Abstract:Atmospheric O3 pollution has become the primary summer air pollutant in many parts of the country and has already caused crop yield reductions. Atmospheric O3 exposure is intermittent in nature; however, its specific effects on common crop yields are not yet clear. In this experiment, a study on yield and biomass of wheat and soybean was initiated by setting up five treatments with different concentrations of different intermittent exposures (continuous exposure CE, 6 days of exposure stopping the 3-day cycle for 6d3C, 6 days of exposure stopping the 6-day cycle for 6d6C, fumigation for 12 days stopping the 6-day cycle for 12d6C, and fumigation for 12 days stopping the 12-day cycle for 12d12C), utilizing open-top static chambers. The results showed that: 1. there was a significant negative linear correlation between O3 exposure dose (AOT40) and relative crop yield, with relative wheat and soybean yield decreasing linearly with increasing AOT40; 2. wheat and soybean yield and biomass of each component showed a significant linear decrease with increasing AOT40, however, no significant decreases were observed in wheat leaf and spike biomass. Soybean leaf biomass and stalk biomass did not reach the significant level (P=0.12) although there was a tendency to increase; 3. For soybean, there was no significant difference in the response of biomass of each fraction to AOT40 under different intermittent exposure treatments, whereas the effect of intermittent exposure of wheat to 12d12C was significantly greater in the former than that of 12d6C on the leaf biomass. in conclusion, the effect of different intermittent O3 exposures on wheat and soybean yields in response to AOT40, but the differences in leaf volume response in wheat indicated the presence of intermittent effective recovery in wheat. The biomass response between crops and AOT40 under intermittent O3 exposure may be related to the fertility period, duration, and sequence of exposure.