Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.
Sci Total Environ. 2019 Apr 20;662:796-804. doi: 10.1016/j.scitotenv.2019.01.263. Epub 2019 Jan 23.
Mangroves are subject to contamination of polybrominated diphenyl ethers (PBDEs) due to waste and wastewater disposal, and aquaculture effluent (AE) from nearby aquaculture activities. However, the response of mangrove plants to these two stresses and their interaction has seldom been reported. A six-month microcosm study, planted with either Kandelia obovata (Ko) or Avicennia marina (Am), the two most dominant species in South China mangrove swamps, was conducted to investigate the effects of BDE-99, and the interactions of BDE-99 (one of the most abundant PBDE congeners) and AE on growth and physiological responses of these plants. In addition to mixed stressors, both stressors were also applied individually. Results showed that Avicennia was more tolerant to BDE-99 contamination than Kandelia, as reflected by the reduced biomass, but increased superoxide radical (O) release and malondialdehyde (MDA) content in Kandelia. Addition of AE alleviated toxicity of BDE-99 in Kandelia by promoting biomass but lowering oxidative stress and MDA production. The hormesis model also demonstrated that the interaction between BDE-99 and AE on leaf and root MDA and O content in both Kandelia and Avicennia were mostly antagonistic. Activities of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) in both leaf and root of Kandelia were reduced by BDE-99. On the contrary, BDE-99 significantly enhanced the three enzyme activities in Avicennia root at month 3. Addition of AE also significantly enhanced root CAT, POD and SOD activities, and leaf SOD in both plant species to remove excess ROS produced under BDE-99 exposure. These results indicated that the tolerance of mangrove plants to oxidative stresses depended on antioxidative enzymes that were inducible.
红树林易受到多溴联苯醚（PBDEs）的污染，这是由于废物和废水处理以及附近水产养殖活动的养殖废水（AE）造成的。然而，红树林植物对这两种胁迫的反应及其相互作用很少有报道。本研究开展了为期六个月的微宇宙实验，种植在中国南方红树林沼泽中最占优势的两种物种——秋茄（Kandelia obovata，Ko）和桐花树（Avicennia marina，Am），以研究 BDE-99 的影响，以及 BDE-99（最丰富的多溴联苯醚同系物之一）和 AE 对这些植物生长和生理响应的相互作用。除了混合胁迫外，还单独应用了这两种胁迫。结果表明，桐花树比秋茄更能耐受 BDE-99 的污染，这反映在秋茄的生物量减少，但超氧自由基（O）释放和丙二醛（MDA）含量增加。添加 AE 通过促进生物量减轻了 BDE-99 对秋茄的毒性，但降低了氧化应激和 MDA 的产生。激素模型还表明，BDE-99 和 AE 对两种植物叶片和根 MDA 和 O 含量的相互作用大多是拮抗的。BDE-99 降低了秋茄叶片和根中 CAT、SOD 和 POD 的活性。相反，BDE-99 在第 3 个月显著增强了桐花树根中这三种酶的活性。添加 AE 也显著增强了两种植物的根 CAT、POD 和 SOD 活性以及叶片 SOD 活性，以清除 BDE-99 暴露下产生的过量 ROS。这些结果表明，红树林植物对氧化应激的耐受取决于可诱导的抗氧化酶。
