COMPOSITION OF THE WALLS OF POLLEN GRAINS OF THE SEAGRASS AMPHIBOLIS-ANTARCTICA

The composition of walls isolated from pollen grains of the seagrass A mphibolis antarctica was determined. Glucose, galactose, and rhamnose were the major neutral monosaccharides in the wall polysaccharides, an d fucose, arabinose, xylose, and mannose were present in minor proport ions. No apiose, a monosaccharide present in the wall polysaccharides of the vegetative parts of the seagrass Heterozostera tasmanica, was f ound. Large amounts of uronic acid (mainly as galacturonic acid) were found in the walls. The monosaccharides were probably present in cellu lose and pectic polysaccharides, the latter comprising neutral pectic galactans, and rhamnogalacturonans containing high proportions of rham nose. The walls contained a small amount of protein; glycine and lysin e were the amino acids present in the highest proportions. Histochemic al examination of isolated walls confirmed the presence of polyanionic components (pectic polysaccharides), beta-glucans (cellulose), and pr otein. The composition of the walls is discussed in relation to analys es of the walls of pollen grains and vegetative organs of other plants .