Supplementary calcium enhances plant growth and fruit yield in strawberry cultivars grown at high (NaCL) salinity
Strawberry (Fragaria × ananassa Duch) cvs. 'Oso Grande' and 'Camarosa' were grown in sand culture out-of-doors to investigate the effectiveness of supplementary calcium (Ca) applied into nutrient solution on plants grown at high (35 mM) NaCl concentration. Treatments were: (1) nutrient solution alone (C); (2) nutrient solution plus 35 mM NaCl (C + S); (3) nutrient solution and 35 mM sodium chloride plus supplementary 5 mM Ca as CaCl supplied in nutrient solution (C + S + Ca). Dry matter, fruit yield and chlorophyll content of plants grown at high NaCl were less than those at normal nutrient solution. Supplementary Ca ameliorated the negative effects of salinity on plant growth and fruit yield. Water use by plants decreased with elevated NaCl and increased with supplementary Ca. Membrane permeability increased with high NaCl application and these increases in membrane permeability were decreased with supplementary Ca. Sodium (Na) concentration in plant tissues increased in both cultivars in the high NaCl level. Concentrations of Ca were at deficient ranges in the plants grown at high NaCl levels and these deficiencies were corrected by supplementary Ca.