地表臭氧浓度升高对陆地生态系统影响的研究进展

浓度不断升高的地表臭氧(O₃)已成为全球性环境问题, 中国也不例外。目前, 高浓度O₃对叶片光合气体交换、植物生长或生物量的影响已备受关注, 但有关O₃对生态系统层次的研究还相对稀缺且存在较大的不确定性。该文梳理了近40年来地表O₃浓度及其影响相关领域的发展趋势和研究热点, 回顾了地表O₃浓度升高对植物影响的研究手段和评估方法, 综述了地表O₃浓度升高对陆地生态系统影响方面取得的重要进展, 主要包括植物应对O₃胁迫的响应机制、地表O₃对粮食产量和作物品质、生态系统固碳能力、群落结构和地下过程的影响及地表O₃污染区域风险; 此外, 针对目前研究的不足, 对未来研究进行了展望。建议利用先进的完全开放式O₃熏蒸系统模拟O₃浓度升高对生态系统影响的同时加强对地下生态过程的研究, 开展O₃与其他环境因子的复合作用研究; 关注O₃污染对粮食安全的影响; 开展联网研究, 建立统一评价体系; 探索减缓地表O₃污染的生态防控措施; 以期为地表O₃污染生态效应领域的发展提供助力。

Progress in the effects of elevated ground-level ozone on terrestrial ecosystems

Rising ground-level ozone (O₃) is currently an essential environmental issue in the world, especially in China. While research on the effects of O₃ on leaf photosynthetic gas exchange, plant growth and biomass has received a lot of attention, ecosystem-scale studies are however scarce and subject to great uncertainties. This article combs trends and hotpots of ground-level O₃ concentration and its effects on plants and ecosystems over the past 40 years. Research techniques and assessment methods for studying the ecological effects of ozone pollution are covered. The most important advances on the impacts of elevated ozone on terrestrial ecosystem are reviewed: plant response mechanisms, effects on grain yield, crop quality, carbon sequestration capacity, community structure and below-ground processes of different terrestrial ecosystems. Finally, regional risk assessment of the O₃ pollution is discussed. Considering the main knowledge gaps, future research should focus on belowground ecosystem response to elevated O₃ and should also incorporate O₃ and multi-factor experiments using Free-Air Ozone Concentration Elevation (FACE) system. More attention should also be paid on food security, establishment of Asian ozone network, standardization of risk assessment approach, and exploration of ecological measures to reduce the negative effects of O₃ pollution. This review can help to promote more studies on the ecological effects of ground-level O₃ pollution.