SURVEY OF POLLEN AND POLLENKITT LIPIDS–CHEMICAL CUES TO FLOWER VISITORS?

Abstract

A chemical survey of pollen lipids was carried out to examine the composition of pollenkitt in relation to that of whole pollen and to evaluate the possible role of pollenkitt as the principal carrier of chemical cues used by flower visitors. Investigated pollen was collected from 69 angiosperm species (28 families) in California. Lipid extracts of pollenkitt and of the internal portion of pollen were analyzed for each species using thin‐layer chromatography. Neutral lipids (energy storage and essential oil constituents) were most diverse in pollenkitt, while polar lipids (mostly membrane constituents) were found almost exclusively in the internal pollen fraction. Patterns in neutral lipid compositions suggest that pollenkitt may provide pollen with species‐specific odors. Yellow pigments were observed in pollen of most species, with carotenoids predominating in pollenkitt and flavonoids in the internal fraction. Phenolic and heterocyclic nitrogen compounds were found in the lipid extracts of several species.