Pollen Wall Enzymes: Taxonomic Distribution and Physical Localisation*

Publisher Summary Wall proteins are rapidly lost when the pollen grain is moistened, and so are not readily detectable by standard procedures using fixed material. Observations were accordingly made on freeze-sectioned material. Proteins were localized by properties other than enzymic activity, UV microscopy and naphthol yellow S staining being used. In the mature, dormant pollen, most of the detectable hydrolase activity was found to be associated with the walls, with very little in the protoplast of the vegetative cell. Exceptionally low activity was observed in the poral intine of the cultivars of Zea mays examined in comparison with other grasses. In the species of Liliaceae and Amaryllidaceae, the thin intines show much less activity; although in the large grains of Lilium spp., the hydrolases are readily detectable in the colpial zone. In both Gladiolus and Ambrosia , antigens are also present in the superficial Pollenkitt .