A rapid effect of kinetin on rehydration of tobacco leaf tissue.

Partly dehydrated tobacco leaf tissue (Nicotiana rustica), stripped of the lower epidermis, was used to study the effect of kinetin on the rate of rehydration. Depending on the rate of rehydration in untreated tissue, kinetin either increased or decreased rehydration rates. The response to kinetin was very rapid and could be discerned in less than 2 minutes. On extensive dehydration, the tissue lost the capacity to respond to kinetin. Salinity stress, which decreases the endogenous level of cytokinins in the plant, conditions the leaf to stimulation of rehydration by kinetin.It is suggested that cytokinins may play a role in controlling water permeability of the leaf tissue.