ABSTRACT
As most of the water absorbed by plants is lost by transpiration, reducing plant transpiration could conserve irrigation water and minimize plant water stress. The term antitranspirants refers to a series of compounds intended for this purpose. A decrease in transpiration rate can be achieved either by covering the canopy with film-forming polymers, or by regulating stomatal aperture. Substantial research has investigated the effects of various antitranspirants on transpiration, other physiological activities, and growth. As it was assumed that polymers were less permeable to CO2 than to water, and that the chemicals that close the stomata inhibit photosynthesis as much as transpiration, research on antitranspirants became limited. Thus, it is surprising that a large number of studies on antitranspirants were conducted thereafter. Many (but not all) of those that were conducted during the last two decades will be assessed herein.
