria with various salinity tolerances were selected to study their competitive ability with the invasive hydrilla (Hydrilla verticillata) under increased salinity conditions. Increased salinity suppressed the growth of hydrilla and provided an advantage to vallisneria ecotypes with high salinity tolerance and high growth rates. Finally, I conducted a salinity tolerance assessment on 14 wetland plants including native and invasive species prominent to Florida: southern naiad (Najas guadalupensis), Illinois pondweed (Potamogeton illinoensis), hydrilla, lemon bacopa (Bacopa caroliniana), alligatorweed (Alternanthera philoxeroides), hygrophila (Hygrophila polysperma), mexican waterlily (Nymphaea mexicana), spatterdock (Nuphar lutea), crested floatingheart (Nymphoides cristata), pickerelweed (Pontederia cordata), broadleaf sagittaria (Sagittaria latifolia), torpedograss (Panicum repens), pond apple (Annona glabra), and Brazilian peppertree (Schinus terebinthifolius). I utilized the LC50 estimations to determine how plant communities in Florida might react to increased salinity condition. Among tested plants only a few invasive species such as alligatorweed, torpedograss and Brazilian peppertree were able to tolerate as high as 20 parts per thousand (ppt), while most of the selected plants were eliminated when salinity reached 4 to 10 ppt. These results improve our understanding about plant species’ response to increased salinity conditions.
... It can play a major role in both the ecological distribution of organisms and their patterns of evolutionary diversification. Taxa consisting of adaptively plastic genotypes may inhabit a broad range of environmental conditions (Sultan, 2003;Chambell et al., 2005). ...
The history of biosystematics research and its impacts on climate goes before political ramifications. Climate change is altering the environments and likely to result in changes in the distribution of species, flowering times; migrate and adapt to the new environmental conditions; or extinction. Adaptive capacity is the ability of the plants to adapt to the impacts of climate change. Adaptation process is going in nature through phenotypic plasticity, natural selection or migration or polyploidization. The options are not mutually exclusive. Phenotypic plasticity may be the most efficient way of adaptation to a new environment. Polyploidization may increase tolerance to diverse ecological conditions and the high incidence of polyploidy in plants indicates its adaptive significance. Population having polyploid pillar complex is a good backup support towards microevolution and speciation, a mode of adaptation. The paper discusses about these biosystematics approaches towards adaptation to new environmental conditions resulting from climate change. It also discusses about the role of taxonomists under the changed circumstances. It is evident from the review that a set of biosystematics data along with other ecological and conservation information needs to be included in Flora and Monographs. It reveals that it was as far as worked out at the Paris Botanical Congress 1954 and put up by Stebbins in a series of proposals, termed as “Stebbins’ Ten Points” that needs further enrichment. Bangladesh J. Plant Taxon. 28(1): 277-287, 2021 (June)
Population studies of Rindera tetraspis Pall., a rare endemic species of the steppe zone of the European part of Russia and Kazakhstan, were carried out. The study of the habitats of 11 populations in the Orenburg Region and the Republic of Kazakhstan has shown that the species is confined to various variants of calciphyte steppes on chalk substrates or sandstones. In terms of most morphometric indicators, the northern coenopopulation “Rodnichny” is the leader; the minimum values are noted in the coenopopulation “Verkhnechebendinskie Chalk Mountains, northern extremity”. The discriminant analysis has revealed morphostructural differences between individuals from the majority of coenopopulations. In terms of vitality, four coenopopulations are prosperous, seven ones are depressed. The optimal conditions for the species growth are in the northern part of its range, in more favorable climatic conditions in terms of temperature and humidity, mainly on soils of sand origin. When moving southward, a decrease in size parameters of individuals is observed, associated with insufficient moisture, while their morphological diversity increases. The state of R. tetraspis coenopopulations is stable, but the species is not provided with proper protection measures, so further monitoring of its habitats and improvement of conservation measures are necessary.
Weeds in agricultural settings continually adapt to stresses from ecological and anthropogenic sources, in some cases leading to resistant populations. However, consequences of repeated sub‐lethal exposure of these stressors on fitness and stress “memory” over generations remain poorly understood. We measured plant performance over a transgenerational experiment with Arabidopsis thaliana where plants were exposed to sub‐lethal stress induced by the herbicides glyphosate or trifloxysulfuron, stresses from clipping or shading in either one (G1) or four successive generations (G1–G4), and control plants that never received stress. We found that fourth‐generation (G4) plants that had been subjected to three generations of glyphosate or trifloxysulfuron stress produced higher post‐stress biomass, seed weight, and rosette area as compared to that produced by plants that experienced stress only in the first generation (G1). By the same measure, clipping and shade were more influential on floral development time (shade) and seed weight (clipping) but did not show responsive phenotypes for vegetative metrics after multiple generations. Overall, we found that plants exhibited more rapid transgenerational vegetative “stress memory” to herbicides while reproductive plasticity was stressor dependent and similar between clipping/shade and anthropogenic stressors. Our study suggests that maternal plant stress memory aids next‐generation plants to respond and survive better under the same stressors.
Simple Summary
Plants adapt themselves to harsh environmental conditions by changing morphological parameters through phenotypic plasticity. Plants modify their functional traits and allocate biomass to either tolerate or resist the stress caused by their variable habitats. In this study, we observed that Aeluropus lagopoides, being among the few halophytic palatable species of salt marshes, adapt to the harsh salt marshes of different eco-regions by significantly modifying its morphological and physiological traits. Due to this structural modification, this plant showed great potential to rehabilitate different inland and coastal saline flat areas (sabkha), taking saline agriculture and soil remediation into consideration.
Abstract
Understanding the response variation of morphological parameters and biomass allocation of plants in heterogeneous saline environments is helpful in evaluating the internal correlation between plant phenotypic plasticity mechanism and biomass allocation. The plasticity of plants alters the interaction among individuals and their environment and consequently affects the population dynamics and aspects of community and ecosystem functioning. The current study aimed to assess the plasticity of Aeluropus lagopoides traits with variation in saline habitats. Understanding the habitat stress tolerance strategy of A. lagopoides is of great significance since it is one of the highly palatable forage grass in the summer period. Five different saline flat regions (coastal and inland) within Saudi Arabia were targeted, and the soil, as well as the morphological and physiological traits of A. lagopoides, were assessed. Comprehensive correlation analyses were performed to correlate the traits with soil, region, or among each other. The soil analysis revealed significant variation among the five studied regions for all measured parameters, as well as among the soil layers showing the highest values in the upper layer and decreased with the depth. Significant differences were determined for all tested parameters of the morphological and reproductive traits as well as for the biomass allocation of A. lagopoides, except for the leaf thickness. In the highly saline region, Qaseem, A. lagopoides showed stunted aerial growth, high root/shoot ratio, improved root development, and high biomass allocation. In contrast, the populations growing in the low saline region (Jizan) showed the opposite trend. Under the more stressful condition, like in Qaseem and Salwa, A. lagopoides produce low spikes in biomass and seeds per plant, compared to the lowest saline habitats, such as Jouf. There was no significant difference in physiological parameters except stomatal conductance (gs), which is highest in the Jizan region. In conclusion, the population of A. lagopoides is tolerant of harsh environments through phenotypic plasticity. This could be a candidate species to rehabilitate the saline habitats, considering saline agriculture and saline soil remediation.
In the context of a continuously increasing human population that needs to be fed, with environmental protection in mind, nitrogen use efficiency (NUE) improvement is becoming very important. To understand the natural variation of traits linked to nitrogen uptake efficiency (UPE), one component of NUE, the multiparent advanced generation intercross (MAGIC) winter wheat population WM-800 was phenotyped under two contrasting nitrogen (N) levels in a high-throughput phenotyping facility for six weeks. Three biomass-related, three root-related, and two reflectance-related traits were measured weekly under each treatment. Subsequently, the population was genetically analysed using a total of 13,060 polymorphic haplotypes and singular SNPs for a genome-wide association study (GWAS). In total, we detected 543 quantitative trait loci (QTL) across all time points and traits, which were pooled into 42 stable QTL (sQTL; present in at least three of the six weeks). Besides Rht-B1 and Rht-D1, candidate genes playing a role in gibberellic acid-regulated growth and nitrate transporter genes from the NPF gene family, like NRT 1.1, were linked to sQTL. Two novel sQTL on chromosomes 5A and 6D showed pleiotropic effects on several traits. The high number of N-specific sQTL indicates that selection for UPE is useful specifically under N-limited conditions.
Background and aims:
Climate-change induced warmer spring temperatures advance tree leaf-out and result in earlier shading of the forest floor. Climate change also leads to more frequent droughts. Forest understorey herbs may respond to these environmental changes by varying traits at different hierarchical levels of organisation. While trait mean variation at the inter-individual level in response to environmental changes is well-studied, little is known about how variation at the intra-individual level responds.
Methods:
We sampled genets of the forest understorey herb Galium odoratum from 21 populations in three regions in Germany, varying in microclimatic conditions. The genets were transplanted into a common garden, where we applied shading and drought treatments. We measured plant height, leaf length and width, and calculated the coefficient of variation (CV) at different hierarchical levels: intra-population, intra-genet, intra-ramet and intra-shoot.
Key results:
Variance partitioning showed that intra-shoot CV represented most of the total variation, followed by intra-ramet CV. We found significant variation in CV of plant height and leaf width among populations of origin, indicating that CV is at least partly genetically based. The soil temperature at populations' origins correlated negatively with CV in plant height, suggesting adaptation to local conditions. Furthermore, we observed that early shade led to increased intra-ramet CV in leaf length, while drought reduced intra-shoot CV in leaf width. Finally, intra-shoot leaf width mean and CV were independent under control conditions but correlated under drought.
Conclusions:
Our experimental results reveal correlations of intra-individual variation with soil temperature, indicating that intra-individual variation can evolve and may be adaptive. Intra-individual variation responded plastically to drought and shading, suggesting functional changes to improve light capture and reduce evapotranspiration. In conclusion, intra-individual variation makes up the majority of total trait variation in this species and can play a key role in plant adaptation to climatic change.
Evolutionary developmental biology, or 'evo-devo', is the study of the relationship between evolution and development. Dealing specifically with the generative mechanisms of organismal form, evo-devo goes straight to the core of the developmental origin of variation, the raw material on which natural selection (and random drift) can work. Evolving Pathways brings together contributions that represent a diversity of approaches. Topics range from developmental genetics to comparative morphology of animals and plants alike, and also include botany and palaeontology, two disciplines for which the potential to be examined from an evo-devo perspective has largely been ignored until now. Researchers and graduate students will find this book a valuable overview of current research as we begin to fill a major gap in our perception of evolutionary change.
Tree species have the ability to respond to different levels of light, changing their morphophysiological characteristics. The present study aimed to analyze the influence of light on the growth of three tree species from the Atlantic Forest biome. Growth variables, chlorophyll and carotenoid content, carbohydrates content and leaf anatomical aspects were investigated in the plants kept under two levels of light (80% shading and in full sun) at 60 and 120 days. The results showed that the three species have plastic responses, which allowed them to survive in both light levels. However, Machaerium brasiliense Vogel did not show differences for most growth variables, when kept under shade or full sun, indicating performance similar in both light conditions. Cordia trichotoma (Vell.) Arráb. ex Steud. and Triplaris americana L. presented different responses when maintained at different light levels, such as higher dry biomass, greater thickness of the palisade parenchyma, and greater total thickness of the leaves when kept in full sun. Shade-tolerant species (M. brasiliense) showed higher content of total soluble carbohydrates in the roots of plants kept in shade, representing plasticity in the physiological response of the plant. The two pioneer species have better growth and physiological performance in the higher light intensity treatment. In general, M. brasiliense is less plastic in relation to the other two species. Thus, the pioneers species, C. trichotoma and T. americana, could be used in the early phases of restoration of degraded areas due to their ability to perform better under higher luminosity.
Several aspects of genotype-environment interaction may act to modulate natural selection in populations that encounter variable environments. In this study the norms of reaction (phenotypic responses) of 20 cloned genotypes from two natural populations of the annual plant Polygonum persicaria were determined over a broad range of controlled light environments (8%-100% full sun). These data reveal both the extent of functionally adaptive phenotypic plasticity expressed by individual genotypes, and the patterns of diversity among genotypes for characters relevant to fitness, in response to an environmental factor that is both highly variable within populations and critical to growth and reproduction.
This paper investigates the effects of parental environment and genotype on offspring provisioning, structure, and growth traits in the annual plant Polygonum persicaria. Replicate offspring were studied from cloned individuals of five parental genotypes grown in high vs. low light, soil moisture, and soil nutrients. Genotypic norms of reaction were determined for ecologically important offspring traits. The effects on those traits of parental genotype, parental environment, and their interaction were tested by analysis of variance. The results showed that parental genotypes altered offspring traits in response to particular resource limits, such that offspring quality was maintained or enhanced despite parental resource deprivation. By maximizing the probability of offspring success, resource-deprived parental plants may partly offset the reduction in their fitness due to lower offspring number. Although overall patterns of plasticity were common to all parents, even this small sample revealed differences among parental genotypes in their response to environment. This may reflect the degree to which variation in fitness-related offspring traits occurs within parents and hence is unavailable to selection.
Recent studies in plant populations have found that environmental heterogeneity and phenotypic selection vary at local spatial scales. In this study, I ask if there is evolutionary change in response to environmental heterogeneity and, if so, whether the response occurs for characters or character plasticities. I used vegetative clones of Mimulus guttatus to create replicate populations of 75 genotypes. These populations were planted into the natural habitat where they differed in mean growth, flowering phenology, and life span. This phenotypic variation was used to define selective environments. There was variation in fitness (flower production) among genotypes across all planting sites and in genotype response to the selective environment. Offspring from each site were grown in the greenhouse in two water treatments. Because each population initially had the same genetic composition, variation in the progeny between selective environments reveals either evolutionary change in response to environmental heterogeneity or environmental maternal effects. Plants from experimental sites that flowered earlier, had shorter life spans and were less productive, produced offspring that had more flowers, on average, and were less plastic in vegetative allocation than offspring of longer-lived plants from high-productivity areas. However, environmental maternal effects masked phenotypic differences in flower production. Therefore, although there was evidence of genetic differentiation in both life-history characters and their plasticities in response to small-scale environmental heterogeneity, environmental maternal effects may slow evolutionary change. Response to local-scale selective regimes suggests that environmental heterogeneity and local variation in phenotypic selection may act to maintain genetic variation.
A number of recent studies have indicated that life history characteristics (e.g., number of offspring, offspring size, age at sexual maturity) are strongly affected by proximate environmental factors such as prey availability. Evaluating this phenotypic plasticity will be crucial to a complete understanding of the evolution of life history traits, because the occurrence of such variability casts doubt on the common assumption that the values of life history characteristics expressed in nature are the outcome of long-term natural selection. In this study, the authors manipulated the diets of a captive-bred colony of the viviparous snake Thamnophis marcianus to determine to what degree the reproductive characteristics of this species were determined by food intake. They found that both number of offspring and clutch mass were significantly affected by prey availability, but that relative clutch mass and offspring size were fixed relative to diet. The data suggest that like other organisms, T. marcianus shows a gradient in phenotypic plasticity, with some traits more canalized than others. Therefore, intraspecific comparisons of life history characteristics should not be made without information on which traits are subject to phenotypic plasticity.
This chapter considers the nature, role, and evolutionary implications of phenotypic plasticity as an adaptive property in plants. Plasticity is here defined as variation in phenotypic expression of a genotype that occurs in response to particular environmental conditions and which enhances the capacity of the individual to survive and reproduce under those conditions. A distinction is made [following Dobzhansky (1969) and Harper (1982)] between adaptive, defined as conferring a benefit on the organism with regard to its present relationship with its environment, and adapted, which describes a character that is thought to be the product of natural selection over previous generations—i.e., which was adaptive in the past and was therefore fixed by natural selection. “Adapted” refers to the causal origin of the character in evolutionary history; “adaptive” says nothing about the origin of the trait, but merely describes its present value in a given environment.
The C-4 African grass, Pennisetum setaceum (fountaingrass), has a greater altitudinal distribution than any other grass on the island of Hawaii. Clones of P. setaceum were reciprocally transplanted among coastal dry grassland, montane dry shrubland, and subalpine dry forest sites on the leeward side of Hawaii to evaluate the contribution of local adaptation and individual tolerance to the broad ecological amplitude of this grass. Physiological, growth, and reproductive responses differed among sites without evidence of local adaptation. Greatest tiller production and the highest photosynthetic rates were observed at the mid-altitude site, but plants at the coastal site attained greater basal areas, aboveground biomass, and number of inflorescences. Correlation among the responses of different plant characters was environmentally dependent, suggesting that the integrated expression of these characters is also plastic. Few differences in plant responses, however, were attributable to a population's origin or the site-by-population interaction; resident populations and introduced populations responded similarly at each site. Furthermore, few characters exhibited variation among clones, indicating that these populations likely possess little genetic variation. Limited clonal variation was, however, detected for net photosynthesis, the ratio of internal to ambient CO2 concentration (c(i)/c(a)), and specific leaf area, but only on two of five dates over a 1-yr period. Phenotypic plasticity for both individual characters and the integration of physiological and morphological characters have apparently been most important in allowing P. setaceum to become dominant across diverse habitats on Hawaii.
To achieve a coherent evolutionary theory, it is necessary to account for the effects of the environment on the process of development. Phenotypic plasticity is the change in the expressed phenotype of a genotype as a function ot the environment. Various measures of plasticity exist, many of which can be united within the framework of a polynomial function. This function is the norm of reaction. For the special case of a linear reaction norm, genetic variation can be partitioned into portions that are independent and dependent on the environment. From this partition two heritability measures are derived which can be used, alternatively, to compare populations or make predictions about the response to selection. Genetically, plasticity is likely due both to differences in allelic expression across environments and to changes in interactions among loci; plasticity is not a function of heterozygosity. Plasticity responds to both artificial and natural selection. The evolution of plasticity is modeled in three ways: optimality models, quantitative genetic models, and gametic models. All models make similar predictions about the conditions that will favor plasticity. In need of further development are the extension of quantitative genetic models, and structured population models; also needed are data on the true shapes of reaction norms and genetic variation and covariation for nonlinear reaction norm parameters and multiple environments.
: Phenotypic plasticity is often assumed to be adaptive, but this hypothesis has rarely been tested. To support the hypothesis, it is necessary to demonstrate that the phenotype induced in each relevant environment confers high fitness in that environment, rel-ative to alternative phenotypes. Unfortunately, such tests are difficult to perform because plasticity prevents the expression of inappro-priate phenotypes within each environment. Genetic and physio-logical manipulation can be used very effectively to extend the range of phenotypes within environments and thus provide powerful tools for testing the adaptive plasticity hypothesis. The expression of spe-cific genes involved in cue perception or signal transduction can be altered by mutation or the introduction of transgenes, thus altering the plastic response of an organism to environmental cues. It is also possible to alter the cue itself or to manipulate the developmental response physiologically so as to obtain alternative phenotypes. The relative fitness of these alternative phenotypes can then be measured in each relevant environment. However, these techniques will be most useful when combined with techniques such as phenotypic selection analysis to identify the specific traits under selection in natural pop-ulations. We illustrate these approaches using phytochrome-mediated "shade avoidance" responses in plants as a model system. We review the genetic and physiological mechanisms underlying these responses, illustrate how genetic manipulation can elucidate their adaptive value, and discuss the use of physiological manipulation to measure natural selection on plasticity in the wild.
Metrosideros polymorpha, a dominant tree species in Hawaiian ecosystems, occupies a wide range of habitats. Complementary field and common-garden
studies of M. polymorpha populations were conducted across an altitudinal gradient at two different substrate ages to ascertain if the large phenotypic
variation of this species is determined by genetic differences or by phenotypic modifications resulting from environmental
conditions. Several characteristics, including ecophysiological behavior and anatomical features, were largely induced by
the environment. However, other characteristics, particularly leaf morphology, appeared to be mainly determined by genetic
background. Common garden plants exhibited higher average rates of net assimilation (5.8 μmol CO2 m−2 s−1) and higher average stomatal conductance (0.18 mol H2O m−2 s−1) than their field counterparts (3.0 μmol CO2 m−2 s−1, and 0.13 mol H2O m−2 s−1 respectively). Foliar δ13C of most common-garden plants was similar among sites of origin with an average value of −26.9‰. In contrast, mean values
of foliar δ13C in field plants increased substantially from −29.5‰ at low elevation to −24.8‰ at high elevation. Leaf mass per unit area
increased significantly as a function of elevation in both field and common garden plants; however, the range of values was
much narrower in common garden plants (211–308 g m−2 for common garden versus 107–407 g m−2 for field plants). Nitrogen content measured on a leaf area basis in common garden plants ranged from 1.4 g m−2 to 2.4 g m−2 and from 0.8 g m−2 to 2.5 g m−2 in field plants. Photosynthetic nitrogen use efficiency (PNUE) decreased 50% with increasing elevation in field plants and
only 20% in plants from young substrates in the common garden. This was a result of higher rates of net CO2 assimilation in the common garden plants. Leaf tissue and cell layer thickness, and degree of leaf pubescence increased significantly
with elevation in field plants, whereas in common garden plants, variation with elevation of origin was much narrower, or
was entirely absent. Morphological characteristics such as leaf size, petiole length, and internode length decreased with
increasing elevation in the field and were retained when grown in the common garden, suggesting a potential genetic basis
for these traits. The combination of environmentally induced variability in physiological and anatomical characteristics and
genetically determined variation in morphological traits allows Hawaiian M. polymorpha to attain and dominate an extremely wide ecological distribution not observed in other tree species.
Life history responses of four Daphnia magna clones at two food levels were studied to assess the importance of maturation instar on the plasticity of fitness responses under simulated mortality regimes. Females of the clones studied could vary offspring size with consequent effects on their maturation time. Significant genetic variability in life history and fitness responses, measured as the intrinsic rate of population increase, within and across food levels was observed, but most of this variation could be attributed to maturation instar differences among clones within and across environments. In the laboratory, without extrinsic mortality, females maturing earlier always had higher fitness than those maturing later, indicating a clear fitness cost of delaying maturity. Nevertheless using a model, we showed that the observed maturation instar effects on life history responses can lead to differences in fitness under different size-selective predation regimes, such that females with delayed maturity have higher fitness under invertebrate predation while females maturing earlier have higher fitness under fish predation regimes. These results suggest that intraclonal variation in offspring size and hence in the number of maturation instars can be an adaptation to living in habitats subject to temporal fluctuations in fish and invertebrate predation pressure.
Plant form and spatial structure reflect the basic architectural blue-print of a plant. In most plant species, the expression of the structural blue-print is systematically altered during ontogeny resulting in predictable changes in the allometry of plant structures and in the types of structures that are produced. The expression of the structural blue-print or the timing of ontogenetic changes is also frequently altered by environmental conditions. This latter source of variability, referred to as phenotypic plasticity, is manifested through changes in the timing and rates of meristem initiation and development, the likelihood that meristems will remain dormant or commit to different demographic fates (i.e., vegetative vs. reproductive structures), or the size and structure of the organs formed. Complex interactions among these components can result in considerable differences in form and spatial structure among individuals of the same species. This paper focuses on the importance of these different components in determining the architecture of clonal plants with long internode connections between ramets.
A case study is presented that attempts to separate ontogenetic variation and phenotypic plasticity in two stoloniferous species with different structural blue-prints, in their responses to shading. In both species the rate of ontogenetic development responded to intermediate shading levels, but only at very low levels of light availability did plastic changes in branch formation occur. Under shaded conditions the two species achieved similar changes in their architecture in conspicuously different ways. We discuss how different mechanisms leading to a given
architecture can be distinguished and what the ecological implications of this are.
Sex expression (the proportions of staminate and hermaphrodite flowers produced) in andromonoecious Solarium hirtum is phenotypically plastic, and there is genetic variation for sex expression plasticity. Changes in sex expression phenotype are inherently the result of altered development. However, the underlying developmental components of sex expression plasticity and of differences in plasticity among genotypes are unknown. This study takes an explicitly genetic and developmental approach to the study of phenotypic plasticity and examines changes in sex expression of ten clonally replicated genotypes at three levels of organization: among inflorescences, within inflorescences, and at the level of developing floral meristems. Changes in sex expression of individuals and differences among individuals are the result of a predictable interplay of resource, architectural, and floral level response within the hierarchical construction of the shoot system. Phenotypic plasticity of whole plant sex expression is ultimately due to sexual lability of individual developing flowers: floral sex is not determined until a primordium size of 9–10 mm. Until that time, sex expression remains labile and developing floral primordia can respond to changes in plant resource status. This flower level developmental lability, however, is expressed within the constraints set by the architecture and ontogenetic history of the organism. Only those floral primordia produced in distal portions of each inflorescence are labile, capable of developing into either a staminate or hermaphrodite flower, whereas those primordia in basal positions invariably develop as hermaphrodite flowers. The genotypes differ with respect to the architectural components of phenotypic plasticity and it is this architectural variation that results in differences in plasticity among genotypes. The phenomenon, in which the developmental fate of a primordium depends upon where and when it is produced within the architecture of an organism and what events have preceded it during ontogeny, can be termed “ontogenetic contingency.”
Recent studies in plant populations have found that environmental heterogeneity and phenotypic selection vary at local spatial scales. In this study, I ask if there is evolutionary change in response to environmental heterogeneity and, if so, whether the response occurs for characters or character plasticities. I used vegetative clones of Mimulus guttatus to create replicate populations of 75 genotypes. These populations were planted into the natural habitat where they differed in mean growth, flowering phenology, and life span. This phenotypic variation was used to define selective environments. There was variation in fitness (flower production) among genotypes across all planting sites and in genotype response to the selective environment. Offspring from each site were grown in the greenhouse in two water treatments. Because each population initially had the same genetic composition, variation in the progeny between selective environments reveals either evolutionary change in response to environmental heterogeneity or environmental maternal effects. Plants from experimental sites that flowered earlier, had shorter life spans and were less productive, produced offspring that had more flowers, on average, and were less plastic in vegetative allocation than offspring of longer-lived plants from high-productivity areas. However, environmental maternal effects masked phenotypic differences in flower production. Therefore, although there was evidence of genetic differentiation in both life-history characters and their plasticities in response to small-scale environmental heterogeneity, environmental maternal effects may slow evolutionary change. Response to local-scale selective regimes suggests that environmental heterogeneity and local variation in phenotypic selection may act to maintain genetic variation.
SYNOPSIS. Morphological and physiological plasticity is often thought to represent an adaptive response to variable environments. However, determining whether a given pattern of plasticity is in fact adaptive is analytically challenging, as is evaluating the degree of and limits to adaptive plasticity. Here we describe a general methodological framework for studying the evolution of plastic responses. This framework synthesizes recent analytical advances from both evolutionary ecology and functional biology, and it does so by integrating field experiments, functional and physiological analyses, environmental data, and genetic studies of plasticity. We argue that studies of plasticity in response to the thermal environment may be particularly valuable in understanding the role of environmental variation in the evolution of plasticity: not only can thermally-relevant traits often be mechanistically and physiologically linked to the thermal environment, but also the variability and predictability of the thermal environment itself can be quantified on ecologically relevant time scales. We illustrate this approach by reviewing a case study of seasonal plasticity in the extent of wing melanization in Western White Butterflies (Pontia occidentalis). This review demonstrates that 1) wing melanin plasticity is heritable, 2) plasticity does increase fitness in nature, but the effect varies between seasons and between years, 3) selection on existing variation in the magnitude of plasticity favors increased plasticity in one melanin trait that affects thermorégulation, but 4) the marked unpredictability of short-term (within-season) weather patterns substantially limits the capacity of plasticity to match optimal wing phenotypes to the weather conditions actually experienced. We complement the above case study with a casual review of selected aspects of thermal acclimation responses. The magnitude of thermal acclimation ("flexibility") is demonstrably modest rather than fully compensatory. The magnitude of genetic variation (crucial to evolutionary responses to selection) in thermal acclimation responses has been investigated in only a few species to date. In conclusion, we suggest that an understanding of selection and evolution of thermal acclimation will be enhanced by experimental examinations of mechanistic links between traits and environments, of the physiological bases and functional consequences of acclimation, of patterns of environmental variability and predictability, of the fitness consequences of acclimation in nature, and of potential genetic constraints.
Submergence in water induces drastic changes in the morphology of deepwater or floating rice including a rapid internodal elongation. To study the genetic and developmental bases for its phenotypic plasticity, experiments were carried out using a perennial wild rice accession with deepwater tolerance and a non-deepwater rice cultivar. Selection for deepwater tolerance was performed under 1-m deep water conditions, and backcrosses were made up to the BC 5 generation to transfer a gene(s) for deepwater tolerance into the intolerant cultivar. The results indicated that a recessive gene ( dw 3 ) was responsible for deepwater tolerance, and plants with dw 3 induced internodal elongation in response to submergence. Plants without dw 3 showed no internodal elongation and soon died. However, the responsive ability of dw 3 was markedly reduced after floral initiation, showing that the induction of internodal elongation was developmentally regulated. Submerged plants with dw 3 also showed an increased number of elongated internodes, as well as nodal tillering and nodal rooting, suggesting that changes in relative timing of developmental events due to dw 3 induced profound plastic responses in deepwater rice under submerged conditions.
The norms of reaction (phenotypic responses) of 20 cloned genotypes from two natural populations of the annual Polygonum persicaria were determined over a broad range of controlled light environments (8-100% full sun). As a result of the functional similarity of genotypes conferred by both phenotypic plasticity and interaction among characters, morphologically diverse genotypes within each population shared equivalent reproductive fitnesses across the full range of light environments. Enormous fitness differentials did result from light treatment itself, however. Such environmentally evoked fitness differences would act to promote maintenance of genetic diversity. (See also 95L/02324 and 02351). -from Authors
Epilobium hirsutum was almost unaffected but Chamerion (=Chamaenerion) angustifolium was seriously harmed by 31 days of waterlogging which reduced dry weight production and total leaf area of adult plants. The first symptom of damage in C. angustifolium was total wilting which occurred within 12 hours of flooding; it was followed by the slow recovery of the upper leaves and death of the lower leaves. Within a few days of flooding, E. hirsutum commenced adventitious root formation from primordia already present near the stem base.-from Author
Growth of autotrophic plants is directly and dramatically influenced by the intensity of light — the driving force of photosynthesis — which provides nearly all of the carbon and chemical energy needed for plant growth. Moreover, light intensity (quantum flux density) is perhaps the most conspicuous environmental variable with which plants must cope. Contrasting terrestrial habitats may differ by at least two orders of magnitude in the daily quantum flux available for photosynthesis. In any habitat the quantum flux density varies seasonally, diurnally, and spatially (such as within a canopy of a given plant stand).
MASSIMO PICLIUCCI Phenotypic Plasticity BEYOND NATURE AND NURTURE tor more than nvo decades rlic concept of phenotypic plasticity has allowed re- searchers to go beyond the nature-nurture dichotomy to gain deeper insights into how organisms arc shaped by the
The ecological distribution of species is influenced by individual patterns of response to environment for traits that contribute to fitness. Comparative data on fitness responses to complex environments are particularly valuable for understanding the relation of plasticity to ecological breadth. This study compares individual phenotypic plasticity for components of fitness in four congeneric annual plant species with contrasting ecological distributions (Polygonum cespitosum, P. hydropiper, P. lapathifolium, and P. persicaria). Replicate seedlings of 32 inbred lineages drawn from five natural populations per species were grown to maturity under controlled conditions in all 12 possible combinations of low and high light; dry, moist, and flooded soil; and poor vs, rich nutrients. Timing of reproduction, total reproductive output, offspring size, and allocation to reproduction were determined for each plant. The data revealed highly complex differences among the species in patterns of plastic response for fitness traits (i.e., high-order species-by-environment interaction effects). These plasticity differences illuminate the species' known differences in ecological distribution. Individuals of the broad ecological generalist P. persicaria maintained fecundity and offspring size in poor conditions and also reproduced at extremely high levels when given plentiful resources. In contrast, P. lapathifolium plants showed high fitness in favorable treatments but sharply delayed and decreased reproduction as well as offspring size when deprived of light and other resources; this species is restricted in nature to high-light, moist sites. Conversely, P. hydropiper plants increased reproductive output relatively little in resource-rich environments, which may explain why this species is not an invasive colonizer. Although other factors evidently limit P. cespitosum to shaded habitats, the ability shown by plants in this species to maintain offspring size and output across a range of environments may be a factor in its extremely rapid spread. These results confirm that ecological breadth of distribution may reflect not an equable, constant pattern of fitness response, but rather the ability to both maintain fitness in resource-poor environments and opportunistically maximize fitness in favorable conditions. These results contribute three important insights to our understanding of the relation of phenotypic plasticity to ecological breadth: ecologically important species differences in fitness plasticity may entail (a) multiple environmental factors, as well as (b) a number of distinct fitness components; furthermore (c) neither reproductive plasticity nor constancy per se is necessarily associated with ecological breadth.
SUMMARY This paper focuses on phenotypic plasticity as a major mode of adaptation in plants. A methodological critique examines difficulties in studying plasticity, including the conceptually critical distinction between functionally adaptive and inevitable aspects of response. It is argued that plasticity studies depend critically upon the genotypic sample, the choice of environmental factors and factor states, and the definition of phenotypic traits. Examples are drawn from recent studies showing adaptive response by genotypes to physical aspects of the environment, as well as to biotic factors such as neighbour density and the presence of bacterial symbionts. Alterations of offspring traits by parental plants of Polygonum persicaria are discussed as a cross-generational aspect of plastic response to environment. Finally, individual plasticity and local ecotypes are examined as alternative bases of species ecological breadth, and methodological problems in distinguishing these alternatives are discussed.
Examines the variation in an individual's phenotype contributed by the maternal parent beyond the equal chromosomal contribution expected from each parent. Cytoplasmic genetic, endosperm nuclear and maternal phenotypic effects are distinguished. Such maternal influences are especially pronounced in the seed (size, mineral composition, dormancy and germination), but can also be evident at the seedling and adult stages (eg in yield components and male sterility).-P.J.Jarvis
The whole-tree leaf area of a poplar derives from three different shoot types, current terminal, sylleptics and proleptics. The response of these architectural components to two sharply contrasting environments was examined in two replicated plantations containing a cloned interspecific hybrid pedigree of Populus trichocarpa and P. deltoides that included the original parents, two F1 parents, and 375 F2 genotypes. In the warmer, sunnier, and better-watered environment of interior Boardman, Oregon, 2-year-old trees produced more, larger, and wider leaves, as well as more and longer branches, than in the cooler and more cloudy coastal conditions of Clatskanie, Oregon. Sylleptic branches were phenotypically more plastic than the other elements of the crown. Most trees produced significantly more and longer sylleptics in the near-optimal growth environment in Boardman than in the suboptimal environment of Clatskanie. In both environments, all crown traits displayed significant genotype effects in the F2 family, but for most traits, broad-sense heritabilities were statistically larger in Clatskanie (0.44–0.78) than Boardman (0.28–0.70). For all traits except for the number of sylleptics, the values of across-environment genetic correlations were significantly larger than zero but less than one, indicating that nonparallel responses of genotypes to environment had led to significant genotypeenvironment interactions, although some genetic basis was shared between the two environments. A nonsignificant genetic correlation of sylleptic number expressed in the two different environments suggests that the phenotypic plasticity of this trait is under strong genetic control. All architectural traits, except for branch and canopy traits of sylleptics, were correlated with growth more strongly in Clatskanie than Boardman. In both environments, contrary to observations in an earlier study, proleptic traits were better predictors of stem height and basal area growth than sylleptic traits.Keywords: broad-sense heritability, genetic correlation, phenotypic plasticity, Populus, proleptics, sylleptics
Earlier studies of habitat-specific subpopulations of mixed clonal and sexual freshwater snails of the species Potamopyrgus antipodarum have revealed clinal variation by depth in several life-history traits, risk of parasite infection, mixed population structure, and the genetic structure of the clonal population. Clinal variation is pronounced in life-history traits: snails are larger and start reproduction later in the deeper habitats. The proportion of clonal individuals increases with depth, and many clones are habitat-specific. While these patterns are well documented, it is not known which processes have led to the observed genetic divergence in the clonal population. In this study, we experimentally investigated the contribution of phenotypic plasticity to habitat-specific life-history trait variation using reciprocal transplant experiments with adult and juvenile snails. Assessment of phenotypic plasticity is important because canalized habitat-specific life-history trait variation is one of the alternative explanations for habitat-specific genetic divergence seen in the clonal population. However, if life-history trait variation is largely due to adaptive phenotypic plasticity, canalized optimization of life-history traits is unlikely to explain the divergence observed in the clonal structure. We found significant habitat-induced variation for growth rate, proportion of brooding females, brood size, number of surviving offspring, and juvenile survival, indicating that much of the life-history variation must be considered the result of phenotypic plasticity. Based on these results, it seems that life-history trait divergence is unlikely to explain habitat-specific clonal structure. In contrast, we found genetically based differences in resistance to parasite infections; snails of the deeper Isoetes habitat were more susceptible to infection than snails of the shallow shorebank habitat. To our surprise, we found only a few habitat-by-origin interactions that could directly contribute to the maintenance of the observed habitat-specific clonal structure. One potentially im-portant interaction, however, was that in the deeper Isoetes habitat, reproductive output of snails transplanted from the shallow habitat was lower than that of resident snails. In addition, we also found that survival of clonal snails may be poorer in unfamiliar habitats than that of sexual P. antipodarum, potentially promoting the maintenance of habitat-specific clonal assemblages. Thus, higher parasite resistance of shallow-water snails in both habitats and lower reproductive output of shallow-water snails in the deep habitat are likely to contribute to the maintenance of the habitat-specific clonal structure in P. antipodarum populations, whereas most of the observed variation in life-history traits seems to be due to phenotypic plasticity, which is likely to be adaptive.
Taxa that are divided into separate populations with low levels of interpop-ulation dispersal have the potential to evolve genetically based differences in their phe-notypes and the plasticity of those phenotypes. These differences can be due to random processes, including genetic drift and founder effects, or they can be the result of different selection pressures among populations. I investigated population-level differences in pred-ator-induced phenotypic plasticity in eight populations of larval wood frogs (Rana sylvatica) over a small geographic scale (interpopulation distances of 0.3–8 km). Using a common-garden experiment containing predator and no-predator environments, I found population differences in behavior, morphology, and life history. These responses exhibited a habitat-related pattern: the four populations from closed-canopy ponds did not differ from each other in any of their phenotypes whereas the four populations from open-canopy ponds did differ from each other in these traits. This phenotypic pattern matches the pattern of competitors and predators found in these two types of ponds. Based on two years of pond surveys, the four closed-canopy ponds contained very similar competitor and predator assemblages while the assemblages of the four open-canopy ponds were more diverse and highly variable among open-canopy ponds. When combined with past studies, which demonstrate that predators and competitors select for alternative behavioral and morphological traits, these patterns suggest that the population differences may have arisen via natural selection and not via random mutation or drift. In a second experiment, I cross-transplanted two of the populations into each other's ponds to determine if the populations were locally adapted to the conditions of their native pond (using low and high competition crossed with the presence or absence of a lethal predator). The populations continued to exhibit phenotypic differences, and one of the two populations tested exhibited superior growth in its native pond. This suggests that some wood frog populations are adapted to the local conditions of their natal pond and that localized selection by predation and competition may be the underlying mechanism. Col-lectively, these experiments indicate that taxa that are divided into discrete populations and face different predator and competitor environments can evolve different phenotypically plastic responses.
1 Understanding the relative distributions of ecological generalists vs. specialists requires precise characterization of the environmental ranges of closely related taxa. The ecological breadth of four annual species in the genus Polygonum was determined from field measurements taken from five natural populations per species in a common geographical range.
2 Significant early and late-season differences among the species were found for available light (photosynthetically active radiation) at canopy and mid-canopy levels, and for soil temperature, moisture availability, macronutrient content, pH, cation exchange capacity (CEC) and structure, at two depths. Field sites within each species also differed significantly for these variables.
3 The field distribution of P. persicaria covers the broadest range of habitats, from moderate shade with very dark microsites to full insolation, cool to very warm soils, flooded to dry moisture conditions, and organic, high-nutrient to nutrient-poor soils.
4Polygonum lapathifolium is comparatively intolerant of shade, particularly early in the growth season. Although this species occurs in flooded to moderately dry conditions and in poor as well as rich soils, its moisture and nutrient ranges do not include such low extremes as those of P. persicaria, and its range of soil temperatures is also narrower.
5Polygonum cespitosum is restricted to low-light habitats and to consistently moist soils that do not flood. The species is, however, found in a moderately broad range of soil types and macronutrient availabilities. Polygonum cespitosum occurs in extremely low-light habitats that are evidently beyond the shade tolerance of the other species.
6Polygonum hydropiper is restricted to high-light sites with highly organic, consistently very moist or flooded soils. Unlike its congeners, this species can tolerate flooded soils during seedling establishment. The species is limited to soils with high early nitrate and calcium content, moderate CEC, and pH close to 6.0, but tolerates a broad range of soil temperatures.
7 The occurrence of spatial and temporal environmental variability within as well as among field populations of Polygonum species suggests that tolerance of such variability may result from individual phenotypic plasticity rather than from ecotypic adaptation of entire populations.
— Plastic stem-elongation responses to the ratio of red:far-red (R:FR) wavelengths enable plants to match their phenotype to local competitive conditions. However, elongation responses early in the life history may occur at the cost of reduced plasticity later in the life history, because elongation influences both allocation patterns and structural integrity. A common-garden experiment was performed to test whether seedling responses to R:FR affect biomass allocation, biomass accumulation, and subsequent plasticity to the cue. Seedlings of Abutilon theophrasti were stimulated to elongate by low R:FR treatments, and subsequent growth and plasticity was compared with nonelongated individuals. Elongated seedlings were less responsive than nonelongated ones to a second bout of low R:FR. Thus, seedling plasticity to R:FR reduces subsequent responsiveness to this cue. This negative association across life-history stages suggests an important constraint on the evolution of plastic stem responses, because selection in A. theophrasti has previously been shown to favor increases in early elongation in combination with increased later elongation. The reduced responsiveness of elongated seedlings to R:FR appeared to result from a structural feedback mechanism, indicating that the opportunity cost of early responses may be lower in environments providing structural support.
Trade-offs between traits are a fundamental component of life history theory. However, because individuals may differ in the amount of energy available for allocation between traits, expected negative relationships are often difficult to detect or may become positive. The latter can occur when both traits are phenotypically plastic in response to variation in environmental productivity. We tested this hypothesis by analyzing expected trade-offs between egg mass and clutch size, and total clutch mass and post-nesting condition, in a population of Galápagos lava lizards (Microlophus delanonis) that experienced marked annual and seasonal variation in rainfall. Due to its close relationship with overall mass (reproductive plus post-nesting mass), we considered rainfall to be a suitable indicator of environmental productivity. Females that reproduced during periods of low rainfall produced smaller and fewer eggs, and had lower post-nesting body mass independent of body size (snoutvent length). This pattern was found in comparisons both between and within individuals that nested in dry and wet periods, respectively. The relationships between egg mass and clutch size, and total clutch mass and post-nesting mass, were positive when data were combined across years and seasons. Restriction of the analysis to comparisons within time periods (in effect, holding productivity constant), resulted in negative Correlations between egg mass and clutch size, and weakened relationships between total clutch mass and post-nesting mass. We conclude that phenotypic plasticity in reproduction obscures life history trade-offs and that plasticity may be more important to the fitness of females than a particular value for an individual reproductive trait.
There are numerous studies of between-individual variation in the expression of sexually selected traits, but relatively few of variation within individuals. We investigated within-individual variation, both between and within years, in the size of the sexually selected white forehead patch of the male collared flycatcher, Ficedula albicollis. Patch size was determined from direct measurements of maximum height and width and by image analysis of photographs. Measures obtained by the two methods were highly correlated with each other. Male patch size showed significant repeatability both within and between years, but repeatability was lower for patch width than for patch height. Recent reanalysis of published data suggests that sexual selection acts mostly on the width of the patch rather than the height, suggesting that the component of patch size subject to sexual selection is most plastic. We found that, within individuals, forehead patch width changed in a predictable manner within years, becoming significantly smaller later in the breeding season. This effect was more pronounced in males with an initially larger patch. Patch size also changed predictably between years: males whose parental effort we manipulated experimentally showed corresponding changes in patch size between years, confirming an earlier finding from this population. Our results show that the size of sexually selected traits can vary within individuals, both in response to trade-offs with other life history traits, and also over short timescales. Such variation in the expression of sexually selected traits is important not only for the information it may provide about the processes controlling variation in such traits, but also because failure to account for it will reduce the accuracy of any attempt to quantify selection on them.
Publisher Summary This chapter focuses on evolutionary significance of phenotypic plasticity in plants. The expression of an individual genotype is modified by its environment. The amount by which it can be modified is termed its plasticity. This plasticity can be either morphological or physiological; these are interrelated. The plasticity of a character is related to the general pattern of its development, and apart from this, that plasticity is a general property of the whole genotype. Plasticity of a character appears to be specific for that character, specific in relation to particular environmental influences, specific in direction, under genetic control not necessarily related to heterozygosity, and able to be radically altered by selection. Because plants are static organisms, plasticity is of marked adaptive value in a great number of situations. Examples of all these situations in plant species are discussed. They indicate that adaptation by plasticity is a widespread and important phenomenon in plants and has evolved differently in different species. The mechanisms involved in plasticity are varied. At one extreme, the character shows a continuous range of modification dependent on the intensity of the environmental stimulus. At the other, the character shows only two discrete modifications. The stimulus causing these modifications may be direct or indirect. The mechanisms found can be related to the particular environmental situation involved.
Floodplains and wetlands are highly suitable for plant ecological studies, whether for agricultural interests, nature conservation or basic science. Traditional work has entailed a descriptive approach at the community or individual plant level. Nowadays these studies are evolving into physiological research on relationships between flooding stress and vegetation zonation. Current experiments aim to unravel the adaptive mechanisms whereby terrestrial plants cope with the peculiar conditions of the floodplain, from the whole plant down to the cell.