Sensitivity of stomata and water use efficiency to high CO₂

Abstract

Abstract The observed responses of stomata to carbon dioxide are reviewed, and the interaction of other known factors on the sensitivity to CO 2 are summarized. The role of stomatal response to CO 2 is discussed, and it is argued that while the effect of the CO 2 response in normal daily stomatal behaviour is presently poorly understood the stomatal response to CO 2 will have major impact in improving water use efficiency in future CO 2 atmospheres. However, the attenuation of this increase is emphasized so that increases at the crop level will probably be much smaller than those observed at the single leaf assimilation level.