Effect of Water Deficit Stress on Photosynthetic Pigment Concentration and Quantitative Activity of Some Antioxidants in Wheat

The purpose of this study was to investigate the effect of different levels of water deficit on some biochemical characteristics in the seedling stage of wheat in three cultivars. For this purpose, a factorial experiment based on a completely randomized design was conducted in the greenhouse University of Mohaghegh Ardabili with two factors, the first factor of water deficit (35, 60 and 85% of field capacity (control)) and wheat cultivars (Pishgam, Pishtaz and Baharan) in three replications. Water stress was applied in the three-leaf stage for 10 days and then seedlings were sampled to measure photosynthetic pigment concentrations and biochemical parameters. The results showed that with increasing water deficit, the activity of antioxidant enzymes catalase, peroxidase and polyphenol oxidase and proline increased. The highest and lowest concentrations of photosynthetic pigments belonged to Baharan cultivars and Pishtaz, respectively, under the conditions of no stress and severe water limitation. Carotenoid content and percentage of total protein in Baharan and Pishgam wheat cultivars increased under non-stress conditions. In general, it seems that Baharan cultivar has reduced the destructive effects of dehydration due to its high tolerance to stress among other cultivars studied and also by increasing the activity of antioxidant enzymes and adaptive metabolites.