2,2',4,4'-四溴联苯醚(BDE-47)对青萍的毒性效应

孙源, 邱念伟*, 王仁君*
曲阜师范大学生命科学学院, 山东曲阜273165

通信作者:邱念伟;E-mail: nianweiqiu@163.com; wangrenjun2002@126.com

摘 要:

为了解2,2',4,4'-四溴联苯醚(BDE-47)对水生植物的毒性, 以水生模式植物青萍(Lemna minor)为研究对象, 采用序批式培养方式进行培养, 从种群生长、光合功能和抗氧化能力等方面系统研究了不同浓度BDE-47胁迫对青萍的毒性效应。结果表明: 在0~15 μg•L-1 BDE-47处理下, 青萍生物量随时间变化的生长曲线均呈“S”型, 说明在0~15 μg•L-1 BDE-47浓度范围内, 单位面积上青萍生物量的增长受密度的制约。当BDE-47浓度为5 μg•L-1时, 已显著抑制青萍的生长, 内禀增长率显著低于对照; 但此时青萍叶绿素含量与对照相比没有明显变化。随着BDE-47处理浓度的增大(≥10 μg•L-1), 对青萍生长的抑制效应更为显著, 叶绿素含量逐渐下降。BDE-47达到20 μg•L-1时, 则导致青萍黄化死亡。可溶性蛋白含量随着BDE-47浓度的增大呈显著的下降趋势。光合参数Fv/FmPI则显示, 5 μg•L-1 BDE-47就显著影响青萍的光合功能, 质膜透性也显著增大。青萍SOD和POD活性在BDE-47浓度为5~10 μg•L-1时上升, 然后在15~20 μg•L-1时下降。MDA含量则随着BDE-47浓度的升高而逐渐增加。以上结果表明低浓度(5 μg•L-1)的BDE-47即对青萍产生显著的毒害作用, 表现为影响青萍的光合功能, 抑制光合色素和蛋白质合成, 改变质膜透性, 对细胞造成过氧化伤害。上述结果为全面了解BDE-47对水生植物的毒性提供了理论支持。

关键词:2,2',4,4'-四溴联苯醚; 青萍; 毒性效应; 生长; 光合作用; 抗氧化酶

收稿:2016-08-18   修定:2016-09-19

资助:山东省自然科学基金(2009ZRB01461和ZR2015DL009)、国家自然科学基金(31200400)和中国博士后科学基金项目(2016M592158)。

Toxic effect of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on Lemna minor

SUN Yuan, QIU Nian-Wei*, WANG Ren-Jun*
College of Life Sciences, Qufu Normal University, Qufu, Shandong 273165, China

Corresponding author: QIU Nian-Wei; E-mail: nianweiqiu@163.com; wangrenjun2002@126.com

Abstract:

This study investigated the toxic effect of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on Lemna minor, a model hydrophyte. L. minor was cultured by sequencing batch cultivation. The toxic effects of BDE-47 on L. minor were analyzed from the perspectives of growth, photosynthesis and antioxidant capacity. The results indicated that the growth curves of L. minor were sigmoidal curves when BDE-47 concentration was 0–15 μg•L-1, indicating that the density restriction apply to the growth of L. minor under 0–15 μg•L-1 BDE-47. Significant inhibition effect on the growth of L. minor was observed under 5 μg•L-1 BDE-47, with the intrinsic rate of L. minor were significantly lower than that in control group. At this case, chlorophyll contents in L. minor leaves had no obvious change compared with control group. Along with the increase of added BDE-47 (≥10 μg•L-1), the inhibition effect became greater with chlorophyll contents decreased, until yellowed and died under 20 μg•L-1 BDE-47. The content of soluble protein showed a negative correlation with the increase of BDE-47 concentration. As photosynthetic indexes (Fv/Fm, PI) indicated, photosynthetic function of L. minor plants was obviously inhibited even 5 μg•L-1 BDE-47 existed. Moreover, the permeability of plasma membrane ascended along with the increase of BDE-47 concentration. SOD and POD activity in L. minor raised when BDE-47 was in range of 5–10 μg•L-1, whereas decreased under 15–20 μg•L-1 BDE-47. MDA content gradually increased along with the increase of BDE-47 concentration. The results above indicate that BDE-47 has obvious toxic effects on L. minor even at very low concentrations (5 μg•L-1), which declined photosynthetic function, inhibited synthesis of chlorophyll and protein, increased plasma membrane permeability, and caused peroxide damage to cell. This study provides a better understanding for investigating the toxic effects of BDE-47 on hydrophytes.

Key words: 2,2',4,4'-tetrabromodiphenyl ether; Lemna minor; the toxic effect; growth; photosynthesis; antioxidant enzymes

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