STOMATAL RESPONSES TO HUMIDITY AND WATER POTENTIALS OF EPIDERMAL AND MESOPHYLL TISSUE

Effects of ambient humidity on relative water contents (RWC) and water potentials were measured separately for epidermal and mesophyll tissues in leaves of two species. Water potentials did not always change in the same direction as RWC within the same tissue and rarely were the changes in water potential and RWC of one tissue correlated with those of the other. The nature of the humidity responses of stomata in certain species is discussed in relation to these results and to the anatomical properties of epidermal tissues. © 1978 Oxford University Press.