An experiment to investigate the ameliorative effects of foliar potassium phosphate sprays on salt-stressed strawberry plants

Abstract

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 KH₂PO₄to 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 KH₂PO₄ as a foliar application (C+Fo); (3) nutrient solution + 35 mM NaCl (C+S); and (4) nutrient solution + 35 mM sodium chloride + 4 mM KH₂PO₄as 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 KH₂PO₄sprays ameliorated the negative effects of salinity on plant growth and fruit yield. Water use by plants decreased with elevated NaCl and increased with foliar KH₂PO₄ sprays. Membrane permeability increased with high NaCl and was reduced by KH₂PO₄ 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 KH₂PO₄.