تأثیرات تنش خشکی بر صفات مورفولوژیک و فعالیت آنزیم‌های آنتی اکسیدان دو رقم کلزا (Brassica napus)

Drought stress is a critical and inevitable phenomenon damages successful crop production in various intensity every year in different parts of the world during different times. This research was done to evaluate the effects of drought stress on some traits related to leaf (leaf weight, leaf area and chlorophyll content) root (root weight) and shoot (weight and length) further enzymatic antioxidants activity of superoxide dismutase (SOD) and peroxidase (POD) in sensitive Hyola308 and resistant SLM046 cultivars of Brassica napus. Experiments were done according to factorial design on the base of completely randomized design with four replications for morphological and physiological traits and 2 replications for enzyme assays. Seedlings were cultured in MS medium suspension including 0%, 3%, 6%, 12% and 15% w/v PEG 6000. Leaf samples were collected at 0, 3, 6, 12, 24, 48, 72 hours after culture subsequently. Traits evaluation showed significant difference between two cultivars. Leaf area and weight, shoot length and root weight were decreased with the increment of PEG amounts and stress exposure time in both cultivars. Chlorophyll content in sensitive cultivar was higher than in resistant cultivar significantly. Drought stress induced significant shoot weight reduction in both cultivars. According to results, intensity of response and SOD activity in resistant cultivar was more than in sensitive cultivar. POD activity was high in SLM046 in severe drought condition and in Hyola308 this activity was increased at initial times of drought stress.