新除草剂HNPC-C9908对小球藻生长的影响研究

Effects of Novel Sulfonylurea Herbicide HNPC-C9908 on Growth of Green Algae Chlorella pyrenoidosa

HNPC-C9908[2-(4-甲氧基-6-甲硫基嘧啶-2-基)氨基甲酰基氨基磺酰基苯甲酸甲酯]是国家南方农药创制中心湖南基地研制成功的具有自主知识产权的一种新型磺酰脲类除草剂,主要用于小麦田各种阔叶杂草和一些禾本科杂草的防除。以蛋白核小球藻ChlorellapyrenoidosaChick为对象,研究了HNPC-C9908对藻类的毒性效应及其致毒机理。实验结果表明,HNPC-C9908对蛋白核小球藻生长具有明显影响,在低浓度(1mg/L)时具有刺激藻细胞生长的作用,高浓度(>25mg/L)时表现出明显的抑制作用,其对蛋白核小球藻生长的96h-EC50值为29.12mg/L。参照国家有关建议评价标准,HNPC-C9908对蛋白核小球藻属于低毒。同时,HNPC-C9908对蛋白核小球藻叶绿素含量也有影响。藻细胞叶绿素含量随药剂浓度的增加而下降,表现出良好的剂量-效应关系。在HNPC-C9908作用下,蛋白核小球藻细胞中可溶性蛋白质含量和两种清除活性氧自由基的关键性酶——超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均有明显的变化,低浓度时表现出应激性上升,而高浓度时明显受到抑制,其对藻细胞可溶性蛋白质含量、SOD和POD活性的96h-IC50值分别为26.27、15.25和13.76mg/L,说明SOD和POD活性的降低是HNPC-C9908的存在使蛋白核小球藻产生过量活性氧自由基进而引起膜脂过氧化及细胞膜?

HNPCC9908 is a novel sulfonylurea herbicide discovered by Hunan Branch of the National Pesticide R&D South Center, Changsha, China, which is effective in controlling various broadleaf weeds and some grasses in the wheat field. Toxicity and toxic mechanism of HNPCC9908 to the green algae, Chlorella pyrenoidosa Chick, were studied in the laboratory. The experimental results showed that HNPCC9908 had obvious effects on the growth of the algae, depending upon the concentrations. The growth stimulation was observed under the low concentration of 1 mg/L HNPCC9908, and the obvious inhibition of the growth of the green algae under the high concentration of more than 25 mg/L. Its 96hEC50 value of HNPCC9908 against the algae growth was 29.12 mg/L, indicating that HNPCC9908 was considered as a low toxic pesticide to the green algae. Meanwhile, HNPCC9908 also exhibited some inhibitory influences on the photosynthesis pigments such as chlorophyll a and b. The chlorophyll content of the algae cells declined with the increasing concentration of HNPCC9908, showing the good concentrationeffect relationship. In the presence of HNPCC9908, the soluble protein content, the two key enzymes responsible for eliminating the active oxygen superoxide dismutase (SOD) and peroxidase (POD) activity in the algae cells exhibited the obvious changes. The irritable increases of the protein content, SOD and POD activity in the algae cells were observed under the low concentration, and significant inhibitions appeared under the high concentration with the 96 hIC50 values of 26.27 mg/L, 15.25 mg/L and 13.76 mg/L, respectively, demonstrating that HNPCC9908 resulted in the decline of SOD and POD activity in the algae cells, making the active oxygen excessive and accumulative, algae cell membrane lipid peroxidation, and thus caused the damage of the algae cells.