Effects of foliar application of calcium on tomato plant underdrought stress in greenhouse conditions

This study was carried out in the Birlik village of Silopi district of Şırnak province in the spring term of 2020. In this study, it was aimed to determine the response of tomato plant to foliar applied calcium under drought stress. The study was carried out in 4 application levels [(100% irrigation (control), 50% irrigation, 50% irrigation + 1% calcium and 100% irrigation + 1% calcium)] and 3 replications according to randomized blocks experimental design. Calcium sulfate (CaSO4) was applied on the tomato plant by spraying at a rate of 1% from the leaves and the plant was exposed to drought stress by applying 50% water restriction. Thus, it was investigated whether the foliar application of 1% calcium sulfate in tomato plants can tolerate drought stress. In the study, the evaluation of green parts, the amount of chlorophyll in the leaves, the amount of dry matter in the leaf, the temperature of the leaves and the relative moisture content of the leaves were measured. In addition, fruit width and length, average fruit weight, total fruit yield, the amount of dry matter in the fruit, fruit pulp firmness, pH, EC amount of fruit juice, fruit wall thickness, water-soluble dry matter amount, number of seeds, macro and micro in leaves and fruit. nutrient elements (Ca, K, Mg, N, Cu, Fe, Mn, Zn), total phenolic and flavonoid compounds and chlorophyll concentration (chlorophyll a, b, total chlorophyll) analyzes were made. As a result of the research, it was determined that the foliar application of calcium sulfate increased the magnesium concentration, the amount of chlorophyll, the relative moisture content of the leaves and the firmness of the fruit flesh. In addition, drought stress and calcium sulfate application were found to be quite effective on macro and micro nutrient contents, total phenolic and flavonoid compounds amount and chlorophyll concentration (chlorophyll a, b, total chlorophyll) in tomato plant leaves and fruit. When all the findings obtained from the study were evaluated, it was revealed that calcium sulfate (CaSO4) had promising effects in terms of drought tolerance of tomato plant.