CYTOCHEMICAL REACTIVITY OF POLLEN WALLS

Abstract

Cytochemical staining reactions in pollen grain walls of three species of Compositae, Ambrosia trifida, Artemisia pycnocephala and Gerbera jamesonii, were examined. The intine gives positive reactions for protein and for insoluble polysaccharides including pectic acid, callose and hemicellulose. The exine gives positive reactions for protein and for extractable lipids. In addition the structural material of the exine, sporopollenin, gives positive reactions for aliphatic double bonds and for closely packed anionic sites. Sporopollenin gives negative results to common cytochemical tests for lignin but reacts the same as lignin to metachromatic dyes. Some staining differences between exine-1 and exine-2 were noted.