Stomatal Responses of Heath Plants to Water Deficits

Abstract

A simple technique for differen-tiating between the responses of plants to water stress is described. This involves following the water loss of cut shoots and determining the relative turgidity at which stomatal closure occurs. This point can be found by plotting rates of water loss and is independent of the conditions of measurement. The method was used to differentiate between species of ericaceous plants (Calluna vulgaris, Erica tetralix, E. cinerea) and between individuals of the same species (Calluna vulgaris) from different habitats. The results show good agreement with field observations.