The response of marigold (Tagetes erecta Linn.) to ozone: impacts on plant growth and leaf physiology

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• 作者：Ning Yang ; Xiaoke Wang ; Feixiang Zheng ; Yuanyuan Chen
• 关键词：Ascorbic acid ; Biomass ; Jasmonic acid ; Marigold ; Ozone ; Stomatal aperture
• 刊名：Ecotoxicology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：26
• 期：1
• 页码：151-164
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment, general; Ecotoxicology; Ecology; Environmental Management;
• 出版者：Springer US
• ISSN：1573-3017
• 卷排序：26

文摘

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 O₃ has been reported earlier, but the mechanisms underlying the O₃ effect 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 O₃ exposure, the O₃ flux 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 O₃ exposure, 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 O₃ exposure. In conclusion, the impacts of elevated O₃ on marigold plants may be ascribed to increased O₃ flux into leaves and reduced protective capacity of leaves to convert oxidized to reduced ASA and synthesize endogenous JA.