Membrane Transport in Guard Cells

Abstract

Abstract One of the most fascinating processes in land plants is the ability to regulate gas exchange and transpiration by the opening and closing of the stomatal pore. The guard cells of stomata serve dual, sometimes conflicting functions in regulating photosynthetic carbon dioxide uptake while minimising water loss by transpiration. Guard cells incorporate complex, flexible and robust membrane transport and control mechanisms. The dominant pathways for potassium, anion, calcium and proton transport have been characterised, both at the plasma membrane and tonoplast, much of this work drawing on electrophysiological techniques such as voltage and patch clamping. Recent genetic and genomic advances have led to the identification of the corresponding genes for several of these transporters. This article summarises the recent progress in guard cell membrane transport and outlooks for a systems biological approach using quantitative kinetic and homeostatic modelling to guide future research work. Key Concepts: Guard cells depend on concurrent regulation of parallel and antiparallel transport pathways. Plasma membrane and tonoplast transport must be coordinated for stomatal function. Quantitative approaches to kinetic and homeostatic modelling in guard cells will greatly benefit stomatal biology.