Influence of foliar-applied calcium nitrate on strawberry plants grown under salt-stressed conditions

Abstract

A pot experiment was carried out with strawberry (Fragaria × ananassa Duch) cultivars Oso Grande and Camarosa in sand culture to investigate the effects of foliar-applied calcium nitrate [Ca(NO₃)₂] to plants grown at high salinity (NaCl, 35 mmol/L). Treatments were (i) nutrient solution alone (C), (ii) nutrient solution + Ca(NO₃)₂ (9 mmol/L) as a foliar application (C+Fo), (iii) nutrient solution + NaCl (35 mmol/L) (C+S) and (iv) nutrient solution + NaCl (35 mmol/L) + Ca(NO₃)₂ (9 mmol/L) as a foliar application twice weekly (C+S+Fo). The plants grown at high NaCl had less dry matter and lower fruit yield and chlorophyll content than those grown in normal nutrient solution for both cultivars. Foliar Ca(NO₃)₂ sprays ameliorated the negative effects of salinity on plant growth, chlorophyll content and fruit yield. Membrane permeability increased with high NaCl and was reduced by Ca(NO₃)₂ sprays. Sodium concentration in plant tissues increased in both cultivars in the high NaCl treatment. Concentrations of calcium and nitrogen were much lower in plants grown in high NaCl than in unstressed plants and foliar Ca(NO₃)₂ sprays increased concentrations of both nutrients.