Effects of exogenous calcium chloride (CaCl(2)) (20 mM) on photosynthetic gas exchange, photosystem II photochemistry, and the activities of antioxidant enzymes in tobacco plants under high temperature stress (43°...
详细信息
Effects of exogenous calcium chloride (CaCl(2)) (20 mM) on photosynthetic gas exchange, photosystem II photochemistry, and the activities of antioxidant enzymes in tobacco plants under high temperature stress (43°C for 2 h) were investigated. Heat stress resulted in a decrease in net photosynthetic rate (P(n)), stomatal conductance as well as the apparent quantum yield (AQY) and carboxylation efficiency (CE) of photosynthesis. Heat stress also caused a decrease of the maximal photochemical efficiency of primary photochemistry (f(v)/f(m)). On the other hand, CaCl(2) application improved P(n), AQY, and CE as well as f(v)/f(m) under high temperature stress. Heat stress reduced the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), whereas the activities of these enzymes either decreased less or increased in plants pretreated with CaCl(2); glutathione reductase (GR) activity increased under high temperature, and it increased more in plants pretreated with CaCl(2). There was an obvious accumulation of H(2)O(2) and O(2)(-) under high temperature, but CaCl(2) application decreased the contents of H(2)O(2) and O(2)(-) under heat stress conditions. Heat stress induced the level of heat shock protein 70 (HSP70), while CaCl(2) pretreatment enhanced it. These results suggested that photosynthesis was improved by CaCl(2) application in heat-stressed plants and such an improvement was associated with an improvement in stomatal conductance and the thermostability of oxygen-evolving complex (OEC), which might be due to less accumulation of reactive oxygen species.
为使《英语沙龙》(初级版)的读者在英语学习中遇到语言、词汇和西方文化等方面问题时,有机会与外国专家进行书面交谈,我们特请美国专家 Danny 先生主持"Ask Danny"专栏。Danny 先生从事英语教育和编辑工作多年。他热情洋溢、...
详细信息
为使《英语沙龙》(初级版)的读者在英语学习中遇到语言、词汇和西方文化等方面问题时,有机会与外国专家进行书面交谈,我们特请美国专家 Danny 先生主持"Ask Danny"专栏。Danny 先生从事英语教育和编辑工作多年。他热情洋溢、乐于助人,不管你的英语水平如何,他都很乐意回答你的提问。快快参与吧!
暂无评论