title: The response of marigold (Tagetes erecta Linn.) to ozone: impacts on plant growth and leaf physiology.
abstract: Progressively increasing ozone (O3) concentrations pose a potential threat to the value of marigold (Tagetes erecta Linn.), a plant widely used in urban landscaping. The response of marigold to elevated O3has been reported earlier, but the mechanisms underlying the O3effect have not been clearly elucidated. In the present study, we exposed marigold "Moonsong Deep Orange" plants to elevated O3, including ambient non-filtered air (NF) plus 60 ppb (NF+60) and 120 ppb (NF+120) O3, to assess visible injury and the possible physiological consequences of this pollutant. Yellow lesions appeared after 4 days under NF+120 treatment and 12 days under NF+60 treatment, with 85.6% and 36.8% of the leaves being injured at harvest time, respectively. Compared with NF, NF+60 inhibited leaf photosynthesis, stem-diameter growth, and biomass production significantly, while the parameters were decreased more by NF+120. Although the stomatal conductance decreased under elevated O3exposure, the O3flux into leaves increased by 28.0-104.8% under NF+60 treatment and 57.5-145.6% under NF+120 treatment. The total ascorbic acid (ASA) content increased due to elevated O3exposure, while the reduced ASA content did not, resulting in a decreased ratio of reduced to total ASA. A lower level of jasmonic acid (JA) was observed under elevated O3exposure. In conclusion, the impacts of elevated O3on marigold plants may be ascribed to increased O3flux into leaves and reduced protective capacity of leaves to convert oxidized to reduced ASA and synthesize endogenous JA.
authors.affiliation: State Key Laboratory of Urban and Region Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Urban and Region Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Urban and Region Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. zhengfeixiang@caas.cn.|Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China. zhengfeixiang@caas.cn.
authors.forename: Feixiang
authors.initials: F
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Urban and Region Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D018533:Biomass; D010126:Ozone / Q000633:toxicity*; D010788:Photosynthesis / Q000187:drug effects; D063245:Plant Development / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology*; D031686:Tagetes / Q000187:drug effects / Q000502:physiology*
chemical_list: D000393:Air Pollutants; D010126:Ozone
keywords: Ascorbic acid; Biomass; Jasmonic acid; Marigold; Ozone; Stomatal aperture