Adaptation to Water Deficits: a Changing Perspective

Abstract

This paper briefly reviews the current developments on the role of leaf hydration on leaf growth and photosynthesis and concludes that changes in growth and stomatal action are not always closely correlated with changes in leaf hydration. A case is developed for soil and root water relations affecting leaf growth and stomatal function, and a role for plant growth regulators is postulated. The influence of this changed perspective on the adaptation of plants to water deficits is discussed. In particular, the importance of the adaptation of roots to water deficits is highlighted and the need for more studies on the interaction between the shoot and the root is emphasized.