Explanation for the Stomatal Response of Excised Leaves to Kinetin

CYTOKININS stimulate the transpiration of excised leaves of various graminaceous genera1–3. The increases in transpiration caused by kinetin are associated with increases in the average stomatal aperture of treated leaves and decreases in their stomatal resistance1,4, but the mechanism underlying the stomatal response has not been explained. We have tried to rectify this situation.