An overview of models of stomatal conductance at the leaf level

Abstract

Stomata play a key role in plant adaptation to changing environmental conditions as they control both water losses and CO2 uptake. Particularly, in the context of global change, simulations of the consequences of drought on crop plants are needed to design more efficient and water-saving cropping systems. However, most of the models of stomatal conductance (gs) developed at the leaf level link gs to environmental factors or net photosynthesis (Anet), but do not include satisfactorily the effects of drought, impairing our capacity to simulate plant functioning in conditions of limited water supply. The objective of this review was to draw an up-to-date picture of the gs models, from the empirical to the process-based ones, along with their mechanistic or deterministic bases. It focuses on models capable to account for multiple environmental influences with emphasis on drought conditions. We examine how models that have been proposed for well-watered conditions can be combined with those specifically designed to deal with drought conditions. Ideas for future improvements of gs models are discussed: the issue of co-regulation of gs and Anet; the roles of CO2, absissic acid and H2O2; and finally, how to better address the new challenges arising from the issue of global change. © 2010 Blackwell Publishing Ltd.