Elevated O3 threatens biological communications mediated by plant volatiles: A review focusing on the urban environment

Plant volatiles, particularly biogenic volatile organic compounds (BVOCs), emitted in urban areas have attracted attention as olfactory signals between plants and other organisms, including insects. However, in urban areas, elevated ozone (O3) levels inhibit plant growth and degrade olfactory signals, including both insect pheromones and BVOCs, resulting in disrupted biological communication. In this article, we review recent findings on how O3 modifies olfactory interactions, focusing on both the emitters and receivers of these signals. The influence of O3 on herbivorous insects and their enemies alters the pressure caused by herbivorous damage in the field, which can affect the development of the defensive capacities of plants at the hereditary level. To address the challenges posed by O3 in biological interactions, BVOC characteristics (e.g., emission rate and species, blend composition, O3 reactivity, and oxidative products) and O3 effects on insects (e.g., preference and antennal detectivity) should be clarified. At the same time, BVOC emissions are expected to increase with rising temperatures, which will likely increase the impact of BVOCs on O3 formation in the future. Therefore, it is necessary to devise strategies, such as selecting non- or low BVOC emitters, to regulate BVOC emissions from urban greening plants and mitigate O3 risks to olfactory interactions and plant health.

城市环境中释放的植物挥发性物质，尤其是生物源挥发性有机化合物（biogenic volatile organic compounds, BVOCs），作为植物与包括昆虫在内的其他生物之间的嗅觉信号，已受到学界广泛关注。然而在城市区域中，升高的臭氧（O3）浓度会抑制植物生长，并降解包括昆虫信息素与BVOCs在内的嗅觉信号，进而扰乱生物间的信息交流。本文综述了臭氧如何调控嗅觉互作的最新研究进展，重点关注该类信号的释放者与接收者。臭氧对植食性昆虫及其天敌的影响，会改变田间植食性虫害所带来的选择压力，进而可从遗传层面影响植物防御能力的演化。为应对臭氧对生物互作造成的挑战，亟需明确BVOCs的相关特性（如释放速率与释放物种、混合组分、臭氧反应活性及氧化产物），以及臭氧对昆虫的影响（如行为偏好与触角检测能力）。与此同时，随着气温升高，BVOCs的释放量预计将增加，这可能在未来进一步加剧BVOCs对臭氧形成的影响。因此，有必要制定相关策略——例如选择无BVOCs释放或低BVOCs释放的植物——来调控城市绿化植物的BVOCs排放，以减轻臭氧对嗅觉互作与植物健康带来的风险。