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采用开顶式气室熏蒸法,设置自然条件下臭氧(O3)浓度(对照,约40 nmol·mol~(-1))、80、160及200 nmol·mol~(-1)4个臭氧浓度,观测了不同浓度臭氧条件下银杏叶片可见伤害、活性氧生成量、抗氧化酶活性及相关基因表达变化情况,分析大气臭氧浓度升高对植物活性氧代谢的影响.结果表明:160和200 nmol·mol~(-1)O_3熏蒸明显伤害银杏叶片,80 nmol·mol~(-1)与对照无差异,无可见伤害.O_3处理20 d后,160和200 nmol·mol~(-1)条件下银杏叶片的超氧自由基(O_2-·)产生速率显著高于80 nmol·mol~(-1)和对照,而80 nmol·mol~(-1)与对照无差异;O_3处理40 d后,160和200 nmol·mol~(-1)熏蒸下叶片过氧化氢(H_2O_2)含量显著高于80 nmol·mol~(-1)和对照,而过氧化氢酶(CAT)活性显著高于80 nmol·mol~(-1)和对照,各臭氧处理抗坏血酸过氧化物酶(APX)活性均低于对照.熏蒸40 d后,CAT、APX基因的转录表达持续加强;防御素(GbD)的表达强度则随着臭氧浓度的增加及熏蒸时间的延长而呈显著加强.高浓度臭氧胁迫可使银杏叶片活性氧生成量增加、抗氧化酶活性下降、相关基因表达水平上调,有明显可见叶片伤害.
Ozone concentration (40 nmol · mol -1, control), 80, 160 and 200 nmol · mol -1 ozone concentration , Observed under different concentrations of ozone ginkgo leaf visible damage, reactive oxygen species production, antioxidant enzyme activity and related gene expression changes, analysis of atmospheric ozone concentration on the active oxygen metabolism of plants.The results showed that: 160 and 200 nmol · Mol -1 O 3 could obviously injure the leaves of Ginkgo biloba L. There was no difference between 80 nmol · mol -1 and control and there was no visible damage.When 20 and 200 nmol · mol -1 The generation rate of superoxide radical (O_2- ·) in Ginkgo biloba leaves was significantly higher than that of 80 nmol · mol -1 and control, while 80 nmol · mol -1 had no difference with control. After O 3 treatment for 40 days , The content of hydrogen peroxide (H 2 O 2) was significantly higher than that of 80 nmol · mol -1 (-1) in the fumigation of 160 and 200 nmol · mol -1, while the activity of catalase (CAT) was significantly higher than 80 nmol · mol -1 and control, the activity of each ozone treated ascorbate peroxidase (APX) was lower than that of the control.After 40 days of fumigation, the transcriptional expression of CAT and APX genes continued to strengthen; the expression of defensin (GbD) With the intensity Ozone concentration and fumigation time was significantly enhanced.High concentration of ozone stress can increase the generation of reactive oxygen species in ginkgo leaves, antioxidant enzyme activity decreased, the expression of related genes increased, there are obvious visible leaf injury.