The present study investigated to what extent there is a link between root tissue structure and ecological strategies of plant species ; such a link is known for leaf tissue structure. We investigated experimentally root tissue mass density, root diameter and several characteristics of root anatomy in the axile roots of 19 perennial grass species from different habitats and related these parameters to the ecological behaviour of the species. Root characteristics were assessed in new roots produced by mature plants grown under standardized conditions. The ecological behaviour was characterized in terms of relative growth rate (RGR), plant height at maturity and ecological indicator values for nutrients, light and tolerance to mowing according to Ellenberg. We found a striking dichotomy between root anatomical characteristics associated with interspecific variation in RGR and those associated with variation in plant height. RGR correlated with anatomical characteristics that contribute to root robustness, whereas plant height correlated with characteristics associated with axile root hydraulic conductance. RGR correlated negatively with tissue mass density (TMD r ) in roots. Interspecific variation in TMD r was explained by the proportion of stele in the cross-sectional area (CSA) of the axile root and the proportion of cell wall in the CSA of the stele. For a given root diameter, slow growing species had smaller, albeit more numerous, xylem vessels, indicating a higher resistance to cavitation and protection against embolisms. Plant height correlated positively with root CSA, total xylem CSA and mean xylem vessel CSA, indicating a need for a high transport capacity in roots of species that attain a large size at maturity. TMD r correlated positively with dry matter content in leaves. The results emphasize the close relationship between tissue structure and growth characteristics at the whole-plant level.
We compared the ability of three closely related species, Uvularia perfoliata, U. sessilifolia, and U. puberula, to forage and explore patches in nutritionally homogeneous and heterogeneous environments. The species differed in type and function of plagiotropic stems and the extent of clonality and physiological integration. Our aim was to determine (1) whether selective placement of roots in high-nutrient patches, i.e., foraging, was accompanied by facilitatory morphological changes such as internode elongation or increased branching, (2) whether foraging ability of species depended on the extent of physiological integration, and (3) how variability in environmental quality influenced the performance of each species. We studied the growth of each species over two seasons in experimental environments. Uvularia perfoliata and U. puberula foraged in high-nutrient patches in heterogeneous environments. Uvularia sessilifolia did not show selective placement of roots. The two clonal species, U. perfoliata and U. sessilifolia, did not show any changes in architectural traits predicted to facilitate foraging. The nonclonal species, U. puberula, was the strongest forager and the most physiologically integrated species, U. sessilifolia, was the weakest forager, in line with the view that physiological integration limits foraging efficiency. Variability in environmental quality had little effect on the performance of the three species. Yield and estimators of fitness were not greater in treatments where more high-quality patches were encountered consecutively than in treatments where fewer high-quality patches were encountered consecutively during growth.
A growth analysis was conducted with 24 central European grass species in full daylight to test whether traits underlying interspecific variation in relative growth rate (RGR) are the same in full daylight as they are at lower light, and whether this depends on the ecological characteristics of the studied species, i.e., their requirements with respect to nutrient and light availability. In contrast to studies with herbaceous species at lower light, net assimilation rate (NAR) contributed more than leaf area ratio (LAR) or specific leaf area (SLA) to interspecific variation in RGR. This was associated with a larger interspecific variation in NAR than found in experiments with lower light. Without the two most shade‐tolerant species, however, the contribution of LAR and its components to interspecific variation in RGR was similar or even higher than that of NAR. Leaf dry matter content correlated negatively with RGR and was the only component of LAR contributing in a similar manner to variation in LAR and RGR. There was a positive correlation between NAR and biomass allocation to roots, which may be a result of nutrient‐limited growth. RGR correlated negatively with biomass allocation to leaves. Leaf thickness did not correlate with RGR, as the positive effect of thin leaves was counterbalanced by their lower NAR. Low inherent RGR was associated with species from nutrient‐poor or shady habitats. Different components constrained growth for these two groups of species, those from nutrient‐poor habitats having high leaf dry matter content, while those from shady habitats had thin leaves with low NAR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.