Karl J Niklas

Karl J Niklas
Cornell University | CU · Department of Plant Biology

About

534
Publications
155,139
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
26,349
Citations
Citations since 2017
114 Research Items
9758 Citations
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
Introduction
Please direct all reprint requests to kjn2@cornell.edu. I will do my best to respond to them.

Publications

Publications (534)
Article
Stomatal density (SD) is important to photosynthetic rates. However, it is time-consuming to measure SD. Here, we provide a method for estimating SD based on the scaling relationship between SD and mean nearest neighbour distance (MNND) of sampled stomatal centres. 397 leaves from eight Magnoliaceae species were used for this study. For each leaf,...
Article
Full-text available
Understanding the altitudinal patterns of plant stoichiometry in seeds is critical for characterizing important germination and dormancy strategies, soil seed bank composition, seed predation probability, efficiency of seed dispersal and seedling performance, and to predict how biodiversity might be influenced by climate change. However, our unders...
Article
Full-text available
A review of the fossil record coupled with insights gained from molecular and developmental biology reveal a series of body plan transformations that gave rise to the first land plants. Across diverse algal clades, including the green algae and their descendants, the plant body plan underwent a unicellul ar $\to$ colonial $\to$ simple multicellular...
Article
Full-text available
"Diminishing returns" in leaf economics occurs when increases in lamina mass (M), which can either be represented by lamina dry mass (DM) or fresh mass (FM), fail to produce proportional increases in leaf surface area (A), such that the scaling exponent (a) for the M vs. A scaling relationship exceeds unity (i.e., a > 1.0). Prior studies have shown...
Article
Full-text available
Leaf functional traits are important indicators of plant growth and ecosystem dynamics. Despite a wealth of knowledge about leaf trait relationships, a mechanistic understanding of how biotic and abiotic factors quantitatively influence leaf trait variation and scaling is still incomplete. We propose that leaf water content (LWC) inherently affects...
Article
Full-text available
Leaf shape and size can vary between hybrids and their parents. However, this has seldom been quantitatively tested. Photinia × fraseri is an important landscaping plant in East Asia as a hybrid between evergreen shrubs P. glabra and P. serratifolia. Its leaf shape looks like that of P. serratifolia. To investigate leaf shape, we used a general equ...
Article
The plant economics spectrum describes the trade‐off between plant resource acquisition and storage, and sheds light on plant responses to environmental changes. However, the data used to construct the plant economics spectrum comes mainly from seed plants, thereby neglecting vascular non‐seed plant lineages such as the ferns. To address this omiss...
Article
1. The quantification of the allocation of nitrogen (N) and phosphorus (P) among plant organs is essential to improve our understanding of plant growth, life‐history strategies, and ecosystem nutrient and energy cycles. However, allocation strategies of N and P between terrestrial plant leaves and fine roots are unclear. 2. Here, we compiled a glob...
Article
Full-text available
Many natural objects exhibit radial or axial symmetry in a single plane. However, a universal tool for simulating and fitting the shapes of such objects is lacking. Herein, we present an R package called ‘biogeom’ that simulates and fits many shapes found in nature. The package incorporates novel universal parametric equations that generate the pro...
Presentation
Full-text available
Dear colleagues, the association of tree consultants SAG Baumstatik e.V. would like to invite you to this upcoming event: In the course of the SAG Summer School 2022 in Trieste, a public conference with speakers of SAG Baumstatik and international guests will take place on Thursday, 21st of July 2022. There, lectures on some topics of the SAG Sum...
Article
Earth’s drylands store large amounts of organic carbon and thus play an important role in regulating atmospheric CO2 concentrations and mitigating climate change. However, little is known about the magnitude and the drivers of organic carbon stocks because of limited data, in particular in desert ecosystems. To fill this gap, we surveyed 763 plots...
Article
Full-text available
The material properties of the cells and tissues of an organism dictate, to a very large degree, the ability of the organism to cope with mechanical stress induced by externally applied forces. It is, therefore, critical to understand how these properties differ across diverse species and how they have evolved. Herein, a large data base (N = 84 spe...
Article
Full-text available
The Montgomery equation predicts leaf area as the product of leaf length and width multiplied by a correction factor. It has been demonstrated to apply to a variety of leaf shapes. However, it is unknown whether tree size (measured as the diameter at breast height) affects leaf shape and size, or whether such variations in leaf shape can invalidate...
Article
Full-text available
Premise of study: Competition is an important driver of tree mortality, and thus affects forest structure and dynamics. Tree architectural traits, such as height-to-diameter (H-D) and branch length-to-diameter (L-d) relationships are thought to influence species competitiveness by affecting light capture. Unfortunately, little is known about how t...
Article
Full-text available
Background Nitrogen (N) and phosphorus (P) are important elements for plant metabolism and growth. Therefore, the quantification of the scaling relationship of N to P in plant organs can help us understand many fundamental ecological processes. The general scaling relationships between N and P in leaves and in fine roots have been reported. As comp...
Article
Recently, a universal equation by Narushin, Romanov, and Griffin (hereafter, the NRGE) was proposed to describe the shape of avian eggs. While NRGE can simulate the shape of spherical, ellipsoidal, ovoidal, and pyriform eggs, its predictions were not tested against actual data. Here, we tested the validity of the NRGE by fitting actual data of egg...
Article
Sexual dimorphism in body size has been observed for many insect species. However, whether dimorphism influences the flight performance for closely related insects or between the genders of conspecifics has seldom been examined. Wing loading (i.e., body mass/total wing area, WL = M/A) is an important indicator of flight efficiency and maneuverabili...
Article
Water use efficiency (WUE) links carbon and water cycling and has been recognized as important in understanding the carbon-water budget of terrestrial ecosystems. However, there are few studies comparing WUE at leaf and ecosystem levels in response to environmental variables on a global scale. Here, we compare global-scale patterns and the drivers...
Article
Soil microbes play key roles in driving and regulating nutrient cycling in terrestrial ecosystems. However, a lack of global-scale information regarding the distribution of soil microbial biomass carbon (SMB C), nitrogen (SMB N), and phosphorus (SMB P) in terrestrial ecosystems has limited our ability to incorporate the broad-scale soil microbial n...
Article
Julius Sachs (1832–1897), who has been quite rightly called “the father of plant physiology,” was a German physiologist of international standing, whose research interests contributed to virtually every branch of the plant sciences, and whose work presaged plant molecular biology and systems biology. Here, we focus on one of his last publications,...
Article
Full-text available
Leaf lamina mass and area are closely correlated with the photosynthetic capacity and competitive ability of plants, whereas leaf age has been demonstrated to affect physiological processes such as photosynthesis. However, it remains unknown whether the lamina mass vs. area scaling relationship is influenced by leaf age, which is important for unde...
Article
Full-text available
Premise: Across species, main leaf vein density scales inversely with leaf area (A). Yet, minor vein density manifests no clear relationship with respect to A, despite having the potential to provide important insights into the trade-off among the investments in leaf mechanical support, hydraulics, and light interception. Methods: To examine thi...
Article
Premise: The phenomenon called "diminishing returns" refers to the scaling relationship between lamina mass (M) vs. lamina area (A) in many species, i.e., M ∝ Aα>1 , where αis the scaling exponent exceeding unity. Prior studies have focused on the scaling relationships between lamina dry mass (DM) and A, or between fresh mass (FM) and A. However,...
Article
Virtually all forms of life, from single-cell eukaryotes to complex, highly differentiated multicellular organisms, exhibit a property referred to as symmetry. However, precise measures of symmetry are often difficult to formulate and apply in a meaningful way to biological systems, where symmetries and asymmetries can be dynamic and transient, or...
Article
Full-text available
Determining large‐scale patterns of plant elemental concentrations and stoichiometry along environmental gradients is critical for understanding plant adaptive strategies and predicting ecosystem biogeochemistry processes. However, it remains unclear as to how plant carbon (C), nitrogen (N), and phosphorus (P) concentrations and their stoichiometry...
Article
Full-text available
The whole‐plant economics spectrum (PES) refers to the trade‐offs among the many plant functional traits that are commonly used as indicators of major adaptive strategies, thereby providing insights into plant distributions, ecosystem processes, and evolution. However, there are few studies of what may be called the whole‐plant economic spectrum (P...
Article
Full-text available
The shape of leaf laminae exhibits considerable diversity and complexity that reflects adaptations to environmental factors such as ambient light and precipitation as well as phyletic legacy. Many leaves appear to be elliptical which may represent a ‘default’ developmental condition. However, whether their geometry truly conforms to the ellipse equ...
Article
Abiotic-biotic interactions have shaped organic evolution since life first began. Abiotic factors influence growth, survival, and reproductive success, whereas biotic responses to abiotic factors have changed the physical environment (and indeed created new environments). This reciprocity is well-illustrated by land plants who begin and end their e...
Article
Fine-root nitrogen (N) and phosphorus (P) concentrations play an important role in driving ecological processes such as nutrient cycling in terrestrial ecosystems. Previous studies have demonstrated that the N versus P scaling relationship for fine roots (<2 mm in diameter) on average follows a 0.82-power law across plant functional groups and ecos...
Article
Premise: Leaf mass (M) and lamina surface area (A) are important functional traits reported to obey a scaling relationship called "diminishing returns" (i.e., M ∝ Aα>1 ). Previous studies have focused primarily on eudicots and ignored whether the age of leaves affects the numerical value of the scaling exponent (i.e., α). Methods: The effect of...
Article
Full-text available
Many plant species produce ovate leaves, but there is no general parametric model for describing this shape. Here, we used two empirical nonlinear equations, the beta and Lobry–Rosso–Flandrois (LRF) equations, and their modified forms (referred to as the Mbeta and MLRF equations for convenience), to generate bilaterally symmetrical curves along the...
Article
Full-text available
Physical principles and laws determine the set of possible organismal phenotypes. Constraints arising from development, the environment, and evolutionary history then yield workable, integrated phenotypes. We propose a theoretical and practical framework that considers the role of changing environments. This 'ecomechanical approach' integrates func...
Article
Full-text available
Dietary differences are often observed among generalist herbivores co‐occurring in the same community. However, the factors underlying the differences remain poorly understood. In the context of insect herbivores, we hypothesized that interspecific dietary differences are associated with life history traits. Specifically, we hypothesized that the s...
Article
Climate change can indirectly affect ecosystem functions including detritus decomposition by modifying physiological traits, feeding behavior, and species interactions (including consumptive and non-consumptive top-down cascading effects) of decomposing arthropods. It is known that the effect of climate change on decomposition can be negative, neut...
Article
Full-text available
The extent to which key factors at the global scale influence plant biomass allocation patterns remains unclear. Here, we provide a theory about how biotic and abiotic factors influence plant biomass allocation and evaluate its predictions using a large global database for forested communities. Our analyses confirm theoretical predictions that temp...
Article
Full-text available
Nitrogen (N) and phosphorus (P) are associated with the life history of all organisms. Soil microbes play essential roles in nutrient cycling and ecosystem dynamics. As compared to plants, however, our understanding of the soil microbial N versus P scaling relationship remains limited. In this study, we used a comprehensive dataset comprising 2210...
Article
Full-text available
The discipline called biomimetics attempts to create synthetic systems that model the behavior and functions of biological systems. At a very basic level, this approach incorporates a philosophy grounded in modeling either the behavior or properties of organic systems based on inferences of structure–function relationships. This approach has achiev...
Article
Full-text available
1 Rare plant species often suffer less damage than common species because of positive density‐dependent herbivory, and it has been suggested that this “rare species advantage” fosters plant species coexistence. However, it is unknown whether rare species have an advantage when pollination interactions are also considered. 2 We hypothesized that a “...
Article
Full-text available
Plant phenology differs largely among coexisting species within communities that share similar habitat conditions. However, the factors explaining such phenological diversity of plants have not been fully investigated. We hypothesize that species traits, including leaf mass per area (LMA), seed mass, stem tissue mass density (STD), maximum plant he...
Article
Full-text available
Climate warming exerts profound effects on plant community composition. However, responses to climate warming are often reported at the community and functional type levels, but not at the species level. To test whether warming-induced changes are consistent among community, functional type, and species levels, we examined the warming-induced chang...
Article
1. Studies show that plant defenses influence the host‐use of herbivores and tend to be evolutionarily more labile than herbivore traits (e.g., feeding preferences). However, all previous studies have focused exclusively on non‐volatile plant defenses thereby overlooking the roles of plant volatiles. 2. We hypothesized that volatiles are equally im...
Article
Full-text available
Many cross-sectional shapes of plants have been found to approximate a superellipse rather than an ellipse. Square bamboos, belonging to the genus Chimonobambusa (Poaceae), are a group of plants with round-edged square-like culm cross sections. The initial application of superellipses to model these culm cross sections has focused on Chimonobambusa...
Article
Full-text available
Nitrogen (N) and phosphorus (P) play important roles in many aspects of plant biology. The allocation of N and P in plant vegetative organs (i.e., leaves, stems, and fine roots) is critical to the regulation of plant growth and development. However, how these elements are allocated in seeds is unclear. The aim of this study was to explore the N and...
Article
Premise: The nondestructive measurement of leaf area is important for expediting data acquisition in the field. The Montgomery equation (ME) assumes that leaf area (A) is a proportional function of the product of leaf length (L) and width (W), i.e., A = cLW, where c is called the Montgomery parameter. The ME has been successfully applied to calcula...
Article
Full-text available
The scaling relationship between either leaf dry or fresh mass (M) and surface area (A) can reflect the photosynthetic potential and efficiency of light harvesting in different broad-leaved plants. In growing leaves, lamina area expansion is typically finished before the completion of leaf biomass accumulation, thereby affecting the M vs. A scaling...
Article
Cellular differentiation is one of the hallmarks of complex multicellularity, allowing individual organisms to capitalize on among-cell functional diversity. The evolution of multicellularity is a major evolutionary transition that allowed for the increase of organismal complexity in multiple lineages, a process that relies on the functional integr...
Article
Full-text available
Applications in remote inspection and medicine have motivated the recent development of innovative thin, flexible-backboned robots. However, such robots often experience difficulties in maintaining their intended posture under gravitational and other external loadings. Thin-stemmed climbing plants face many of the same problems. One highly effectiv...
Article
Full-text available
Plant metabolism determines the structure and dynamics of ecological systems across many different scales. The metabolic theory of ecology (MTE) quantitatively predicts the scaling of metabolic rate as a function of body size and temperature. However, the role of tissue water content has been neglected even though hydration significantly affects me...
Article
Full-text available
The leaf economics spectrum (LES) characterizes multivariate correlations that confine the global diversity of leaf functional traits onto a single axis of variation. Although LES is well established for traits of sun leaves, it is unclear how well LES characterizes the diversity of traits for shade leaves. Here, we evaluate LES using the sun and s...
Article
Full-text available
The leaf economics spectrum (LES) characterizes multivariate correlations that confine the global diversity of leaf functional traits onto a single axis of variation. Although LES is well established for traits of sun leaves, it is unclear how well LES characterizes the diversity of traits for shade leaves. Here, we evaluate LES using the sun and s...
Article
Full-text available
Key message A highly significant and positive scaling relationship between bamboo leaf dry mass and leaf surface area was observed; leaf shape (here, represented by the quotient of leaf width and length) had a significant influence on the scaling exponent of leaf dry mass vs. area. ContextThe scaling of leaf dry mass vs. leaf area is important for...
Article
Full-text available
The leaves of vines exhibit a high degree of variability in shape, from simple oval to highly dissected palmatifid leaves. However, little is known about the extent of leaf bilateral symmetry in vines, how leaf perimeter scales with leaf surface area, and how this relationship depends on leaf shape. We studied 15 species of vines and calculated (i)...
Article
Premise: Perhaps the most rapid period of vascular plant evolution occurred during the Silurian-Devonian time interval. Yet, few quantitative analyses have established the extent to which anatomical, morphological, or reproductive features contributed to this episode of tracheophyte diversification. Methods: Phylogenetic analyses were performed...
Article
Sorghum bicolor (L.) Moench is the fifth most commonly grown cereal crop worldwide with unrivaled drought tolerance compared with other cereal crops. Drought and heat tolerance and high biomass yield potential make sorghum a promising bioenergy crop. However, stem lodging is a significant problem that results in substantial yield losses. Stem biome...
Article
Full-text available
Aim Fine roots play an important role in biogeochemical cycling in terrestrial ecosystems. However, our understanding of large scale biogeographical patterns and drivers of fine‐root C:N:P stoichiometry is extremely limited. Location China. Methods We compiled data for fine‐root carbon (C), nitrogen (N) and phosphorus (P) concentrations at 165 si...
Article
Full-text available
Background and aims: The "diminishing returns" hypothesis postulates that the scaling exponent governing the lamina area versus lamina mass scaling relationships has, on average, a numerical value less than one. Theoretically, a similar scaling relationship may exist at the twig level. However, this possibility has not been explored empirically. Me...
Article
Full-text available
The multiple origins of multicellularity had far-reaching consequences ranging from the appearance of phenotypically complex life-forms to their effects on Earth's aquatic and terrestrial ecosystems. Yet, many important but as yet unanswered questions remain. For example, do all lineages and clades share an ancestral developmental predisposition fo...
Article
Full-text available
The trade-off between leaf number and individual leaf size on current-year shoots (twigs) is crucial to light interception and thus net carbon gain. However, a theoretical basis for understanding this trade-off remains elusive. Here, we argue that this trade-off emerges directly from the relationship between annual growth in leaf and stem mass, a h...
Article
The behaviour of the iconic ichnogenus Chondrites is re-evaluated based on review of existing literature and analysis of novel data (macroscopic, thin section and ESEM-EDX observations; CT-scans and resin peels of modern analogues; computer-controlled serial grinding; morphometric analysis and theoretical morphology). The bedding plane expression o...
Article
Full-text available
The ontogeny of seed plants usually involves a dormant dehydrated state and the breaking of dormancy and germination, which distinguishes it from that of most organisms. Seed germination and seedling establishment are critical ontogenetic stages in the plant life cycle and both are fueled by respiratory metabolism. However, the scaling of metabolic...
Article
Full-text available
There is convincing evidence for a scaling relationship between leaf dry weight (DW) and leaf surface area (A) for broad-leaved plants, and most estimates of the scaling exponent of DW vs. A are greater than unity. However, the scaling relationship of leaf fresh weight (FW) vs. A has been largely neglected. In the present study, we examined whether...
Article
Full-text available
1.Leaves and roots may differ in nitrogen (N), phosphorus (P), and N:P stoichiometry; which can influence plant growth and ecosystem functioning. As compared to leaves, however, relatively little is known about the N vs. P scaling relationship and N:P stoichiometry in root systems, particularly in fine roots. 2.We used a global data set comprising...
Article
Full-text available
With few exceptions, terrestrial plants are anchored to substrates by roots that experience bending and twisting forces resulting from gravity- and wind-induced forces. Mechanical failure occurs when these forces exceed the flexural or torsional tolerance limits of stems or roots, or when roots are dislodged from their substrate. The emphasis of th...
Article
Full-text available
Living beings obey physical laws, and this applies at all scales of the organism, from the interaction of the whole organism with its environment to subcellular processes. Biomechanics research enhances our understanding of the manner in which biological organisms cope with and exploit physical principles and how the functional design of cells, tis...
Article
Physical laws and processes influence the ability of plants to exchange mass and energy with their external environments, thereby directly influencing global ecosystem functions such as water and CO2 cycles. Six fundamental physical laws and processes (e.g., Fick's law of diffusion and the Euler-Greenhill equation for elastic self-similarity) are r...
Article
Full-text available
Organisms as diverse as bacteria, fungi, plants, and animals manifest a property called “polarity.” The literature shows that polarity emerges as a consequence of different mechanisms in different lineages. However, across all unicellular and multicellular organisms, polarity is evident when cells, organs, or organisms manifest one or more of the f...
Article
Full-text available
1. Female insects lay eggs on low‐quality plants, resulting in progeny with no or low reproductive potential; this is referred to as ‘suboptimal oviposition’ in this study. 2. Here, it is reported that suboptimal oviposition of a tephritid fly species (Tephritis femoralis) supports the populations of parasitoid wasp species in a Tibetan alpine mead...
Article
Full-text available
The mean and variance of ecological measures usually follow a power-law relationship, referred to as Taylor's power law (TPL). Leaves are important organs for photosynthesis, and leaf size is closely related to photosynthetic potential. Leaf size has different physical measures, such as leaf length, area, and fresh or dry weight. However, it has no...
Article
Full-text available
The simplified Gielis equation (SGE)can approximately describe the leaf shapes of many different broad-leaved plant species by replacing two parameters of the SGE with leaf width and leaf length with a floating ratio (c–value)to adjust for leaf length. In this study, we tested the validity of the SGE in predicting leaf area using 20 bamboo species,...
Article
Full-text available
Plant biomass allocation patterns are important to understanding and predicting ecosystem carbon cycles and other important ecological processes. Consequently, many attempts have been made to study these patterns. However, most studies focus on data from species in temperate forests to the neglect of data from desert species adapted to arid conditi...