Effects of n-butanol and filipin on membrane permeability of developing wheat endosperms with different sterol phenotypes.

Sterols are considered structural components of higher plant membranes on the basis of their presence in membrane-containing subcellular fractions [1—3], their effect on plant membrane permeability when added exogenously [4,5] and the sensitivity of plant cells to the polyene antibiotic filipin [6—8], which action is known to depend on the presence of sterols in the membrane (see [8]). Our recent finding of a gene that controls the free sterol level of developing wheat endosperm [9—11] allows to investígate whether endogenous sterol modifies membrane permeability in the same way as that added externally. We report here on the effect of «-butanol and filipin on the leakage properties of developing wheat endosperms with different genetically determined free sterol levéis.