2,2’,4,4’-四溴联苯醚（BDE-47）对两种海洋微藻的毒性效应研究

发布时间：2018-01-02 13:22

  本文关键词：2,2’,4,4’-四溴联苯醚（BDE-47）对两种海洋微藻的毒性效应研究　出处：《国家海洋局第一海洋研究所》2015年硕士论文　论文类型：学位论文

  更多相关文章： BDE-47 海洋微藻 光合色素 超氧化物歧化酶(SOD) 丙二醛

【摘要】：多溴联苯醚(polybrominated diphenyl ethers, PBDE)是一类具有生态风险性的新型持久性有机污染物,自上世纪70年代以来被用作溴化阻燃剂和添加剂,广泛应用于保护电子产品、纺织品和泡沫等塑料制品。多溴联苯醚可以通过渗出或者挥发等方式进入到环境中,且具有的迁移性、蓄积性和持久性等特点,这些特点决定了这类化合物不仅在环境中长期残留,而且可以进行生物富集和放大,从而影响生物体的正常生理活动,其对海洋环境的影响也引起了国内外研究人员的广泛关注,因此评价研究PBDEs在环境中的行为十分必要。但是,目前有关PBDEs对海洋微藻的毒性效应鲜见报道,因而无法客观评价此类化合物的海洋生态风险性。微藻是海洋生态系统的初级生产者,其种类多样性和生物量影响海洋生态系统的结构功能,在食物链中具有非常重要的作用,同时具有对毒物敏感、繁殖快和易获得等优点,能在短时间内得到污染物对其种群及世代的影响研究,是较为理想的指示生物。本文选用了环境中含量较高、分布较广泛的PBDEs的代表性同系物—2,2’,4,4’-四溴联苯醚(2,2',4,4'-Tetrabromodiphenyl Ether, BDE-47)作为研究对象,以常见海洋微藻叉鞭金藻(Dicrateria inornata)、中肋骨条藻(Skeletonema costatum)、三角褐指藻(Phaeodactylum tricornutum)、小球藻(Chlorella vulgaris)为受试生物,研究了BDE-47对四种海洋微藻的急性毒性效应,得到BDE-47对四种微藻的96 h半效应浓度(96 h-EC5o)。在此基础上,研究了不同浓度BDE-47作用下叉鞭金藻(Dicrateria inornata)、中肋骨条藻(Skeletonema costatum)的叶绿素荧光参数(Fv/Fm、Fv/Fo、rETR、ΦPSII)、光合色素(叶绿素a (Chl-a)、叶绿素c(Chl-c)和类胡萝卜素(Car))含量、可溶性蛋白含量、超氧化物歧化酶(Superoxide dismutase, SOD)活性和丙二醛(Malondialdehyde, MDA)含量的变化,以及藻细胞形态的变化,以探讨BDE-47对海洋微藻的致毒机理。主要研究结果如下：(1)BDE-47对叉鞭金藻和中肋骨条藻的96 h-EC5o值分别为163 μg·L-1和648648μg·L-1, BDE-47对叉鞭金藻属于极高毒性物质,而对中肋骨条藻属于高毒性物质；在可助溶浓度范围内未能检测到BDE-47对三角褐指藻和小球藻96h-EC50。BDE-47对四种微藻的毒性大小顺序为：叉鞭金藻中肋骨条藻三角褐指藻)小球藻。(2)中肋骨条藻的光合特性指标Fv/Fm、Fv/Fo、rETR、ΦPSII均随着BDE-47浓度升高而显著降低；BDE-47对叉鞭金藻的光合特性指标影响与浓度和胁迫时间有关。低浓度BDE-47对叉鞭金藻的Fv/Fm、Fv/Fo值起促进作用,而高浓度的BDE-47对叉鞭金藻的Fv/Fm、Fv/Fo、OPSII则起抑制作用,显著低于对照组；24 h时叉鞭金藻的rETR、ΦPSII随着BDE-47浓度的升高而降低,而rETR值到48 h和72 h恢复到对照组水平,ΦPSII值则到96 h恢复到对照组水平。(3)低浓度(50μg·L-1～100 μg·L-1)的BDE-47对中肋骨条藻的Chl-a、Chl-c、Car含量的无显著影响,而中、高浓度(200μg·L-1～600μg·L-1)污染物的影响则体现为Chl-a、Chl-c、Car的含量显著增加,且随着BDE-47浓度的增加而增加；低浓度(25 μg·L-1～50μg·L-1)的BDE-47对叉鞭金藻的Chl-a、Car含量没有显著影响,能促进Chl-c的合成,而高浓度(150μg·L-1～200μg·L-1)的BDE-47能够抑制三种色素的合成。(4)各浓度组BDE-47对中肋骨条藻的可溶性蛋白含量呈诱导-抑制的时间变化趋势,而对叉鞭金藻则主要表现为诱导作用。48h内各浓度组中肋骨条藻和叉鞭金藻SOD酶活性均被显著诱导；72h后较低浓度组两种微藻SOD酶活性均恢复到对照组水平,而较高浓度BDE-47污染下,中肋骨条藻SOD活性被显著诱导,叉鞭金藻SOD活性则被显著抑制。BDE-47胁迫72h后,各浓度组中肋骨条藻和叉鞭金藻MDA含量均显著高于对照组,并且诱导率随BDE-47浓度增加而增加。(5)扫描电镜结果显示,随着BDE-47浓度的增大,两种藻细胞形态均受到破坏,出现细胞破碎、失水、鞭毛脱落等现象。透射电镜结果表明,对照组叉鞭金藻细胞器清晰均匀分布在基质中,而BDE-47处理下,叶绿体皱缩,类囊体排列散乱,线粒体数目增加,细胞基质变浑浊,表明细胞器受到严重损伤。
[Abstract]:Polybrominated diphenyl ethers (polybrominated diphenyl, ethers, PBDE) is a kind of ecological risk model of persistent organic pollutants, since the last century since 70s has been used brominated flame retardants and additives, widely used in electronic products, textiles and foam plastic products. PBDEs can seep through volatilization or etc. enter into the environment, and the migration, accumulation characteristics and durability, these characteristics determine the compounds in the environment not only long-term residue, but also for bioaccumulation and amplification, from normal physiological activities and influence of the organism, its impact on the marine environment has aroused extensive attention at home and abroad the staff, therefore the study on Evaluation of PBDEs behavior in the environment is necessary. However, the PBDEs of marine microalgae toxicity is rarely reported, and thus cannot be objective evaluation Marine ecological risk of such compounds. Microalgae are the primary producers of the marine ecosystem, the species diversity and biomass of the structure and function of the marine ecosystem, plays a very important role in the food chain, and is sensitive to poison, and easy to obtain the advantages of fast breeding, can influence on the study of pollutant the population and generations in a short period of time, is an ideal biological indicator. In this paper, the environment with high content, widely distributed PBDEs representative 2,2 ', homologues of 4,4' - four polybrominated diphenyl ether (2,2', 4,4'-Tetrabromodiphenyl, Ether, BDE-47) as the research object, taking the common marine microalgae Dicrateria (Dicrateria inornata), Skeletonema costatum (Skeletonema costatum), phaeodactylumtricornutum (Phaeodactylum tricornutum) (Chlorella vulgaris), Chlorella as the test organism and the effects of BDE-47 on four kinds of Marine Micro The acute toxicity of algae, get half effect concentration of 96 h BDE-47 to four kinds of microalgae (96 h-EC5o). On this basis, the effects of different concentrations of BDE-47 under the action of Dicrateria (Dicrateria inornata), Skeletonema costatum (Skeletonema costatum) the chlorophyll fluorescence parameters (Fv/Fm, Fv/Fo, rETR, PSII), photosynthetic pigments (chlorophyll a (Chl-a), chlorophyll C (Chl-c) and carotenoid (Car) content), soluble protein content, superoxide dismutase (Superoxide dismutase, SOD) activity and malondialdehyde (Malondialdehyde, MDA) content changes, and changes in algal cell morphology, to investigate the BDE-47 the toxic mechanism of marine microalgae. The main results are as follows: (1) BDE-47 on Dicrateria and Skeletonema costatum 96 h-EC5o = 163 g L-1 and 648648 g L-1, BDE-47 of Dicrateria belongs to high toxic substances, which belongs to the high toxicity of Skeletonema. Algae 鐗╄川锛涘湪鍙�鍔╂憾娴撳害鑼冨洿鍐呮湭鑳芥＃�

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