PERMEABILITY OF ISOLATED CUTICLES OF PRUNUS-LAUROCERASUS TO SOLUBLE CARBOHYDRATE

Permeabilities of isolated cuticles of Prunus laurocerasus L. were mea sured for glucose, fructose and sucrose from the inner morphological s urface of the cuticle to the outer morphological surface of the cuticl e. The kinetics of passage of the three sugars through cuticular membr ane were quite different. For short times of up to 6 h, glucose crosse d the cuticle faster than fructose and sucrose, whose diffusion was si milar. No change of permeability was observed when epicuticular waxes were removed from the leaf surface by stripping with a nitrocellulose film, even when the soluble cuticular lipids were extracted by rinsing in chloroform. Whatever the type of cuticular membrane (control, stri pped, or dewaxed cuticular membrane), glucose was always permeated the best. The possible role of the soluble cuticular lipids in determinin g soluble carbohydrate cuticular permeability is discussed.