Feedforward Responses of Stomata to Humidity

Abstract

Models for the responses of stomatal conductance to changes in humidity difference between leaf and air are developed. Feedforward of the stomatal response to humidity difference is present when stomata respond to a portion of the rate of transpiration of the leaf that is unaffected by changes in stomatal aperture (cuticular transpiration). A simple linear model of the responses of conductance is sufficient to predict many phenomena reported in the literature. These include the presence, under specified conditions, of a peak rate of transpiration, and an increase in the conductance and humidity difference at which this peak occurs, with increased general levels of stomatal opening.