title: Combined toxicity of cadmium and copper in Avicennia marina seedlings and the regulation of exogenous jasmonic acid.
abstract: Seedlings of Avicennia marina were exposed to single and combined metal treatments of cadmium (Cd) and copper (Cu) in a factorial design, and the combined toxicity of Cu and Cd was tested. The effects of the exogenous jasmonic acid (JA) on chlorophyll concentration, lipid peroxidation, Cd and Cu uptake, antioxidative capacity, endogenous JA concentration, and type-2 metallothionein gene (AmMT2) expression in seedlings of A. marina exposed to combined metal treatments were also investigated. A binary mixture of low-dose Cd (9 µmolL(-1)) and high-dose Cu (900 µmolL(-1)) showed toxicity to the seedlings, indicated by the significant augmentation in leaf malondialdehyde (MDA) and reduction in leaf chlorophylls. The toxicity of the combined metals was significantly alleviated by the addition of exogenous JA at 1 µmolL(-1), and the chlorophyll and MDA contents were found to be restored to levels comparable to those of the control. Compare to treatment with Cd and Cu only, 1 and 10 µmolL(-1) JA significantly enhanced the ascorbate peroxidase activity, and 10 µmolL(-1) JA significantly decreased the uptake of Cd in A. marina leaves. The relative expression of leaf AmMT2 gene was also significantly enhanced by 1 and 10 µmolL(-1) JA, which helped reduce Cd toxicity in A. marina seedlings.
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China; Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, China. Electronic address: zzyan@sklec.ecnu.edu.cn.
authors.forename: Zhongzheng
authors.initials: Z
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China; Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
authors.forename: Xiuzhen
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China; Institute of Estuarine and Coastal Research, East China Normal University, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Hong Kong, China. Electronic address: bhntam@cityu.edu.hk.
authors.forename: Nora Fung-Yee
authors.initials: NF
authors.lastname: Tam
mesh_terms: D032407:Avicennia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D002734:Chlorophyll / Q000378:metabolism; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D003517:Cyclopentanes / Q000494:pharmacology*; D004347:Drug Interactions; D015227:Lipid Peroxidation / Q000187:drug effects; D008315:Malondialdehyde / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism; D054883:Oxylipins / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D014873:Water Pollutants; D002104:Cadmium; D002734:Chlorophyll; D008315:Malondialdehyde; C011006:jasmonic acid; D003300:Copper; D008668:Metallothionein
keywords: Combined metals; Jasmonic acid; Mangrove; Metallothioneins; Stress