Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar |
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| Authors: | Xiangyang Yuan Vicent Calatayud Feng Gao Silvano Fares Elena Paoletti Yuan Tian Zhaozhong Feng |
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| Institution: | 1. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco‐Environmental Sciences, Chinese Academy of Sciences, Beijing, China;2. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China;3. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China;4. Fundación CEAM, Valencia, Spain;5. Research Centre for Soil‐Plant System, Council for Agricultural Research and Economics, Rome, Italy;6. National Research Council, Sesto, Fiorentino, Italy;7. Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China |
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| Abstract: | The combined effects of ozone (O3) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal‐filtered air, CF, and non‐filtered air +40 ppb, E‐O3) and soil water stress (well‐watered, WW, and mild drought, MD, one‐third irrigation) for 96 days. Consistent with light‐saturated photosynthesis (Asat), intercellular CO2 concentration (Ci) and chlorophyll content, isoprene emission depended on drought, O3, leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (?40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th–15th from the apex) than in upper leaves (6th–8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up‐scaled to the entire‐plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E‐O3. Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality. |
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| Keywords: | climate change drought forests ground‐level ozone isoprene emission leaf area photosynthesis poplar tropospheric O3 |
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