Evaluate the response of the enzyme ascorbate peroxidase to drought stress at different reproductive stages of Lentil genotypes

In order to evaluate the activities relationship in some of the antioxidant enzymes with drought tolerance, 10 lentils advanced lines were planted in the form of randomized complete block design with three replications at two full irrigation and drought stress conditions in Islamic Azad University Research Farm of Ardabil in 2011. Based on plant need in the optimal moisture conditions, the irrigation was performed using the leaky method. Only one irrigation stage (Planting time) was performed in the terminal drought conditions in the spring. From flowering stage onwards removable plastic cover was used to prevent rainwater reaching. During the 10, 20 and 30 days after the reproductive stage, samples were prepared from both normal and stress conditions. Then enzymatic extraction using Sairam et al. method and Ascorbate peroxidase enzyme according to Nakano and Asada method was measured. The results showed that with time and increasing stress intensity, Ascorbate peroxidase enzyme activity is initially increased and then decreased which agrees with the results of several studies and were inconsistent with others. The reduction of enzymatic activity under stress can be attributed to the synthesis reduction or increase the decomposition rate of these enzymes. This phenomenon suggests that with time and increasing stress intensity, the reduction of relative content of leaf water act as a limiting factor in the synthesis of Enzyme proteins