Cell-wall proteins in pollen and roots of Lilium longiflorum: extraction and partial characterization.

Cell-wall proteins of pollen grains, in-vitro-germinated pollen and young roots of Lilium longiflorum were studied by gel electrophoresis and amino-acid analysis. The proteins were removed from extensively purified walls by successive saline and alkali extractions. The major part including the hydroxyproline-containing proteins is covalently bound to the wall. Clear differences were observed between the proteins, especially the glycoproteins, of the pollen grain and the pollen tube. During elongation of the tubes some proteins decrease in quantity and many new proteins appear. The amount of protein in the cell walls is much lower in roots than in pollen and the root cell walls also contain fewer glycoproteins.