The Experts below are selected from a list of 11778 Experts worldwide ranked by ideXlab platform
Karl J. Niklas - One of the best experts on this subject based on the ideXlab platform.
-
maximum plant height and the biophysical factors that limit it
Tree Physiology, 2007Co-Authors: Karl J. NiklasAbstract:Basic engineering theory and empirically determined allometric relationships for the Biomass Partitioning patterns of extant tree-sized plants show that the mechanical requirements for vertical growth do not impose intrinsic limits on the maximum heights that can be reached by species with woody, self-supporting stems. This implies that maximum tree height is constrained by other factors, among which hydraulic constraints are plausible. A review of the available information on scaling relationships observed for large tree-sized plants, nevertheless, indicates that mechanical and hydraulic requirements impose dual restraints on plant height and thus, may play equally (but differentially) important roles during the growth of arborescent, large-sized species. It may be the case that adaptations to mechanical and hydraulic phenomena have optimized growth, survival and reproductive success rather than longevity and mature size.
-
Biomass Partitioning and leaf n p stoichiometry comparisons between tree and herbaceous current year shoots
Plant Cell and Environment, 2006Co-Authors: Karl J. Niklas, Edward D CobbAbstract:We compare the Biomass Partitioning patterns and the nitrogen/phosphorus (N,P) stoichiometry of the current-year shoots of tree and herbaceous species and ask whether they scale in the same ways. Our analyses indicate that few statistically significant differences exist between the shoot Biomass Partitioning patterns of the two functional species-groups. In contrast, statistically significant N,P - stoichiometric differences exist between the two functional groups. Across all species, dry leaf mass scales nearly as the square of basal stem diameter and isometrically with respect to dry stem mass. However, total leaf N scales as the 1.37-power and as the 1.09-power of total leaf P across herbaceous and tree shoots, respectively. Therefore, tree shoots can be viewed as populations of herbs elevated by their older, woody herbaceous cohorts. However, tree leaf stoichiometry cannot be modelled in terms of herbaceous N,P - leaf stoichiometry.
-
a phyletic perspective on the allometry of plant Biomass Partitioning patterns and functionally equivalent organ categories
New Phytologist, 2006Co-Authors: Karl J. NiklasAbstract:Contents Summary 27 I. Introduction 28 II. Statistical considerations 30 III. Phyletic considerations and the null hypothesis 31 IV. Observable Biomass-Partitioning patterns 32 V. Two intraspecific digressions 34 VI. The functional equivalence hypothesis 35 VII. Plato's cave 38 VIII. Conclusions 38 Acknowledgements 39 References 39 Summary Biomass-Partitioning patterns influence the functioning of aquatic and terrestrial vegetation at all levels, ranging from individual growth and reproduction to the flow of mass and energy through entire communities. For this reason, leaf, stem and root dry Biomass-Partitioning patterns across taxonomically and ecologically diverse seed plants (spermatophytes) have been intensively investigated, both empirically and theoretically. By contrast, phyletically disparate plants (e.g. green and brown algal macrophytes, mosses and pteridophytes) have not been examined to determine whether the Partitioning of their body parts into ‘leaf’, ‘stem’ and ‘root’ analogs accords with that of spermatophytes. In this review, the Biomass-Partitioning patterns of siphonous and brown algal macrophytes, mosses and pteridophytes were compared allometrically with those of spermatophytes and were shown to be largely in statistical accordance (thus lending support to the hypothesis that a single scaling relationship exists across eukaryotic photoautotrophs). This concordance is argued to support the hypothesis of functional equivalence across analogous, but developmentally different, body parts, a feature that permits the use of simpler biological model systems with which to derive analytical explanations for the Biomass-Partitioning patterns reported for more complex seed plants.
-
a phyletic perspective on the allometry of plant Biomass Partitioning patterns and functionally equivalent organ categories
New Phytologist, 2006Co-Authors: Karl J. NiklasAbstract:Biomass-Partitioning patterns influence the functioning of aquatic and terrestrial vegetation at all levels, ranging from individual growth and reproduction to the flow of mass and energy through entire communities. For this reason, leaf, stem and root dry Biomass-Partitioning patterns across taxonomically and ecologically diverse seed plants (spermatophytes) have been intensively investigated, both empirically and theoretically. By contrast, phyletically disparate plants (e.g. green and brown algal macrophytes, mosses and pteridophytes) have not been examined to determine whether the Partitioning of their body parts into 'leaf', 'stem' and 'root' analogs accords with that of spermatophytes. In this review, the Biomass-Partitioning patterns of siphonous and brown algal macrophytes, mosses and pteridophytes were compared allometrically with those of spermatophytes and were shown to be largely in statistical accordance (thus lending support to the hypothesis that a single scaling relationship exists across eukaryotic photoautotrophs). This concordance is argued to support the hypothesis of functional equivalence across analogous, but developmentally different, body parts, a feature that permits the use of simpler biological model systems with which to derive analytical explanations for the Biomass-Partitioning patterns reported for more complex seed plants.
-
on the vegetative Biomass Partitioning of seed plant leaves stems and roots
The American Naturalist, 2002Co-Authors: Karl J. Niklas, Brian J EnquistAbstract:Abstract: A central goal of comparative life‐history theory is to derive the general rules governing growth, metabolic allocation, and Biomass Partitioning. Here, we use allometric theory to predict the relationships among annual leaf, stem, and root growth rates (GL, GS, and GR, respectively) across a broad spectrum of seed plant species. Our model predicts isometric scaling relationships among all three organ growth rates: \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $G_{\mathrm{L}\,}\propto G_{\mathrm{S}\,}\propto G_{\mathr...
Brian J Enquist - One of the best experts on this subject based on the ideXlab platform.
-
consistency between an allometric approach and optimal Partitioning theory in global patterns of plant Biomass allocation
Functional Ecology, 2007Co-Authors: Megan C Mccarthy, Brian J EnquistAbstract:Summary 1Optimal Partitioning theory (OPT) suggests that plants should allocate Biomass to the organ that acquires the most limiting resource. An implied assumption of this is that there are trade-offs in allocation between leaf, stem and root functions. 2Recently, an alternative approach, allometric Biomass Partitioning theory (APT), was developed to predict how plants should divide their metabolic production between leaves, stems and roots, based on the constraints of body size. APT predicts that, for an allometrically ideal plant, leaf mass should scale to the 3/4th power of body size, and stem and root mass should scale isometrically to body size. 3In this study, we combine OPT with APT by investigating Biomass Partitioning not accounted for by allometric constraints across broad environmental gradients. 4Intraspecific variability in Biomass allocation shows correlations with environmental factors that would be predicted by OPT. However, interspecifically, these patterns either do not appear or are greatly reduced. 5Our study suggests that, after size is accounted for, intraspecific residual variation in Biomass allocation may be partially explained by environmental factors in a manner consistent with OPT. However, the particular patterns vary between species, obscuring large-scale patterns. 6In summary, differences due to environmental variability can be incorporated with allocation patterns related to total mass to help understand how plants should allocate Biomass in response to changes in both size and environment.
-
general patterns of taxonomic and Biomass Partitioning in extant and fossil plant communities
Nature, 2002Co-Authors: Brian J Enquist, John P Haskell, Bruce H TiffneyAbstract:A central goal of evolutionary ecology is to identify the general features maintaining the diversity of species assemblages. Understanding the taxonomic and ecological characteristics of ecological communities provides a means to develop and test theories about the processes that regulate species coexistence and diversity. Here, using data from woody plant communities from different biogeographic regions, continents and geologic time periods, we show that the number of higher taxa is a general power-function of species richness that is significantly different from randomized assemblages. In general, we find that local communities are characterized by fewer higher taxa than would be expected by chance. The degree of taxonomic diversity is influenced by modes of dispersal and potential biotic interactions. Further, changes in local diversity are accompanied by regular changes in the Partitioning of community Biomass between taxa that are also described by a power function. Our results indicate that local and regional processes have consistently regulated community diversity and Biomass Partitioning for millions of years.
-
on the vegetative Biomass Partitioning of seed plant leaves stems and roots
The American Naturalist, 2002Co-Authors: Karl J. Niklas, Brian J EnquistAbstract:Abstract: A central goal of comparative life‐history theory is to derive the general rules governing growth, metabolic allocation, and Biomass Partitioning. Here, we use allometric theory to predict the relationships among annual leaf, stem, and root growth rates (GL, GS, and GR, respectively) across a broad spectrum of seed plant species. Our model predicts isometric scaling relationships among all three organ growth rates: \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $G_{\mathrm{L}\,}\propto G_{\mathrm{S}\,}\propto G_{\mathr...
-
canonical rules for plant organ Biomass Partitioning and annual allocation
American Journal of Botany, 2002Co-Authors: Karl J. Niklas, Brian J EnquistAbstract:Here we review a general allometric model for the allometric relationships among standing leaf, stem, and root Biomass (M L , M S , and M R , respectively) and the exponents for the relationships among annual leaf, stem, androot Biomass production or "growth rates" (G L , G S , and G R , respectively). This model predicts that M L « M s 3/4 M R 3/4 such that M S « M R and that G L G S G R . A large synoptic data set for standing plant organ Biomass and organ Biomass production spanning ten orders of magnitude in total plant body mass supports these predictions. Although the numerical values for the allometric "constants" governing these scaling relationships differ between angiosperms and conifers, across all species, standing leaf, stem, and root Biomass, respectively, comprise 8%, 67%, and 25% of total plant Biomass, whereas annual leaf, stem, and root Biomass growth represent 30%, 57%, and 13% of total plant growth. Importantly, our analyses of large data sets confirm the existence of scaling exponents predicted by theory. These scaling "rules" emerge from simple biophysical mechanisms that hold across a remarkably broad spectrum of ecologically and phyletically divergent herbaceous and tree-sized monocot, dicot, and conifer species. As such, they are likely to extend into evolutionary history when tracheophytes with the stereotypical "leaf," "stem," and "root" body plan first appeared.
-
Global allocation rules for patterns of Biomass Partitioning in seed plants
Science, 2002Co-Authors: Brian J Enquist, Karl J. NiklasAbstract:A general allometric model has been derived to predict intraspecific and interspecific scaling relationships among seed plant leaf, stem, and root Biomass. Analysis of a large compendium of standing organ Biomass sampled across a broad sampling of taxa inhabiting diverse ecological habitats supports the relations predicted by the model and defines the boundary conditions for above- and below-ground Biomass Partitioning. These canonical Biomass relations are insensitive to phyletic affiliation (conifers versus angiosperms) and variation in averaged local environmental conditions. The model thus identifies and defines the limits that have guided the diversification of seed plant Biomass allocation strategies.
Christian Ammer - One of the best experts on this subject based on the ideXlab platform.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.
Peter Schall - One of the best experts on this subject based on the ideXlab platform.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.
Michael Beck - One of the best experts on this subject based on the ideXlab platform.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.
-
Biomass allocation to roots and shoots is more sensitive to shade and drought in european beech than in norway spruce seedlings
Forest Ecology and Management, 2012Co-Authors: Peter Schall, Christina Lodige, Michael Beck, Christian AmmerAbstract:Abstract We investigated the effect of light availability and soil moisture on growth and Biomass Partitioning of Norway spruce and European beech seedlings in a three (light availability levels) × two (soil moisture levels) factorial greenhouse experiment. The effects of factor levels on allocation to Biomass compartments were analyzed using ANCOVA. As plant allocation patterns are size-dependent, tree size was used as a covariate. In both tree species, growth and Biomass allocation to above and belowground plant components were affected by light availability. European beech showed a distinct increase in allocation to leaves, stem and branch Biomass at the expense of fine and coarse roots with decreasing light availability. For Norway spruce, only allocation to stem Biomass increased and allocation to fine root Biomass decreased under low light. To drought a significant increase of the percentage of belowground compartments was found for European beech but not for Norway spruce. Overall, European beech seedlings were more plastic than Norway spruce seedlings. European beech seedlings appear better able to adjust Biomass Partitioning to resource availability. In contrast Norway spruce responded languidly. Our results indicate that Biomass Partitioning is not only driven by ontogeny, and thus tree size, but is environmentally determined to a substantial degree. A possible explanation for this divergence from other results on the role of ontogeny in Biomass Partitioning may be that seedling plasticity in response to limited resources declines with increasing age and/or time of exposure to the limited resources.