title: Moderate drought did not affect the effectiveness of ethylenediurea (EDU) in protecting Populus cathayana from ambient ozone.
abstract: A field study was conducted to evaluate the effects of ambient ozone (O3) on an O3-sensitive poplar (Populus cathayana) by using ethylenediurea (EDU) as a chemical protectant under two soil water treatments (well-watered (WW) and moderate drought (MD, 50-60% of WW in volumetric soil water content). EDU was applied as foliar spray at 0, 300, 450, and 600ppm. Photosynthetic parameters, pigment contents, leaf nitrogen, antioxidant capacity, growth, and biomass were measured. The 8h (9:00-17:00) average ambient O3 concentration was 71.7ppb, and AOT40 was 29.2ppmh during the experimental period (9 June to 21 September), which was high enough to cause plant injury. MD had significantly negative effects on P. cathayana, as indicated by reduced photosynthesis, growth, and biomass, and higher MDA contents. On the other hand, EDU significantly increased photosynthesis rate, chlorophyll a fluorescence, Vcmax and Jmax, photosynthetic pigments, total antioxidant capacity, tree growth and biomass accumulation, and reduced lipid peroxidation, but there was no significant interaction between EDU and drought for most parameters, indicating that EDU can efficiently protect Populus cathayana against ambient O3 and the protection was not affected by soil water contents when soil water reached moderate drought level. Among all doses, EDU at 450ppm provided maximum protection. Comparison of EDU-treated and non-treated P. cathayana could be used as a biomarker system in risk assessment of the effects of ambient O3 on forest health.
authors.affiliation: State key laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, China; University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China; Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture P. R. China, Beijing University of Agriculture, Beijing 102206, China; Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Xin
authors.affiliation: State key laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, China; University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Yuan
authors.affiliation: State key laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, China; University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Shang
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003-9320, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Manning
authors.affiliation: Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture P. R. China, Beijing University of Agriculture, Beijing 102206, China.
authors.forename: Aizhen
authors.initials: A
authors.lastname: Yang
authors.affiliation: Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture P. R. China, Beijing University of Agriculture, Beijing 102206, China. Electronic address: wyn1951@126.com.
authors.forename: Younian
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State key laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, China; University of Chinese Academy of Sciences, Shijingshan District, Beijing 100049, China; Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture P. R. China, Beijing University of Agriculture, Beijing 102206, China. Electronic address: fzz@rcees.ac.cn.
authors.forename: Zhaozhong
authors.initials: Z
authors.lastname: Feng
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D055864:Droughts; D010126:Ozone / Q000009:adverse effects*; D010671:Phenylurea Compounds / Q000378:metabolism*; D032107:Populus / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D020011:Protective Agents / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D010671:Phenylurea Compounds; D020011:Protective Agents; C032766:ethylene diurea; D010126:Ozone
keywords: Ambient ozone; Drought; Ethylenediurea; Photosynthesis; Poplar