Differential distribution of specific indole alkaloids in leaves of Catharanthus roseus

Abstract

In leaves of the periwinkle plant (Catharanthus roseus (L.) G. Don) idioblasts are randomly distributed in the mesophyll. They are distinguishable from ordinary palisade and spongy parenchyma cells as large, refractile, and autofluorescent cells. Density gradient centrifugation of protoplasts derived from leaves resulted in fractions enriched in idioblast protoplasts. Analysis of indole alkaloid composition by high pressure liquid chromatography has shown that idioblasts are enriched in vindoline and catharanthine relative to other mesophyll cells. The significance of these observations for attempts to produce specific indole alkaloids in cell cultures is discussed.