Phosphorus Metabolism of Germinating Oat Seeds

Abstract

Changes in the major phosphorus [P] substances in Avena sativa during the 1st 8 days of dark germination was investigated. The endosperm, roots, and shoots were analyzed separately for acid soluble-P, phytic acid-P, inorganic-P (Pi), lipid-P, nucleic acid-P, and proein-P. Phytic acid-P composed 53% while the sum of lipid-P, nucleic acid-P and protein-P composed 27% of the total seed. The reserve P materials were mobilized and transferred to the developing axis. The P from phytic acid appeared almost entirely as Pi in the roots and shoots. A close stoichiometry existed between the rate of loss of nucleic acid-P from the endosperm and its rate of appearance in the roots and shoots. No net synthesis of nucleic acid occurred during the 8-day period. The rate of synthesis of lipid-P in the roots and shoots exceeded its rate of disappearance from the endosperm during the 1st 4 days of germination. Protein-P increased in the roots and shoots during germination, but at a rate less than its rate of disappearance from the endosperm. Over-all aspects of P metabolism associated with germination of oats were described.