【摘要】 乙草胺是一种主要用于防除禾本科杂草的酰胺类除草剂,苄嘧磺隆是一种用于防除阔叶杂草的磺酰脲类除草剂,乙·苄复配制剂由于扩大了除草谱而被广泛应用于稻田中,但大量使用也带来了环境隐患。本研究从长期施用乙·苄复配制剂的稻田土壤中筛选到1个可耐受600 mg/L苄嘧磺隆的乙草胺降解复合菌系,从中分离到4个细菌菌株66C-1、66C-2、66C-3、66C-4,利用形态、生理生化及分子生物学方法,分别鉴定为粘质沙雷式菌(Serratia marcescens)、Psedomona shunanensis、恶臭假单胞菌(Pseudomonas putida)和硝化还原假单胞菌(Pseudomonas nitroreducens)。这4个菌株等比例混合构成的降解菌系HXDW可以利用乙草胺为唯一碳源、但不能利用丁草胺、异丙甲草胺和吡氟酰草胺等其他酰胺类除草剂。降解菌系HXDW在乙草胺初始浓度为100 mg/L的无机盐培养基中,0.1%~2.0%Na Cl浓度范围内生长良好,最适培养温度为25℃。提取降解菌系不同部位粗酶液对50 mg/L乙草胺进行处理,胞外提取液的24 h乙草胺降解率为44.95%,表明降解菌系HXDW对乙草胺的降解作用主要存在于胞外。更多还原

【Abstract】 Acetochlor is a kind of amide herbicide which is mainly used to control gramineous weeds.Bensulfuron-Methyl is a kind of sulfonylurea herbicide which is used to control broadleaf weeds.Because of widely weed-control spectrum,acetochlor and bensulfuron-methyl compounded weedicide is used in paddy field,however a large number of use also caused the environmental problems.In this study,a mixed bacteria could degrade acetochlor and resistant to 600 mg/L bensulfuron-methyl,was screened from the long used this compounded weedicide’s paddy soil.Four bacterial strains 66 C-1,66 C-2,66 C-3 and 66 C-4 were isolated from this mixed flora and identified as Serratia marcescens,Psedomona shunanensis,Pseudomonas putida and Pseudomonas nitroreducens using morphological,physiological,biochemical and molecular biology methods,respectively.The composite microbial system HXDW,which is consisted of four strains’ s equal proportion mixture,can use acetochlor as the sole carbon source,but couldn’t utilize butachlor,metolachlor,diflufenican and other amides herbicides.The HXDW grew well in mineral salt medium with 100 mg/L acetochlor,0.1%~2.0% Na Cl concentration,and 25℃ culture temperature.Acetochlor-degrading rate of extracellular crude enzyme was 44.95%after 24 hours incubation with 50 mg/L herbicide concentration,and it showed that the HXDW degradation was mainly found in extracellular.更多还原