Effect of Calcium Salts on Salinity Stress on Morphology and Biochemical Estimation of Rice Seedlings

Abstract

Soil salinity is one of the major abiotic stresses affecting plant growth and productivity globally as well in the Sunderban area of West Bengal. The study comprises comparison of the effect of the combined action of sodium chloride (NaCl) and three types of calcium salts calcium chloride (CaCl2), calcium sulphate (CaSO4) and calcium carbonate (CaCO3) on three rice varieties (‘Chinsurah Nona-2’, ‘Dudherswar’ and ‘Pratiksha’) both morphological and biochemical estimations, i.e. shoot growth, chlorophyll, proline, starch and reducing sugar content and antioxidants expressions. The results show maximum recovery of shoot growth in 15 mM-CaSO4 with 200 mM NaCl treatment set with respect to seedlings stressed with only 200 mM NaCl, i.e. 32% in variety ‘Chinsurah Nona-2’ and 10.5% in variety ‘Pratiksha’, whereas ‘Dudherswar’ variety shows 1.2 times recovery in 10 mM-CaCO3 set. In case of chlorophyll content in the following sets, 5 mM CaCl2, 15 mM CaSO4 and 10 mM CaCO3 are showing best recovery. Similarly, for proline, starch and reducing sugar content, 10 mM CaSO4 and 15 mM CaCO3 sets show best results against 200 mM NaCl. For antioxidant expression in ‘Chinsurah Nona-2’ variety, the catalase activity increased 4.7 times in 5 mM CaCO3 set followed by three times increase in ascorbate peroxidase activity in 10 mM CaCO3, and for lipid peroxidation, 79% decrease observed in 10 mM CaCl2. In ‘Pratiksha’ variety, 28% increase in catalase activity in 5 mM CaCO3 set and 86% decrease in ascorbate peroxidase activity in 15 mM CaSO4, 1.4 times increase in glutathione reductase activity, 5 mM CaCO3 and lipid peroxidation activity showed 59% decrease in 10 mM CaSO4. ‘Dudherswar’ variety showed marked response in all the antioxidant estimations in comparison with the other varieties, 5.5 times increase in superoxide dismutase activity in 15 mM CaCl2 set, 11 times increase in catalase activity in 5 mM CaSO4, 89% increase in ascorbate peroxidase activity in 5 mM CaCO3 the glutathione reductase activity highest increased (103%) in 10 mM CaCl2 and 65% decrease in lipid peroxidation activity in 10 Mm CaSO4. The study reveals that CaCO3 followed by CaSO4 is better than CaCl2 to combat NaCl stress.