Effect of Drought Stress on Lipid Peroxidation and Proline Content in Cotton Root

Oxidative damage and antioxidant responses were compared in two cotton cultivars: drought-resistant (CCRI-60) and drought-sensitive (CCRI-27). Cotton seedlings were subjected to PEG-6000 solutions with two different osmotic potentials, and changes in the antioxidant enzyme activities were investigated. Increasing PEG concentration reduced root length and vigor, increased H2O2, malondialdehyde (MDA), and proline contents, decreased or showed no change in antioxidant enzyme levels and increased glutathione reductase activity in CCRI-27. On the other hand, CCRI-60 showed increased root length and vigor, no substantial variation in MDA content, increased antioxidant enzyme activities, and significantly increased glutathione reductase (GR) activity and proline content. Differences in the activation of antioxidant defense systems suggested a role for activated oxygen species in the cellular toxicity of drought stress. Overall, the cultivar CCRI-60 was better able to resist drought as indicated by better growth due to the higher free radical scavenging capacity, and better protection mechanism. Therefore, this results could be used to select or create new varieties of cotton plants to obtain a better productivity under water deficit conditions.