Studies on the Use of Cetyl Alcohol as a Transpiration Suppressor

Abstract

The incorporation of cetyl alcohol into the rooting medium (vermiculite) of wheat plants at a concentration of 5% (wjw) caused a significant reduction in transpiration (expressed on a leaf area basis) in three out of four experiments. However, this effect was accompanied by a significant reduction in photosynthesis (per unit leaf area) and also in plant dry weight. The concentration of phosphorus in the tissue of treated plants was not reduced. The presence of 1 % cetyl alcohol caused no significant transpiration reduction, but did cause a significant depression in photosynthesis and dry weight. The dry weight suppression with 1 % cetyl alcohol was more severe if soil was substituted for vermiculite. The application of cetyl alcohol as a foliar spray reduced transpiration rates but also caused the ultimate death of the treated tissue j the solvent alone did not affect the plants. It is suggested that cetyl alcohol reduces transpiration rates by increasing the resistance to the entry of water into the root system, but that the growth-inhibitory effects of cetyl alcohol preclude its use as a transpiration suppressor.