Change in physiological and biochemical parameters under drought stress in salt-tolerant and salt-susceptible eggplant genotypes

This study was carried out to determine the changes in chlorophyll and ion contents, lipid peroxidation level, and antioxidative enzyme activities of 4 eggplant genotypes (Mardin Kiziltepe (MK), Burdur Merkez (BM), Artvin Hopa (AH), and Kerner (K)) with different salt tolerance levels under drought stress. Experiments were conducted in a greenhouse with controlled climatic conditions. When the plants reached the 3-4 leaves stage, 3 different treatments were applied to create the drought levels. The first condition in the study was obtained through control application treatment (D-0), which was depletion of 40% of the available water holding capacity. The second application (D-1) was depletion of 90% of the available water holding capacity. The third application (D-2) was no applied irrigation water. Plants were analyzed with regards to chlorophyll and ion contents, lipid peroxidation levels, and antioxidative enzyme activities. Significant differences were observed among interactions of genotypes and levels of drought stress in chlorophyll and ion (K+, Ca2+, Zn2+, Mn2+, and Fe2+) contents, lipid peroxidation levels, and activities of antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT, glutathione reductase-GR, and ascorbate peroxidase-APX). The chlorophyll and ion contents of eggplant genotypes under drought stress decreased. However, different levels of lipid peroxidation and a ntioxidativc enzyme activities were observed. The situation changed depending on genotypes. Lipid peroxidation levels increased under drought stress, especially in salt-sensitive genotypes (All and K). On the other hand, the activities of antioxidativc enzymes in the salt tolerant MK and BM genotypes significantly increased. With regard to the investigated traits, salt-tolerant genotypes were also found to be quite tolerant against drought stress.