Potassium Affects Sodium Content in Tomato Plants Grown in Hydroponic Cultivation under Saline-sodic Stress

Summary

The tomato cultivars Edkawi and UC 82B (Lycopersicon esculentum Mill.) were grown hydroponically in a solution [electrical conductivity (EC) 2.4 dS·m -1] containing 150 m m Na (EC 11.4 dS·m -1), 37 m m of K (EC 14.1 dS·m -1), or 75 m m of K (EC 19.7 dS·m -1). The leaf Na content of `Edkawi' and `UC 82B' reached values of 1717 and 2022 mmol·kg -1 dry weight at EC 19.7 dS·m -1, respectively. The high levels of K in the hydroponic solution reduced the Na concentration in the roots, petioles, and stems, but not in the leaves. Potassium concentrations in the petioles of `Edkawi' and `UC 82 B' reached values of 2655 and 2966 mmol·kg -1 dry weight, respectively. At these elevated ECs, the Ca concentrations in the leaves of `Edkawi' and `UC 82B' were 30% and 40% lower than in the control, respecti