Chemical composition and microstructure of waxy plant surfaces: triterpenoids and fatty acid derivatives on leaves of Kalanchoe daigremontiana

Abstract

AbstractThe vast surfaces of plant leaves are protected by a coating of cuticular waxes. While the bulk composition of wax mixtures from various plant species has been reported, chemical information on the outermost leaf surface is lacking to date. The goal of the present study was to explore the use of ToF‐SIMS for surface analyses of plant leaves of the species Kalanchoe daigremontiana. It was found that the two major wax triterpenoids, glutinol and friedelin, were both present at the lower leaf surface in high concentrations. In contrast, the predominant wax alkane, tritriacontane, was not detectable by ToF‐SIMS. Three other unidentified compounds that had not been detected in the bulk wax mixture were present at the surface, further demonstrating that the outermost layer of molecules differed drastically in composition from the underlying wax mixture. Mapping experiments showed that all compounds were distributed fairly homogenously across the lower leaf surface, exhibiting no apparent gradients across epidermal cells and within the surface area of individual cells Copyright © 2010 John Wiley & Sons, Ltd.