Pacific Northwest Research Station, Western Wildlands Environmental Threats Assessment Center, US Forest Service, Bend, OR, USA.
Department of Botany and Plant Sciences, University of California, Riverside, CA, USA.
Plant Biol (Stuttg). 2020 Jan;22 Suppl 1:12-37. doi: 10.1111/plb.12971. Epub 2019 Mar 12.
Tropospheric ozone (O ) is an important stressor in natural ecosystems, with well-documented impacts on soils, biota and ecological processes. The effects of O on individual plants and processes scale up through the ecosystem through effects on carbon, nutrient and hydrologic dynamics. Ozone effects on individual species and their associated microflora and fauna cascade through the ecosystem to the landscape level. Systematic injury surveys demonstrate that foliar injury occurs on sensitive species throughout the globe. However, deleterious impacts on plant carbon, water and nutrient balance can also occur without visible injury. Because sensitivity to O may follow coarse physiognomic plant classes (in general, herbaceous crops are more sensitive than deciduous woody plants, grasses and conifers), the task still remains to use stomatal O uptake to assess class and species' sensitivity. Investigations of the radial growth of mature trees, in combination with data from many controlled studies with seedlings, suggest that ambient O reduces growth of mature trees in some locations. Models based on tree physiology and forest stand dynamics suggest that modest effects of O on growth may accumulate over time, other stresses (prolonged drought, excess nitrogen deposition) may exacerbate the direct effects of O on tree growth, and competitive interactions among species may be altered. Ozone exposure over decades may be altering the species composition of forests currently, and as fossil fuel combustion products generate more O than deteriorates in the atmosphere, into the future as well.
对流层臭氧 (O ) 是自然生态系统中的一个重要胁迫因素，其对土壤、生物区系和生态过程的影响已有充分记录。O 通过对碳、养分和水文动态的影响，在生态系统中对单个植物和过程产生影响。O 对个别物种及其相关微生物和动物群的影响通过生态系统逐级上升到景观水平。系统损伤调查表明，全球敏感物种的叶片都会受到损伤。然而，即使没有可见的损伤，也可能对植物的碳、水和养分平衡产生有害影响。由于对 O 的敏感性可能遵循粗糙的植物类群（一般来说，草本作物比落叶木本植物、草和针叶树更敏感），因此仍然需要使用气孔 O 吸收来评估类和物种的敏感性。对成熟树木径向生长的研究，结合与幼苗进行的许多对照研究的数据，表明环境 O 会降低某些地区成熟树木的生长。基于树木生理学和林分动态的模型表明，O 对生长的适度影响可能会随着时间的推移而积累，其他压力（长时间干旱、过量氮沉积）可能会加剧 O 对树木生长的直接影响，物种之间的竞争相互作用也可能会改变。几十年来的臭氧暴露可能正在改变当前森林的物种组成，随着化石燃料燃烧产物产生的 O 比大气中降解的 O 多，未来也是如此。
