Foliar morphology and canopy nitrogen as predictors of light-use efficiency in terrestrial vegetation

• Published in: Agricultural and forest meteorology 2003-03, Vol.115 (3), p.163-171
• Main Authors: Scott Green, D., Erickson, John E., Kruger, Eric L.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Leaf area index; Leaf mass per area; Leaf nitrogen content; Light-use efficiency; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Net primary productivity; Nutrition. Photosynthesis. Respiration. Metabolism
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/S0168-1923(02)00210-1

The net primary productivity (NPP) of a plant community is often positively and linearly related to the amount of photosynthetically active radiation absorbed by its canopy (APAR). The slope of this relationship is governed by the efficiency ( ε) of APAR use in biomass production (NPP=APAR× ε). This intuitive model offers a promising means of generating large-scale NPP estimates, but its utility is compromised by our inability to explain considerable differences in ε across species, functional groups, and environments. Using data from the literature, we examined the possibility that variation in ε was governed largely by two chemical and morphological characteristics of the vegetation, canopy nitrogen content ( N canopy) and the canopy average for leaf mass per unit area ( M area). Specifically, we hypothesized that ε was positively related to the quotient of N canopy (adjusted for the fraction of incident PAR absorbed by the canopy, f PAR) and M area. This ε index accounts for the dependence of light utilization on the quantity of photosynthetic “machinery” ( N canopy) and its inherent efficiency, which is inversely related to M area. Across a wide array of C 3 species, functional groups and environments, ε (based on aboveground NPP) was strongly and positively related to [ N canopy/ f PAR]/ M area ( r 2=0.85, P