Studies on plant cuticle

Abstract
SUMMARY: A standardized test of permeability to aqueous solutions is described. No diffusion of copper from solutions of copper acetate or sulphate or of mercury from a solution of phenylmercuric acetate occurs through stomata‐free leaf membranes containing 0.1 mg./cm.2 or more of cutin, but diffusion occurs through membranes containing stomata. Wax is an important barrier to the penetration of mercury through cuticular discs of apple fruits, but the effect of the wax depends upon its composition. Sorption of mercury by the discs is increased by an increase in the percentage content of esters in the wax, by a rise in temperature or in the presence of wetter.