Penetration of iron and some organic substances through isolated cuticular membranes.

Cuticular membranes were isolated enzymically from tomato fruits and from the dorsal and ventral surfaces of the leaves of Euonymus japonicus. Penetration of Fe from FeSO(4) and FeEDDHA (ferric ethylenediamine di(o-hydroxyphenylacetate) in the absence and presence of urea through the isolated cuticular membranes was studied. Fe from FeSO(4) penetrated more rapidly through the cuticles than Fe from FeEDDHA. Urea reduced the penetration of Fe from FeSO(4) and FeEDDHA. Binding of Fe on the inner surfaces of tomato fruit cuticles was also reduced by EDDHA.The results on the rates of penetration of (14)C-labeled organic substances suggest a possible relationship with their molecular weights. Permeability coefficients for these solutes have been derived for the 3 types of cuticles, using Fick's equation. The penetration rates of all substances through stomatous cuticles far exceeded those through astomatous cutioles.