An experiment to investigate the ameliorative effects of foliar potassium phosphate sprays on salt-stressed strawberry plants
A pot experiment was carried out with strawberry (Fragaria × ananassa Duch) cvv. Oso Grande and Camarosa in sand culture to investigate the effects of foliar application of 4 mM KHPO to plants grown both at high NaCl concentration (35 mM) supplied via roots and in complete nutrient solution. Treatments were (1) nutrient solution (C); (2) nutrient solution + 4 mM KHPO as a foliar application (C+Fo); (3) nutrient solution + 35 mM NaCl (C+S); and (4) nutrient solution + 35 mM sodium chloride + 4 mM KHPO as a foliar application twice weekly (C+S+Fo). The plants grown at high NaCl had less dry matter, fruit yield, and chlorophyll content than those grown in normal nutrient solution for both cultivars. Foliar KHPO sprays ameliorated the negative effects of salinity on plant growth and fruit yield. Water use by plants decreased with elevated NaCl and increased with foliar KHPO sprays. Membrane permeability increased with high NaCl and was reduced by KHPO sprays. Sodium concentration in plant tissues increased in both cultivars in the high NaCl treatment. Concentrations of P and K were in the deficient range in plants grown at high NaCl and these deficiencies were corrected by foliar KHPO.