Department of Agriculture, Food, and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
Institute of Sustainable Plant Protection, National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Firenze, Italy.
Environ Sci Pollut Res Int. 2018 Mar;25(9):8137-8147. doi: 10.1007/s11356-016-8194-8. Epub 2016 Dec 19.
Physiological and biochemical responses to ozone (O) (150 ppb, 8 h day, 35 consecutive days) of two Italian provenances (Piedmont and Tuscany) of Fraxinus excelsior L. were evaluated, with special attention to the role of phenylpropanoids. Our results indicate (i) the high O sensitivity especially of Piedmont provenance (in terms of visible injury, water status, and photosynthetic apparatus); (ii) although the intra-specific sensitivity to O between provenances differs (mainly due to different stomatal behaviors since only Tuscany plants partially avoided the uptake of the pollutant gas), both provenances showed detoxification and defense mechanisms; (iii) the crucial participation of phenylpropanoids, with a key role played by flavonoids (especially quercitrin): among this class of metabolites, isoquercitrin is the principal player in the lower O sensitivity of Tuscany plants, together with lignins; (iv) although coumarins (typical compounds of Fraxinus) were severely depressed by O, isofraxidin was triggered suggesting a key role in reactive oxygen species (ROS) detoxification, as well as trans-chalcone. Furthermore, the different behavior of verbascoside and oleuropein among provenances lead us to speculate on their influence in the tentatively repair or acclimation shown by Piedmont plants at the end of the exposure. Finally, the intra-specific O sensitivity may be also due to de novo peaks triggered by O not yet associated to some chemicals.
评估了两种意大利起源（皮埃蒙特和托斯卡纳）的欧洲白蜡树（Fraxinus excelsior L.）对臭氧（O）（150 ppb，8 h·天，35 天连续暴露）的生理和生化反应，特别关注苯丙烷类的作用。我们的结果表明：（i）高 O 敏感性，尤其是皮埃蒙特起源（表现在可见损伤、水分状态和光合机构方面）；（ii）尽管种内对 O 的敏感性在起源之间存在差异（主要是由于不同的气孔行为，因为只有托斯卡纳植物部分避免了污染物气体的吸收），但两种起源都表现出解毒和防御机制；（iii）苯丙烷类的关键参与，以类黄酮（特别是槲皮素）发挥关键作用：在这一类代谢物中，异槲皮苷是托斯卡纳植物 O 敏感性较低的主要参与者，与木质素一起；（iv）尽管香豆素（欧洲白蜡树的典型化合物）被 O 严重抑制，但异夫沙定被触发，表明其在活性氧（ROS）解毒中起关键作用，以及反式查尔酮。此外，verbascoside 和 oleuropein 在起源之间的不同行为使我们推测它们在皮埃蒙特植物在暴露结束时表现出的暂定修复或适应中的影响。最后，种内 O 敏感性也可能是由于尚未与某些化学物质相关联的 O 触发的新峰所致。
