A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This...A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This strain could grow on pendimethalin as a sole carbon source and degrade 99.5%of 100 mg/L pendimethalin within 2.5 days in batch liquid culture,demonstrating a greater efficiency than any other reported strains.Three metabolic products,6-aminopendimethalin,5-amino-2-methyl-3-nitroso-4-（pentan-3-ylamino） benzoic acid,and 8-amino-2-ethyl-5-（hydroxymethyl）-1,2-dihydroquinoxaline-6-carboxylic acid,were identified by HPLC-MS/MS,and a new microbial degradation pathway was proposed.A nitroreductase catalyzing nitroreduction of pendimethalin to 6-aminopendimethalin was detected in the cell lysate of strain Y3.The cofactor was nicotinamide adenine dinucleotide phosphate（NADPH） or more preferably nicotinamide adenine dinucleotide（NADH）.The optimal temperature and pH for the nitroreductase were 30℃ and 7.5,respectively.Hg^（2＋）,Ni^（2＋）,Pb^（2＋）,Co^（2＋）,Mn^（2＋） Cu^（2＋）,Ag~＋,and EDTA severely inhibited the nitroreductase activity,whereas Fe^（2＋）,Mg^（2＋）,and Ca^（2＋） enhanced it.This study provides an efficient pendimethalin-degrading microorganism and broadens the knowledge of the microbial degradation pathway of pendimethalin.展开更多
There is little information on the tolerance of dry bean to pendimethalin. Field studies were conducted in 2007 to 2009 at Exeter, Ontario and in 2008 and 2009 at Ridgetown, Ontario to evaluate tolerance of black, cra...There is little information on the tolerance of dry bean to pendimethalin. Field studies were conducted in 2007 to 2009 at Exeter, Ontario and in 2008 and 2009 at Ridgetown, Ontario to evaluate tolerance of black, cranberry, kidney, otebo, pink, pinto, Small Red Mexican and white bean to the pendimethalin applied preplant incorporated at 1080 and 2160 g.a.i.ha-1. Pendimethalin PPI caused minimal injury in most market classes of dry bean at 1 and 2 WAE. There was no injury in various market classes of dry bean with the low dose at 1 and 2 weeks after emergence (WAE). However, at the high dose there was 0 to 4% injury at 1 WAE and 0 to 7% injury at 2 WAE in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Pendimethalin PPI was more injurious in white bean than in black, cranberry, kidney, otebo, pink, pinto and SRM bean. Pink and SRM bean exhibited the most tolerance to pendimethalin applied PPI at 1080 g.ai.ha-1 or 2160 g.ai.ha-1. Pendimethalin caused no adverse effect on plant height, shoot dry weight, seed moisture content and seed yield of black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Based on these results, there is an adequate margin of crop safety for pendimethalin applied PPI at the proposed dose of 1080 g.ai.ha-1 in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean in Ontario.展开更多
Kinetics of the sorption of the herbicide, pendimethalin (3,4-Dimethyl-2,6-dinitro-N-pentan-3-yl-aniline) on four soil samples obtained from the banks of Rivers Benue and Katsina-Ala, in Central Nigeria was studied by...Kinetics of the sorption of the herbicide, pendimethalin (3,4-Dimethyl-2,6-dinitro-N-pentan-3-yl-aniline) on four soil samples obtained from the banks of Rivers Benue and Katsina-Ala, in Central Nigeria was studied by contacting 5.0 g soil samples with 100 mL 7 × 10<sup>-6</sup> M herbicide solution. The sorption was monitored by following the herbicide concentration in the aqueous phase spectrophotometrically at one hour intervals for 5 hours (at 25°C, 35°C, 45°C, 55°C and 65°C, respectively). Pseudo-first order kinetics treatment of the data showed that sorption rates as well as the accompanying activation energies were low, indicating that physical adsorption is the operative mechanism for its retention in the soils and that the herbicide tended to reside more in the aqueous phase, which raised its potential to contaminate natural water systems, when applied on the field.展开更多
[目的]为明确二甲戊灵和扑草净对北苍术田杂草安全防除的混用比例。[方法]采用温室盆栽法测定了二甲戊灵和扑草净不同混用比例对马唐、牛筋草、反枝苋和马齿苋的生物活性及北苍术安全性后,根据选择性指数,采用随机区组法测定了2种除草...[目的]为明确二甲戊灵和扑草净对北苍术田杂草安全防除的混用比例。[方法]采用温室盆栽法测定了二甲戊灵和扑草净不同混用比例对马唐、牛筋草、反枝苋和马齿苋的生物活性及北苍术安全性后,根据选择性指数,采用随机区组法测定了2种除草剂不同混用比例对北苍术田间杂草除草效果。[结果]二甲戊灵与扑草净按质量比2∶1混用后以不同剂量施于杂草和北苍术,对北苍术与反枝苋和马齿苋的选择性指数分别提高12.06和14.96,其按质量比1∶2比例混用后以不同浓度施以杂草和北苍术,对北苍术与马唐和牛筋草的选择性指数分别提高11.75和13.88;二甲戊灵有效成分用量480 g a.i./hm^(2)和扑草净有效成分用量160 g a.i./hm^(2)混用后对牛筋草、狗尾草表现为增效作用,对反枝苋和马齿苋表现为相加作用,其对杂草的总株防效和鲜质量防效较高且对北苍术安全。[结论]二甲戊灵+扑草净用量为480+160 g a.i./hm^(2)时可用于北苍术田土壤封闭处理防除杂草。展开更多
基金supported by the National Science and Technology Support Plan(No.2012BAD15B03)the China Postdoctoral Science Foundation(Nos.2014M561660 and 2013T60546)the Jiangsu Postdoctoral Science Foundation(No.1301114C)
文摘A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This strain could grow on pendimethalin as a sole carbon source and degrade 99.5%of 100 mg/L pendimethalin within 2.5 days in batch liquid culture,demonstrating a greater efficiency than any other reported strains.Three metabolic products,6-aminopendimethalin,5-amino-2-methyl-3-nitroso-4-（pentan-3-ylamino） benzoic acid,and 8-amino-2-ethyl-5-（hydroxymethyl）-1,2-dihydroquinoxaline-6-carboxylic acid,were identified by HPLC-MS/MS,and a new microbial degradation pathway was proposed.A nitroreductase catalyzing nitroreduction of pendimethalin to 6-aminopendimethalin was detected in the cell lysate of strain Y3.The cofactor was nicotinamide adenine dinucleotide phosphate（NADPH） or more preferably nicotinamide adenine dinucleotide（NADH）.The optimal temperature and pH for the nitroreductase were 30℃ and 7.5,respectively.Hg^（2＋）,Ni^（2＋）,Pb^（2＋）,Co^（2＋）,Mn^（2＋） Cu^（2＋）,Ag~＋,and EDTA severely inhibited the nitroreductase activity,whereas Fe^（2＋）,Mg^（2＋）,and Ca^（2＋） enhanced it.This study provides an efficient pendimethalin-degrading microorganism and broadens the knowledge of the microbial degradation pathway of pendimethalin.
文摘There is little information on the tolerance of dry bean to pendimethalin. Field studies were conducted in 2007 to 2009 at Exeter, Ontario and in 2008 and 2009 at Ridgetown, Ontario to evaluate tolerance of black, cranberry, kidney, otebo, pink, pinto, Small Red Mexican and white bean to the pendimethalin applied preplant incorporated at 1080 and 2160 g.a.i.ha-1. Pendimethalin PPI caused minimal injury in most market classes of dry bean at 1 and 2 WAE. There was no injury in various market classes of dry bean with the low dose at 1 and 2 weeks after emergence (WAE). However, at the high dose there was 0 to 4% injury at 1 WAE and 0 to 7% injury at 2 WAE in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Pendimethalin PPI was more injurious in white bean than in black, cranberry, kidney, otebo, pink, pinto and SRM bean. Pink and SRM bean exhibited the most tolerance to pendimethalin applied PPI at 1080 g.ai.ha-1 or 2160 g.ai.ha-1. Pendimethalin caused no adverse effect on plant height, shoot dry weight, seed moisture content and seed yield of black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Based on these results, there is an adequate margin of crop safety for pendimethalin applied PPI at the proposed dose of 1080 g.ai.ha-1 in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean in Ontario.
文摘Kinetics of the sorption of the herbicide, pendimethalin (3,4-Dimethyl-2,6-dinitro-N-pentan-3-yl-aniline) on four soil samples obtained from the banks of Rivers Benue and Katsina-Ala, in Central Nigeria was studied by contacting 5.0 g soil samples with 100 mL 7 × 10<sup>-6</sup> M herbicide solution. The sorption was monitored by following the herbicide concentration in the aqueous phase spectrophotometrically at one hour intervals for 5 hours (at 25°C, 35°C, 45°C, 55°C and 65°C, respectively). Pseudo-first order kinetics treatment of the data showed that sorption rates as well as the accompanying activation energies were low, indicating that physical adsorption is the operative mechanism for its retention in the soils and that the herbicide tended to reside more in the aqueous phase, which raised its potential to contaminate natural water systems, when applied on the field.
文摘【目的】研究砜吡草唑与二甲戊灵混配对棉田阔叶杂草的防除效果,并评价其安全性。【方法】设置40%砜吡草唑SC和330 g/L二甲戊灵EC混配田间药效试验,评价各处理对棉田龙葵、灰绿藜、反枝苋、马齿苋和苘麻等阔叶杂草的防效及其对棉花生产的安全性。【结果】各处理棉花出苗率为80.56%~83.61%,与对照相比差异未达显著水平。砜吡草唑SC 120、180和240 g a.i./hm^(2)分别与330 g/L二甲戊灵EC 742.5 g a.i./hm^(2)混配后,药后30 d对棉田阔叶杂草的株防效分别为89.15%、92.03%和97.83%,药后45 d株防效分别为87.94%、91.49%和95.56%,鲜重防效分别为90.80%、93.16%和95.65%,混配药剂对棉田阔叶杂草的株防效和鲜重防效均优于单剂处理。各供试处理与对照相比,棉花增产幅度达9.89%~16.45%。【结论】40%砜吡草唑SC 120~180 g a.i./hm^(2)与330 g/L二甲戊灵EC混配可用作棉花田防除阔叶杂草,对棉花出苗安全。
文摘[目的]为明确二甲戊灵和扑草净对北苍术田杂草安全防除的混用比例。[方法]采用温室盆栽法测定了二甲戊灵和扑草净不同混用比例对马唐、牛筋草、反枝苋和马齿苋的生物活性及北苍术安全性后,根据选择性指数,采用随机区组法测定了2种除草剂不同混用比例对北苍术田间杂草除草效果。[结果]二甲戊灵与扑草净按质量比2∶1混用后以不同剂量施于杂草和北苍术,对北苍术与反枝苋和马齿苋的选择性指数分别提高12.06和14.96,其按质量比1∶2比例混用后以不同浓度施以杂草和北苍术,对北苍术与马唐和牛筋草的选择性指数分别提高11.75和13.88;二甲戊灵有效成分用量480 g a.i./hm^(2)和扑草净有效成分用量160 g a.i./hm^(2)混用后对牛筋草、狗尾草表现为增效作用,对反枝苋和马齿苋表现为相加作用,其对杂草的总株防效和鲜质量防效较高且对北苍术安全。[结论]二甲戊灵+扑草净用量为480+160 g a.i./hm^(2)时可用于北苍术田土壤封闭处理防除杂草。
