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Mycorrhizal Networks Facilitate Tree Communication, Learning, and Memory
Abstract
Mycorrhizal fungal networks linking the roots of trees in forests are increasingly recognized to facilitate inter-tree communication via resource, defense, and kin recognition signaling and thereby influence the sophisticated behavior of neighbors. These tree behaviors have cognitive qualities, including capabilities in perception, learning, and memory, and they influence plant traits indicative of fitness. Here, I present evidence that the topology of mycorrhizal networks is similar to neural networks, with scale-free patterns and small-world properties that are correlated with local and global efficiencies important in intelligence. Moreover, the multiple exploration strategies of interconnecting fungal species have parallels with crystallized and fluid intelligence that are important in memory-based learning. The biochemical signals that transmit between trees through the fungal linkages are thought to provide resource subsidies to receivers, particularly among regenerating seedlings, and some of these signals appear to have similarities with neurotransmitters. I provide examples of neighboring tree behavioral, learning, and memory responses facilitated by communication through mycorrhizal networks, including, respectively, (1) enhanced understory seedling survival, growth, nutrition, and mycorrhization, (2) increased defense chemistry and kin selection, and (3) collective memory-based interactions among trees, fungi, salmon, bears, and people that enhance the health of the whole forest ecosystem. Viewing this evidence through the lens of tree cognition, microbiome collaborations, and forest intelligence may contribute to a more holistic approach to studying ecosystems and a greater human empathy and caring for the health of our forests.
... The ERM forages soil that is not accessible to the root system thus granting increased access to elements that are needed in large amounts by host plants, notably phosphorus (P) and nitrogen (N; Wipf et al., 2019). A fascinating feature of the ERM is its capacity to interconnect numerous plants belonging to the same or different species (Rhodes, 2017;Simard, 2018;Simard et al., 1997), forming common mycorrhizal networks (CMNs), often coined the 'wood-wide web' (Rhodes, 2017). ...
... The potential functional consequences of such underground physical connections linking individual plants challenge our thinking of resource capture and multitrophic interactions, and as a result has spawned numerous popular views, sometimes exaggerated, extolling the virtues of CMNs for both natural and managed systems (Simard, 2018). Such enthusiasm for CMNs is not surprising given their functional capabilities. ...
... fungi (Toju et al., 2015). In those networks some trees were linked with up to 48 other trees, forming distinct hubs (Simard, 2018). The ability of some ECM fungi to form such inter-connected networks clearly offers opportunities for exploitation to enhance key ecosystem services related to forestry and forest restoration. ...
Mycorrhizal fungi are key components of soil biodiversity that offer potential to provide sustainable solutions for land management, notably in agriculture and forestry. Several studies conducted in controlled environments show that key functional attributes of common mycorrhizal networks (CMNs), which inter-link different plants, are influenced by management practices. Here, we highlight the need to consider how land management affects the ubiquity and function of CMNs in nature to maximize the role of mycorrhizal fungi in enhancing ecosystem services. We emphasize that CMNs can sometimes negatively affect aspects of plant performance, but there remain major gaps in understanding before explicit consideration of CMN management can be delivered. Summary Most mycorrhizal fungi have the capacity to develop extensive extraradical myce-lium, and thus have the potential to connect multiple plants and form a 'common mycorrhizal network'. Several studies have shown that these networks can influence plant establishment, nutrition, productivity and defense, nutrient distribution and storage, and multitrophic interactions. However, many of these studies have focused on the importance of common mycorrhizal networks in ecological contexts and there has been less emphasis in managed systems, including croplands, grassland, agrofor-estry and forestry, on which humankind relies. Here we review the evidence of the potential importance of common mycorrhizal networks in managed systems, and provide insight into how these networks could be managed effectively to maximize the functions and outputs from managed systems. We also emphasize possible negative effects of common mycorrhizal networks on plant performance and question popular views that mycorrhizal networks may offer a panacea for enhancing ecosystem services. We highlight the need to gain greater insight into the ubiquity, functioning, and response to management interventions of common mycorrhizal networks and, critically, the need to determine the extent to which these networks can add value to the promotion of mycorrhizal colonization. K E Y W O R D S agroecosystems, forestry, land management, plant to plant signaling, restoration, soil biodiversity, sustainable agriculture
... Notwithstanding the zoocentrism of the wilderness concept, the emerging science of vegetal cognition -including studies of intelligence, communication and behaviour -is transforming our understanding and knowledge of, and thus the stories we tell about, plants and the wild (Gagliano 2018a;Gorzelak et al. 2015;Simard 2018;Wohlleben 2016). According to this rapidly -expanding body of research, vegetal life exhibits a multitude of behaviours congruous with intelligence, including learning by association, acting spontaneously, recognising the self, deciding among options, correcting errors in judgement, communicating with kin through chemical vocabularies, remembering past interactions with animals and, even, blocking traumatic memories in order to enhance the fitness of future generations (Trewavas 2014, 255-266). ...
... Associative learning serves a range of ecological functions from danger avoidance to social interchange (Gagliano 2018, 217). Studies indicate that trees communicate with each other using subterranean messages facilitating the recognition of neighbouring flora through mycorrhizas and exudates (Simard 2018). Unlike animals, moreover, plants must negotiate above -and below -ground habitats, 'each with different problems that require intelligent mastery' (Trewavas 2016, 543). ...
... The attribution of agencies to plants broadens knowledge of life -rather than promulgating hierarchies between life forms -and, in so doing, advances methods of researching wilderness in an age of climate change and anthropogenic excess. As Simard (2018) comments in relation to the Douglas fir forests, 'the lens of tree cognition, microbiome collaborations, and forest intelligence may contribute to a more holistic approach to studying ecosystems and a greater human empathy and caring for the health of our forests ' (191). The second is a new ethics of wild -undomesticated and uncultivated -other -than -human creatures predicated on the recognition of intelligence as intrinsic to complex systems. ...
... This communication, on the other hand, is thought to happen more swiftly and efficiently between plants via speech transmission across networks, or "wired communication" (Gagliano 2013). Although the exact manner of communication is unknown (Simard 2018), these communication signals are sent between fungal synapses and trees and/or plants by diffusion or active transport processes (mass flow) along source-sink gradients (Twieg et al. 2007;Simard et al. 2015). For example, leaf photosynthetic activity in donor plants causes N and C source-sink gradients that allow amino acids to be transported to mycorrhizal roots, which are subsequently transferred by mass flow from the connecting mycelium to the xylem of the connected recipient sink plants. ...
... This is insufficient to account for the complex plant activity observed in roots. It is hypothesized, however, that when plants have a symbiotic relationship with mycorrhizal fungus, this supplies them with the topology and energy required for advanced thinking (Simard 2018). The "topology" of a communication network refers to the organization of various elements (nodes and connections). ...
... The finest examples are neurons and axons, which are nodes and links in the human's brain. Mycorrhizal fungal micelles, which connection plants and plants, are an example of this in nature (Simard 2018). ...
Plants, animals, and even microbes well communicate with each other if we look at nature in cartoon terms. However, in the real world, there is little evidence on how this communication is established. In this context, we have focused on how plants communicate with mycorrhizal fungi and how they communicate with each other using mycorrhizal networks. We divide this communication in the rhizosphere into three categories: (i) communication of the plant with the fungus (plantish), (ii) communication of the fungus with the plant (fungish), and (iii) communication among plants through mycorrhizal networks (wired communication). We propose that molecules involved in inter-kingdom symbiotic communication, such as strigolactones, chitin-related compoundsand cutin monomers in plant-fungal communication, are initially unrelated to symbiosis, but they play important roles in its development. It’s not, however, known exactly whether the dialogue between plant-fungi is fungish or plantish; Despite this, since it is a language on which they agree, we consider it appropriate to call this language “symbioticish”. Moreover, mycorrhizal networks offer inter-plant communication by transferring nutrients, stress signalsand allelochemicals. We present evidence showing that these mycorrhizal networks impart sophisticated intelligence to plants and that their topology is similar to that of the human’s brain, with some features including scale-free and small-world network topology. The evidence presented in this review can contribute to the study of plant-mycorrhizal fungus communication and mycorrhizal networks in the inter-plant communication by establishing a better human empathy, taking a more holistic approach to examining ecosystems and caring about the health of our plants.
... In order to maintain itself on low internal entropy and to compensate the entropy increase of its habitat, any organism (a tree, in this case) produces by living and growing, a process that consists in continually taking in orderliness from its environment (Schrödinger, 1945). For this, a sophisticated mechanism is needed to perceive the environment, to use and store (e.g., in the annual growth ring) the information subsequently available for behavioural adaptations (Simard, 2018). ...
... The spatial interaction is the primary factor that influences tree growth (Assmann, 1970;Gadow and Hui, 1999), but its unequivocal explanation in terms of competition is increasingly avoided. Instead, the ecological modelling recently emphasizes the essential relevance of the functioning of each component for the benefit of the group association, leaving behind the organismic-individualistic model and fostering a more holistic approach to studying ecosystems (Simard, 2018). The highly integrated plant communities represented by forests are often characterized by supportive relations between the individual trees such as mutual adaptation or protection (Gadow and Hui, 1999), and intraspecific facilitation (Callaway and Mahall, 2007;Kunstler et al., 2011;Ehlers et al., 2016;Barker et al., 2017). ...
... In this context, it is important to highlight that kinfacilitation increases coexistence and prevails in stressful habitats with limited resources (Kunstler et al., 2011;Ehlers et al., 2016). Several hypotheses have been proposed to explain the mechanism by which plants recognize their neighbours for communicating and optimally interacting with each other, particularly between conspecifics in social groups: kin recognition through root exudates (Callaway and Mahall, 2007;Ehlers et al., 2016) or mycorrhizal fungal networks (Simard, 2018), volatile molecules emitted as warning signals, electrical signals, and neighbour-altered light-wavelength ratios (Callaway and Mahall, 2007). From this perspective, only competition is promoted in managed stands, actually eliminating the kin collaborators of a tree through the extractions made. ...
The trees’ ability to respond and adjust to very different growing conditions during their lifespans varies depending on tree species and the site-specific situations. Identifying the underlying mechanisms and the individual drivers that may affect the patterns of tree growth is crucial in ecological and economic terms. How long can forest trees grow and sustain biomass accumulation, with increasing age, is still under debate. In order to determine the factors that influence growth releases for silver fir (Abies alba Mill.) trees in a temperate old-growth forest of Romania's Southern Carpathians, an analysis of radial and basal area growth patterns was initiated. Dendroecological methods were used to reconstruct radial growth both at the individual level, but especially at the group level, in four clusters obtained by a prior k-cluster analysis depending on social status. The study results showed that the growth rate of older trees increases continuously for this species at stand level, even after the typical harvesting age in managed forests. Although the direction and intensity of the climate-growth correlations at individual level were very different, the considered climatic variables explaining little to none of the growth variation, the cumulative response of the analysed trees to climate change is directly correlated with the mean July-August temperature, confirming the capacity of the silver fir to tolerate drought. Our results demonstrate that the trees of the same species are able to obtain together a temporal plasticity in strategies, exceeding the adaptability of individuals considered separately and suggest the positive impact of facilitative intraspecific interactions on forest growth.
... And unsurprisingly, bigger and older trees made more connections. Suzanne Simard calls them 'Mother Trees' (Simard 2012(Simard , 2018a(Simard , 2018b shown in Figs. 4 and 5 which are nuclei of life where connections converge. ...
... Mother Trees, particularly the ancient cedars and spruces of the Pacific West Coast, may also transmit nutrients through the forest with their massive MN, thereby feeding the entire ecosystem (Simard 2018b(Simard , 2015Wohlleben 2018). ...
In this article, we are presenting a new nature-inspired metaheuristic optimization algorithm that we call the Mycorrhiza Tree Optimization Algorithm (MTOA) focused on solving optimization problems. The algorithm is inspired by the relationship between trees and the Mycorrhiza Network (MN). In this relationship, there are interactions such as defense, communication, resource exchange and habitat colonization between the Trees and the MN. The Lotka–Volterra continuous systems (Predator–Prey, Cooperative and Competitive Models) were used for the design of the algorithm. To verify the efficiency of the algorithm, experiments with 36 mathematical functions were performed, but we are only presenting results of the functions with which comparisons were made with other methods. Hypothesis tests were also carried out, where in most of the results the MTOA algorithm was better by 70% and only in the experiments in 100 dimensions it was better by 60%. We believe that the algorithm has the potential to solve problems in control and optimization of neural networks, for which experimentation will be done as future work.
... For instance, a mycelium network is constructed by mushrooms and allows for the sharing of resources such as carbon or phosphorus to improve the use of nutrients coming from nonliving resources such as water or sunlight. Furthermore, some kinds of trees share carbon with smaller plants that do not receive sufficient sunlight (Simard, 2018). ...
... If trees cooperate with each other to survive and evolve (Simard, 2018), perhaps we as human beings are missing the opportunity to evolve by emphatically driving competition in the economy. ...
In the context of discussions regarding the relevance of innovation to the task of building new economic models that foster sustainable development, this paper focuses on clarifying and specifying the term “ecosystem”, which is typically used as a metaphor. Taking into account research concerning biological ecosystems, the article describes the components, structures and dynamics that biological ecosystems share in common with business, entrepreneurial, and innovation ecosystems, which together form one aspect of economic ecosystems as a whole. The paper utilizes primary data that were collected through a mixed methodology involving participatory workshops and an online survey instrument that involved members of innovation-oriented entrepreneurial ecosystems in eight cities throughout Europe and Latin America from June 2019 through February 2020.
Drawing on complex system theory as a unifying approach to describe and explain the components and structural conditions of any ecosystem, whether biological or economic, this paper proposes a theoretical approach and metrics that can be used to attain a better understanding of the social dynamics of ecosystems. Based on observations from the field of biology, it is proposed that such structural conditions tend toward equilibrium when they are constructed mainly through collaborative mechanisms. The results are shown graphically based on the data collected, utilizing metrics taken from complex network analysis and mathematical modeling from the perspective of complex system theory. This paper finds that the ecosystemic approach is more than a metaphor and can functionally describe how an ecosystem is structured and how it works by opening a wider path toward comprehending the dynamics underlying the interactions among components of economic ecosystems and their environment. The paper concludes by proposing that collaboration relationships among actors provide the required characteristics to increase balance and resilience in economic ecosystems.
... However, the true nature of plants and trees is based on the fact that their roots are structurally and functionally connected through fungal hyphae networks. In some sense, these networks are analogous to our human invention of the internet because the latest advances suggest that they serve not only for exchange of nutrients and water, but also for chemical and electrical long-distance signaling (Simard et al. 1997;Song et al. 2010;Barto et al. 2012;Gorzelak et al. 2015Gorzelak et al. , 2020Sasse et al. 2018;Simard 2018;Volkov et al. 2019;Volkov and Shtessel 2020). Obviously, the true nature of plants is hidden underground, which would explain why plants are generally considered to be devoid of agency, cognition, and intelligence. ...
... They invest their carbon-based photosynthetic substances to control the rhizosphere microbiota communities and soil as a life-friendly biotop (Barlow 2010a, b;Barlow and Fisahn 2013;Novoplansky 2019;Baluška andMancuso 2020, 2021). Future experimental studies will focus on the ecological, cognitive and electrophysiological aspects of the root-wide-web (Simard et al. 1997;Lee et al. 2013;Simard 2018;Giovannetti et al. 2006;Fukasawa et al. 2020;Volkov et al. 2019;Volkov and Shtessel 2020;Kokkoris et al. 2021) spanning large areas of the Earth surface. Unfortunately, these intact forest areas are shrinking and this has serious consequences for the life-friendly climate (Baluška and Mancuso 2020). ...
Plant roots are generally hidden from our sight, growing and living underground in alliances with symbiotic fungi. In order to find enough water and critical mineral nutrients, they explore large areas of soil with their root apices acting as plant cognition-based brain-like organs allowing them to use kin recognition, self/non-self recognition as well as swarm intelligence. Importantly, fungal hyphae integrate root systems into huge root-wide webs which allow not only the sharing of water and mineral nutrients, but also support long-distance chemical and electric signals. Roots use neuronal molecules such as glutamate and GABA supported by their specific receptors, as well as actin-based synapses and the plant-specific action potentials, to perform all their social activities and cognitive navigation for soil exploration.
... Whereas soil bacterial and fungal communities interact with plants in many different ways (e.g., promoting or impacting plant productivity and health), the roles of arbuscular mycorrhizal fungi (AMF) are mostly associated with the improvement of plant nutrition (especially phosphorus) and alleviation of abiotic and biotic stresses (Pozo and Azcón-Aguilar, 2007;Pozo et al., 2010;Plouznikoff et al., 2016). The concept that these fungi may form common mycorrhizal networks (CMNs) interconnecting plants is nowadays widely recognized (Simard et al., 1997;Rhodes, 2017;Simard, 2018) suggesting their potential roles in nutrients exchange. Indeed, for ectomycorrhizal fungi, these belowground interconnections have been reported to favor nitrogen, phosphorus (He et al., 2003;Selosse et al., 2006), and carbon (Selosse and Roy, 2009) exchanges. ...
Most plants are connected belowground via common mycorrhizal networks (CMNs). In their presence, the transmission of warning signals from diseased to uninfected plants has been reported. However, current studies have all been conducted in pots making it difficult to discriminate direct from indirect contribution of hyphae to the transmission of the signals. Here, we conducted an in vitro study with potato plantlets connected by a CMN of the arbuscular mycorrhizal fungus Rhizophagus irregularis. The plantlets were grown in physically separated compartments and their connection ensured only by the CMN. The donor potato plantlets were infected by Phytophthora infestans and defense genes analyzed 24, 48 and 120 h post-infection (hpi) in the uninfected receiver potato plantlets. Twenty-four hpi by the pathogen, PAL, PR-1b, ERF3, and LOX genes were significantly upregulated, whereas no significant transcript variation was noticed 48 and 120 hpi. The exact nature of the warning signals remains unknown but was not associated to microorganisms other than the AMF or to diffusion mechanisms through the growth medium or induced by volatile compounds. The defense response appeared to be transitory and associated with the jasmonic acid or ethylene pathway. These findings demonstrate the direct involvement of hyphae in the transmission of warning signals from diseased to uninfected potato plantlets and their indubitable role in providing a route for activating defense responses in uninfected plants.
... The fungi amplify the absorptive area of the roots, thus helping the plant absorb water and nutrients such as phosphorus. Plants repay the fungi with photoassimilates (Simard, 2018). This association allows plants to perceive items outside of their own reach. ...
Up until the middle of the 19th century, some data about plant behavior could be found in books dealing with comparative psychology. The tendency gradually faded away, and the topic was almost exclusively treated in literature dealing with plant physiology. In recent years, however, there has been a revamping of psychological terminology and theorizing to describe, explain, and formulate hypotheses on the evidence that many of the sophisticated behaviors plants exhibit are an expression of cognitive competences that are generally attributed to human and nonhuman animals. In this work I shall discuss a selection of experimental studies supporting the idea that plants could be defined as cognitive agents. Experiments showing that the behavior of plants is controlled by a representation of its goal, episodic-like memory, and decision-making will be described. It is not, however, my intention to embrace any position as to whether or to what degree plants are conscious. Rather, I hope to (re)fuel the discussion within the psychological community that will point in the direction of integrating studies concerning adaptive plant behavior within the wider field of comparative psychology. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
... Similar to bacteria and viruses for mammals, fungi are the most important plant pathogens worldwide [17,18] and represent an increasing threat to certain groups of animals, including amphibians [19][20][21]. Fungi are also invaluable components of soils and forests [22][23][24], and are currently emerging as important members of the human microbiome (i.e., mycobiome) [25][26][27]. Currently, our protocol for DNA extraction for high-throughput microbiome sequencing focuses on describing bacterial/ archaeal taxa, and has not yet been tested to additionally describe Fungi. ...
Microbial communities contain a broad phylogenetic diversity of organisms; however, the majority of methods center on describing bacteria and archaea. Fungi are important symbionts in many ecosystems and are potentially important members of the human microbiome, beyond those that can cause disease. To expand our analysis of microbial communities to include data from the fungal internal transcribed spacer (ITS) region, five candidate DNA extraction kits were compared against our standardized protocol for describing bacteria and archaea using 16S rRNA gene amplicon- and shotgun metagenomics sequencing. The results are presented considering a diverse panel of host-associated and environmental sample types and comparing the cost, processing time, well-to-well contamination, DNA yield, limit of detection and microbial community composition among protocols. Across all criteria, the MagMAX Microbiome kit was found to perform best. The PowerSoil Pro kit performed comparably but with increased cost per sample and overall processing time. The Zymo MagBead, NucleoMag Food and Norgen Stool kits were included.
... By contrast, shoots are not enjoying such a symbiotic social life based on direct intracellular organism-organism connections [23][24][25], although the phylosphere is also abundant with plant-supporting fungi and microorganisms. Vascular plants form root-fungal networks [141] not only for nutrition and water [142,143] but also for information exchange [144][145][146][147] ...
Vascular plants are integrated into coherent bodies via plant-specific synaptic adhesion domains, action potentials (APs) and other means of long-distance signalling running throughout the plant bodies. Plant-specific synapses and APs are proposed to allow plants to generate their self identities having unique ways of sensing and acting as agents with their own goals guiding their future activities. Plants move their organs with a purpose and with obvious awareness of their surroundings and require APs to perform and control these movements. Self-identities allow vascular plants to act as individuals enjoying sociality via their self/non-self-recognition and kin recognition. Flowering plants emerge as cognitive and intelligent organisms when the major strategy is to attract and control their animal pollinators as well as seed dispersers by providing them with food enriched with nutritive and manipulative/addictive compounds. Their goal in interactions with animals is manipulation for reproduction, dispersal and defence.
This article is part of the theme issue ‘Basal cognition: multicellularity, neurons and the cognitive lens’.
... Ericoid mycorrhiza belong to Phallales, Boletales, and Russulales orders of Basidiomycota, and establish symbiotic relationships with 400 plant species from the Monotropoideae subfamily of Ericaceae. These plants do not have chlorophyll and obtain 85-100% of required carbon from fungi, which are simultaneously connected to autotroph nurse trees (Min, Chang-Qin, Yong-Peng, Welti, Moreau & Selosse, 2012, Simard, 2018. Some Brassicaceae and Proteaceae plants do not participate in mycorrhizal relationships, and are considered to be non-mycorrhizal symbiotic plants (Tedersoo et al. , 2020). ...
... An extreme case is the so-called 'walking palm', which is able to relocate itself away from its germination point (Bodley and Benson, 1980). Recent research has shown that mycorrhizal fungal networks linking the roots of trees in forests allow abilities such as perception, learning and memory in trees, and have a topology similar to neural networks (Simard, 2018). Some plants capture insects ( fig. ...
Can scientific laws be discussed on philosophical grounds? a reply to naïve arguments on 'predators' proposed by Bramble (2021). A recent paper by Bramble (2021) argues that given that predators inflict pain and fear on their prey we have the moral right to act to minimize these effects. The author proposes two alternatives. The first is to transform predators by 'genetically modifying them so that their offspring gradually evolve into herbivores'. The second is simply 'painlessly killing predators', which is the title of Bramble's essay. We address the misconceptions that Bramble uses as central in his arguments and present scientific reasoning to discuss the ethical implications of disregarding scientific knowledge when addressing animal welfare and animal rights.
We conclude that both Bramble's alternatives are nonsensical, not only from a scientific point of view, but also, and more importantly, from ethical grounds.
... These findings further highlight the great ecological importance of AM fungi in natural-and agro-ecosystems. In fact, the above cited ERM network, can connect roots of different plant species enabling nutrient (N and P in particular) transfer from one plant (donor) to another (receiver) depending on the biomass strength, functioning as an unique super-organism [85,86]. ...
Arbuscular mycorrhizal (AM) fungi are root symbionts that provide mineral nutrients to the host plant in exchange for carbon compounds. AM fungi positively affect several aspects of plant life, improving nutrition and leading to a better growth, stress tolerance, and disease resistance and they interact with most crop plants such as cereals, horticultural species, and fruit trees. For this reason, they receive expanding attention for the potential use in sustainable and climate-smart agriculture context. Although several positive effects have been reported on photosynthetic traits in host plants, showing improved performances under abiotic stresses such as drought, salinity and extreme temperature, the involved mechanisms are still to be fully discovered. In this review, some controversy aspects related to AM symbiosis and photosynthesis performances will be discussed, with a specific focus on nitrogen acquisition-mediated by AM fungi.
... Similar to the aerial part of the plant, the primary development and formatting follow genetically programmed intrinsic patterns (Novoplansky, 2019), but the fate of root morphology is strongly adjusted by extrinsic environmental signals. These adjustments by exogenous cues reflect the phenotypic plasticity of plants, which allow them to cope with the fact that they are sessile organisms existing in a continuously changing environment (Simard, 2018). In A. thaliana, the root consists of three major zones: the meristematic zone (MZ), the elongation zone (EZ), and the differentiation zone (DZ). ...
Reactive oxygen species (ROS) are naturally produced by several redox reactions during plant regular metabolism such as photosynthesis and respiration. Due to their chemical properties and high reactivity, ROS were initially described as detrimental for cells during oxidative stress. However, they have been further recognized as key players in numerous developmental and physiological processes throughout the plant life cycle. Recent studies report the important role of ROS as growth regulators during plant root developmental processes such as in meristem maintenance, in root elongation, and in lateral root, root hair, endodermis and vascular tissue differentiation. All involves multifaceted interplays between steady-state levels of ROS with transcriptional regulators, phytohormones, and nutrients. In this review, we attempt to summarize recent findings about how ROS are involved in multiple stages of plant root development during cell proliferation, elongation and differentiation.
... Ectomycorrhizae also can enhance plant tolerance to drought by improving the plant-soil contact surface, water conductivity in the host plant, and resistance to high soil salinity by restricting sodium uptake into plant tissues and activating stress response pathways (Pickles & Simard 2017). As in most ecosystems, Neotropical communities rely on adults (hub trees) to support seedling growth and maintain diversity (Simard 2018). Therefore, ecological restoration should strive to enhance the establishment of these interactions. ...
As restoration ecology begins to engage more formally with the role of belowground interactions, we note that there is an even greater gap in knowledge of the role ectomycorrhizae (ECMs) have in ecological restoration in the neotropical region. Even though there are a few records of ECMs in the Neotropics not much is known about their function. Here we highlight This article is protected by copyright. All rights reserved. the underestimated importance of ECMs in neotropical coastal zones, discuss how we could use the vegetation on the coast of the Atlantic Forest, called restinga, as a model to investigate tropical ECMs, and explore further possibilities that can be used in restoration projects.
... Beech and fir communities impacted by gap dynamics and their associated growth oscillations from suppression to release can harbor much older trees than areas where competition for resources is less intense, as is the case in large clearings or in managed stands (Fig. 5;Di Filippo et al., 2017). Clonal regenerations (Sillett et al., 2020) and mycorrhizal networks, formed predominantly in the root systems of canopy trees, can favor survival of juveniles in the understory, thereby facilitating tree establishment as well as sustain survival of suppressed trees during their initial life (Simard, 2018). In vertically complex tropical forests, stem ages of understory trees can then be comparable to those of dominant individuals (Hubau et al., 2019). ...
Large, majestic trees are iconic symbols of great age in living organisms. Published evidence suggests that trees do not die because of genetically programmed senescence in their meristems, and rather are killed by an external agent or a disturbance event. Long tree lifespans are therefore allowed by specific combinations of life‐history traits within realized niches that support resistance to, or avoidance of, extrinsic mortality. Another requirement for trees to achieve their maximum longevity is either sustained growth over extended periods of time or at least the capacity to increase their growth rates when conditions allow it. The growth plasticity and modularity of trees can then be viewed as an evolutionary advantage that allows them to survive and reproduce for centuries and millennia. As more and more scientific information is systematically collected on tree ages under various ecological settings, it becomes clear that tree longevity is a key trait for global syntheses of life history strategies, especially in connection with disturbance regimes and their possible future modifications. In addition, we challenge the long‐held notion that shade‐tolerant, late‐successional species have longer lifespans than early‐successional species by pointing out that tree species with extreme longevity do not fit this paradigm. Identifying extremely old trees is therefore the groundwork not only for protecting and/or restoring entire landscapes, but also to revisit and update classic ecological theories that shape our understanding of environmental change.
... such as degrowth and anticonsumption; Hobson 2013), we reimagine what production and consumption look like as interconnected capacity-building processes (e.g. symbiosis, mutually-enriching relationships, interconnected systems; Kohn 2013;Simard 2018;Stamets 2005). ...
This article takes stock of sustainability research in marketing and argues for developing a Strong Sustainability Research (SSR) program, led by a Consumer Culture Theory (CCT) approach. First, I define weak vs. strong sustainability and identify two main problems with continuing to research business with the weak sustainability approach. Second, I discuss past approaches to sustainability research in marketing, which primarily promote weak sustainability. Third, I use the agriculture industry to illustrate how an SSR program in marketing could be developed to bring insights to practitioners and policy makers and build new modes of production, consumption and exchange. Finally, I suggest that the SSR program facilitates collaboration between mainstream marketing and CCT researchers by providing a common ontological platform that can transform epistemological differences into complementary strengths. I argue SSR is a way that marketing research can gain broad impact and relevance.
... From a communicational perspective, there is therefore not much sense in restricting the material world to the world of rocks, tables, and computers, as most organizational scholars keep doing. Communication, in order to occur, always needs to materialize into something or someone, whether we speak about communication between neurons, trees (Simard, 2018), computers, or employees. Studying the (organizational) world communicatively thus amounts to accounting for its materiality and relationality. ...
Although we have to welcome the renewed interest in socio-materiality in organization studies, I claim that we are yet to understand what taking matter seriously really means. The mistake we especially need to stop making consists of automatically associating matter to something that can be touched or seen, that is, something tangible or visible, an association that irremediably leads us to recreate a dissociation between the world of human affairs and the so-called material world. To address this issue, I mobilize a communication-centered perspective to elaborate that (1) materiality is a property of all (organizational) phenomena and that (2) studying these phenomena implies a focus on processes of materialization, that is, ways by which various beings come to appear and make themselves present throughout space and time. In the paper I conceptualize the contours of these materialization processes and discuss the implications of this perspective on materiality for organizational theory and research.
... Intraspecific facilitation is strongly mediated by the presence of mycorrhizae [67,68]. Kin selection is one of the scenarios that could explain this pattern because common mycorrhizal networks connect plants, facilitate nutrient and defense transfer, and allow kin recognition [69]. For example, Pickles et al. [70] have shown that carbon transfer through mycorrhizal networks is much higher between fullsibs than between unrelated seedlings. ...
While antagonistic interactions between plants have been a major topic of eco-evolutionary research, little evidence exists on the evolution of positive plant interactions (i.e., plant facilitation). Here, we first summarize the existing empirical evidence on the role of facilitation as a selection pressure on plants. Then, we develop a theoretical eco-evolutionary framework based on fitness-trait functions and interaction effectiveness that provides predictions for how facilitation-related traits may evolve. As evolution may act at levels beyond the individual (such as groups or species), we discuss the subject of the units of evolutionary selection through facilitation. Finally, we use the proposed formal evolutionary framework for facilitation to identify areas of future research based on the knowledge gaps detected.
... Communication also takes place underground, thanks to the interactions of roots with the mycelial networks of mycorrhizal fungi (Johnson & Gilbert, 2015;Simard, 2018;Simard et al., 2012). Studies have found that the symbiotic exchange of information of fungi and plant roots results in flexible and adaptive changes on the plant's side, including rapid changes in physiology, gene regulation, and defense response (Gorzelak et al., 2015;Song et al., 2015). ...
Unlike animal behavior, behavior in plants is traditionally assumed to be completely determined either genetically or environmentally. Under this assumption, plants are usually considered to be noncognitive organisms. This view nonetheless clashes with a growing body of empirical research that shows that many sophisticated cognitive capabilities traditionally assumed to be exclusive to animals are exhibited by plants too. Yet, if plants can be considered cognitive, even in a minimal sense, can they also be considered conscious? Some authors defend that the quest for plant consciousness is worth pursuing, under the premise that sentience can play a role in facilitating plant's sophisticated behavior. The goal of this article is not to provide a positive argument for plant cognition and consciousness, but to invite a constructive, empirically informed debate about it. After reviewing the empirical literature concerning plant cognition, we introduce the reader to the emerging field of plant neurobiology. Research on plant electrical and chemical signaling can help shed light into the biological bases for plant sentience. To conclude, we shall present a series of approaches to scientifically investigate plant consciousness. In sum, we invite the reader to consider the idea that if consciousness boils down to some form of biological adaptation, we should not exclude a priori the possibility that plants have evolved their own phenomenal experience of the world. Cognitive Biology > Evolutionary Roots of Cognition Philosophy > Consciousness Neuroscience > Cognition A climbing bean (Phaseolus vulgaris) with needle electrodes inserted into its main stem aimed to reveal the underpinnings at work as it responds to the environment. At the Minimal Intelligence Laboratory, we seek to correlate the behavior of plants and phytoneural activity in order to study plant cognition and sentience.
... Network connections between organisms are capable of utilizing the equivalent of a type of biological "internet", providing parallel systems of communication, circulation, nutrient exchange, immunological, and structural support throughout the tissues and glands of the human body. 9 This diverse, ubiquitous amalgamation of human tissue with non-human micro-organisms interacts and cooperates in every essential aspect of life, beginning with sexual attraction, bonding, reproduction and conception onwards, supporting the development of the entire body including the nervous, fundamental, synergistic symbiosis that functions as a "superorganism" of integrated and mutually inter-dependent species. 11 Not only does human life depend on the microbiome for normal healthy growth, development and survival, but the microbiome, which has adapted itself to the human organism, is reciprocally dependent on the human body for its own survival. ...
Human health is intimately linked to the ecology and diversity of the human microbiome. Together, the human organism and the human microbiome work as a complex super-organism throughout the human life cycle. Microbiome science provides direct evidence and substantiation of the fundamental principles of homeopathy, including holism, psychosomatics, direction of cure, the Law of Similars, individuality and susceptibility, minimum dose, and homeostasis. Whilst many conventional (allopathic) medical treatments irreversibly damage the ecology of the microbiome and trigger chronic immune dysfunction and inflammation, the future sustainability of the entire field of medicine depends on the ability to recognize these inconvenient biological truths and to embrace a safer approach based on this evidence. Fortunately, one of the oldest forms of clinically verifiable, evidence-based, and ecologically sustainable medicine, that does not harm the microbiome, already exists in the form of homeopathy.
... Existem debates e controvérsias atuais sobre evidências de que vegetais têm inteligência distribuída, capacidades de escolhas, respostas, aprendizado, memorização, mimetização, intencionalidade, linguagem e cooperação entre si, além de manipular quimicamente os animais (GAGLIANO e GRIMONPREZ, 2015;MANCUSO, 2019;MARDER, 2012). Comunicam-se em redes subterrâneas, e "árvores mãe" fornecem quantidades diferentes de elementos para cultivar mudas ao seu redor, criando ainda um sistema de imunização coletivo (SIMARD, 2018). Para Jones e Cloke (2008), vegetais são autônomos e possuem formas de agência ativa que costumam ser atribuídas apenas aos humanos. ...
Based on an ethnoarchaeological study on plaitworks technology of the Mapuera River peoples (northwest of Pará state of Brazil), the present paper discusses materials and the modern concept of material culture, submitting both to Amerindian’s ontology and cosmovision. Articulating cosmopolitics, ecology of practices, transduction, and individuation concepts, the paper proposes that to plait is not an exclusively human’s know-how. Plaitworks are bodies basically made of metamorphosed vegetables and their lives emerged from technical operations permeated by negotiations. The plaitworks agency is linked to their respective corporealities and to the subjectivities and powers of part of the vegetables that make up their bodies. Although perishable, plaitworks are persistent in the lives of the Mapuera River Amerindian peoples.
... 19 In a contribution to Memory and Learning in Plants, Suzanne Simard traces the patterns of 'neighboring tree behavioral, learning, and memory responses facilitated by communication through mycorrhizal networks' to note several similarities between these networks and the neural networks we commonly associate with brains. 20 Which is to say that Simard is suggesting that mycorrhizal relations communicate as processes of learning, as well as sustenance. ...
Thinking fungi as a way of considering randomness gives rise, in particular, to thinking about categorization, comparison, as well as creating (more-than-human) communities through strange and unexpected commonalities. These ideas inform comparative literature more broadly, along with the desire to identify and understand culturally codified motifs – that is, meanings as they gather around particular images and generate certain ideas of being in the world. By bringing fungi to the table, this contribution considers agency and ruin with contemporary narrativized deliberations on all kinds of fungi matter(s). Textually, it examines memoirs, (new) nature writing, as well as cultural studies work on fungi; theoretically, it draws on etymology and systems of classification more broadly, impulses from new materialism, as well as STS-informed deliberations on knowledge generation, classification, and circulation.
Please ask for a copy if you want to read it.
... Communication that involved exchanging chemical messages through leaflets and talking to their roots [106]. Trees have a brain called the root that has the power to learn and memory and to extend it to future decisions [109]. Forests are one of the most dynamic creatures around us. ...
This paper presents a new metaheuristic algorithm called Trees Social Relations Optimization Algorithm (TSR). TSR inspired by the hierarchical and collective life of trees in the jungle. The main priority of the collective consciousness of the trees is the survival of the woods. The trees try to reduce the damage in various ways so that the forest can develop. Organizing trees, protecting young seedlings, and their communication mechanism create a complex structure based on swarm intelligence that is the inspiration for designing an algorithm to solve existing problems. In TSR, each answer considered as a tree and a set of solutions defined as a sub-jungle. Sub-jungles are interconnected and help each other to get the right answer. The use of parallel and synchronized sub-jungles with its dedicated operators will increase the accuracy and shorten the time to reach an acceptable response. The TSR algorithm can use in continuous and discrete problems and, therefore, can use in a wide range of issues. Numerous experiments on standard and various benchmarks, as well as some classic and new issues, show that our proposed algorithm provides appropriate and acceptable answers in both time and accuracy to some similar algorithms.
... This pivotal case provides important lessons for forest management and adaptation in other contexts, and the major concerns of our participants are not unique to BC. For instance, recent progress in forest ecology has demonstrated that scientific knowledge about the ways in which trees anchor broader ecological processes remains nascent (38,39), and public trust in decisionmaking processes is fundamental to the effective governance of shared or publicly managed resources (40). However, public ownership of BC's forests creates an expectation of responsible public stewardship (23) that may not exist in regions where private land tenure is more common. ...
Climate change threatens the social, ecological, and economic benefits enjoyed by forest-dependent communities worldwide. Climate-adaptive forest management strategies such as genomics-based assisted migration (AM) may help protect many of these threatened benefits. However, such novel technological interventions in complex social–ecological systems will generate new risks, benefits, and uncertainties that interact with diverse forest values and preexisting risks. Using data from 16 focus groups in British Columbia, Canada, we show that different stakeholders (forestry professionals, environmental nongovernmental organizations, local government officials, and members of local business communities) emphasize different kinds of risks and uncertainties in judging the appropriateness of AM. We show the difficulty of climate-adaptive decisions in complex social–ecological systems in which both climate change and adaptation will have widespread and cascading impacts on diverse nonclimate values. Overarching judgments about AM as an adaptation strategy, which may appear simple when elicited in surveys or questionnaires, require that participants make complex trade-offs among multiple domains of uncertain and unknown risks. Overall, the highest-priority forest management objective for most stakeholders is the health and integrity of the forest ecosystem from which all other important forest values derive. The factor perceived as riskiest is our lack of knowledge of how forest ecosystems work, which hinders stakeholders in their assessment of AM’s acceptability. These results are further evidence of the inherent risk in privileging natural science above other forms of knowledge at the science–policy interface. When decisions are framed as technical, the normative and ethical considerations that define our fundamental goals are made invisible.
... This meaning communicated by so many of the research participants contributes to appreciative lifelong learning in everyone. In forests, mother trees may be doing something similar when they share their collective memory of trauma in the forest as a lesson for younger trees to learn from (Simard, 2018). ...
by Southam, Theresa, Ph.D., Fielding Graduate University, 2020, 307; 27739045
Abstract (Summary)
27,000 Sunrises: Everyday Contributions of Grateful and Giving Age 70+ Adults
by
THERESA SOUTHAM
Although the increasingly older population has been described as a burden (Doron, 2013; Rozanova, 2010), older adults who are willing to take up the hard work of elderhood have important gifts to contribute (Conley, 2018; Jenkinson, 2018b; Pevny, 2014; Schachter-Shalomi & Miller, 2014). Older adults’ contributions have been studied predominantly as tangible services, missing important, less tangible services that were found to contribute to the sustainable nature of communities. This critical ethnographic study reveals the meanings age 70+ older adults make with others in their everyday lives.
Of the main participants, seven were male and two female; one was indigenous (n=9). The other people that older adults interacted with and who were included in this study (n=16) were family, friends, workshop participants, and work colleagues. The researcher conducted “go-alongs” in order to observe and document everyday life. Main participants completed life maps, LifeForward Plans and a questionnaire, including measures of wisdom, generativity, and transcendence.
Two meanings—Create and Share Other Realities and Value the Connection between People and Place— and three meaning-making processes—Turn Grief to Gratitude to Giving, Continue to Grow, and Shape Future through Ordinary Acts of Kindness— were examined for their contributions to more sustainable and compassionate communities. One example of the meaning Create and Share Other Realities is exemplified in the supplementary video to this dissertation Chris opening up worlds that didn’t exist (Southam, 2019). A new model was created where grief and gratitude drive generativity, rather than cultural demand (McAdams, Hart, & Maruna, 1998). A fifth dimension of self-actualization was added to the Foray (4A) model of lifelong learning (Corley, 2011) resulting in a new model Foray (4A+) – Beyond Self.
Future research on the developmental tasks of older adults and on communication approaches that lead to sustainability are needed. Renewed calls for elderhood could strengthen the social, environmental, and economic well-being of our communities.
Keywords: elder, elderhood, meaning, meaning-making, older adults, community, sustainability, wisdom, generativity, transcendence, developmental tasks of older adults, ageism, denial of death, conscious aging, successful aging, critical applied ethnography, go-along, life map, communication
Supplemental files can be found at https://pqdtopen.proquest.com/doc/2377687834.html?FMT=ABS
... In the interval since Darwin, science has learned that all living systems-cells, organisms, species (including Homo sapiens) and ecosystems-survive in extensive networks of interaction and group cooperation (Cohen, 2016;Cohen and Marron, 2020;Sachs et al., 2004). A few examples include the dependence of every multicellular organism on a microbiome (Blaser, 2014); the symbiotic web of forest trees and fungi (Simard, 2018) ; and the collaboration and symbiosis that create a coral colony (Rosenberg et al., 2007). The biosphere is sustained by these interactions; the biosphere is a world wide web of interactions. ...
Autoencoding is a machine-learning technique for extracting a compact representation of the essential features of input data; this representation then enables a variety of applications that rely on encoding and subsequent reconstruction based on decoding of the relevant data. Here, we document our discovery that the biosphere evolves by a natural process akin to autoencoding. We establish the following points: (1) A species is defined by its species interaction code. The species code consists of the fundamental, core interactions of the species with its external and internal environments; core interactions are encoded by multi-scale networks including molecules-cells-organisms. Species interaction codes both map and construct the species' environment. (2) The survival of fitted species is computed by natural autoencoding: the fittedness of species interactions is proven by successful decoding of evolving species into sustained ecosystems; survival of the fitted supplants Darwinian struggle and domination of the "fittest" only. DNA is only one element in natural autoencoding. (3) Natural autoencoding and artificial autoencoding techniques manifest defined similarities and differences. Biosphere autoencoding accounts for survival-of-the-fitted and sheds a new light on the mechanism of evolution. Evolutionary autoencoding renders evolution amenable to new approaches to computer modeling.
... In return, fungi behave as skilled root extensions that explore and interact formidably with soil, nurturing and protecting their host. Furthermore, the exploring mycelium of the fungi can associate with several other trees simultaneously, enabling forest trees to physically link together and establish complex below-ground communication networks (Molina and Horton 2015;Simard 2018). In Pewen trees, studies have shown a high degree of mycorrhizal fungal colonization on their roots (Diehl and Despite that mycorrhizal networks in Pewen forests have not been explored in detail, the formation of a common mycelium that links trees within and between species has been reported for temperate forests elsewhere (Smith and Read 2010). ...
... The nutrient exchange mutualism between arbuscular mycorrhizal fungi (AMFs) and their host plants qualifies as a biological market [62,41,74,73]. ...
Fungal organisms can perceive the outer world in a way similar to what animals sense. Does that mean that they have full awareness of their environment and themselves? Is a fungus a conscious entity? In laboratory experiments we found that fungi produce patterns of electrical activity, similar to neurons. There are low and high frequency oscillations and convoys of spike trains. The neural-like electrical activity is yet another manifestation of the fungal intelligence. In this paper we discuss fungal cognitive capabilities and intelligence in evolutionary perspective, and question whether fungi are conscious and what does fungal consciousness mean, considering their exhibiting of complex behaviours, a wide spectrum of sensory abilities, learning, memory and decision making. We overview experimental evidences of consciousness found in fungi. Our conclusions allow us to give a positive answer to the important research questions of fungal cognition, intelligence and forms of consciousness.
... Les réseaux communs de mycorhizes permettent donc les échanges longue distance entre les plantes 958 interconnectées (Bücking et al. 2016;Simard 2018). Il existe donc une zone de bénéfice net où la 959 compétition laisse place à la facilitation grâce aux mycorhizes qui connectent les arbres adultes aux survie des jeunes arbres lors de la phase de régénération (Coll et al. 2003). ...
A better understanding of plant interactions would improve the management of natural and artificial forest regeneration. It is well established that Molinia (Molinia caerulea), a monopolist species of understory, has a particularly depressive effect on young sessile oak (Quercus petraea) establishment and growth. Large capacity of Molinia in water and soil nutrients uptake leads to strong competition by resources exploitation. However, it seems that other interactions are involved in the relationship between young oak and Molinia. Thus, the allelopathic properties of Molinia have been suggested, but no study has shown such an effect on oak. Inversely, young oak seems to facilitate Molinia growth. Oak-Molinia interaction thus has the singularity of being antagonistic: the Molinia inhibits oak growth while this one favors grass growth, but the mechanisms involved are not entirely known. The aim of this thesis was to analyze the functional and ecophysiological mechanisms involved in the interactions between young sessile oak and Molinia. The experiments carried out in the thesis show that (i) oak quickly transfers nitrogen to Molinia by the underground pathways (rhizodeposition of nitrogen compounds in the soil) favoring grass growth, (ii) Molinia presence in the same pot leads to a decrease in the lateral root rate and ectomycorhization rate of oak and (iii) Molinia rhizodeposes secondary metabolites different from those of oak and have an allelopathic potential. In line with current work, the thesis puts into perspective that the chemical compounds emitted by plants in the soil act as real direct or indirect signals (via the biological communities of the soil) and induce neighbors modifications in their metabolism and / or their growth.
... Chemical cues can be conveyed through the mycorrhizal network, as can allelopathic substances ( mycorrhizal fungi may convey allelopathic compounds, whose negative effect may undo the benefit of the N supply (Barto et al., 2011;Gorzelak et al., 2015). The mycorrhizal network can be used by plants to transfer N compounds to a neighbour (He et al., 2019;Simard, 2018), which may be beneficial at least for one plant partner in the network (Figure 1, circle 3). Teste et al. (2015) showed that a plant can transfer up to 4% of its N to another plant through the mycorrhizal network. ...
The nitrogen (N) economics of plants are generally described in terms of functional traits and how these affect N availability in a given environment. However, recent studies have shown that plant symbionts play a crucial role in plant N economics. A plant together with its symbiont can be considered as a meta‐organism, the holobiont. Plant‐associated symbionts are shaped by the plant, thereby extending the plant’s phenotype. Decomposers also play an important role in plant N economics yet are usually not included in the plant holobiont. ▪In this review, we show the important roles that both symbionts and decomposers play in plant N economics. We focus on how plants respond to fluctuating N availability in a complex interaction network, which includes the plant’s strategies and its interactions and feedback loops with the soil biota and with neighbouring plants, through competition for N by exploitation and interference. ▪Synthesis: Plant N economics and the outcome of plant‐plant interactions in a community cannot be fully described solely through the functional traits of plant individuals. Properties emerging from the interaction network bring new insights into plant N economics. Further research is now needed to gain a deeper understanding of plant N economics and resource economics in plant communities by integrating a broader extended plant phenotype.
... The prioritization of certain nonhumans' rights over others (e.g., cattle over trees) has also created immense tensions between human stakeholders as ecosystems are frequently denied welfare, rights, and agency in the U.S., especially under the Trump Administration. Trees have demonstrated mycelium networks which contribute to learning and memory (Simard, 2018;Piñuela et al., 2021). Nimble policy frameworks must account for flora such as trees to be understood as living individuals with extensive movement and communication that extends throughout nearby habitat and greater ecosystems. ...
Ecosystem governance is a highly contested issue where competing human stakeholder groups wield unequal power over nonhuman species. Pluralistic approaches to ecosystem governance consider a diversity of voices and disciplines to apply translational ecological knowledge to policy. However, the rights, agency, and welfare of nonhuman species – at the abstract (macro) and individual (micro) levels – are rarely considered, distancing nonhumans from human interests. This ‘othering’, results in nonhumans being treated as subservient to humans in power relations, which can result in poor welfare and even death. This study draws on multispecies ethnography, posthumanism, multispecies livelihoods, decolonial ecology, and translational ecology literature to critically review current paradigms in ecosystem governance and questions how to represent nonhumans equitably in ecosystem governance. This essay also considers qualitative data collected during 15 months of a multi-sited, multispecies ethnographic study that explored wolf-human (Canis lupus) relations in the western United States during the Trump Administration. A pluralistic posthumanist wildlife-human coexistence framework for translational ecology is presented that emphasizes nonhumans’ rights, welfare, and agency in ecosystem governance.
Forests are now universally thought of as Complex Adaptive Systems. The adaptive capacity of these ecosystems is directly proportional to their resistance, resilience and adaptability/plasticity. These attributes are, in turn, a function of the degree of biocomplexity (compositional, structural and functional/relational) obtained by the system itself. Because a forest can reach a high level of complexity, an adequate three-dimensional physical space and a very long time span must be ensured. Managed forests are often limited in surface (due to physical or ecological fragmentation) and in height (due to too early and intense cuts, which does not allow the canopy to occupy all the available biospace) making them more simplified and therefore less resilient. As regards time, the diversity between human time and forest time is not often taken into account, attempting to accelerate, in an unnatural way, the growth and succession of the structural phases. Speed is the enemy of complexity, especially relational complexity, on which the ability of forests to respond to external disturbances is based. Global change and the new challenges for the planet’s future require a decisive change in the criteria and methods of forest management, also considering the great value of ecosystems left to undisturbed natural evolution.
Doğanın sağladığı ürün ve hizmetler, hayatımızı her alanda doğrudan veya dolaylı olarak etkiler. Bu konunun önemi, eskiden beri bilinse de ekosistem hizmetleri konusundaki farkındalık son dönemde
artmıştır. Sürdürülebilir orman yönetiminde orman ekosistemlerinin planlanması ve yönetimi en önemli konulardan biri haline gelmiştir.
Bu bölümde orman ekosistem hizmetlerinin önemi, dünyadan ve ülkemizden planlama ve yönetim deneyimleri anlatılmıştır.
Kitabın tümünü DKM internet sitesinden indirebilirsiniz: http://www.dkm.org.tr/Dosyalar/YayinDosya_VareNtJy.pdf
Research that combines approaches from cognitive psychology and integrative biology has indicated that human learning and memory have been selected through evolutionary processes that enable growth, survival and reproduction through the interaction of the centralised nervous system with the environment.
Science fiction (SF), through its various generic conventions, provides a stage for exploring many dimensions of the Anthropocene: It enables challenges to time, to species, to causalities, to space-time coherences, and also to singularity. Tade Thompson’s- Wormwood trilogy engages several non-linear metaphors in engendering a nonhuman other, most specifically internet networks and fungi becoming. The alien sentience rendered in the trilogy offers an – amorphous and yet simultaneously very concrete – other against which humans must rally, themselves at the brink of the threat of extinction. Wormwood’s xenosphere – an atmosphere permeated with ›xenoforms‹, a kind of alien fungi which can interact with humans – constitutes only one of the many ways in which this SF world challenges the modes with which we organise our knowledges of our world.
Background: Microbiome-Inspired Green Infrastructure (MIGI) was recently proposed as an integrative system to promote healthy urban ecosystems, through multidisciplinary design. Specifically, MIGI is defined as nature-centric infrastructure restored and/or designed and managed to enhance health-promoting interactions between humans and environmental microbiomes, whilst sustaining microbially-mediated ecosystem functionality and resilience. MIGI also aims to stimulate a research agenda that focuses on considerations for the importance of urban environmental microbiomes.
Objectives: In this paper we provide details of what MIGI entails from a bioscience and biodesign perspective, highlighting the potential dual benefits for human and ecosystem health. We present ‘what is known’ about the relationship between urban microbiomes, green infrastructure and environmental factors that may affect urban ecosystem health (ecosystem functionality and resilience as well as human health). We discuss how to start operationalising the MIGI concept based on current available knowledge, and present a horizon scan of emerging and future considerations in research and practice. We conclude by highlighting challenges to the implementation of MIGI and propose a series of workshops to discuss multi-stakeholder needs and opportunities.
Discussion: This article will enable urban landscape managers to incorporate initial considerations for the microbiome in their development projects to promote human and ecosystem health. However, overcoming the challenges to operationalising MIGI will be essential to furthering its practical development. Although the research is in its infancy, there is considerable potential for MIGI to help deliver sustainable urban development driven by considerations for reciprocal relations between humans and the foundations of our ecosystems –– the microorganisms.
Plants are living information-processing organisms with highly adaptive behavior, allowing them to prosper in a harsh and fluctuating environment in spite of being sessile. Lacking a central nervous system, plants are distributed systems orchestrating complex computational processes performed at the tissue level. Here I consider plant tropisms as a useful input-output system boasting a robust mathematical description, naturally permitting a dialogue between mathematical modeling and biological observations. I propose tropisms as an ideal framework for the study of plant computational processes, allowing us to infer the relationship between observed tropic responses and known stimuli. I concentrate on macroscopic models, and elucidate this approach by presenting recent examples focusing on computational processes involved at different hierarchical levels of interactions: a plant's interaction with itself and its internal state, with the abiotic environment, and with neighboring plants.
This is a technical treatise for the scientific-minded readers trying to expand their intellectual horizon beyond the straitjacket of materialism. It is dedicated to those scientists and philosophers who feel there is something more, but struggle with connecting the dots into a more coherent picture supported by a way of seeing that allows us to overcome the present paradigm and yet maintains a scientific and conceptual rigor, without falling into oversimplifications. Most of the topics discussed are unknown even to neuroscientists, biologists, philosophers, and yet are based on the findings published in their own mainstream peer reviewed literature or on deep insights of the scientific, philosophical and spiritual giants of the past.
A scientific, philosophical, and spiritual overview of the relationship between science and spirituality, neuroscience and the mystery of consciousness, mind and the nature of reality, evolution and life. A plaidoyer for a science that goes beyond the curve of reason and embraces a new synthesis of knowledge. The overcoming of the limitations of the intellect into an extended vision of ourselves and Nature. A critique of physicalism, the still-dominant doctrine that believes that all reality can be reduced to matter and the laws of physics alone. A review and reassessment of the old and new philosophical and metaphysical ideas which attempts to bring closer Western and Eastern traditions where science, philosophy, consciousness, Spirit and Nature are united in a grand vision that transcends the limited conventional scientific and philosophical paradigm. A possible answer to the questions of purpose and meaning and the future evolution of humankind beyond a conception that posits a priori a purposeless and meaningless universe. A report of the new scientific discoveries of a basal intelligence in cells and plants, on the question if mind is computational, the issue of free will, the mind-body problem, and the so called ‘hard problem of consciousness’. An essay on ancient as modern philosophical conceptions, from the One of Plotinus, the God of Spinoza until the recent revival of panpsychism or the universal consciousness. A journey into quantum physics from the perspective of philosophical idealism and an invitation to adopt new ways of seeing that might help us to transform our present understanding, expanding it into an integral cosmology, with a special emphasis on the spiritual and evolutionary cosmology of the Indian seer Sri Aurobindo.
Not just a philosophical and metaphysical meditation but, rather, an appeal to work towards a change of consciousness, a widening of our perspective towards a new way of seeing beyond a purely mechanistic worldview to avoid a social, environmental and economic collapse. Humans are transitional beings that will have to make a choice: relapse into a pre-rational state or evolve towards a new trans-rational species supported by an ideal of human unity in diversity as the expression of a spiritual evolutionary process, the call of the Spirit on Nature.
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Recent studies in biology, ecology, and medicine make it clear that relationships between living organisms are complex and comprise different forms of collaboration and communication in particular in getting food. It turns even out that relations of collaboration and valuing are more important than those of aggression and predation. I will outline the ways organisms select and value specific items in their network of living and non-living entities. No organism eats everything; all organisms prefer certain foods, companions, and habitats. Relations between organisms are established on the basis of communication, exchange of signs, actions and goods, through mutual learning processes on all levels of life. Micro, meso and macro organisms participate in this process of valuing and communication. Animals and plants therefore show features that were traditionally attributed only to humans, like selfless assistance. The usual distinction between humans and other living beings on the basis of human’s sensitivity for altruism, language and values crumbles down due to the circumstance that also non-human living beings are prone to selfless assistance, communication and valuing.
Under natural conditions, plants are always associated with a well-orchestrated community of microbes—the phytomicrobiome. The nature and degree of microbial effect on the plant host can be positive, neutral, or negative, and depends largely on the environment. The phytomicrobiome is integral for plant growth and function; microbes play a key role in plant nutrient acquisition, biotic and abiotic stress management, physiology regulation through microbe-to-plant signals, and growth regulation via the production of phytohormones. Relationships between the plant and phytomicrobiome members vary in intimacy, ranging from casual associations between roots and the rhizosphere microbial community, to endophytes that live between plant cells, to the endosymbiosis of microbes by the plant cell resulting in mitochondria and chloroplasts. If we consider these key organelles to also be members of the phytomicrobiome, how do we distinguish between the two? If we accept the mitochondria and chloroplasts as both members of the phytomicrobiome and the plant (entrained microbes), the influence of microbes on the evolution of plants becomes so profound that without microbes, the concept of the “plant” is not viable. This paper argues that the holobiont concept should take greater precedence in the plant sciences when referring to a host and its associated microbial community. The inclusivity of this concept accounts for the ambiguous nature of the entrained microbes and the wide range of functions played by the phytomicrobiome in plant holobiont homeostasis.
Due to ongoing climate change, forests are expected to face significant disturbances more frequently than in the past. Appropriate management is intended to facilitate forest regeneration. Because European temperate forests mostly consist of trees associated with ectomycorrhizal (ECM) fungi, understanding their role in these disturbances is important to develop strategies to minimize their consequences and effectively restore forests. Our aim was to determine how traditional (EXT) and nonintervention (NEX) management in originally Norway spruce (Picea abies) forests with an admixture of European larch (Larix decidua) affect ECM fungal communities and the potential to interconnect different tree species via ECM networks 15 years after a windstorm. Ten plots in NEX and 10 plots in EXT with the co-occurrences of Norway spruce, European larch, and silver birch (Betula pendula) were selected, and a total of 57 ECM taxa were identified using ITS sequencing from ECM root tips. In both treatments, five ECM species associated with all the studied tree species dominated, with a total abundance of approximately 50% in the examined root samples. Because there were no significant differences between treatments in the number of ECM species associated with different tree species combinations in individual plots, we concluded that the management type did not have a significant effect on networking. However, management significantly affected the compositions of ECM symbionts of Norway spruce and European larch but not those of silver birch. Although this result is explained by the occurrence of seedlings and ECM propagules that were present in the original forest, the consequences are difficult to assess without knowledge of the ecology of different ECM symbionts.
The sugar maple (Acer saccharum) is one of the most emblematic plants and symbols of Canada. It is especially important in the province of Québec that produces approximately three quarters of the world’s prized maple syrup. Articulating ways of questioning from biosemiotics and the ecological humanities, I will reflect on the manner in which feeding and caring play out in the concrete, situated practice that is maple sugaring. Doing so, I will address three points: the expression of semiosis in forests, husbandry in the maple stand and the production of syrup, and finally caring relationships involving humans and trees. Maple sugaring thus appears replete with (bio)semiosis, mind networks that grow through and among bodies.
Mechanically programmable, reconfigurable micro/nanoscale materials that can dynamically change their mechanical properties or behaviors, or morph into distinct assemblies or swarms in response to stimuli have greatly piqued the interest of the science community due to their unprecedented potentials in both fundamental research and technological applications. To date, a variety of designs of hard and soft materials, as well as actuation schemes based on mechanisms including chemical reactions and magnetic, acoustic, optical, and electric stimuli, have been reported. Herein, state‐of‐the‐art micro/nanostructures and operation schemes for multimodal reconfigurable micro/nanomachines and swarms, as well as potential new materials and working principles, challenges, and future perspectives are discussed. State‐of‐the‐art micro/nanomaterials and schemes for multimodal reconfigurable micro/nanomachines, their dynamic assemblies, and swarming/collective behaviors are reviewed. Potential new materials and working principles are discussed along with the challenges and perspectives.
The 2019–2020 Victorian bushfires have had wide-ranging impacts on the state’s biodiversity, including to populations of threatened species (DELWP 2020). There has been no formal assessment of the impacts to cryptogam species; namely the bryophytes (mosses, liverworts, hornworts), freshwater algae and fungi (including lichens).
A workshop was conducted on 12th March 2020 to prioritise conservation actions that are deemed necessary in the context of impacts to cryptogams caused by the fires. Actions have been identified as short-term and longer-term with consideration to threats and other factors, such as data deficiencies which hamper the ability to prioritise conservation actions.
A review of database information for the bushfire extent boundary revealed 52 bryophyte taxa that are state advisory listed and confirmed as having suitable habitat which was impacted. For other groups, the total number of all taxa (rare, threatened or otherwise) included 47 algae and 134 fungi / lichens. These have been ranked as high, medium or low priority to assist in formulating actions.
Actions proposed include recommendations for broader programs on cryptogam conservation, as well as targeted assessments of high priority species which have likely been impacted by the fires. We have made conservative estimates of investment required across all groups within the next 1–2 years of $892,000 with further investment required in 3–5 years of $888,000–1,279,000. This investment aims to provide a coordinated approach to better understand impacts to a very large number of cryptogam species caused by catastrophic bushfire events, climate change and associated threats. Shorter fire intervals is noted in particular as a likely substantial threat for many species. Such information is critical for achieving Victoria’s biodiversity management objectives.
Soft robotics aims at creating systems with improved performance of movement and adaptability in unknown, challenging, environments and with higher level of safety during interactions with humans. This Roadmap on Soft Robotics covers selected aspects for the design of soft robots significantly linked to the area of multifunctional materials, as these are considered a fundamental component in the design of soft robots for an improvement of their peculiar abilities, such as morphing, adaptivity and growth. The roadmap includes different approaches for components and systems design, bioinspired materials, methodologies for building soft robots, strategies for the implementation and control of their functionalities and behaviour, and examples of soft-bodied systems showing abilities across different environments. For each covered topic, the author(s) describe the current status and research directions, current and future challenges, and perspective advances in science and technology to meet the challenges.
More than 80% terrestrial plants establish mutualistic symbiosis with soil-borne arbuscular mycorrhizal fungi (AMF). These fungi not only significantly improve plant nutrient acquisition and stress resistance, but also mitigate heavy metal phytotoxicity, Furthermore, the extraradical mycorrhizal mycelia can form common mycorrhizal networks (CMNs) that link roots of multiple plants in a community. Here we show that the networks mediate migration of heavy metal cadmium (Cd) from maize (Zea mays L.) to soybean (Glycine max (Linn.) Merr.) plants. CMNs between maize and soybean plants were established after inoculation of maize plants with AMF Funneliformis mosseae. Application of CdCl2 in maize plants led to 64.4% increase in the shoots and 48.2% increase in the roots in Cd content in CMNs-connected soybean plants compared to the control without Cd treatment in maize. Meanwhile, although the CMNs-connected soybean plants did not directly receive Cd supply, they upregulated transcriptional levels of Cd transport-related genes HATPase and RSTK 2.13- and 5.96-fold, respectively, induced activities of POD by 44.8% in the leaves, and increased MDA by 146.2% in the roots. Furthermore, Cd addition inhibited maize growth but mycorrhizal colonization improved plant performance in presence of Cd stress. This finding demonstrates that mycorrhizal networks mediate the transfer of Cd between plants of different species, suggesting a potential to use CMNs as a conduit to transfer toxic heavy metals from main food crops to heavy metal hyperaccumulators via intercropping.
Background: Microbiome-Inspired Green Infrastructure (MIGI) was recently proposed as an integrative system to promote healthy urban ecosystems, through multidisciplinary design. Specifically, MIGI is defined as nature-centric infrastructure restored and/or designed and managed to enhance health-promoting interactions between humans and environmental microbiomes, whilst sustaining microbially-mediated ecosystem functionality and resilience. MIGI also aims to stimulate a research agenda that focuses on considerations for the importance of urban environmental microbiomes. Objectives: In this paper we provide details of what MIGI entails from a bioscience and biodesign perspective, highlighting the potential dual benefits for human and ecosystem health. We present ‘what is known’ about the relationship between urban microbiomes, green infrastructure and environmental factors that may affect urban ecosystem health (ecosystem functionality and resilience as well as human health). We discuss how to start operationalising the MIGI concept based on current available knowledge, and present a horizon scan of emerging and future considerations in research and practice. We conclude by highlighting challenges to the implementation of MIGI and propose a series of workshops to discuss multi-stakeholder needs and opportunities. Discussion: This article will enable urban landscape managers to incorporate initial considerations for the microbiome in their development projects to promote human and ecosystem health. However, overcoming the challenges to operationalising MIGI will be essential to furthering its practical development. Although the research is in its infancy, there is considerable potential for MIGI to help deliver sustainable urban development driven by considerations for reciprocal relations between humans and the foundations of our ecosystems –– the microorganisms.
Plants play a more active role in shaping their environment than most climate models assume. Understanding their specific behavior could have profound impact on predicting future climate changes.
An enduring aim of research in the psychological and brain sciences is to understand the nature of individual differences in human intelligence, examining the stunning breadth and diversity of intellectual abilities and the remarkable neurobiological mechanisms from which they arise. In this Opinion article, we survey recent neuroscience evidence to elucidate how general intelligence (g) emerges from individual differences in the network architecture of the human brain. The reviewed findings motivate new insights about how network topology and dynamics account for individual differences in g, represented by the Network Neuroscience Theory. According to this framework, g emerges from the small-world topology of brain networks and the dynamic reorganization of its community structure in the service of system-wide flexibility and adaptation.
Sound and its use in communication have significantly contributed to shaping the ecology, evolution, behavior, and ultimately
the success of many animal species. Yet, the ability to use sound is not a prerogative of animals. Plants may also use sound,
but we have been unable to effectively research what the ecological and evolutionary implications might be in a plant’s life.
Why should plants emit and receive sound and is there information contained in those sounds? I hypothesize that it would be
particularly advantageous for plants to learn about the surrounding environment using sound, as acoustic signals propagate
rapidly and with minimal energetic or fitness costs. In fact, both emission and detection of sound may have adaptive value
in plants by affecting responses in other organisms, plants, and animals alike. The systematic exploration of the functional,
ecological, and evolutionary significance of sound in the life of plants is expected to prompt a reinterpretation of our understanding
of these organisms and galvanize the emergence of novel concepts and perspectives on their communicative complexity.
Processes governing the fixation, partitioning, and mineralization of carbon in soils are under increasing scrutiny as we develop a more comprehensive understanding of global carbon cycling. Here we examined fixation by Douglas-fir seedlings and transfer to associated ectomycorrhizal fungi, soil microbes, and full-sibling or nonsibling neighbouring seedlings. Stable isotope probing with 99% (13) C-CO2 was applied to trace (13) C-labelled photosynthate throughout plants, fungi, and soil microbes in an experiment designed to assess the effect of relatedness on (13) C transfer between plant pairs. The fixation and transfer of the (13) C label to plant, fungal, and soil microbial tissue was examined in biomass and phospholipid fatty acids. After a 6 d chase period, c. 26.8% of the (13) C remaining in the system was translocated below ground. Enrichment was proportionally greatest in ectomycorrhizal biomass. The presence of mesh barriers (0.5 or 35 μm) between seedlings did not restrict (13) C transfer. Fungi were the primary recipients of (13) C-labelled photosynthate throughout the system, representing 60-70% of total (13) C-enriched phospholipids. Full-sibling pairs exhibited significantly greater (13) C transfer to recipient roots in two of four Douglas-fir families, representing three- and fourfold increases (+ c. 4 μg excess (13) C) compared with nonsibling pairs. The existence of a root/mycorrhizal exudation-hyphal uptake pathway was supported.
The establishment of common mycelial networks by mycorrhizal fungi shared between host plants depends on the ability of neighboring plants to enter into mycorrhizal associations with compatible fungal species. Such compatibility is governed by the potential mycorrhiza specificities of the symbionts. Mycorrhiza specificities exist along a continuum from low specificity (association with multiple partners) to high specificity (association with one or few partners). Although the ability of symbionts to form mycorrhizas may be largely governed by host-fungus gene interactions as influenced by co-evolutionary events, mycorrhizal associations in natural ecosystems can also be influenced by environmental factors (e.g. soil) and biological factors (e.g. different neighboring host species), phenomena referred to as “ecological specificity.” For example, in natural settings, mycorrhizal fungi often express “host preference” wherein fungi may be more common on a particular host in mixed-host settings than would be expected by random species assemblage within the fungal and plant communities. Mycorrhiza specificity phenomena significantly influence plant community dynamics, particularly plant succession. Early seral plants can positively affect the establishment of later-seral plants by maintaining commonly shared mycorrhizal fungi, and thus affecting the function of common mycelial networks over time. Such knowledge provides guidance for ecosystem managers to maintain “legacy” early -seral plants that benefit later-seral plants via shared mycorrhizal fungus species. Understanding specificity phenomena is also crucial for predicting the successful migration of plants and compatible mycorrhizal fungi during climate change. We review mycorrhiza specificity terminology and types of specificity phenomena, and suggest use of common terms to provide consistency in addressing this research topic. We also provide extensive examples from diverse ecosystems on the ability (or inability) of neighboring plants to develop common mycelial networks.
Almost all higher organisms, including plants, insects, and mammals, are colonized by complex microbial communities and harbor a microbiome. Emerging studies with plants reveal that these microbiomes are structured and form complex, interconnected microbial networks. Within these networks, different taxa have different roles, and keystone species have been identified that could be crucial for plant health and ecosystem functioning. A new paper in this issue of PLOS Biology by Agler et al. highlights the presence of microbial hubs in these networks that may act as mediators between the plant and its microbiome. A next major frontier is now to link microbiome composition to function. In order to do this, we present a number of hypothetical examples of how microbiome diversity and function potentially influence host performance.
Language is often considered a key feature of being human, and human linguistic behavior has been adopted as the universal template for studying the nature of language and its evolution. Yet it is not always clear what ''language'' actually is, and the lack of definition calls into question the notion that human language is unique because it has no equivalent in any nonhuman species. We ask whether the use of language is truly an activity, a form of behavior, which makes us so unique and unlike other species. We tackle this question by examining language from an ecological perspective and then considering language from a wider biological viewpoint, one that enables us to explore language as a meaning-making activity at the core of every form of life, including plants. We examine how innovative philosophical thinking and scientific research similarly call into question the current limits of language in describing the botanical world and human-plant dynamics. By providing an overview of the most recent empirically grounded advances in our understanding of the ''language'' of others, and particularly plants, we propose that the nonhuman world is not lacking in language the way we think it is. Ultimately, the overall aim is to invite the emergence of a new truly interdisciplinary dialogue to inspire novel approaches in further philosophical and scientific investigations, where language and its power are re-focused toward conceptualizing a more integrated perception of the world.
Adaptive behavior of plants, including rapid changes in physiology, gene regulation and defense response can be altered when linked to neighbouring plants by a mycorrhizal network. Mechanisms underlying the behavioral changes include mycorrhizal fungal colonization by the mycorrhizal network or interplant communication via transfer of nutrients, defense signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, but also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioral changes in ectomycorrhizal plants can depend on environmental cues, the identity of the plant neighbor and the characteristics of the mycorrhizal network. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicates that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems.
Published by Oxford University Press on behalf of the Annals of Botany Company.
Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts living in the roots of 80% of land plant species, and developing extensive, belowground extraradical hyphae fundamental for the uptake of soil nutrients and their transfer to host plants. Since AM fungi have a wide host range, they are able to colonize and interconnect contiguous plants by means of hyphae extending from one root system to another. Such hyphae may fuse due to the widespread occurrence of anastomoses, whose formation depends on a highly regulated mechanism of self recognition. Here, we examine evidences of self recognition and nonself incompatibility in hyphal networks formed by AM fungi and discuss recent results showing that the root systems of plants belonging to different species, genera and families may be connected by means of anastomosis formation between extraradical mycorrhizal networks, which can create indefinitely large numbers of belowground fungal linkages within plant communities.
Extensive regions of interior Douglas-fir (Pseudotsuga menziesii var. glauca, IDF) forests in North America are being damaged by drought and western spruce budworm (Choristoneura occidentalis). This damage is resulting from warmer and drier summers associated with climate change. To test whether defoliated IDF can directly transfer resources to ponderosa pine (Pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme response. We grew pairs of ectomycorrhizal IDF 'donor' and ponderosa pine 'receiver' seedlings in pots and isolated transfer pathways by comparing 35 μm, 0.5 μm and no mesh treatments; we then stressed IDF donors either through manual defoliation or infestation by the budworm. We found that manual defoliation of IDF donors led to transfer of photosynthetic carbon to neighboring receivers through mycorrhizal networks, but not through soil or root pathways. Both manual and insect defoliation of donors led to increased activity of peroxidase, polyphenol oxidase and superoxide dismutase in the ponderosa pine receivers, via a mechanism primarily dependent on the mycorrhizal network. These findings indicate that IDF can transfer resources and stress signals to interspecific neighbors, suggesting ectomycorrhizal networks can serve as agents of interspecific communication facilitating recovery and succession of forests after disturbance.
1.From the phytocentric perspective, a mycorrhizal network (MN) is formed when the roots of two or more plants are colonized by the same fungal genet. MNs can be modelled as interaction networks with plants as nodes and fungal genets as links. The potential effects of MNs on facilitation or competition between plants are increasingly recognized, but their network topologies remain largely unknown. This information is needed to understand the ecological significance of MN functional traits.2.The objectives of this study were to describe the interaction network topologies of MNs formed between two ectomycorrhizal fungal species, Rhizopogon vesiculosus and R. vinicolor, and interior Douglas-fir trees at the forest stand scale, identify factors leading to this structure and to contrast MN structures between forest plots with xeric versus mesic soil moisture regimes.3.Tuberculate mycorrhizas were sampled in six 10 x 10 m plots with either xeric or mesic soil moisture regimes. Microsatellite DNA markers were used to identify tree and fungal genotypes isolated from mycorrhizas and for comparison with reference tree boles above-ground.4.In all six plots, trees and fungal genets were highly interconnected. Size asymmetries between different tree cohorts led to non-random MN topologies, while differences in size and connectivity between Rhizopogon species-specific sub-network components contributed towards MN nestedness. Large mature trees acted as network hubs with a significantly higher node degree compared to smaller trees. MNs representing trees linked by R. vinicolor genets were mostly nested within larger, more highly connected R. vesiculosus-linked MNs.5.Attributes of network nodes showed that hub trees were more important to MN topology on xeric than mesic sites, but the emergent structures of MNs were similar in the two soil moisture regimes.6.Synthesis: This study suggests MNs formed between interior Douglas-fir trees and R. vesiculosus and R. vinicolor genets are resilient to the random loss of participants, and to soil water stress, but may be susceptible to the loss of large trees or fungal genets. Our results regarding the topology of MNs contribute to the understanding of forest stand dynamics and the resilience of forests to stress or disturbance.This article is protected by copyright. All rights reserved.
The most common system responses attributed to microfloral grazers (protozoa, nematodes, microarthropods) in the literature are increased plant growth, increased N uptake by plants, decreased or increased bacterial populations, increased CO"2 evolution, increased N and P mineralization, and increased substrate utilization. Based on this evidence in the literature, a conceptual model was proposed in which microfloral grazers were considered as separate state variables. To help evaluate the model, the effects of microbivorous nematodes on microbial growth, nutrient cycling, plant growth, and nutrient uptake were examined with reference to activities within and outside of the rhizosphere. Blue grama grass (Bouteloua gracilis) was grown in gnotobiotic microcosms containing sandy loam soil low in inorganic N, with or without chitin amendments as a source of organic N. The soil was inoculated with bacteria (Pseudomonas paucimobilis or P. stutzeri) or fungus (Fusarium oxysporum), with half the bacterial microcosms inoculated with bacterial-feeding nematodes (Pelodera sp. or Acrobeloides sp.) and half the fungal microcosms inoculated with fungal-feeding nematodes (Aphelenchus avenae). Similar results were obtained from both the unamended and the chitin-amended experiments. Bacteria, fungi, and both trophic groups of nematodes were more abundant in the rhizosphere than in nonrhizosphere soil. All treatments containing nematodes and bacteria had higher bacterial densities than similar treatments without nematodes. Plants growing in soil with bacteria and bacterial-feeding nematodes grew faster and initially took up more N than plants in soil with only bacteria, because of increased N mineralization by bacteria, NH"4^+-N excretion by nematodes, and greater initial exploitation of soil by plant roots. Addition of fungal-feeding nematodes did not increase plant growth or N uptake because these nematodes excreted less NH"4^+-N than did bacterial-feeding nematode populations and because the N mineralized by the fungus alone was sufficient for plant growth. Total shoot P was significantly greater in treatments with fungus or Pelodera sp. than in the sterile plant control or treatments with plants plus Pseudomonas stutzeri until the end of the experiment. The additional mineralization that occurs due to the activities of microbial grazers may be significant for increasing plant growth only when mineralization by microflora alone is insufficient to meet the plants' requirements. However, while the advantage of increased N mineralization by microbial grazers may be short-term, it may occur in many ecosystems in those short periods of ideal conditions when plant growth can occur. Thus, these results support other claims in the literature that microbial grazers may perform important regulatory functions at critical times in the growth of plants.
I. II. III. IV. V. VI. References SUMMARY: For survival, plants have to efficiently adjust their phenotype to environmental challenges, finely coordinating their responses to balance growth and defence. Such phenotypic plasticity can be modulated by their associated microbiota. The widespread mycorrhizal symbioses modify plant responses to external stimuli, generally improving the resilience of the symbiotic system to environmental stresses. Phytohormones, central regulators of plant development and immunity, are instrumental in orchestrating plant responses to the fluctuating environment, but also in the regulation of mycorrhizal symbioses. Exciting advances in the molecular regulation of phytohormone signalling are providing mechanistic insights into how plants coordinate their responses to environmental cues and mycorrhizal functioning. Here, we summarize how these mechanisms permit the fine-tuning of the symbiosis according to the ever-changing environment.
© 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
It is increasingly recognised that plants are highly sensitive organisms that perceive, assess, learn, remember, resolve problems, make decisions and communicate with each other by actively acquiring information from their environment. However, the fact that many of the sophisticated behaviours plants exhibit reveal cognitive competences, which are generally attributed to humans and some non-human animals has remained unappreciated. Here, I will outline the theoretical barriers that have precluded the opportunity to experimentally test such behavioural/cognitive phenomena in plants. I will then suggest concrete alternative approaches to cognition by highlighting how (1) the environment offers a multitude of opportunities for decision-making and action and makes behaviours possible, rather than causing them; (2) perception in itself is action in the form of a continuous flow of information; (3) all living organisms viewed within this context become agents endowed with autonomy rather than objects in a mechanistically conceived world. These viewpoints, combined with recent evidence, may contribute to move the entire field towards an integrated study of cognitive biology.
Published by Oxford University Press on behalf of the Annals of Botany Company.
Plant-mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant-fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant-fungal symbiosis in subtropical forests is complex in that it includes "non-typical" plant-fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in that associations with multiple functional (or phylogenetic) groups of fungi are ubiquitous among plants. Moreover, ectomycorrhizal fungal symbionts of fagaceous plants may "invade" the roots of neighboring non-fagaceous plants, potentially influencing the interactions between non-fagaceous plants and their arbuscular-mycorrhizal fungal symbionts at a fine spatial scale.
Mycelial fungi grow as indeterminate adaptive networks that have to forage for scarce resources in a patchy and unpredictable environment under constant onslaught from mycophagous animals. Development of contrast-independent network extraction algorithms has dramatically improved our ability to characterise these dynamic macroscopic networks and promises to bridge the gap between experiments in realistic experimental microcosms and graph-theoretic network analysis, greatly facilitating quantitative description of their complex behaviour. Furthermore, using digitised networks as inputs, empirically-based minimal biophysical mass-flow models already provide a high degree of explanation for patterns of long-distance radiolabel movement, and hint at global control mechanisms emerging naturally as a consequence of the intrinsic hydraulic connectivity. Network resilience is also critical to survival and can be explored both in silico by removing links in the digitised networks according to particular rules, or in vivo by allowing different mycophagous invertebrates to graze on the networks. Survival depends on both the intrinsic architecture adopted by each species and the ability to reconnect following damage. It is hoped that a comparative approach may yield useful insights into not just fungal ecology, but also biologically inspired rules governing the combinatorial trade-off between cost, transport efficiency, resilience and control complexity for self-organised adaptive networks in other domains.
Ectomycorrhizal (EM) networks are hypothesized to facilitate regeneration under abiotic stress. We tested the role of networks in interactions between P. menziesii var. glauca trees and conspecific seedlings along a climatic moisture gradient to: (1) determine the effects of climatic factors on network facilitation of Pseudotsuga menziesii (Mirb.) Franco var. glauca (Mayr) seedling establishment, (2) infer the changing importance of P. menziesii var. glauca parent trees in conspecific regeneration with climate, and (3) parse the competitive from facilitative effects of P. menziesii var. glauca trees on seedlings. When drought conditions were greatest, seedling growth increased when seedlings could form a network with trees in the absence of root competition, but was reduced when unable to form a network. Survival was maximized when seedlings were able to form a network in the absence of root competition. Seedling stem natural abundance δ13C increased with drought due to increasing water use efficiency, but was unaffected by distance from tree or network potential. We conclude that P. menziesii seedlings may benefit from the presence of established P. menziesii trees when growing under climatic drought, but that this benefit is contingent upon the establishment of an EM network prior to the onset of summer drought. These results suggest that networks are an important mechanism for EM plants establishing in a pattern consistent with the stress-gradient hypothesis, and therefore the importance of EM networks to facilitation in regeneration of EM trees is expected to increase with drought.
In the course of plant evolution, there is an obvious trend toward an increased complexity of plant bodies, as well as an increased sophistication of plant behavior and communication. Phenotypic plasticity of plants is based on the polar auxin transport machinery that is directly linked with plant sensory systems impinging on plant behavior and adaptive responses. Similar to the emergence and evolution of eukaryotic cells, evolution of land plants was also shaped and driven by infective and symbiotic microorganisms. These microorganisms are the driving force behind the evolution of plant synapses and other neuronal aspects of higher plants; this is especially pronounced in the root apices. Plant synapses allow synaptic cell-cell communication and coordination in plants, as well as sensory-motor integration in root apices searching for water and mineral nutrition. These neuronal aspects of higher plants are closely linked with their unique ability to adapt to environmental changes.
Mycorrhizal networks, defined as a common mycorrhizal mycelium linking the roots of at least two plants, occur in all major terrestrial ecosystems. This review discusses the recent progress and challenges in our understanding of the characteristics, functions, ecology and models of mycorrhizal networks, with the goal of encouraging future research to improve our understanding of their ecology, adaptability and evolution. We focus on four themes in the recent literature: (1) the physical, physiological and molecular evidence for the existence of mycorrhizal networks, as well as the genetic characteristics and topology of networks in natural ecosystems; (2) the types, amounts and mechanisms of interplant material transfer (including carbon, nutrients, water, defence signals and allelochemicals) in autotrophic, mycoheterotrophic or partial mycoheterotrophic plants, with particular focus on carbon transfer; (3) the influence of mycorrhizal networks on plant establishment, survival and growth, and the implications for community diversity or stability in response to environmental stress; and (4) insights into emerging methods for modelling the spatial configuration and temporal dynamics of mycorrhizal networks, including the inclusion of mycorrhizal networks in conceptual models of complex adaptive systems. We suggest that mycorrhizal networks are fundamental agents of complex adaptive systems (ecosystems) because they provide avenues for feedbacks and cross-scale interactions that lead to self-organization and emergent properties in ecosystems. We have found that research in the genetics of mycorrhizal networks has accelerated rapidly in the past 5 y with increasing resolution and throughput of molecular tools, but there still remains a large gap between understanding genes and understanding the physiology, ecology and evolution of mycorrhizal networks in our changing environment. There is now enormous and exciting potential for mycorrhizal researchers to address these higher level questions and thus inform ecosystem and evolutionary research more broadly.
Extraradical mycelia of mycorrhizal fungi are normally the "hidden half" of the symbiosis, but they are powerful underground influences upon biogeochemical cycling, the composition of plant communities, and agroecosystem functioning. Mycorrhizal mycelial networks are the most dynamic and functionally diverse components of the symbiosis, and recent estimates suggest they are empowered by receiving as much as 10% or more of the net photosynthate of their host plants. They often constitute 20%-30% of total soil microbial biomass yet are undetected by standard measures of biomass used by soil scientists and agromomists. Mycorrhizal mycelia provide extensive path- ways for carbon and nutrient fluxes through soil, often exceeding tens of metres per gram of soil. We consider the amounts of photosynthate "power" allocated to these mycelial networks and how this is used in fungal respiration, bio- mass, and growth and in influencing soil, plant, and ecosystem processes. The costs and functional "benefits" to plants linking to these networks are fungal specific and, because of variations in physiology and host specificity, are not shared equally; some plants even depend exclusively on these networks for carbon. We briefly assess the potential con- tribution of extraradical mycorrhizal mycelium to sustainable agriculture and maintenance of biodiversity and highlight technologies that promise new vistas and improved fine-scale resolution of the dynamic spatial and temporal function- ing of these networks in soil.
Understanding ectomycorrhizal fungal (EMF) community structure is limited by a lack of taxonomic resolution and autecological information. Rhizopogon vesiculosus and Rhizopogon vinicolor (Basidiomycota) are morphologically and genetically related species. They are dominant members of interior Douglas-fir (Pseudotsuga menziesii var. glauca) EMF communities, but mechanisms leading to their coexistence are unknown. We investigated the microsite associations and foraging strategy of individual R. vesiculosus and R. vinicolor genets. Mycelia spatial patterns, pervasiveness and root colonization patterns of fungal genets were compared between Rhizopogon species and between xeric and mesic soil moisture regimes. Rhizopogon spp. mycelia were systematically excavated from the soil and identified using microsatellite DNA markers. Rhizopogon vesiculosus mycelia occurred at greater depth, were more spatially pervasive, and colonized more tree roots than R. vinicolor mycelia. Both species were frequently encountered in organic layers and between the interface of organic and mineral horizons. They were particularly abundant within microsites associated with soil moisture retention. The occurrence of R. vesiculosus shifted in the presence of R. vinicolor towards mineral soil horizons, where R. vinicolor was mostly absent. This suggests that competition and foraging strategy may contribute towards the vertical partitioning observed between these species. Rhizopogon vesiculosus and R. vinicolor mycelia systems occurred at greater mean depths and were more pervasive in mesic plots compared with xeric plots. The spatial continuity and number of trees colonized by genets of each species did not significantly differ between soil moisture regimes.
The arbuscular mycorrhizal (AM) symbiosis is responsible for huge fluxes of photosynthetically fixed carbon from plants to the soil. Carbon is transferred from the plant to the fungus as hexose, but the main form of carbon stored by the mycobiont at all stages of its life cycle is triacylglycerol. Previous isotopic labeling experiments showed that the fungus exports this storage lipid from the intraradical mycelium (IRM) to the extraradical mycelium (ERM). Here, in vivo multiphoton microscopy was used to observe the movement of lipid bodies through the fungal colony and to determine their sizes, distribution, and velocities. The distribution of lipid bodies along fungal hyphae suggests that they are progressively consumed as they move toward growing tips. We report the isolation and measurements of expression of an AM fungal expressed sequence tag that encodes a putative acyl-coenzyme A dehydrogenase; its deduced amino acid sequence suggests that it may function in the anabolic flux of carbon from lipid to carbohydrate. Time-lapse image sequences show lipid bodies moving in both directions along hyphae and nuclear magnetic resonance analysis of labeling patterns after supplying ¹³C-labeled glycerol to either extraradical hyphae or colonized roots shows that there is indeed significant bidirectional translocation between IRM and ERM. We conclude that large amounts of lipid are translocated within the AM fungal colony and that, whereas net movement is from the IRM to the ERM, there is also substantial recirculation throughout the fungus.
The roots of most plants are colonized by symbiotic fungi to form mycorrhiza, which play a critical role in the capture of nutrients from the soil and therefore in plant nutrition. Mycorrhizal Symbiosis is recognized as the definitive work in this area. Since the last edition was published there have been major advances in the field, particularly in the area of molecular biology, and the new edition has been fully revised and updated to incorporate these exciting new developments. . Over 50% new material . Includes expanded color plate section . Covers all aspects of mycorrhiza . Presents new taxonomy . Discusses the impact of proteomics and genomics on research in this area.
We are re-addressing species concepts in the Rhizopogon vinicolor species complex (Boletales, Basidiomycota) using sequence data from the internal-transcribed spacer (ITS) region of the nuclear ribosomal repeat, as well as genotypic data from five microsatellite loci. The R. vinicolor species complex by our definition includes, but is not limited to, collections referred to as R. vinicolor Smith, R. diabolicus Smith, R. ochraceisporus Smith, R. parvulus Smith or R. vesiculosus Smith. Holo- and/or paratype material for the named species is included. Analyses of both ITS sequences and microsatellite loci separate collections of the R. vinicolor species complex into two distinct clades or clusters, suggestive of two biological species that subsequently are referred to as R. vinicolor sensu Kretzer et al and R. vesiculosus sensu Kretzer et al. Choice of the latter names, as well as morphological characters, are discussed.
Terrestrial fungi are commonly studied in the laboratory, growing on artificial media in which nutrients are typically homogeneously distributed and supplied in superabundance, the environment is sterile and microclimate (temperature, moisture, gaseous regime) usually relatively constant. This contrasts with the natural environment, in which: nutrients are often patchily and sparsely distributed or not readily available, because they are locked in recalcitrant material (e.g. lignin); many other organisms are encountered, including other fungi, bacteria and invertebrates; and microclimate is constantly changing, both temporally and spatially. This chapter explores the ways in which fungi cope with environmental heterogeneity. Similar situations are faced by macroorganisms and analogies are drawn. Emphasis is placed on basidiomycetes, not only because they have been studied in most detail, but because of their dominant role as decomposers and mutualistic symbionts (Boddy & Watkinson, 1995; Smith & Read, 1997) and because they are better adapted to respond to environmental heterogeneity over scales ranging from micrometres to many metres than are other fungi. Both saprotrophic and ectomycorrhizal Basidiomycota form extensive mycelial systems in woodland soil and litter, but it is the former that are the focus of this review. Saprotrophic, cord-forming Basidiomycota that ramify at the soil–litter interface, interconnecting disparate litter components, provide most examples. The key feature of these fungi that fits them for growth in environments where resources are heterogeneously distributed is that they are non-resource-unit restricted, i.e. they can grow out of one resource in search of others. © Cambridge University Press 2007 and Cambridge University Press, 2009.
Systems as diverse as genetic networks or the World Wide Web are best described as networks with complex topology. A common property of many large networks is that the vertex connectivities follow a scale-free power-law distribution. This feature was found to be a consequence of two generic mech-anisms: (i) networks expand continuously by the addition of new vertices, and (ii) new vertices attach preferentially to sites that are already well connected. A model based on these two ingredients reproduces the observed stationary scale-free distributions, which indicates that the development of large networks is governed by robust self-organizing phenomena that go beyond the particulars of the individual systems.
Rhizopogon is the largest genus of hypogeous Basidiomycota, with worldwide distribution among Pinaceae. Several Rhizopogon species are important members of ectomycorrhizal (ECM) fungal communities, contributing significantly to sporocarp productivity and ECM dominance. They occur in young and old forest stands alike and in diverse habitats. This ecological amplitude was recognized early in the twentieth century when Rhizopogon species were observed as dominant ECM fungi on Pinus in exotic plantations. Consequently, Rhizopogon has been the focus of considerable application research in forestry. The ease of culturing from sporocarps, manipulation of pure cultures of Rhizopogon and practical use of spore inoculation has made Rhizopogon a model genus to explore morphological, physiological, ecological, and symbiotic mutualisms of ECM. Nearly 200 papers have been published on Rhizopogon taxonomy, host range and specificity, ECM morphology, distribution, ecology, physiology, and applications in forestry.
Dendroctonus ponderosae has killed millions of Pinus contorta in western North America with subsequent effects on stand conditions, including changes in light intensity, needle deposition, and the composition of fungal community mutualists, namely ectomycorrhizal fungi. It is unknown whether these changes in stand conditions will have cascading consequences for the next generation of pine seedlings. To test for transgenerational cascades on pine seedlings, we tested the effects of fungal inoculum origin (beetle-killed or undisturbed stands), light intensity and litter (origin and presence) on seedling secondary chemistry and growth in a glasshouse. We also tracked survival of seedlings over two growing seasons in the same stands from which fungi and litter were collected. Fungal communities differed by inoculum origin. Seedlings grown with fungi collected from beetle-killed stands had lower monoterpene concentrations and fewer monoterpene compounds present compared with seedlings grown with fungi collected from undisturbed stands. Litter affected neither monoterpenes nor seedling growth. Seedling survival in the field was lower in beetle-killed than in undisturbed stands. We demonstrate that stand mortality caused by prior beetle attacks of mature pines have cascading effects on seedling secondary chemistry, growth and survival, probably mediated through effects on below-ground mutualisms.
© 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
Summary
1. Carbon (C), nutrients and water (H2O) have been known for five decades to flow between plants through ectomycorrhizal (EM) networks. This flux has the potential to affect plant and fungal performance and resource distribution within communities.
2. We asked two questions: 1) What are the pathways and mechanisms for C, nutrient and H2O fluxes between plants through EM networks? 2) What are the magnitude, fate and importance of C, nutrient and H2O transfer among EM plants?
3. Mycorrhizal networks provide a distinct pathway for resource fluxes among plants and mycorrhizal fungi, partitioning them away from other competing soil microbes and plant roots in the soil matrix, and potentially providing a competitive advantage (or disadvantage) for some individuals involved in the network. Carbon and nutrients flow symplastically and apoplastically through mycorrhizal symbionts, hyphae and rhizomorphs along source-sink gradients across the networking mycelia and plant community. Hydraulic redistribution from wetter to drier soil or plant pools can also be facilitated by mycorrhizal networks following water potential gradients.
4. Carbon fluxes through EM networks have been shown to supply 0-10% of autotrophic, up to 85% of partial myco-heterotrophic (MH), and 100% of fully MH plant C. This C supply has been loosely associated with increased survival and growth of autotrophic plants, but shown to be essential for survival of MH plants. Network-mediated nitrogen (N) fluxes between N2-fixing and non-N2-fixing plants have supplied up to 40% of receiver N, and this has been associated with increased plant productivity. Fluxes between non-N2-fixing plants have supplied <5% of receiver N. Hydraulic redistribution involving EM fungi has supplied up to 50% of plant water, and in some cases this has been shown as essential for plant survival, but how much of this water transfers through EM networks remains uncertain. Phosphorus transfer through EM networks has not been adequately demonstrated.
5. Overall, this review chapter shows that resource fluxes though EM networks are sufficiently large in some cases to facilitate plant establishment and growth. Resource fluxes through EM networks may thus serve as a method for interactions and cross-scale feedbacks for development of communities, consistent with complex adaptive system theory. How this may affect ecosystem stability depends on the environment.
1. Plants recognize their kin and respond to growing with relatives with changes in functional traits. Here, we integrate competition and evolutionary theory to evaluate these changes. 2. We draw parallels between the definitions and empirical measurement of competitive effect and competitive response from competition theory, and the costs and benefits of altruistic and selfish behaviours from kin selection theory. 3. Do plants compete less with relatives, as these parallels suggest? While functional traits respond to the presence of relatives or strangers, no study has directly demonstrated that plants are less competitive with siblings. 4. However, there are empirical challenges in identifying the competitive value of traits that are measured destructively, such as root allocation. 5. If these challenges can be addressed, kin recognition responses can offer new insights into plant competition.
Common mycorrhizal networks (CMNs) link multiple plants together. We hypothesized that CMNs can serve as an underground conduit for transferring herbivore-induced defence signals. We established CMN between two tomato plants in pots with mycorrhizal fungus Funneliformis mosseae, challenged a 'donor' plant with caterpillar Spodoptera litura, and investigated defence responses and insect resistance in neighbouring CMN-connected 'receiver' plants. After CMN establishment caterpillar infestation on 'donor' plant led to increased insect resistance and activities of putative defensive enzymes, induction of defence-related genes and activation of jasmonate (JA) pathway in the 'receiver' plant. However, use of a JA biosynthesis defective mutant spr2 as 'donor' plants resulted in no induction of defence responses and no change in insect resistance in 'receiver' plants, suggesting that JA signalling is required for CMN-mediated interplant communication. These results indicate that plants are able to hijack CMNs for herbivore-induced defence signal transfer and interplant defence communication.
Forest die-off caused by mountain pine beetle (MPB) is rapidly transforming western North American landscapes. The rapid and widespread death of lodgepole pine will likely have cascading effects on biodiversity. One group particularly prone to such declines associated with MPB are ectomycorrhizal fungi, symbiotic organisms that can depend on pine for their survival, and are critical for stand regeneration. We evaluated the indirect effects of MPB on above- (community composition of epigeous sporocarps) and belowground (hyphal abundance) occurrences of ectomycorrhizal fungi across 11 forest stands. Along a gradient of mortality (0-82% pine killed), macromycete community composition changed; this shift was driven by a decrease in the species richness of ectomycorrhizal fungi. Both the proportion of species that were ectomycorrhizal and hyphal length in the soil declined with increased MPB-caused pine mortality; less than 10% of sporocarp species were ectomycorrhizal in stands with high pine mortality compared with greater than 70% in stands without MPB attacks. The rapid range expansion of a native insect results not only in the widespread mortality of an ecologically and economically important pine species, but the effect of MPB may also be exacerbated by the concomitant decline of fungi crucial for recovery of these forests.