甲磺隆对微囊藻生长和光合系统的影响

摘要

Metsulfuron-methyl is one of the sulfonylurea herbicides, which have been widely used throughout the world because of its significant advantages and safety. However, long-term use of Metsulfuron-methyl will impose a threat to aquatic ecosystems. Algae are frequently the major primary producers in aquatic ecosystems, often as an indicator to study water pollutants. In this study, dominant species of cyanobacteria (Microcystis aeruginosa PCC7806) were selec-ted to deeply perceive the effect of Metsulfuron-methyl on the growth and photosynthetic of Microcystis aeruginosa. The achieved results showed that the growth of M. aeruginosa PCC7806 was significantly inhibited when the concen-tration of Metsulfuron-methyl exceeds 80 mg/L. The EC50of the growth of M. aeruginosa PCC7806 was 81.998 mg/L by regression and Probit analysis. The results of cytochrome studies demonstrated that the content of chlorophyll a and carote-noids in unit cell of the treatment group on the 6th day was lower than that of in the control group, and when the con-centration of Metsulfuron-methyl was 80 mg/L, the carotenoids content was remarkably lower than that of in the con-trol group. The results of kinetics of chlorophyll fluorescence showed that the energy ( ET0/RC) captured by the unit re-action center for electron transport (φE0) was used for quantum yield of photosynthetic of electron transport, which is extraordinary suppressed on the 6th day of the experiment. The results of chlorophyll fluorescence induction and cytochrome analy-sis showed that Metsulfuron-methyl could negatively affect the electronic properties of the electron acceptor in the pho-tosynthetic reaction center. In summary, Metsulfuron-methyl may act on the electron acceptor side of the photosynthe-tic response center, thereby likely affecting the photosynthetic system of Microcystis aeruginosa.%研究选取了水体常见蓝藻优势种类——铜绿微囊藻(Microcystis aeruginosa PCC7806)作为研究对象,了解磺酰脲类除草剂甲磺隆(Metsulfuron-methyl)对铜绿微囊藻生长和光合系统的影响.研究表明, 当甲磺隆浓度大于80 mg/L时, 对铜绿微囊藻的生长具有显著抑制.通过回归分析和Probit分析, 甲磺隆对铜绿微囊藻生长的EC50为81.998 mg/L.细胞色素研究结果显示,实验第6天,各浓度处理下单位细胞内Chl.a和类胡萝卜素含量均低于对照组, 且当甲磺隆浓度为80 mg/L时, 单位细胞内类胡萝卜素含量显著低于对照组.快速叶绿素荧光诱导动力学变化结果分析显示, 实验第6天甲磺隆胁迫下单位反应中心捕获的用于电子传递的能量( ET 0/RC)及单位反应中心用于电子传递的量子产额(φE0)受到显著抑制,综合细胞色素变化结果显示,甲磺隆能显著抑制光合系统反应中心电子受体侧电子性能.综上所述, 甲磺隆可能作用于光合系统反应中心电子受体侧, 从而对铜绿微囊藻光合系统造成影响.