全球变化，特别是近地层臭氧浓度升高，已经越来越严重地威胁到我国粮食安全，因此有必要深入研究臭氧暴露对农作物的伤害机制和危害程度。本研究将针对自然界臭氧暴露的间歇性特点，重点研究间歇性臭氧暴露下的农作物自我修复机制和响应衰减特性。通过开展间歇性与连续性臭氧暴露模拟对比实验，在臭氧暴露间歇期间和间歇性臭氧暴露过程中，观测农作物受害症状、生长和产量变化，分析农作物光合作用和抗氧化系统的相关物质、酶和基因表达等变化，探讨臭氧暴露间歇期间农作物自我修复机制，评价间歇性臭氧暴露下农作物响应衰变特性。分析臭氧暴露强度、暴露期长短以及间歇期长短对农作物恢复能力、适应能力和产量损失的影响，定量间歇性臭氧暴露对农作物减产的影响程度及剂量临界阈值，建立间歇性臭氧暴露下农作物产量损失评价方法，评估臭氧造成的我国小麦产量损失及其空间分布，为保障我国粮食安全和确定臭氧污染控制基准提供科学依据。

The crop loss caused by global environmental change, including the increasing ground-level ozone, could threaten national food security. It is necessary to deeply investigate the impact mechanism and damage degree of ozone exposure on crop, especially crop adaptive mechanism and responsive attenuation characteristics under natural interrupted ozone exposure. In manipulative experiments under interrupted and continual ozone exposures, crop leaf symptom and growth are measured, and the substances, enzymes and gene expressions related to crop photosynthesis and active oxygen defense system are analyzed, for exploring crop self-repairing mechanism after ozone exposure and characterizing crop responsive attenuation under interrupted ozone exposure. Furthermore, The influences of ozone exposure intensity and duration and interrupted period length on crop repairing and adaptive capacities and crop loss are investiagted, and ozone induced crop loss and related ozone dose threshold are quantified. Based on the relatiponship between ozone exposure and crop yield loss under interrupted ozone exposure and national ozone monitoring data, we will assess wheat crop loss and its distribution across China. The results would provide scientific basis for formulating the criterion of ozone control in order to quarantine national food security.