Effects of calcium on emergence and seedling growth of castor bean under salinity stress

Calcium Application, Castor Bean Plant, Emergence, Growth, Salinity.A growth chamber study was conducted to assess the interactive effects of salinity and CaCa²⁺ amendment on the emergence and early seedling growth of castor bean (Ricinus communis L.). Seedlings were cultured in wet sands filled with one-half Hoagland solution containing salts either at 0, 50 or 100 mM NaCl. Supplemental CaCl₂ was added at molar mass ratio of NaCl and CaCl2 of 20 : 0, 20 : 1, 20 : 2 and 20 : 3. Increasing salinity level reduced emergence rate, height and leaf area by up to 34.0%, 26.1% and 46.0% respectively. Calcium amendment increased emergence, height, leaf area, dry plant weight, chlorophyll a, b, chlorophyll (a + b) and soluble protein by up to 22.1%, 13.7%, 21.3%, 30.3%, 28.6%, 24.0%, 25.8% and 42.4% respectively. The present study indicates that the negative effects of salinity on emergence and early seedling growth of castor bean could be lessened with exogenous application of CaCa²⁺ at appropriate concentrations.