Photosynthesis-related traits

Fourteen species have been studied by Coste (2002, 2005) to characterize their photosynthetic capacities.

Data

Values by species.

Summary

Coste (2002)

Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO₂ assimilation rate versus intercellular CO₂ mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen and carbon concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf nitrogen and carbon concentrations. No correlation was found between leaf thickness and density. The correlations between area- and mass-based leaf nitrogen concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relative nitrogen allocation to carboxylation and bioenergetics.

Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leaf nitrogen invested in photosynthesis was tightly correlated to photosynthetic capacity.We also used PCA to test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA.We conclude that the large interspecific diversity in photosynthetic capacitywas mostly explained by differences in the relative allocation of N to photosynthesis and not by leaf N concentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.