Université de Lorraine, AgroParisTech, INRA, UMR Silva, 54000 Nancy, France.
Université de Lorraine, AgroParisTech, INRA, UMR Silva, 54000 Nancy, France.
Sci Total Environ. 2019 Mar 15;656:681-690. doi: 10.1016/j.scitotenv.2018.11.307. Epub 2018 Nov 22.
Tropospheric ozone (O) is the main secondary pollutant and considered to be the most damaging for growth and productivity. O is well known to induce oxidative stress and Reactive Oxygen Species accumulation in leaf tissues. Several mechanisms have been suggested to enable trees to cope with such stress; however, their relative contribution to O tolerance is still unclear. Here, ten Euramerican poplar genotypes (Populus deltoides × nigra) were investigated regarding their response to 120 ppb of O for 3 weeks in order to determine main mechanisms and identify the key traits and strategies linked to a better tolerance to O-induced oxidative stress. Results showed that ascorbate peroxidase and ascorbate regeneration through monodehydroascorbate reductase are the main determinants of O tolerance in Euramerican poplar, in protecting photosynthesis capacity from oxidative stress and therefore, maintaining growth and productivity. Besides, stomatal closure was harmful in sensitive genotypes, suggesting that avoiding strategy can be further deleterious under chronic ozone. Finally, O-induced early senescence appeared essential when up scaling leaf-level mechanistic response to whole-plant productivity, in fine-tuning resource reallocation and photosynthesis area.
对流层臭氧（O）是主要的次生污染物，被认为对生长和生产力的破坏性最大。O 会导致叶片组织中氧化应激和活性氧物质的积累，这是众所周知的。已经提出了几种机制来使树木能够应对这种应激；然而，它们对 O 耐受性的相对贡献仍不清楚。在这里，研究了十种欧美杨树基因型（Populus deltoides × nigra）对 120 ppb O 的反应，以便确定主要机制，并确定与更好地耐受 O 诱导的氧化应激相关的关键特征和策略。结果表明，抗坏血酸过氧化物酶和通过单脱氢抗坏血酸还原酶的抗坏血酸再生是欧美杨树 O 耐受性的主要决定因素，它们可以保护光合作用免受氧化应激，从而维持生长和生产力。此外，在敏感基因型中，气孔关闭是有害的，这表明在慢性臭氧下，避免策略可能会进一步有害。最后，当将叶片水平的机制响应扩展到整个植物的生产力时，O 诱导的早期衰老似乎是必不可少的，这可以精细地调整资源再分配和光合作用面积。
