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.

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...

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

42%噁草酮·乙草胺EC对花生田一年生杂草的防除效果

为明确42％噁草酮·乙草胺EC对花生田一年生杂草的防除效果、最佳田间使用剂量及施药技术。田间药效试验结果表明：42％噁草酮·乙草胺EC对花生田一年生杂草有很好的防治效果，且在试验剂量下对花生安全，适宜的施用剂量为810-1080ga．i．／hm^2，兑水600L／hm^2。施药适期为花生播后苗前，施药方法为土壤喷雾处理，药后20天的株防效为91．7％～93．2％，药后40天的株防效为85．7％～87．7％，鲜重防效为82．1％～84．4％。

10%乙草胺·苄嘧磺隆WP防除水稻抛秧田杂草效果

通过田间试验研究10%乙草胺.苄嘧磺隆WP对水稻抛秧田杂草的控制效果和对水稻产量的影响,为水稻抛秧田草害的化学防控提供依据。试验结果表明,10%乙草胺.苄嘧磺隆WP对水稻抛秧田的稗草[Echinochloa crusgalli(L.)Beauv]、鸭舌草[Monochoria vaginalis(Burm.F.)]、异型莎草(Cyperus dif-formis L.)均有良好的防治效果,用量为60～120 g(a.i)/hm2的10%乙草胺.苄嘧磺隆WP对杂草的综合鲜重防效和综合密度防效分别为86.64%～99.08%、89.88%～99.44%,优于对照药剂50%乙草胺EC和10%苄嘧磺隆WP。10%乙草胺.苄嘧磺隆WP增产效果优于对照药剂,在水稻抛秧田具有良好的推广前景。

Effects of pesticides on soil biochemical characteristics of a paddy soil

The impact of triazophos, bensulfuron-methyl, chlobenthiazone on soil biochemical characteristics in a paddy soil under controlled moisture(flooded soil) and temperature(25℃) condition was studied. The electron transport system(ETS)/dehydrogenase activity displayed a negative correlation with triazophos, bensulfuron-methyl, chlobenthiazone concentrations, and the activity decreased as the concentration of the pesticides increased. The higher doses, 5 and 10 field rates, of triazophos, bensulfuron-methyl, chlobenthiazone significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect against the control. The relative toxicity of triazophos, bensulfuron-methyl, chlobenthiazone in decreasing the ETS activity was in the order: triazophos > chlobenthiazone > bensulfuron-methyl, irrespective of the rates of application. Triazophos, bensulfuron-methyl, chlobenthiazone caused an improvement in the soil phenol content and it increased with increasing concentration of triazophos, bensulfuron-methyl, chlobenthiazone. Triazophos, bensulfuron-methyl, chlobenthiazone incorporation did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to ETS activity. The phospholipid content was decreased with the addition of triazophos, bensulfuron-methyl, chlobenthiazone in the order of triazophos > chlobenthiazone > bensulfuron-methyl; and the toxicity of applied amount was in the order: 10 FR(field rate) > 5 FR > 1 0 FR > 0 5 FR > control.

Adsor ption and Degradation of Bensu-lfuron-methyl in Paddy Field

This paper studied adsorption and deyradation of bensulfuron-methyl (BSM) by bioassay method. The results showed that adsorption rate of BSM increased with increasing organic matter content. Degradation velocity of BSM changed fast with pH inreasing and temperature decreasing. There were different degradation of BSM between in water and soil. BSM was degraded rapidly in initial period. Afterward the degradation of BSM was slow dow. With increasing organic matter content deyradation of BSM in water was faster than that in soil.

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.

黄腐酸对乙草胺生物活性及持效期的影响

采用玉米根长法或芽长法研究了黄腐酸对乙草胺的生物活性、持效期和除草效果的影响。结果显示:乙草胺浓度和玉米根芽生长呈明显负线性关系,乙草胺浓度与根芽的线性方程为y1=0.098x1+9.449和y2=0.079x2+22.255,相关系数R1=-0.9916、R2=-0.9809;黄腐酸能够提高乙草胺的生物活性和除草效果,并延长乙草胺的持效期,添加0.25%～4.00%黄腐酸,乙草胺抑制玉米芽长和根长的活性分别提高7.12%～14.27%和6.32%～11.65%,其持效期延长0.46～12.17天;施药后28天,添加0.5%～2.0%的黄腐酸使乙草胺防除稗草的鲜重抑制率提高11.93%～16.88%。