Festuca arundinacea,glutathione S-transferase and herbicide safeners: A preliminary case study to reduce herbicidal pollution

The expression of glutathione S-transferase (GST) activity in Festuca arundinacea was investigated in response to the following herbicide safeners: benoxacor, cloquintocet-mexyl, fenchlorazol-ethyl, fenclorim, fluxofenim and oxabetrinil. All the above compounds enhanced the GST activity tested towards the “model” substrate 1-chloro-2,4-dinitrobenzene (CDNB). Assays of GST activity towards the herbicides terbuthylazine (N ²-tert-butyl-6-chloro-N ⁴-ethyl-1,3,5-triazine-2,4-diamine) and butachlor (N-butoxymethyl-2-chloro-2′,6′-diethylacetanilide) as substrates also showed the ability of the safeners to enhance the enzyme activity towards both these herbicides, with the exception of cloquintocet-mexyl for the enzyme activity towards butachlor. As a consequence of the above effects at a macro-scale level, decreased herbicide accumulation and persistence were ascertained in response to the addition of the safener benoxacor to both terbuthylazine and butachlor treatments. These results are discussed in terms of capacity of benoxacor to induce herbicide detoxification in Festuca arundinacea with a view to utilizing them in reducing herbicide pollution.     

稻田环境与除草剂去草胺降解速率的关系

在稻田自然环境中,去草胺乳油和颗粒剂的残留半衰期,在田水中分别为1.65—2.84d和5.78—6.30d,在土壤中分别为2.67—5.33d和4.95—6.30d.经过水稻一个生育期,去草胺在糙米等样品中的最终残留量均降至可检水平以下.土壤微生物对去草胺的降解起着主导性的作用,在灭菌和不灭菌土壤中的残留半衰期分别为433d和18.50—29.40d.去草胶在涂土等四类不同属性的土壤中的渗漏性大小顺序,依次为涂土、小粉土、青紫泥和红壤.     

一株丁草胺降解菌的分离鉴定及培养条件优化

利用富集培养技术从长期施用丁草胺的稻田土壤中分离得到1株能够降解丁草胺的细菌,标记为LYC-2.经形态特征、生理生化特征和16SrDNA序列分析,将该菌株鉴定为钩杆菌属(Ancylobacter sp.).同时,为探索菌株LYC-2的生长特性和最佳培养条件,利用正交试验设计法考察了接种量、温度、pH值3个因素对菌株LYC-2生长的影响.结果表明,菌株LYC-2的最适生长温度为35℃,最适pH值为7.5.当接种量为6%(体积分数,下同)时,该菌株在含100mg.L-1的丁草胺无机盐基础培养液中培养5d后,可使丁草胺降解率达90.85%以上.     

丁草胺在土壤中吸附特性研究

采用室内模拟试验方法,研究了丁草胺在三种不同有机质含量土壤中的吸附特性曲线,采用批量平衡法,用三种土壤对丁草胺进行吸附,并通过改变三种土壤的投加量、温度和pH进行实验。实验结果表明,丁草胺在三种不同土壤中的吸附平衡时间大约为12h,以快速吸附为主,土壤的有机质含量是影响土壤吸附性能的重要因素,土壤有机质含量与土壤对农药的吸附呈正相关,土壤的投加量越大固相中的吸附量也越大,丁草胺在土壤中的吸附随着温度的升高而减弱,但影响并不明显;碱性条件不利于土壤对丁草胺的吸附量。     

苄·丁可湿性粉剂中丁草胺在稻田土壤和田水中残留动态

采用气相色谱法研究了35%苄·丁可湿性粉剂中丁草胺在2006年和2007年湖北省、广东省2年两地水稻田土壤和水中的残留降解动态和最终残留量.研究结果表明丁草胺在土壤和田水添加回收率分别为82.78%～93.20%和90.31%～93.51%.丁草胺在稻田土壤和田水中降解动态符合一级动力学指数模型,在湖北省和广东省水稻田土壤中的半衰期分别为3.21～3.83 d、2.49～3.66 d,水稻田水中的半衰期分别为1.20～1.66 d、1.13～1.48 d.861 g(a.i.)·hm-2和高剂量1 292 g(a.i.)·hm-2两个剂量施药后丁草胺在稻田土壤中的最终残留量为0.001 0～0.002 9 mg·kg-1.     

甲草胺和丁草胺等除草剂在多介质环境中环境行为综述

本文详细综述了甲草胺和丁草胺的物理化学性质,总结了它们在土壤和水中的迁移,吸附和微生物降解转化,对动植物的毒性和作用机制,酰胺类除草剂在分析检测方面的进展以及在污染的防治与修复方面的一些措施     

稻田环境与除草剂去草胺降解速率的关系

在稻田自然环境中,去草胺乳油和颗粒剂的残留半衰期,在田水中分别为1.65-2.84d和5.78-6.30d,在土壤中分别为2.67-5.33d和4.95-6.30d.经过水稻一个生育期,去草胺在糙米等样品中的最终残留量均降至可检水平以下.土壤微生物对去草胺的降解起着主导性的作用,在灭菌和不灭菌土壤中的残留半衰期分别为433d和18.50-29.40d.去草胶在涂土等四类不同属性的土壤中的渗漏性大小顺序,依次为涂土、小粉土、青紫泥和红壤.     

Biodegradation of acetanilide herbicides acetochlor and butachlor in soil

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matters addition were measured during 35 days lal)oratory incubations. The herbicides were applied to soil alone, soiI-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soilSDBS mixtures and soil-HA mixtures were 4.6d, 6, ld and 5.4d and 5.3d, 4.9d and 5.3d respectively. The biodegradation products were hydroxyacetochlor and 2-melhvl-6-ethvlaniline for acetochlor, and hvdroxvbutachlor and 2,6-diethvlaniline for butachlor.     

乙草胺和丁草胺在土壤中的紫外光化学降解

采用实验室模拟实验研究了水分、pH值和表面活性剂对乙草胺和丁草胺在土壤中的紫外光降解行为的影响。结果表明，在湿度80％的土壤中，丁草胺和乙草胺的光解深度及光解速率均大于无水条件。随土壤pH值的增大，丁草胺在土壤中的光降解速率加快和光解深度加深。低浓度的阴 离子表面活性剂十二烷基苯磺酸钠（DDBS）促进丁草胺在土壤中的光解，使丁草胺在土壤中的光解深度增加。高浓度的DDBS对丁草胺在土壤中的光解有阻碍作用。阳离子表面活性剂十六烷基三甲基溴化铵（HDTMA）对丁草胺在土壤中的光解也有阻碍作用。     

一个硫酸盐还原细菌富集物对丁草胺的厌氧降解

通过多次富集培养，得到一个能有效厌氧降解丁草胺的硫酸盐还原细菌(SRB)富集物，并对该富集物的生长动力学以及生长的最适丁草胺浓度、最适pH和最适温度作了探讨.