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Cadmium Alters Phosphate Level and Suppresses Activity of Phosphorolytic Enzymes in Germinating Rice Seeds
Author(s) -
Shah K.,
Dubey R. S.
Publication year - 1997
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1997.tb01145.x
Subject(s) - acid phosphatase , germination , alkaline phosphatase , phosphatase , enzyme , embryo , isozyme , inorganic pyrophosphatase , oryza sativa , phosphate , biochemistry , cadmium , endosperm , scutellum , enzyme assay , biology , chemistry , botany , microbiology and biotechnology , pyrophosphate , gene , organic chemistry
The effect of increasing concentration of Cd on the metabolic status of phosphate and the activity of its metabolizing enzymes acid phosphatase, alkaline phosphatase and inorganic pyrophosphatase were examined in germinating rice ( Oryza sativa ) seeds. During a 0‐120 h germination period in the two rice cvs., Ratna and Jaya, 500 μM Cd caused a 2‐3‐times increase in phosphate level in embryo axes compared to controls. Cadmium concentration of 500 μM in situ caused about 12‐14% and 20‐30 % decline in acid phosphatase activity in endosperms and embryo axes respectively during 72‐96 h of germination. With 500 μM Cd treatment in situ about 27‐43 % inhibition in alkaline phosphatase activity was noticed in endosperms and 40‐70 % in embryo axes. With 2 mM Cd salt in vitro about 60‐92 % inhibition in the activity of acid phosphatase and 80‐95 % inhibition of alkaline phosphatases was observed in enzyme preparations from embryo axes. However, a Cd level of 50‐100 μM caused stimulation in the activity of inorganic pyrophosphatase. Isoenzymic studies revealed four acid phosphatase isoenzymes in embryo axes with Rf values 0.15, 0.24, 0.36 and 0.49 and three isoenzymes in endosperms with Rf values 0.18, 0.24 and 0.40. The band intensities decreased under Cd treatment. Results indicate possible suppression of the phosphorolytic activities in germinating rice seeds under Cd stress.