[ Objective] The phytotoxicity effect of quinclorac on peanut succeeding seedlings was studied. [ Method] Peanut was taken as the indicator crop, plant height and fresh weight were adopted as bioassay indicator, the b...[ Objective] The phytotoxicity effect of quinclorac on peanut succeeding seedlings was studied. [ Method] Peanut was taken as the indicator crop, plant height and fresh weight were adopted as bioassay indicator, the biological activity of quinclorac on peanut was determined by the method of adding quinclorac in the soil, and the residue dynamic of quinclorac in paddy soil was determined. [Result] The linear correlation equations of peanut plant height and fresh weight with the concentration range of 0.7 -8.0 mg/kg separately were y = 11.235x ＋3.818 6, R^2 = 0.969 1 ; y = 5.973 3x ＋ 6.532 8, R^2 = 0.988 2. There would be no residual phytotoxicity effect when peanut was going to be planted in the same block in the second year. [Condusion] The bioassay method was simple and exact with good repeatability.展开更多
A bacterial strain,designated as LS,was isolated from a contaminated soil and was found to be capable of utilizing quinclorac,bensulfuronmethyl,and a mixture of the two as carbon and energy sources for growth. Strain ...A bacterial strain,designated as LS,was isolated from a contaminated soil and was found to be capable of utilizing quinclorac,bensulfuronmethyl,and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties,16S rDNA sequences,and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L-1 was 90% and 67%,respectively,as measured by high performance liquid chromatography(HPLC) . When a herbicide mixture of 0.34 g L-1 quinclorac and 0.02 g L-1 bensulfuronmethyl was applied as carbon sources,quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%,respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8,respectively. Addition of 0.25 g L-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol,propisochlor,4-chloro-2-methylphenoxyacetic acid sodium(MCPA-Na) and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues.展开更多
Echinochloa crus-galli is a major weed in rice fields in China,and quinclorac has been long used for its control.Over-reliance of quinclorac has resulted in quinclorac resistance in E.crus-galli.Two resistant(R)E.crus...Echinochloa crus-galli is a major weed in rice fields in China,and quinclorac has been long used for its control.Over-reliance of quinclorac has resulted in quinclorac resistance in E.crus-galli.Two resistant(R)E.crus-galli populations from Hunan,China were confirmed to be at least 78-fold more resistant to quinclorac than the susceptible(S)population.No difference in foliar uptake of 14C-labelled quinclorac was detected between the R and S plants.However,a higher level of 14C translocation and a lower level of quinclorac metabolism were found in the R plants.Basal and induced expression levels ofβ-cyanoalanine synthase(β-CAS)gene andβ-CAS activity were not significantly different between the R and S plants.However,the induction expression of 1-aminocyclopropane-1-carboxylic acid oxidase(ACO1)gene by quinclorac treatment was evident in the S plants but not in the R plants.Quinclorac resistance in the two resistant E.crus-galli populations was not likely to be related to foliar uptake,translocation or metabolism of quinclorac,nor to cyanide detoxification viaβ-CAS.Thus,target-site based quinclorac signal reception and transduction and regulation of the ethylene synthesis pathway should be the focus for further research.展开更多
The influence of quinclorac (3,7-dichloroquinoline-8-carboxylic acid) on enzyme activities in flooded paddy soils was assessed under laboratory conditions. The enzymes differed markedly in their response to quinclorac...The influence of quinclorac (3,7-dichloroquinoline-8-carboxylic acid) on enzyme activities in flooded paddy soils was assessed under laboratory conditions. The enzymes differed markedly in their response to quinclorac. Quinclorac inhibited proteinase, hydrogen peroxidase, phosphorylase, and urease activities.The higher the concentration of quinclorac applied, the more significant the inhibition to these observed activities with a longer time required to recover to the level of the control. However, soils supplemented with quinclorac were nonpersistent for proteinase, phosphorylase and urease as opposed to soils without quinclorac. Dehydrogenase activity was also sensitive to quinclorac. Three soil samples with concentrations of quinclorac higher than 1 μg g-1 soil declined to less than 20% of that in the control. However, the highest dehydrogenase activity (up to 3.28-fold) was detected in soils with 2 μg g-1 soil quinclorac on the 25th day after treatment. Quinclorac had a relatively mild effect on saccharase activity at the concentrations used in this experiment and a stimulatory one on soil respiration when added to soil at normal field concentrations.Nonetheless it was inhibited at higher concentrations in paddy soils. Quinclorac is still relatively safe to the soil ecosystem when applied at a normal concentration (0.67 μg g-1 dried soil) but may have some effects on soil enzymes at higher concentrations.展开更多
Objective To investigate the potential effects of herbicide quinclorac (3,7-dichloro-8-quinoline-carboxylic) on the culturable microorganisms in flooded paddy soil. Methods Total soil aerobic bacteria, actinomycetes a...Objective To investigate the potential effects of herbicide quinclorac (3,7-dichloro-8-quinoline-carboxylic) on the culturable microorganisms in flooded paddy soil. Methods Total soil aerobic bacteria, actinomycetes and fungi were counted by a 10-fold serial dilution plate technique. Numbers of anaerobic fermentative bacteria (AFB), denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB) were numerated by three-tube anaerobic most-probable-number (MPN) methods with anaerobic liquid enrichment media. The number of methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB) was determined by the rolling tube method in triplicate. Soil respiration was monitored by a 102G-type gas chromatography with a stainless steel column filled with GDX-104 and a thermal conductivity detector. Results Quinclorac concentration was an important factor affecting the populations of various culturable microorganisms. There were some significant differences in the aerobic heterotrophic bacteria. AFB and DNB between soils were supplemented with quinclorac and non-quinclorac at the early stage of incubation, but none of them was persistent. The number of fungi and DNB was increased in soil samples treated by lower than 1.33μg·g-1 dried soil, while the CFU of fungi and HPAB was inhibited in soil samples treated by higher than 1.33μg·g-1 dried soil. The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days. However, application of quinclorac greatly stimulated the growth of AFB and NFB. MB was more sensitive to quinclorac than the others, and the three soil samples with concentrations higher than 1 μg·g-1 dried soil declined significantly to less than 40% of that in the control, but the number of samples with lower concentrations of quinclorac was nearly equal to that in the control at the end of experiments. Conclusion Quinclorac is safe to the soil microorganisms when applied at normal concentrations (0.67μg·g-1).展开更多
A new high activated organic weedicide quinclorac (3,7-dicholoro-8-quinoxylic acid) was presented, and the optimal synthesis condition of the key step-Skraup cyclization was developed. A new synthesis process by using...A new high activated organic weedicide quinclorac (3,7-dicholoro-8-quinoxylic acid) was presented, and the optimal synthesis condition of the key step-Skraup cyclization was developed. A new synthesis process by using the catalyst of KI was set up,and the yield increased to 95 5%. The relationship between structure and activity of quinclorac and its derivatives was studied to find more active and more mild weedicide, 12 derivatives of this acid were synthesized, and the biological activities of all these compounds were detected, the QSAR equation of this series of compounds was established by Hansch method, which shows that the biological activity is linearly correlated with parameters L, M R, B 1, B 2 and B 4, and -CH 2-CH=CH 2 substituted quinclorac ester was more active and more mild weedicide analysised from QSAR equation.展开更多
[ Objective] The paper was to study the resistance of barnyard grass to quinclorac in double-harvest rice area in Hunan Province of China. [ Method ] Using whole-plant determination method, the resistance of 36 biotyp...[ Objective] The paper was to study the resistance of barnyard grass to quinclorac in double-harvest rice area in Hunan Province of China. [ Method ] Using whole-plant determination method, the resistance of 36 biotypes of barnyard grass to quinclorac in double-harvest rice area in Hunan Province was studied. [ Result ] The biotype collected from Lijiaping Town of Shaoyang County was the most susceptible barnyard grass to quinclerac, and the EC50 value was 70. 253 1 g a. i./hm2 , so it was recognized as the sensitive biotype. The biotypes collected from Caowei Town of Yuanjiang County （ HN3 and HN4 from direct seeding rice fields） and Zhongyukou Town of Nanxian County presented very high resistance to quinclorac ; the ECho values were 1 999. 122 5, 1 664.544 6 and 1 022.739 5 g a. i./hm2, and their resistance indexes reached 28.46, 23.69 and 14.56, respectively, indicating that these throe biotypes hod high level of resistance to quinclo- rac. EC50 values of about 22 biotypes were ranged from 144. 837 3 to 408.289 4 g a. i./hm2, and resistance indexes were ranged from 2.06 to 5.81, indicating that these biotypes hod produced resistance to quinclorac. EC50 values of other 10 biotypes were ranged from 98.032 6 to 138. 660 9 g a. i./hm2, and the resistance in- dexes were ranged from 1.40 to 1.97, indicating that the sensitivity of barnyard grass in these places was decreasing. [ Conclusion] The paper provided guidance for scientific and rational use of quinclorac in paddy fields.展开更多
Quinclorac is one of the main herbicides used in paddy fields in China.Quinclorac residues in paddy soil may significantly influence the growth of sensitive crops such as tobacco.An analytical method employing high pe...Quinclorac is one of the main herbicides used in paddy fields in China.Quinclorac residues in paddy soil may significantly influence the growth of sensitive crops such as tobacco.An analytical method employing high performance liquid chromatography(HPLC)with a diode array detector(DAD)was developed to determine quinclorac residues in paddy soil samples.Quinclorac was extracted from paddy soil samples by 5% ammonia methanol solution(v/v)and cleancd up by solid-phase extraction(SPE)with Bond Elute SAX cartridge.Recoveries of quinclorac at 0.005-1.000 μg·g^-1 were 82.36%-l06.30%,with relative standard deviations(RSDs)of 2.45%-6.83%.The limit of detection(LOD)was 0.001 μg·g^-1 at a signal-to-noise ratio of 3,and the limit of quantification(LOQ)was 0.005 μg·g^-1 The same quinclorac residue samples were further analyzed and confirmed by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The proposed method was successfully applied to the analysis of quinclorac residues from the paddy fields with previous quinclorac treatment in Jiangxi Province.展开更多
Adsorption-desorption characteristics of quinclorac on montmorillonite, attapulgite and goethite were investigated by the batch equilibrium techniques. The sorption mechanisms of minerals were discussed based on sorpt...Adsorption-desorption characteristics of quinclorac on montmorillonite, attapulgite and goethite were investigated by the batch equilibrium techniques. The sorption mechanisms of minerals were discussed based on sorption thermodynamics. The results showed that the adsorption of quinclorac on the 3 minerals was included in both rapid stage and slow equilibrium stage. The adsorption kinetics consisted with the pseudo-second-order equation, the particle diffusion equation, and elovich equations, and among them, fitting from the pseudo-second-order was the best. In addition, it could be seen from the nonzero constant C in the particle diffusion equation that the rate of particle diffusion was not a sole factor. The isotherm adsorption-desorption of quinclorac on the 3 clay minerals all fitted Linear and Freundlich equation very well. The adsorption capacities of minerals for quinclorac followed the order of goethite〉montmorillonite〉attapulgite, The desorption of quinclorac presented obvious hysteresis phenomenon on minerals. The study on thermodynamic behavior indicated that the sorption processes of quinclorec onto minerals were spontaneous, and the sorption spontaneity was strengthened with the temperature increasing.展开更多
文摘[ Objective] The phytotoxicity effect of quinclorac on peanut succeeding seedlings was studied. [ Method] Peanut was taken as the indicator crop, plant height and fresh weight were adopted as bioassay indicator, the biological activity of quinclorac on peanut was determined by the method of adding quinclorac in the soil, and the residue dynamic of quinclorac in paddy soil was determined. [Result] The linear correlation equations of peanut plant height and fresh weight with the concentration range of 0.7 -8.0 mg/kg separately were y = 11.235x ＋3.818 6, R^2 = 0.969 1 ; y = 5.973 3x ＋ 6.532 8, R^2 = 0.988 2. There would be no residual phytotoxicity effect when peanut was going to be planted in the same block in the second year. [Condusion] The bioassay method was simple and exact with good repeatability.
基金the National Natural Science Foundation of China (Nos.40501037 and 30570053)the National Key Technologies Research and Development Program of China during the 11th Five-Year Plan Period(No.2006BAJ08B01).
文摘A bacterial strain,designated as LS,was isolated from a contaminated soil and was found to be capable of utilizing quinclorac,bensulfuronmethyl,and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties,16S rDNA sequences,and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L-1 was 90% and 67%,respectively,as measured by high performance liquid chromatography(HPLC) . When a herbicide mixture of 0.34 g L-1 quinclorac and 0.02 g L-1 bensulfuronmethyl was applied as carbon sources,quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%,respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8,respectively. Addition of 0.25 g L-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol,propisochlor,4-chloro-2-methylphenoxyacetic acid sodium(MCPA-Na) and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 31701803 and 31772182)the Natural Science Foundation of Hunan Province (Grant No. 2017JJ3164) in China and the Australian Grains Research and Development Corporation (GRDC)
文摘Echinochloa crus-galli is a major weed in rice fields in China,and quinclorac has been long used for its control.Over-reliance of quinclorac has resulted in quinclorac resistance in E.crus-galli.Two resistant(R)E.crus-galli populations from Hunan,China were confirmed to be at least 78-fold more resistant to quinclorac than the susceptible(S)population.No difference in foliar uptake of 14C-labelled quinclorac was detected between the R and S plants.However,a higher level of 14C translocation and a lower level of quinclorac metabolism were found in the R plants.Basal and induced expression levels ofβ-cyanoalanine synthase(β-CAS)gene andβ-CAS activity were not significantly different between the R and S plants.However,the induction expression of 1-aminocyclopropane-1-carboxylic acid oxidase(ACO1)gene by quinclorac treatment was evident in the S plants but not in the R plants.Quinclorac resistance in the two resistant E.crus-galli populations was not likely to be related to foliar uptake,translocation or metabolism of quinclorac,nor to cyanide detoxification viaβ-CAS.Thus,target-site based quinclorac signal reception and transduction and regulation of the ethylene synthesis pathway should be the focus for further research.
基金Project supported by the National Natural Science Foundation of China (No. 30370048) the National High Technology Research and Development Program of China (863 Program) (No. 2002A2104101).
文摘The influence of quinclorac (3,7-dichloroquinoline-8-carboxylic acid) on enzyme activities in flooded paddy soils was assessed under laboratory conditions. The enzymes differed markedly in their response to quinclorac. Quinclorac inhibited proteinase, hydrogen peroxidase, phosphorylase, and urease activities.The higher the concentration of quinclorac applied, the more significant the inhibition to these observed activities with a longer time required to recover to the level of the control. However, soils supplemented with quinclorac were nonpersistent for proteinase, phosphorylase and urease as opposed to soils without quinclorac. Dehydrogenase activity was also sensitive to quinclorac. Three soil samples with concentrations of quinclorac higher than 1 μg g-1 soil declined to less than 20% of that in the control. However, the highest dehydrogenase activity (up to 3.28-fold) was detected in soils with 2 μg g-1 soil quinclorac on the 25th day after treatment. Quinclorac had a relatively mild effect on saccharase activity at the concentrations used in this experiment and a stimulatory one on soil respiration when added to soil at normal field concentrations.Nonetheless it was inhibited at higher concentrations in paddy soils. Quinclorac is still relatively safe to the soil ecosystem when applied at a normal concentration (0.67 μg g-1 dried soil) but may have some effects on soil enzymes at higher concentrations.
基金This work was supported by the National 863 Programm of China "Bioengineering Technique Project 2002A2104101
文摘Objective To investigate the potential effects of herbicide quinclorac (3,7-dichloro-8-quinoline-carboxylic) on the culturable microorganisms in flooded paddy soil. Methods Total soil aerobic bacteria, actinomycetes and fungi were counted by a 10-fold serial dilution plate technique. Numbers of anaerobic fermentative bacteria (AFB), denitrifying bacteria (DNB) and hydrogen-producing acetogenic bacteria (HPAB) were numerated by three-tube anaerobic most-probable-number (MPN) methods with anaerobic liquid enrichment media. The number of methanogenic bacteria (MB) and nitrogen-fixing bacteria (NFB) was determined by the rolling tube method in triplicate. Soil respiration was monitored by a 102G-type gas chromatography with a stainless steel column filled with GDX-104 and a thermal conductivity detector. Results Quinclorac concentration was an important factor affecting the populations of various culturable microorganisms. There were some significant differences in the aerobic heterotrophic bacteria. AFB and DNB between soils were supplemented with quinclorac and non-quinclorac at the early stage of incubation, but none of them was persistent. The number of fungi and DNB was increased in soil samples treated by lower than 1.33μg·g-1 dried soil, while the CFU of fungi and HPAB was inhibited in soil samples treated by higher than 1.33μg·g-1 dried soil. The population of actinomycete declined in negative proportion to the concentrations of quinclorac applied after 4 days. However, application of quinclorac greatly stimulated the growth of AFB and NFB. MB was more sensitive to quinclorac than the others, and the three soil samples with concentrations higher than 1 μg·g-1 dried soil declined significantly to less than 40% of that in the control, but the number of samples with lower concentrations of quinclorac was nearly equal to that in the control at the end of experiments. Conclusion Quinclorac is safe to the soil microorganisms when applied at normal concentrations (0.67μg·g-1).
文摘A new high activated organic weedicide quinclorac (3,7-dicholoro-8-quinoxylic acid) was presented, and the optimal synthesis condition of the key step-Skraup cyclization was developed. A new synthesis process by using the catalyst of KI was set up,and the yield increased to 95 5%. The relationship between structure and activity of quinclorac and its derivatives was studied to find more active and more mild weedicide, 12 derivatives of this acid were synthesized, and the biological activities of all these compounds were detected, the QSAR equation of this series of compounds was established by Hansch method, which shows that the biological activity is linearly correlated with parameters L, M R, B 1, B 2 and B 4, and -CH 2-CH=CH 2 substituted quinclorac ester was more active and more mild weedicide analysised from QSAR equation.
基金Supported by National Natural Science Foundation of China(31201530)Special Fund for Agro-scientific Research in the Public Interest(201303031)
文摘[ Objective] The paper was to study the resistance of barnyard grass to quinclorac in double-harvest rice area in Hunan Province of China. [ Method ] Using whole-plant determination method, the resistance of 36 biotypes of barnyard grass to quinclorac in double-harvest rice area in Hunan Province was studied. [ Result ] The biotype collected from Lijiaping Town of Shaoyang County was the most susceptible barnyard grass to quinclerac, and the EC50 value was 70. 253 1 g a. i./hm2 , so it was recognized as the sensitive biotype. The biotypes collected from Caowei Town of Yuanjiang County （ HN3 and HN4 from direct seeding rice fields） and Zhongyukou Town of Nanxian County presented very high resistance to quinclorac ; the ECho values were 1 999. 122 5, 1 664.544 6 and 1 022.739 5 g a. i./hm2, and their resistance indexes reached 28.46, 23.69 and 14.56, respectively, indicating that these throe biotypes hod high level of resistance to quinclo- rac. EC50 values of about 22 biotypes were ranged from 144. 837 3 to 408.289 4 g a. i./hm2, and resistance indexes were ranged from 2.06 to 5.81, indicating that these biotypes hod produced resistance to quinclorac. EC50 values of other 10 biotypes were ranged from 98.032 6 to 138. 660 9 g a. i./hm2, and the resistance in- dexes were ranged from 1.40 to 1.97, indicating that the sensitivity of barnyard grass in these places was decreasing. [ Conclusion] The paper provided guidance for scientific and rational use of quinclorac in paddy fields.
文摘Quinclorac is one of the main herbicides used in paddy fields in China.Quinclorac residues in paddy soil may significantly influence the growth of sensitive crops such as tobacco.An analytical method employing high performance liquid chromatography(HPLC)with a diode array detector(DAD)was developed to determine quinclorac residues in paddy soil samples.Quinclorac was extracted from paddy soil samples by 5% ammonia methanol solution(v/v)and cleancd up by solid-phase extraction(SPE)with Bond Elute SAX cartridge.Recoveries of quinclorac at 0.005-1.000 μg·g^-1 were 82.36%-l06.30%,with relative standard deviations(RSDs)of 2.45%-6.83%.The limit of detection(LOD)was 0.001 μg·g^-1 at a signal-to-noise ratio of 3,and the limit of quantification(LOQ)was 0.005 μg·g^-1 The same quinclorac residue samples were further analyzed and confirmed by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The proposed method was successfully applied to the analysis of quinclorac residues from the paddy fields with previous quinclorac treatment in Jiangxi Province.
基金Supported by Youth Science Foundation of Hunan Agricultural University(15QN30)Agricultural Pesticide Residue Project of Ministry of Agriculture(NYBNYCL20100057)Project of Hunan Department of Science and Technology(2006FJ4266)~~
文摘Adsorption-desorption characteristics of quinclorac on montmorillonite, attapulgite and goethite were investigated by the batch equilibrium techniques. The sorption mechanisms of minerals were discussed based on sorption thermodynamics. The results showed that the adsorption of quinclorac on the 3 minerals was included in both rapid stage and slow equilibrium stage. The adsorption kinetics consisted with the pseudo-second-order equation, the particle diffusion equation, and elovich equations, and among them, fitting from the pseudo-second-order was the best. In addition, it could be seen from the nonzero constant C in the particle diffusion equation that the rate of particle diffusion was not a sole factor. The isotherm adsorption-desorption of quinclorac on the 3 clay minerals all fitted Linear and Freundlich equation very well. The adsorption capacities of minerals for quinclorac followed the order of goethite〉montmorillonite〉attapulgite, The desorption of quinclorac presented obvious hysteresis phenomenon on minerals. The study on thermodynamic behavior indicated that the sorption processes of quinclorec onto minerals were spontaneous, and the sorption spontaneity was strengthened with the temperature increasing.
