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Changes in Phosphorus Fractions and Phytase Activity of Rice Seeds during Germination
Author(s) -
MUKHERJI S.,
DEY B.,
PAUL A. K.,
SIRCAR S. M.
Publication year - 1971
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1971.tb01095.x
Subject(s) - phytase , germination , phosphorus , enzyme , chemistry , phytic acid , enzyme assay , biology , zoology , food science , horticulture , biochemistry , organic chemistry
Abstract The present experiment provides information on the phosphorus compounds in rice seeds and elucidates the changes they undergo during germination. In ungerminated seeds, the bulk of total‐P appears in phytin (about 76 per cent). It is then dephosphorylated in course of germination with a simultaneous accumulation of large amounts of inorganic‐P. Lipid‐P increases very rapidly from 0 to 24 hours. The increase up to 72 hours is gradual, after which it drops at 96 hours and again rises to a maximum after 120 hours. The ester‐P and RNA‐P, fractions increase in concentration with time of germination (except 120 hours). Protein‐P begins to fall after 48 hours, while DNA‐P remains more or less constant throughout the experiment. The two pH optima recorded for phytase activity at 4.0 and 9.0, suggests that there exist two phytases, one acidic and the other alkaline. Both behave similarly during germination with a continuous increase throughout the course of the experiment. The enzyme with an optimal pH at 4 hydrolyses phytin more actively than the other with the pH optimum at 9.0. Phytase shows maximum activity at a stage when most of the phytin has disappeared; the metabolic significance is uncertain.