Dynamic Model of Leaf Photosynthesis with Acclimation to Light and Nitrogen

Abstract

A simple model of photosynthesis in a mature C3leaf is described, based on a non-rectangular hyperbola: the model allows the high-light asymptote of that equation (Pmax) to respond dynamically to light and nitrogen. This causes the leaf light response equation to acclimate continuously to the current conditions of light and N nutrition, which can vary greatly within a crop canopy, and through a growing season, with important consequences for gross production. Predictions are presented for the dynamics of acclimation, acclimated and non-acclimated photosynthetic rates are compared, and the dependence of leaf properties on light and N availability is explored. There is good correspondence of predictions with experimental results at the leaf level. The model also provides a mechanism for a down regulation of photosynthesis in response to increased carbon dioxide concentrations, whose magnitude will depend on conditions, particularly of nitrogen nutrition.