No abstract

As an abiotic stress, adverse germination temperatures cause serious disruptions in physiological and biochemical processes involved in seed germination. Using a factorial experiment, we examined the effects of different seed priming treatments on enzymatic and biochemical performance of rice seeds germination under different temperatures. The results showed that the enzymatic and biochemical activities of all rice genotypes are affected by seed priming agent, especially under low germination temperature. At 15°C, seed priming with ascorbic acid was found the best agent for amylase, α-amylase, soluble sugars, catalase, peroxidase, ascorbate peroxidase, superoxide dismutase respectively with 0.095, 0.047, 29.4, 0.049, 10.9, 1.24 and 2.63 units in NORIN-22 genotype and for protease and soluble proteins with 0.058 and 0.79 units in IRON-70-7053-7 genotype. Among the enzymatic activities, at low germination temperature, the superoxide dismutase and at optimum and high germination temperature, the activity of catalase, peroxidase and Protease were the most important enzymatic activity in occurrence of germination potential in terms of seedling length, vigour index, normal seedling percentage and germination rate. Under priming agents, the highest changes in normal seedling percentage were observed at low and optimum germination temperature by ascorbic acid priming in Hashemi (216.9%) and NORIN-22 (13.2%) genotypes, and at high germination temperature under KCl priming in Hashemi genotype (39.4%).