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Effects of Mesotrione on Photosynthesis and Species Competition in Microcystis sp. and Scenedesmus quadricauda |
Received:June 13, 2014 |
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KeyWord:mesotrione;competition;photosynthesis;Scenedesmus quadricauda;Microcystis sp. |
Author Name | Affiliation | E-mail | NI Yan | Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Institute of Environmental and Chemical Engineering, Nanchang University, Nanchang 330047, China | | WAN Jin-bao | Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Institute of Environmental and Chemical Engineering, Nanchang University, Nanchang 330047, China | jbwan@ncu.edu.cn | LAI Jin-hu | Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Institute of Environmental and Chemical Engineering, Nanchang University, Nanchang 330047, China | | WANG Mao-lan | Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Institute of Environmental and Chemical Engineering, Nanchang University, Nanchang 330047, China | |
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Abstract: |
Mesotrione(2-[4-methylsulfonyl-2-nitrobenzoyl]-1,3-cyclohexanedione) belongs to the triketone family and has been widely utilized to control a wide range of annual grasses and broad-leaved weeds in maize production. It has been detected in the aquatic environments and may have negative impacts on aquatic organisms. In the present study, mono-culture and mixed-culture experiments were carried out to investigate the effects of mesotrione on the photosynthesis and species competition of Microcystis sp. and Scenedesmus quadricauda. Mesotrione at 0.5~10 mg·L-1 decreased the Fv/Fm, Ik, α and ETRmax in both Microcystis sp. and S. quadricauda, with significant correlation found between such decreases and mesotrione concentrations. On the 14th day of exposure, all fluorescence parameters reduced to the minimum values at 10 mg·L-1. Mesotrione had greater effects on the fluorescence parameters in S. quadricauda than in Microcystis sp. Under control conditions, S. quadricauda was dominant over Microcystis sp. However, exposure to 5 mg·L-1 and 10 mg·L-1 mesotrione enhanced the competition of Microcystis sp. The strongest competitive ability was observed in mixed culture of 1:3(Microcystis sp.:S. quadricauda) ratio. Therefore, mesotrione has the potential to promote cyanobacteria bloom. |
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