Water permeability of plant cuticles: permeance, diffusion and partition coefficients

Abstract

Summary. Using isolated cuticular membranes from ten woody and herbaceous plant species, permeance and diffusion coefficients for water were measured, and partition coefficients were calculated. The cuticular membranes of fruit had much higher permeance and diffusion coefficients than leaf cuticular membranes from either trees or herbs. Both diffusion and partition coefficients increased with increasing membrane thickness. Thin cuticles, therefore, tend to be better and more efficient water barriers than thick cuticles. We compared the diffusion coefficients and the water content of cuticles as calculated from transport measurements with those obtained from water vapor sorption. There is good to fair agreement for cuticular membranes with a low water content, but large discrepancies appear for polymer matrix membranes with high permeance. This is probably due to the fact that diffusion coefficients obtained from transport measurements on membranes with high permeance and water content are underestimated. Water permeabilities of polyethylene and polypropylene membranes are similar to those of leaf cuticular membranes. However, leaf cuticles have much lower diffusion coefficients and a much greater water content than these synthetic polymers. This suggests that cuticles are primarily mobility barriers as far as water transport is concerned.

Structural changes and permeability of ivy (Hedera helix L.) leaf cuticles in relation to leaf development and after selective chemical treatments

“…Becker, Kerstiens & Schonherr (1986) reported a value of 4-3 //m for the gravimetrically determined thickness of isolated ivy cuticle. The cuticle of the mature ivy leaf is much thinner than that of Lycopersicon esculentum fruit (14-2 //m) or Buxus sempervirens leaf (ll-2//m) (Chaumat & Chamel, 1991).…”

Cuticle Biosynthesis in Tomato Leaves Is Developmentally Regulated by Abscisic Acid

“…It may be that fruit cuticle does not need to be as dynamically regulated by water stress as the leaf cuticle, since the surface/volume ratio of leaves is far higher than that of fruits and the leaves have stomata, both of which are factors that make leaves more prone to desiccation. Moreover, fruit cuticles of various species are, on average, thicker than leaf cuticles, but are also more permeable (Becker et al, 1986;Araus et al, 1991;Schreiber and Riederer, 1996), suggesting that limiting water loss is more important in leaves than in fruits. Indeed, it has been suggested that transpirational water loss may be necessary for fruit growth (Lee, 1989;Schreiber and Riederer, 1996).…”

Deposition of H15NO3 vapour to white oak, red maple and loblolly pine foliage: experimental observations and a generalized model

“…the more surface water, the more capacity for sorbing HNOg vapour). Data on the thickness of leaf water films is not available but experimental data has shown that ambient vapour pressures lead to variable levels of surface hydration (Chamel et al, 1991) which have been shown to impact the rate of water and ion permeability of cuticles (Becker, Kerstiens & Schonherr, 1986;Berg, 1987). Furthermore, Cadle et al (1991) reported that surface accumulation of HNOg derived nitrate is greater for leaves exposed under 34 versus 27% relative humidity.…”