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

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.