Biochemical Changes in Germinating Rice Seeds under Saline Stress

Abstract

Activity of enzymes viz., amylase, ribonuclease, protease and levels of substrates like starch, sugar, RNA, protein, amino acids were studied in endosperms of germinating rice seeds under different levels of salinity. Inereased salinity decreased germination percentage, seedling growth and water uptake by endosperm. Lower concentration of NaCl caused increase in amylase activity but sharp decrease was observed with higher concentration and so was depletion of starch from endosperm. Levels of snrrose, redueing and total sugars decreased with salinity. Suppression of RNase activity and decrease in RNA content of endosperms were observed under salt treatment. The suppression of RNase activity was about 2 and 4 folds with 0.15 M and 0.30 M NaCl respectively. Salinity inhibited the rate of disappearance of protein from endosperm. Increased protease aetivity was noticed up to 48 h followed by sharp decrease during later hours of germination where maximum inhibition of activity with higher salt concentration was observed. Increase in amino acid content during early hours of germination was observed under saline situation but significant decrease was noticed during later stages of germination.