Tissue and subcellular localization of oligofurostanosides and their specific degrading beta-glucosidase in Dioscorea caucasica Lipsky.

The application of the histochemical technique using the Ehrlich reagent showed that the oligofurostanosides--the steroid glycosides of the furostan series--are localized in idioblasts (special cells--receptacles) of the epidermal layer of Dioscorea caucasica leaves. The activity of oligofurostanoside-specific beta-glucosidase was localized mainly in the membrane fraction of the thylakoides and was also found in the Dioscorea caucasica leaves. We have suggested, that the differential tissue, the subcellular localization of the oligofurostanosides and their degrading enzymes provide the maintenance of the furostanol structure of steroid glycosides which is necessary for their transport within the leaf and from the leaf to the rhizome.