The effects of drought, salt and combined stresses on ion exchanges of eggplant (Solanum melongena L.) seedlings

Abstract

In this study, ion exchanges in eggplant plants exposed to drought, salt, and combined stress were researched. While drought-stressed plants were irrigated at 60% FC, salt-stressed plants were irrigated with water containing 50 mM sodium chloride (NaCl). Plants under combined stress were irrigated with water containing 50 mM sodium chloride (NaCl) at 60% FC. The plants remained under stress conditions for 90 days, after which they were harvested and evaluated for their ion content. Ca2+, K+ and Mg2+ contents in the shoot and root decreased significantly under drought, salt, and combined stresses. The most severe losses were detected in plants grown under combined stress. However, while Na accumulations increased under stress, these increases were more pronounced in the root under combined stress. K+/Na+ and Ca2+/Na+ ratios in the shoot and root under salt and combined stress were found to be lower than those under drought stress. In all stress conditions, especially K+/Na+ and Ca2+/Na+ ratios in the root showed significant decreases compared to the control. These findings showed that when drought and salt stress conditions were separately applied, Ca2+, K+ and Mg2+ accumulations in the shoot were less. On the other hand, the combination of drought and salt increased the ion losses in each stress factor more.