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| Soil moisture deficit exacerbates the ozone-damaging effect of photosynthesis in winter wheat |
| Received:October 13, 2024 |
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| KeyWord:ozone;soil moisture deficit;winter wheat;photosynthesis;interaction |
| Author Name | Affiliation | E-mail | | SHEN Xinzhi | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China | | | WU Rongjun | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China
Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration(ECSS-CMA), Nanjing 210044, China | wurj@nuist.edu.cn | | XU Yansen | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China
Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration(ECSS-CMA), Nanjing 210044, China | | | SHANG Bo | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China
Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration(ECSS-CMA), Nanjing 210044, China | | | FENG Yanru | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China
Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration(ECSS-CMA), Nanjing 210044, China | | | FENG Zhaozhong | School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China
Key Laboratory of Ecosystem Carbon Source and Sink, China Meteorological Administration(ECSS-CMA), Nanjing 210044, China | |
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| Abstract: |
| The study aim to investigate the mechanism underlying the combined effect of surface ozone（O3）pollution and soil moisture （SM）deficit on photosynthetic physiology of winter wheat. Using the O3-FACE system, four treatment groups were established with two levels of O3 exposure and two levels of water treatment：ACK（ambient O3 + water control）, AWS（ambient O3 +water stress）, ECK（elevated O3 + water control）, and EWS（elevated O3 + water stress）. Field experiment were conducted to investigated the individual and combined impacts of SM deficit and O3 stress photosynthetic physiological parameters of winter wheat, and to elucidate the underlying mechanism. The results showed that from the onset of the grain-filling period, compared to the ACK, the AWS treatment led to reductions of the lightsaturated rate of CO2 assimilation（Asat）, leaf stomatal conductance（gs）, intercellular carbon dioxide concentration（Ci）, electron transfer rate （ETR）, chlorophyll content（Chl）, and total antioxidant capacity（TAC）of winter wheat by 23.7%-44.7%, 30.1%-56.3%, 8.0%, 27.3%- 30.3%, 14.9%-18.7%, and 29.2%, while malondialdehyde（MDA）levels increased by 23.3%. In comparison to the ECK, EWS treatment resulted in a more severe decline in Asat（17.4%-66.4%）, gs （49.8%-50.3%）, Ci（1.3%）, ETR（29.7%-44.9%）, Chl（22.1%-37.7%）, and TAC（26.2%）, with a 32.7% increase in MDA. The most pronounced changes were observed in the EWS group compared to ACK, where Asat, gs, Ci, ETR, Chl and TAC were reduced by 53.4%-78.2%, 63.5%-75.5%, 9.9%, 32.7%-56.9%, 36.6%-73.1%, and 47.0%, respectively, while MDA levels increased by 68.1%. Statistical analysis revealed significant interaction effects between SM deficit and O3 stress on Asat, gs, Ci, Chl, TAC, MDA. In conclusion, soil moisture deficit exacerbates the detrimental effects of O3 on photosynthesis in winter wheat. The underlying mechanism involves a reduction in leaf gs and Chl due to SM deficit, leading to insufficient carbon assimilation and impairing the antioxidant system, which, in turn, amplifies lipid peroxidation induced O3 stress and results in a significant decline in Asat. |
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