Instituto de Botânica, Caixa Postal 68041, 04045-972 São Paulo, SP, Brazil.
Ecotoxicol Environ Saf. 2011 Sep;74(6):1645-52. doi: 10.1016/j.ecoenv.2011.06.001. Epub 2011 Jul 8.
The occurrence of visible leaf injury caused by ozone in Ipomoea nil 'Scarlet O'Hara' may be regulated by their redox state, affecting its bioindicator efficiency. Thus, this study aimed to determine whether the redox state of I. nil plants in a subtropical area (São Paulo, SE-Brazil) contaminated by ozone oscillates, and to identify the environmental factors behind these variations. We comparatively evaluated indicators of redox state (ascorbic acid, glutathione, superoxide dismutase, ascorbate peroxidase, glutathione reductase) and leaf injury during nine field experiments of 28 days each. The variations in the redox indicators were explained by the combined effects of chronic levels of ozone and meteorological variables (mainly global solar radiation and air temperature) 3-6 days prior to the sampling days. The ascorbic acid and glutathione were crucial for increasing plant tolerance to ozone. Weak visible injury was observed in all experiments and occurred in leaves with low levels of ascorbic and dehydroascorbic acids.
紫茉莉（Ipomoea nil 'Scarlet O'Hara'）叶片出现可见臭氧损伤可能与其氧化还原状态有关，这会影响其生物指示剂的效率。因此，本研究旨在确定亚热带地区（巴西东南部圣保罗州）受臭氧污染的紫茉莉植株的氧化还原状态是否波动，并确定这些变化背后的环境因素。我们在 9 个为期 28 天的田间试验中，比较评估了氧化还原状态的指标（抗坏血酸、谷胱甘肽、超氧化物歧化酶、抗坏血酸过氧化物酶、谷胱甘肽还原酶）和叶片损伤。氧化还原指标的变化是由臭氧的慢性水平和气象变量（主要是太阳总辐射和空气温度）在前 3-6 天采样日的综合影响所解释的。抗坏血酸和谷胱甘肽对提高植物对臭氧的耐受性至关重要。在所有实验中都观察到轻微的可见损伤，发生在抗坏血酸和脱氢抗坏血酸水平较低的叶片上。
