Comparison of Short-Term Physiological and Biochemical Effects of Drought Stress on Two Wheat Cultivars

Drought stress, which is becoming more frequent and severe, restricts grain production. It is critical to choose wheat (Triticum aestivum L.) cultivars that are drought-resistant enough in progressively arid climates. Early physiological and biochemical responses were measured by applying drought stress to susceptible Bezostaja-1 and tolerant Tosunbey wheat cultivars with three different PEG-6000 concentrations to understand the reliability, selectivity and practicality of tested parameters. Depending on the elevated drought, lengths, fresh-dry-turgor weights, relative water content of both root and stem decreased, and chloropyll amounts increased similarly but in different dimensions in both cultivars. While a decrease was observed in the total thiol content of both, it was determined that this value was 10 times higher in Bezostaja-1 cultivar. While proline amounts peaked at the most severe drought, this value was found to be 2.5 times higher in Bezostaja-1 than in Tosunbey. The protein content is 35% higher in Bezostaja-1. In contrast to glutathione S-transferase theta1 (GSTT1) isozyme, total GST activity increased 53.1% in Bezostaja-1 and 33.6% in Tosunbey, compared to control. This average values are about three times higher in Bezostaja-1 compared to Tosunbey. Of the experimental groups whose band profiles were generated by SDS-PAGE and compared with UPGMA and neighbor-joining methods, moderate to high drought samples of Bezostaja-1 showed explicitly different results and possibly a metabolically distinct response from all others. Besides frequently used ones, total thiol content, total GST activity and changes in the protein bands could be used as useful parameters in the selection of drought-resistant cultivars.