Non-electrolyte permeability of plant cuticles: A critical evaluation of experimental methods.

A method for measurement of non‐electrolyte transport through enzymatically isolated cuticles of Ficus elastica Roxb. var. decora is presented. Permeance coefficients and hold‐up times are determined under steady‐state conditions. The transport system consists of two small reservoirs separated by the cuticle. The compounds tested (4‐nitrophenol and pentachlorophenol) differ widely in lipid solubility and enable a critical evaluation of the apparatus used. The sorption capacity of the cuticle for lipophilic compounds is related to their cuticle/water partition coefficients. The problems of unstirred layers and of membrane integrity are discussed. The permeances measured ranged from 10−11 to 10−5 m s−1, the hold‐up times from 50 s to 22 h. [ABSTRACT FROM AUTHOR]