少根紫萍对铜绿微囊藻胁迫的生化响应模式

Biochemical response pattern of Spirodela punctata under the stress of Microcystis aeruginosa

摘要:

了解在藻类胁迫下浮萍的应激和抗胁迫机制，为提高浮萍水污染修复的应用效益提供参考.本研究设置了不同浓度梯度的铜绿微囊藻与少根紫萍共培养体系，并测生物量、叶绿素、抗氧化酶以及藻毒素等指标.实验结果如下：少根紫萍在低剂量铜绿微囊藻3×108 cells/L, 6×108 cells/L共培条件下可持续富集藻毒素；各组少根紫萍的生长均受到抑制，3×108 cells/L低剂量组在共培养6 d后可以促进少根紫萍的增长；少根紫萍中不同抗氧化酶在铜绿微囊藻胁迫下的酶活变化不同, 3×108 cells/L低剂量组在共培养6 d后过氧化物酶（POD）和谷胱甘肽过氧化物酶（GSHPx）酶活显著提高，共培养12 d后超氧化物歧化酶（SOD）和过氧化氢酶（CAT）酶活有所提高.结果表明铜绿微囊藻胁迫下少根紫萍生长发育受到抑制，低浓度铜绿微囊藻胁迫下可以提高少根紫萍的抗氧化应激能力，过高浓度可能会导致抗氧化酶的异常表达并损害体细胞的正常代谢.

Abstract:

To investigate the response mechanism under Microcystis aeruginosa stress provides reference value on improving application efficiency of duckweed in water pollution repair. In this study, we established a coculture system of Microcystis aeruginosa and Spirodela punctata with different concentration gradients, and measured biomass, total chlorophyll, antioxidant enzymes and microcystin. The main results showed as following: Spirodela punctata cocultivated with Microcystis aeruginosa at 3×108 cells/L, 6×108 cells/L concentration were enriched Microcystin(MCs) continually; the growth of Spirodela punctata was inhibited and the biomass decreased continuously in each group, whereas the fresh weight was increased in lowdose Microcystis aeruginosa (3×108 cells/L) after 6days’ cocultivation; the activities of different antioxidant enzymes were different under the stress of Microcystis aeruginosa, peroxidase (POD) and glutathione peroxidase (GSHPx) activities were significantly increased after 6days’ cocultivation, and superoxide dismutase (SOD) and catalase (CAT) activities were inhibited first while they were both improved after 12 days at 3×108 cells/L. In summary, the growth and development of Spirodela punctata under the stress of Microcystis aeruginosa was inhibited, but the antioxidant capacity of Spirodela punctata could be enhanced under the condition of lower concentration of Microcystis aeruginosa, and excessive concentration of Microcystis aeruginosa might lead to abnormal expression of antioxidant enzymes and affect the metabolism of cells seriously.