Plant Ecology and Climate Change Science Division, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh 226001, India; Department of Forestry & Environmental Science, D.S.B. campus, Kumaun University, Nainital, Uttarakhand 263001, India.
Plant Ecology and Climate Change Science Division, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh 226001, India.
Sci Total Environ. 2021 Aug 15;782:146907. doi: 10.1016/j.scitotenv.2021.146907. Epub 2021 Apr 6.
In this study, the impact of long term exposure of elevated ozone (+20 ppb above ambient) on photosynthetic traits and anti-oxidative defense system of Leucaena leucocephala, a tree of great economic importance, was studied in a Free Air Ozone Concentration Enrichment (O-FACE) facility at different time intervals (6, 12, 18, and 24 months). Results showed that net photosynthesis, photosynthetic pigments and lipid peroxidation were significantly reduced after 6, 12 and 24 months of exposure to elevated ozone (eO) whereas stomatal conductance and transpiration rate were significantly decreased after 12 months of exposure to eO. Antioxidant enzymatic activities (catalase, ascorbate peroxidase and glutathione reductase) were significantly increased after 12 months of exposure to eO Ascorbate was increased significantly after 6 and 12 months of exposure to eO while reduced glutathione content declined significantly after 6 and 24 months of exposure to eO. The study showed that there were several negative long lasting physiological and biochemical responses in Leucaena. The results provide evidence that Leucaena exhibited greater sensitivity to O during initial exposure (up to 12 months) but showed moderate tolerance by the end of the 2nd year.
在这项研究中，利用开路空气臭氧浓度增加设施（O-FACE），在不同时间间隔（6、12、18 和 24 个月）研究了长期暴露在高浓度臭氧（+20ppb 以上环境臭氧浓度）下对银合欢光合作用特性和抗氧化防御系统的影响。结果表明，暴露于高浓度臭氧 6、12 和 24 个月后，净光合作用、光合色素和脂质过氧化作用显著降低，而暴露于高浓度臭氧 12 个月后，气孔导度和蒸腾速率显著降低。暴露于高浓度臭氧 12 个月后，抗氧化酶活性（过氧化氢酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶）显著增加。暴露于高浓度臭氧 6 和 12 个月后，抗坏血酸含量显著增加，而还原型谷胱甘肽含量在暴露于高浓度臭氧 6 和 24 个月后显著下降。研究表明，银合欢存在多种长期的负面生理生化反应。研究结果表明，银合欢在最初暴露（长达 12 个月）时对 O 表现出更高的敏感性，但在第二年结束时表现出中等的耐受性。
