Residue and Degradation Dynamics of Bensulfuron-methyl·Mefenacet 4.2 g/kg Granule in Paddy Field

This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem. A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl.mefenacet 4.2 g/kg granule in rice and paddy system in Hangzhou, Changsha and Nanning of China during 2010 to 2011. The results showed that the average recoveries of bensulfuron-methyl and mefenacet spiked in the paddy soil, paddy water, rice, husk and rice plant at the 3 concentration levels of 0.05, 0.10 and 1.00 mg/kg ranged from 70.78% to 116.06% with the relative standard deviations of 0.91%-10.24%. The limit of detection （LOD） values of bensulfuron-methyl and mefenacet were 0.02 mg/L, and the minimum de- tection quantities were 4.0×10-9 g. The degradation dynamics test was done by spraying at a high dose （270 kg/hm2, bensulfuron-methyl active ingredient was 64.8 g/hm2, mefenacet active ingredient was 1 069.2 g/hm2） by direct spreading method 5-7 d after transplanting, and the final residual test carried out at a low dose （180 kg/hm2, bensuifuron-methyl active ingredient was 43.2 g/hm2, mefenacet active in- gredient was 712.8 g/hm2） and a high dose （270 kg/hm2）. The degradation research of bensulfuron-methyl and mefenacet in paddy water, soil and rice plant suggested that the degradation curves accorded with the first-order kinetics equation, the aver- age half life of bensulfuron-methyl was 5.35, 3.05 and 3.71 d in water, soil and rice plant, respectively, and the average half life of mefenacet was 3.61, 3.29 and 3.88 d in water, soil and rice plant, respectively. The final residues of bensulfuron-methyl and mefenacet were not detected in normal harvest paddy soil, rice straw, husk and brown rice.

Synergistic Effects of Several Additives on Herbicidal Activity of Bensulfuron-methyl

[ Objective] The aim was to select the best additives of bensulfuron-methyl. [ Method ] Taking radish as the testing plant, the synergistic effect of five common additives including Span 60, methyl olelate, silicone oil I, Tween 20 and detergent on the herbicidal activities of bensulfuron-methyl were tested in the la- borotory. [ Results ] The effects of the mixture of various additives and bensulfuran-methyl on relative stem control effect of radish, relative inhibition rate against stem length, relative inhibition rote against abeveground fresh weight, relative inhibition rote aginst root length and root fresh weight were studied, and the results showed that Span 60 and methyl olelate had stronger synergistic effect on the herbicidal activities of bensulfuron-methyl, and the synergistic effect of detergent was the weakest. [ Conclusion ] Span 60 and methyl olelate could be used as the synergistic agents of bensulfuron-methyl, and the study could provide references for se- lecting the additives of bensulfuron-methyl.

Analysis of culturable and unculturable microbial community in bensulfuron-methyl contaminated paddy soils

To investigate the influence of bensulfuron-methyl(BSM)on culturable microbial quantities and unculturable microbial community structures,conventional and molecular biological methods were employed in five BSM treated soils with three replications,respectively. The results obtained with traditional culture-dependent methods showed that a low-level of BSM had slight and transient effects on culturable microorganisms;nevertheless,high concentration of BSM resulted in a dramatic decrease in bacterial colony fo...

Adsorption characteristic of bensulfuron-methyl at variable added Pb^(2+) concentrations on paddy soils

The combined pollution of heavy metal Pb^2＋ and bensulfuron-methyl （BSM）, originating from chemical herbicides, in agroecological environments has become commonplace in southern China. The adsorption of BSM on three paddy soils in the presence of Pb^2＋ was examined using high-performance liquid chromatograph （HPLC）. Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant （R） 〉 0.98, irrespective of the presence of spiked Pb^2＋. Of the various factors influencing BSM sorption, soil pH appeared to be the most influential. The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb^2＋ concentration in soil which indicated that the spiked of Pb^2＋ in paddy soils would promote the sorption of BSM. AGo of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating the adsorption of BSM is mainly physical in nature. The elution of soil dissolved organic matter （DOM） enhanced the adsorption of BSM in paddy soils. The mechanisms involved in the promotion effects of the spiked Pb^2＋ on BSM adsorption might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.

Rapid degradation of bensulfuron-methyl upon repeated application in paddy soils

Rapid degradation of bensulfuron-methyl upon repeated application in paddy soils was studied. The results showed that the DT _ 50 of bensulfuron-methyl was reduced from 16 d to 9 d in soil with one-year bensulfuron-methyl application. Rapid bensulfuron-methyl degradation was happened to previously untreated soil by addition 5% rapid bensulfuron-methyl adapted soil and was inhibited following pre-treatment with broad-spectrum antibiotic chloramphenicol. In bensulfuron-methyl adapted soil mineralisation of 14 C labeled bensulfuron-methyl to 14 CO_2 occurred at a faster rate than with previously untreated soil. It was concluded that rapid bensulfuron-methyl degradation upon repeated application is probably linked to the adaptation of soil bacteria which can utilize bensulfuron-methyl as a source of carbon and energy.

Effect of Bensulfuron-Methyl on Growth of Chlorella pyrenoidosa

To study the growth effects of differing concentrations of bensulfuron-methyl on Chlorella pyrenoidosa and to evaluate the ecological risk, the effects of bensulfuron-methyl on the growth and the content change of chlorophyll and protein in Chlorella pyrenoidosa were studied through 96 h acute toxicity tests. Bensulfuron-methyl accelerated the growth of algae at lower concentrations （〈 1 mg L^-1） with content increase of chlorophyll or protein, and it inhibited the growth of algae at higher concentrations （〉 5 mg L^-1）. The content of chlorophyll or protein in algae cells reduced with the increasing concentration of bensulfuron-methyl, exhibiting the good concentration-effect relationship. The 96 h-EC50 of bensulfuronmethyl upon the algae was 15.7 mg L^-1 Bensulfuron-methyl has inhibiting effect on the growth of Chlorella pyrenoidosa and is low in toxicity.

Research Progress in Microbiological Degradation of Bensulfuron-Methyl Herbicide

This paper reviewed the strategies and methods of screening for microorganisms having strong ability bensulfuron-methyl （BSM）, and discussed BSM degradation pathways and factors affecting its microbial metabolism prospected the research emphasis in the future to remove Finally, it

Effects of temperature and pH on the inhibition of Bensulfuron-Methyl(BSM)

Bensulfuron-Methyl(BSM)is a highly active sul-fonylurea herbicide that effectively controls most an-nual and perennial broadleaf or sedge weeds in paddyfield.However,the activity of BSM is affected byseveral evironmental factors.Using corn seedlings asmaterial,we found that under different temperatures

Expression of sulfur uptake assimilation-related genes in response to cadmium,bensulfuron-methyl and their co-contamination in rice roots

The responses of sulfur （S） uptake assimilation-related genes＇ expression in roots of two rice cultivars to cadmium （Cd）, bensulfuron-methyl （BSM） and their co-contamination （Cd＋BSM） were investigated by gene-chip microarray analysis and quantitative real-time PCR （QRT-PCR） technology. Treatments of Cd and Cd＋BSM induced expression of sulfate transporter and permease genes, and promoted sulfate uptake in rice roots. Cd＋BSM could alleviate Cd toxicity to cv. Fengmeizhan seedlings, probably due to Cd＋BSM promoting greater S absorption by seedlings. Cd and Cd＋BSM induced expression of sulfate assimilation-related genes, and thus activated the sulfur assimilation pathway. Cd and Cd＋BSM induced expression of phytochelatin synthase and metallothionein genes, and induced expression of glutathione S-transferases （GSTs）, glutathione synthase （GS） and S- containing antioxidation enzyme genes, which detoxified Cd2＋. It is suggested that （to cope with the toxicity of Cd, BSM and their co-contamination） the S uptake and assimilation pathway was activated in rice roots by increased expression of related genes, thus enhancing the supply of organic S for synthesis of Cd or BSM resistance-related substances.

Study on the Acute Toxicity and Genetics Toxicity of Bensulfuronk-methyl on Danio rerio

[Objective] The aim was to study the effect of bensulfuron-methyl herbicide on acute toxicity and genetics toxicity of Danio redo. [ Method] Median lethal concentration was calculated by acute toxicity test, and analyzing the herbicide whether existing in potential toxicity to aquatic organisms or not. Based on the study of acute toxicity, genetics toxicity was carried out, by calculating the micronucleus rate to judge bensulfuron-methyl herbicide whether existing in potential toxicity or not. [ Result ] The LD5o （24 h and 48 h） of bensulfuron-methyl herbicide are 0.698 ml/L and 0.637 ml/L respectively, the safe concentration was 0.159 ml/L. The results on the effects of micronucleus （MN） in erythrocytes of Danio redo induced by bensulfuron-methyl at different times and different concentrations showed that the MN rate of control group was 0.010 3%, the highest MN rate of experimental group reached to 0. 372%, it also indicated that bensulfuron-methyl herbicide had genetics toxicity to Danio redo. At the same detection time, there was dose-effect relationship of MN rate in erythrocytes between treatment and control groups with different concentrations. In the same treatment group, the MN rate in erythrocytes reached to peak value at 24 h, and decreased at 48 h and 72 h with the infection time was prolonged. [ Conclusion ] The study provides some basis for scientifically selecting and reasonably using herbicide.

浙江不同稻区耳叶水苋对苄嘧磺隆的抗性比较

采用琼脂法测定了长江三角洲地区宁绍平原和杭嘉湖平原5个稻区(宁波、绍兴、杭州、嘉兴和湖州)稻田耳叶水苋Ammannia arenaria不同生物型对苄嘧磺隆的抗性水平。结果表明,所采集的88种耳叶水苋生物型中,有96.6%已对苄嘧磺隆产生了抗性,其中,低抗(3<抗性指数RI≤10)、中抗(10<RI≤50)和高抗(RI>50)的生物型分别占总数的22.7%、53.4%和20.5%。宁波NB0143-01和绍兴SX077生物型对苄嘧磺隆的RI值分别高达124.4和120.4。5个稻区中,绍兴地区耳叶水苋的抗性水平最高,平均RI值为53.1;宁波次之,平均RI值为35.1;湖州、杭州和嘉兴地区的抗性水平相对较低,平均RI值分别为24.1、19.9和18.7。表明稻田耳叶水苋对苄嘧磺隆的抗性程度较高,且在宁绍平原和杭嘉湖平原稻区已普遍出现抗性。其中在宁绍平原苄嘧磺隆对耳叶水苋的选择压较大,长期连续用药可能是该地区抗性水平高于其他区域的重要原因。这是有关耳叶水苋对苄嘧磺隆抗性种群分布的首次报道。

苄嘧磺隆对水稻田土壤微生物群落功能多样性的影响

采用BIOLOG碳源底物利用法研究了不同浓度苄嘧磺隆(空白对照0 mg·kg-1、田间最大推荐剂量0.4 mg·kg-1和10倍田间最大推荐剂量4mg·kg-1)对水稻田土壤微生物群落功能多样性的影响。对BIOLOG微平板每孔颜色平均变化率(AWCD值)的分析结果表明,低浓度苄嘧磺隆会提高微生物的碳源利用能力,高浓度苄嘧磺隆表现抑制作用,且随着时间延长,苄嘧磺隆对微生物的促进和抑制作用逐渐消失。施药后96 h水稻田土壤微生物群落功能多样性指数(Shannon指数、Simpson指数和McIntosh指数)的数据分析结果表明,苄嘧磺隆会导致水稻田土壤微生物群落的碳源利用能力集中、可利用碳源种类数减少以及碳源利用程度下降。对水稻田土壤微生物群落主成分分析结果表明,苄嘧磺隆改变了水稻田土壤微生物的群落结构,但随着时间延长,苄嘧磺隆对水稻田土壤微生物群落结构的影响逐渐消失。

除草剂苄嘧磺隆在土壤中的吸附

应用平衡法研究了除草剂苄嘧磺隆在 8种土壤中的吸附特性 .结果表明 ,土壤对苄嘧磺隆有很强的吸附性 ,且随供试土壤理化性质的差异其吸附性呈明显变化 .苄嘧磺隆在土壤中的吸附符合Fruendlich方程 ,其在土壤中的吸附常数Kf 与土壤有机质、粘粒含量呈显著正相关 (r =0 73 93 和 0 775 1 ,p <0 0 5 ) ,与土壤 pH呈显著负相关 (r=0 70 68 ,p <0 0 5 ) .苄嘧磺隆在土壤上的吸附自由能为 1 1 4 5～ 1 3 3 8kJ/mol。

苄嘧磺隆对Cu^(2+)在粘土矿物上吸附-脱附的影响

选择两种粘土矿物Ca 蒙脱石和高岭石作为吸附体 ,研究Cu2 +的吸附 脱附行为 ,以及苄嘧磺隆对Cu2 +吸附 脱附的影响 .结果表明 ,Cu2 +在比表面积、CEC大的Ca 蒙脱石上吸附量较高 ;而在比表面积、CEC小的高岭石上吸附量较低 .蒙脱石对Cu2 +的吸附主要是静电吸附 ,吸附的Cu2 +较易脱附 ;高岭石主要通过专性吸附机制而吸附Cu2 +,吸附的Cu2 +较难脱附 .苄嘧磺隆对Cu2 +在粘土矿物上吸附 脱附的影响显著 .苄嘧磺隆增加了Cu2 +在Ca 蒙脱石上的吸附 ,苄嘧磺隆作为桥而连接Ca 蒙脱石和Cu2 +,苄嘧磺隆的浓度越高 ,Cu2 +的吸附量越大 ,解吸量越低 .苄嘧磺隆对Cu2 +在高岭石上吸附的影响 ,则是低pH值增加Cu2 +吸附 ,高pH值时降低Cu2 +吸附 。

抗苄嘧磺隆雨久花ALS基因突变研究

【目的】近年来,中国东北水稻田抗药性雨久花发生严重,部分地区用苄嘧磺隆已无法有效控制该杂草的危害。为明确该杂草抗药性发生的根本原因,本试验从分子水平上研究了稻田杂草雨久花(Monochoria korsakowii)对苄嘧磺隆的抗药性机理,以确定导致抗药性产生的乙酰乳酸合成酶(ALS)氨基酸突变位点。【方法】利用PCR技术,通过对抗药性雨久花生物型和敏感性雨久花生物型ALS片段进行扩增和基因克隆,最后对DNA序列进行测序比对。【结果】与敏感性的雨久花ALS相比,抗药性雨久花生物型的ALS共有3处发生突变,即第197位脯氨酸突变为组氨酸,第200位蛋氨酸突变为缬氨酸,第388位精氨酸突变为组氨酸,其中第197位突变与诸多文献报道相符。【结论】抗药性雨久花ALS第197位的突变可能是雨久花对苄嘧磺隆产生抗药性的主要原因。其它2个氨基酸突变是否也导致杂草对苄嘧磺隆产生抗药性未见相关报道,有待进一步研究。

镉与苄嘧磺隆除草剂单一污染和复合污染土壤的微生物生态效应

土壤微生物生物量碳、微生物生物量氮、基础呼吸以及土壤酶活性是表征土壤质量的重要生物学指标.研究了镉与苄嘧磺隆除草剂的单一污染和复合污染对这些生物学指标的影响随时间的动态变化,结果表明,无论是单一污染还是复合污染对土壤微生物生物量碳和氮、基础呼吸、磷酸酶和蔗糖酶活性的影响均随时间的推移表现为先增加后减小的趋势.镉与苄嘧磺隆除草剂复合污染之间存在很明显的交互作用,对土壤生物学指标的影响依次为:镉与苄嘧磺隆除草剂复合污染>苄嘧磺隆除草剂>镉.

苄嘧磺隆对蛋白核小球藻的生长效应研究

【目的】研究苄嘧磺隆对蛋白核小球藻(Chlorellapyrenoidosa)的生长效应,评价苄嘧磺隆的生态风险。【方法】通过不同浓度的苄嘧磺隆对蛋白核小球藻的96h急性毒性试验,研究苄嘧磺隆对小球藻的生长及藻细胞中叶绿素和蛋白质含量的影响。【结果】低浓度苄嘧磺隆(<1mg·L-1)具有刺激藻细胞生长的作用,其叶绿素含量和蛋白质含量均有明显的增加;高浓度的苄嘧磺隆(>5mg·L-1)抑制藻的生长,藻细胞叶绿素含量和可溶性蛋白质含量随药剂浓度增加而明显下降,且表现出较好的计量-效应关系,其对蛋白核小球藻的96h-EC50值为15.7mg·L-1。【结论】苄嘧磺隆对蛋白核小球藻的生长有一定的抑制作用,属低毒。

苄·二氯(苄嘧磺隆+二氯喹啉酸)复配依据及其在直播稻田的应用前景

就除草剂苄·二氯(苄嘧磺隆+二氯喹啉酸)对稗草的生物活性、共毒系数、配方依据,对水稻的安全性以及在直播稻田的应用效果进行了试验。结果表明,苄嘧磺隆和二氯喹啉酸复配,比单剂有显著的增效,尤以二氯喹啉酸和苄嘧磺隆在复配剂中的含量分别为34%和2%时增效最为显著。苄·二氯的6个配方对水稻株高、分蘖数和植株鲜质量无不良影响,安全性良好。苄嘧磺隆+二氯喹啉酸(18+150)g/hm2至(24+198)g/hm2对稗草、异型莎草、陌上菜和四叶萍的密度防效和植株鲜质量防效均达到优良水平。36%苄·二氯可湿性粉剂(WP)用于水稻直播田,在水稻2叶1心至3叶期处理,使用剂量162~270g/hm2(有效成分)对水稻生长无不良影响,安全性好。使用剂量216~432g/hm2对稗草、水蓼、陌上菜、鸭舌草和丁香蓼的密度防效和植株鲜质量防效均达到了优良水平。与单剂苄嘧磺隆和单剂二氯喹啉酸相比,36%苄·二氯WP的杀草谱提高,杂草整体防效得到改善。

高效液相色谱法同时测定稻田中苄嘧磺隆和苯噻酰草胺残留

建立了同时测定稻田(稻田土壤、水和植株)中苄嘧磺隆和苯噻酰草胺残留量的高效液相色谱(HPLC)分析方法。稻田水样品用二氯甲烷直接萃取;稻田土壤样品用碱性乙腈-二氯甲烷(1∶1,v/v)混合液直接提取;水稻植株样品用碱性二氯甲烷提取后,二氯甲烷提取液经弗罗里硅土柱净化。上述样品溶液采用C18不锈钢色谱柱(150mm×4.6 mm,5μm)分离,流动相为水-甲醇(30∶70,v/v),流速为0.5 mL/min,柱温为30℃,紫外检测波长为238 nm,外标法定量。苄嘧磺隆和苯噻酰草胺在0.05～5.00 mg/L范围内的线性关系均很好(r>0.999 9)。在稻田水、土壤和水稻植株中添加3个水平(0.05,0.10,1.00 mg/kg)的苄嘧磺隆和苯噻酰草胺,两者的回收率均在85.39%～113.33%之间,相对标准偏差为0.91%～10.24%。这表明该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。

苄嘧磺隆对淹水稻田土壤呼吸和酶活性的影响

研究除草剂苄嘧磺隆对淹水稻田土壤生态环境的安全性.以淹水稻田土壤为研究对象,在室内模拟田间试验条件下,通过呼吸作用和酶活测定,定期取样研究苄嘧磺隆施用浓度(0.000、0.067、0.3551、.780、3.553μg?g-1干土)对淹水稻田土壤呼吸强度和土壤酶活性的影响.结果表明,苄嘧磺隆施用初期能刺激土壤呼吸强度,随后产生轻微的抑制作用,这种抑制作用在取样后期逐渐减轻并趋于对照水平.苄嘧磺隆能轻微刺激过氧化氢酶活性,而蔗糖酶活性基本不受苄嘧磺隆施用量的影响,脲酶活性则是先刺激后抑制,多酚氧化酶活性受苄嘧磺隆影响不大.说明施用一定量的苄嘧磺隆对淹水稻田土壤生态环境是安全的.