Amino Acids and Proteins

Abstract

Analyses have shown that all the essential amino acids are present in pollen. The free amino acids do not necessarily reflect the mole ratio of amino acids in pollen protein; polypeptides may also be conjugated with glucosides and pigments. The amino acid content and total nitrogen can vary with the climatic and nutritional conditions of the plants on which the pollen matures. Thus, growing Zea mays under optimum nutrition and light conditions increased the levels of alanine, proline, arginine and protein in its pollen (Tseluiko, 1968). Mature sterile corn pollen had lower levels of proline and increased levels of alanine than viable, fertile pollen (Khoo and Stinson, 1957). Baumane et al. (1968) correlated viability and subspecies of Prunus with amino acid differences during pollen development. Storage and handling methods also modify the free amino acids; extended storage decreased, in particular, glutamine and glutamic acid (Katsumata et al., 1963). Such changes may be very critical for the survival of grass and other ephemeral pollen and may account for some of the quantitative variation in amino acids reported among species (Bieberdorf et al., 1961).