title: Photosynthesis and biochemical responses to elevated O3in Plantago major and Sonchus oleraceus growing in a lowland habitat of northern China.
abstract: A field experiment was carried out to compare the responses to ozone (O3) in two common herbaceous plant species, Plantago major L. and Sonchus oleraceus L., by building open-top growth chambers in situ to simulate O3stress (+O3, 85±5ppb, 9hr/day for 30days) in a lowland habitat in Inner Mongolia, Northern China. Responses to O3of gas exchange, chlorophyll a fluorescence, leaf pigment content, antioxidant capability, soluble protein content, membrane lipid peroxidation and dark respiration (Rd) were analyzed. Results showed that elevated O3exposure significantly reduced the light-saturated net photosynthesis (PNsat), stomatal conductance (gs) and transpiration rate (E) in both species. Although non-significant interactive effect between species and O3on PNsatwas analyzed, the reduction in PNsatin S. oleraceus might be due primarily to the higher fraction of close PSII reaction centers and impaired activities of plant mesophyll cells as evidences by decreased maximum efficiency of PSII photochemistry after dark adapted state (Fv/Fm) and unchanged intercellular CO2concentration (Ci). Besides, biochemical analysis showed that S. oleraceus had lower antioxidant ability compared to P. major. As a result, S. oleraceus was damaged to the larger extent in terms of lipid peroxidation and visible O3injury, indicating that S. oleraceus was more sensitive to O3than P. major. Our results indicated that wild herbaceous plant species growing in a lowland habitat in sandy grassland were sensitive to O3stress and S. oleraceus can be considered as one of the bio-indicators for high O3concentration in semi-arid grassland of northern China.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: shuying5211@126.com.
authors.forename: Benying
authors.initials: B
authors.lastname: Su
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Meihua
authors.initials: M
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: xuhong2004@ibcas.ac.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Xiujie
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Yonggeng
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Su
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Xiang
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D002681:China; D017753:Ecosystem; D010126:Ozone / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects*; D010943:Plantago / Q000502:physiology*; D031184:Sonchus / Q000502:physiology*
chemical_list: D000393:Air Pollutants; D010126:Ozone
keywords: Biochemical analysis; Gas exchange; Herbaceous species; Ozone; Semi-arid grassland