The combined effects of UV-B radiation and herbicides on photosynthesis, antioxidant enzymes and DNA damage in two bloom-forming cyanobacteria

• Published in: Ecotoxicology and environmental safety Vol. 80; pp. 224 - 230
• Main Authors: Chen, Lanzhou, Xie, Mu, Bi, Yonghong, Wang, Gaohong, Deng, Songqiang, Liu, Yongding
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.06.2012; Elsevier
• Subjects: 2-Methyl-4-chlorophenoxyacetic Acid - toxicity; Anabaena; Animal, plant and microbial ecology; Antioxidants; Applied ecology; ascorbic acid; Ascorbic Acid - metabolism; Biological and medical sciences; Bloom-forming cyanobacteria; chlorophyll; Cyanobacteria - drug effects; Cyanobacteria - physiology; Cyanobacteria - radiation effects; Damage; Deoxyribonucleic acid; Diuron - toxicity; DNA Damage; Ecotoxicology, biological effects of pollution; electron transport chain; fluorescence; Fundamental and applied biological sciences. Psychology; General aspects; Geographic information systems; Global Positioning System; global positioning systems; Glycine - analogs & derivatives; Glycine - toxicity; Glyphosate; Herbicides; Herbicides - toxicity; irradiation; light intensity; malondialdehyde; Malondialdehyde - metabolism; MCPA (herbicide); Microcystis; Oxidation-Reduction; Photosynthesis; Photosynthesis - drug effects; Photosynthesis - radiation effects; pigments; reactive oxygen species; Reactive Oxygen Species - metabolism; Repair ability; Satellite navigation systems; superoxide dismutase; Toxicity degree; ultraviolet radiation; Ultraviolet Rays - adverse effects; UV-B radiation; Water Pollutants, Chemical - toxicity; MCPA-Na; PSII; SOD; Bloom-forming cyanobacteria; GPS; MDA; Toxicity degree; UV-B radiation; ASC; Herbicides; RC/CSo; ETo/ABS; CBs; ETo/TRo; Fv/Fm; DCMU; Repair ability; Ecotoxicology; Toxicity; Enzyme; UVB radiation; Pesticides; Genotoxicity; Antioxidant; Herbicide; DNA; Bloom; Cyanobacteria; Bacteria; Environment; Damage; Photosynthesis
• ISSN: 0147-6513; 1090-2414; 1090-2414
• DOI: 10.1016/j.ecoenv.2012.03.007

In this study, we investigated the combined effects of UV-B irradiation and herbicides (glyphosate, GPS; 2-Methyl-4-chlorophenoxyacetic acid, MCPA-Na; 3-(3,4-dichlorophenyl)-1,1-dimethylurea, DCMU) and the antioxidant (ascorbic acid, ASC) on photosynthesis, antioxidant enzymes and DNA damage in two bloom-forming cyanobacteria, Anabaena sp. and Microcystis viridis. UV-B irradiance increased reactive oxygen species (ROS) production, which decreased chlorophyll a fluorescence yield, pigment content and superoxide dismutase (SOD) activity, and increased malondialdehyde (MDA) content and caused serious DNA damage. The degree of these damages was aggravated by the addition of DCMU, GPS and MCPA, and was partially mitigated by the addition of ASC. During the recovery process, the degree and mechanism in restoring DNA damage and photosynthesis inhibition were different by the removal of UV-B and herbicides (DCMU, GPS and MCPA) in both cyanobacteria. These results suggest that the combination of UV-B and exogenous herbicides have detrimental effects on cyanobacterial metabolism through either a ROS-mediated process or by affecting the electron transport chain, and may cause the shifts in the phytoplankton community. ► Effects of UV-B and herbicides on two cyanobacteria were investigated. ► UV-B irradiation could inhibit photosynthesis and destroy DNA strand breaks. ► The addition of herbicides could aggravate the toxicity process. ► The damage mechanisms induced by UV GPS, MCPA and DCMU were different. ► The combined effects may cause the shifts of phytoplankton community.