Pellegrini Elisa, Francini Alessandra, Lorenzini Giacomo, Nali Cristina
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
Environ Sci Pollut Res Int. 2015 Sep;22(17):13083-93. doi: 10.1007/s11356-015-4569-5. Epub 2015 Apr 30.
Ecophysiological and antioxidant traits were evaluated in sage (Salvia officinalis) plants exposed to 120 ppb of ozone for 90 consecutive days (5 h day(-1)). At the end of fumigation, plants showed slight leaf yellowing that could be considered the first visual symptom of leaf senescence. Ozone-stressed leaves showed (1) reduced photosynthetic activity (-70 % at the end of exposure), (2) chlorophyll loss (-59 and -56 % of chlorophyll a and b concentrations, starting from 30 days from the beginning of exposure), and (3) cellular water deficit (-12 % of the relative water content at the end of the fumigation). These phenomena are indicative of oxidative stress in the chloroplasts (as confirmed by the strong degradation of β-carotene) despite the photoprotection conferred by xanthophyll cycle [as demonstrated by the significant rise of de-epoxidation index, reaching the maximum value at the end of the treatment (+69 %)], antioxidant compounds [as confirmed by the increase of phenols (in particular caffeic acid and rosmarinic acid)], and water-soluble carbohydrates (especially monosaccharides). By means of combined ecophysiological and biochemical approaches, this study demonstrates that S. officinalis is able to activate an adaptive survival mechanism allowing the plant to complete its life cycle even under oxidative stressful conditions.
对连续90天（每天5小时）暴露于120 ppb臭氧环境中的鼠尾草（Salvia officinalis）植株的生态生理和抗氧化特性进行了评估。熏蒸结束时，植株叶片出现轻微发黄，这可被视为叶片衰老的首个可见症状。受臭氧胁迫的叶片表现出：（1）光合活性降低（暴露结束时降低70%），（2）叶绿素损失（从暴露开始30天后，叶绿素a和b浓度分别损失59%和56%），以及（3）细胞水分亏缺（熏蒸结束时相对含水量降低12%）。尽管叶黄素循环提供了光保护作用（脱环氧化指数显著升高，在处理结束时达到最大值（+69%））、抗氧化化合物（酚类物质尤其是咖啡酸和迷迭香酸增加得到证实）以及水溶性碳水化合物（尤其是单糖），但这些现象表明叶绿体中存在氧化应激（β-胡萝卜素的强烈降解证实了这一点）。通过综合生态生理和生化方法，本研究表明鼠尾草能够激活一种适应性生存机制，使植株即使在氧化应激条件下也能完成其生命周期。
