The effect of drought stress caused by polyethylene on the level of enzyme activity and amino acidaccumulation in the roots of seedlings of different genotypes rice (Oryza sativa L.)

Drought stress is the limiting factor for rice growth in rice fields. One of the approaches to dealing with the negative effects of stress on crop production is the use of drought-tolerant cultivars. This research was conducted to investigate the effect of drought stress on changes in antioxidant enzyme activity and amino acid accumulation in a number of rice genotypes. In this research, the number of 6 rice genotypes along with the tolerant (Binam) and sensitive (IR64) control cultivars at the seedling stage in the form of a completely random basic design in 3 replications and 4 drought levels (from polyethylene glycol 6000) zero (Yoshida), -0.5, -1 and -1.5 times were investigated in hydroponic culture medium. The results of the analysis of variance showed that there is a significant difference between the examined cultivars and the level of enzyme activity also increased, and genotypes such as Danesh and LP8, which were more tolerant to drought, had a higher level of enzyme activity. The increase in activity in tolerant genotypes has been greater than that in sensitive cultivars. In the analysis of the amino acid profiles of the genotypes introduced above, the activity of glutamic acid, alanine, arginine, leucine and lysine increased significantly with the increase in drought stress. While no significant accumulation of amino acids was observed in the sensitive IR64 genotype under stress. Therefore, it can be concluded that the accumulation of amino acids is closely related to the drought tolerance of tolerant genotypes.