ارزیابی فعالیت برخی آنزیم‌های آنتی‌اکسیدانت در ارقام مختلف برنج تحت تنش عامل بلایت باکتریایی برنج Xanthomonas oryzae pv. oryzae در شرایط گلخانه

Rice is one of the oldest crops grown in the world, and after wheat, it has the highest cultivated land in the world and has a significant role in feeding, income and employment of people in the world and in Iran. Rice diseases are one of the production constraints in many parts of the world. Due to the high spread of rice cultivars with high yield and high nitrogen sensitivity, rice bacterial blight have become an important disease in most rice grown countries in the past three decades, especially in tropical Asian countries. In order to investigate the response of different cultivars to the stress of leaf bacterial blight, the level of activity of certain defensive enzymes suches peroxidase, catalase and superoxide dismutase as a tolerance and sensitivity index was investigated. Four rice varieties of Hashemi, Lenjan, Gilaneh and Firouzan were cultivated in greenhouse conditions and 30 days after seed germination, leaf spraying with bacterial suspension concentration of 107 cells / mill was performed. The results showed that the level of antioxidant enzymes in the resistant cultivars was higher than the susceptible cultivars. In the present study, enzyme activity was significantly correlated with plant resistance and reduction of symptoms, and the variety that had the highest enzyme activity was introduced as a resistant cultivar. Regarding the effect of antioxidant enzymes on the toxicity of ROS accumulation in the plant, which is the result of oxidative stress and the result of the defense mechanism of the plant, the activity of the antioxidant enzymes sweeps up the active oxygen species produced in resistant cultivars, it is more than the cultivars, which ultimately have been more severe in the symptoms of the disease. The amount of enzyme activity in Hashemi variety was different from that of Lenjan, Gilaneh and Firouzan cultivars, and the sensitive cultivar was introduced. The highest enzyme activity was observed in Lenjan cultivar and the most resistant cultivar was introduced. No significant difference was observed between Firouzan and Gilane variety.