Yield, Photosynthetic efficiency and Quality parameters of Cherry tomato as affected by Ca2+ and K+ under NaCl salinity

ABSTRACT: In present study the effects of Ca2+ and K+ elements on production, physiological parameters and fruit quality of cherry tomato plants (Solanum lycopersicum var. ceraiforme) grown under NaCl salinity condition was evaluated. Cherry tomato plants were grown in a controlled-environment greenhouse under hydroponic condition with different nutrient solutions obtained by modifying the Hoagland solution. Treatments were consisted of four concentration of Ca2+ (0.2, 2, 4 and 8 mM) + 60 mM NaCl, four concentrations of K+ (0.2, 2, 7 and14 mM) + 60 mM NaCl, and a control without salt with 7 mM K+/4 mM Ca2+. Salinity decreased total fruit yield to 27%. Fruit quality parameters affected by salt treatment where the fruit peel and pulp firmness, lycopene content and fruit juice pH were decreased, and vitamin C, dry matter and electrical conductivity (EC), titrable acidity (TA) and total soluble solids (TSS) fruit concentrations were increased with salinity in relation to fruits from control treatment. Also, in salinity condition, physiological parameters such as chlorophyll index and Fv/Fm ratio were decreased whereas electrolyte leakage and proline accumulation were increased. Under saline conditions an increased supply of Ca2+ and K+ promoted the fruit fresh weight, the percentage of dry matter, vitamin C, lycopene content, fruit juice pH and EC, but reduced proline accumulation. However, increasing Ca2+ concentration in the nutrient solution decreased TA and TSS of fruit while they were increased by K+ treatment. Physiological parameters also were affected by the Ca2+ and K+ treatments.