Modeling canopy photosynthesis from the biochemistry of the C3 chloroplast

Abstract

This chapter presents the basic equations that have been discussed in detail, with particular emphasis on how they apply to canopy photosynthesis. It focuses on the electron-transport properties, because the photosynthetic rate of many crop canopies is primarily light limited. The maximum rate of electron transport (Jmax) of the canopy was estimated by measuring irradiance response curves on several leaves and multiplying the average Jmax per leaf by the leaf area index of the canopy. It is frequently observed that Rubisco activity is also barely sufficient to account for the observed rates of C02 assimilation by leaves. Acclimation of chloroplasts to the intraleaf light gradient has some influence. Initially, crop growth is exponential as the seedlings rapidly expand their leaf area and intercept more light. No significant variation is seen across a broad range of C3 plants in the quantum yield measured as 02 evolution in saturating C02, when expressed on an absorbed-light basis. Show more