University of Isfahan Journal of Plant Biological Sciences 3041-9603 3 9 2011 11 22 The effect of Salicylic acid on photosynthetic pigments, contents of sugar and antioxidant enzymes under lead stress in Brassica napus L. The effect of Salicylic acid on photosynthetic pigments, contents of sugar and antioxidant enzymes under lead stress in Brassica napus L. 39 52 18820 FA Monireh Ranjbar Department of Biology, Islamic Azad University, Falavarjan Branch, Falavarjan, Iran Hossein Lari Yazdi Department of Biology, Islamic Azad University, Boroujerd Branch, Boroujerd, Iran Sheida Boroumand Jazi Young Researchers Club, Islamic Azad University, Falavarjan Branch, Falavarjan, Iran Journal Article 2016 06 14 This research was done to study the effects of lead and salicylic acid on content of photosynthetic pigments (chlorophylls a, b and a+b), and changes of soluble and insoluble sugars (starch) in roots and shoots of Brassica napus L.. One-week old seedlings of Brassica napus L. were grown in nutrient solution consisting Pb(NO3)2 (0.25, 0.5, 0.75, 1, 1.5 and 2 mmol) and salicylic acid (5 and 10 μmol) for 20 days. The fulfillments were in triplicate and data were statistically analyzed by using full randomize plots, SPSS and Duncan test. Based on the results by increasing the concentrations of Pb (NO3)2 in hydroponic cultures the plants could not tolerate high concentrations of lead (1.5 and 2 mmol). Other lead treated plants showed significant decrease in the amount of chlorophyll a, b and a+b and content of soluble and insoluble sugars in roots and shoot compared to control plants, in the meantime, the activities of catalase and peroxidase enzymes were significantly increased. Decreasing of the amount of chlorophyll a was higher than chlorophyll b in all treatments. There were considerable increases in chlorophyll a, soluble and insoluble sugars in both roots and shoot under lead and salicylic acid treatments. But application of salicylic acid did not show significant effect on the amount of chlorophyll b and a+b, whereas using of salicylic acid under lead treatments decreased activities of catalase and peroxidase enzymes, but salicylic acid did not have significant effect on average of catalase activities in root. On the other hand, an increase of soluble and insoluble sugars and oxidative enzymes could show the role of salicylic acid in increasing tolerance of plants under lead stress. Therefore, salicylic acid had a role in mitigation of damaged caused by oxidative stress. This research was done to study the effects of lead and salicylic acid on content of photosynthetic pigments (chlorophylls a, b and a+b), and changes of soluble and insoluble sugars (starch) in roots and shoots of Brassica napus L.. One-week old seedlings of Brassica napus L. were grown in nutrient solution consisting Pb(NO3)2 (0.25, 0.5, 0.75, 1, 1.5 and 2 mmol) and salicylic acid (5 and 10 μmol) for 20 days. The fulfillments were in triplicate and data were statistically analyzed by using full randomize plots, SPSS and Duncan test. Based on the results by increasing the concentrations of Pb (NO3)2 in hydroponic cultures the plants could not tolerate high concentrations of lead (1.5 and 2 mmol). Other lead treated plants showed significant decrease in the amount of chlorophyll a, b and a+b and content of soluble and insoluble sugars in roots and shoot compared to control plants, in the meantime, the activities of catalase and peroxidase enzymes were significantly increased. Decreasing of the amount of chlorophyll a was higher than chlorophyll b in all treatments. There were considerable increases in chlorophyll a, soluble and insoluble sugars in both roots and shoot under lead and salicylic acid treatments. But application of salicylic acid did not show significant effect on the amount of chlorophyll b and a+b, whereas using of salicylic acid under lead treatments decreased activities of catalase and peroxidase enzymes, but salicylic acid did not have significant effect on average of catalase activities in root. On the other hand, an increase of soluble and insoluble sugars and oxidative enzymes could show the role of salicylic acid in increasing tolerance of plants under lead stress. Therefore, salicylic acid had a role in mitigation of damaged caused by oxidative stress. https://ijpb.ui.ac.ir/article_18820_6f176e4127ab241570ef672aaeae0926.pdf