Ameliorative Effect of CaCl₂ on Growth, Membrane Permeability and Nutrient Uptake in Oryza sativa Grown at High NaCl Salinity

A pot culture was carried out with Oryza sativa L. vari-Co-39, to investigate the effects of supplementary calcium chloride on plants grown at NaCl (50mM) concentration. Treatments were: (1) Control: nutrient solution alone (C); (2) nutrient solution plus 50mM sodium chloride (NaCl); (3) nutrient solution plus 10mM calcium chloride (CaCl₂); (4) nutrient solution plus 15mM calcium chloride (CaCl₂); (5) nutrient solution and 50 mM NaCl plus supplementary 10 mM CaCl₂ (NaCl + CaCl₂); and (6) 50 mM NaCl plus additional mixture of 15 mM CaCl₂ in nutrient solution (NaCl + CaCl₂). The plants grown under salt stress produced low dry weight and relative water content than those grown in standard nutrient solution and in CaCl2 alone. Supplemental calcium chloride added to nutrient solution containing salt significantly improved growth and relative water content. Membrane permeability increased with high NaCl application and these increases in root membrane permeability were decreased with supplementary Ca. The concentration of chloride (Cl) increases highly for all treatments. Sodium (Na) concentration in plant tissues increased in both shoots and roots at high NaCl treatment. Application of supplementary Ca lowered Na concentration. Concentrations of Ca. K and N were at deficient ranges in the plants grown at high NaCl levels and these deficiencies were corrected by supplementary Ca. The ameliorating effect of Ca on growth and physiological variables could reduce the negative effect of salinity of Oryza sativa L., plants.