目的采用脉冲不分流进样气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定茶叶中百菌清、克菌丹残留量。方法样品经酸化后,用丙酮-正己烷混合溶剂提取,经石墨化碳黑固相萃...目的采用脉冲不分流进样气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定茶叶中百菌清、克菌丹残留量。方法样品经酸化后,用丙酮-正己烷混合溶剂提取,经石墨化碳黑固相萃取柱净化,以GC-MS/MS测定。结果本研究在0.05、0.10、1.00、10.00 mg/kg 4个添加水平时的2种农药的回收率为百菌清87.3%~105.0%、克菌丹76.3%~99.2%;相对标准偏差为百菌清1.5%~9.3%、克菌丹2.6%~11.7%;方法定量限均为0.05 mg/kg。该方法还通过了实验室间的协同性验证。结论该方法操作简便、快捷,方法灵敏度、准确度和精密度均满足农药残留检测要求,可在实际中应用和推广。展开更多
Anthracnose,caused by Colletotrichum truncatum and C.gloeosporioides,is amongst the most serious diseases of soybean in China.Picoxystrobin,a quinone outside inhibitor fungicide,is commonly used for the control of ant...Anthracnose,caused by Colletotrichum truncatum and C.gloeosporioides,is amongst the most serious diseases of soybean in China.Picoxystrobin,a quinone outside inhibitor fungicide,is commonly used for the control of anthracnose.Its resistance risk and mechanism in C.truncatum and C.gloeosporioides are unclear.In this study,the sensitivities of 128 C.truncatum and 121 C.gloeosporioides isolates to picoxystrobin were investigated,and unimodal distributions were observed with average EC_(50)values of 0.7740 and 1.1561μg mL^(-1),respectively.Eleven picoxystrobin-resistant mutants of C.truncatum and six mutants of C.gloeosporioides were acquired,with EC_(50)values varying from 5.40-152.96 and 13.53-28.30μg mL^(-1),respectively.Compared to the parental isolates,mutants showed similar or higher relative fitness in conidial production and germination,and pathogenicity.Collectively,the resistance risk of C.truncatum and C.gloeosporioides to picoxystrobin is moderate to high.There was positive cross-resistance between picoxystrobin and pyraclostrobin,but not between picoxystrobin and fluazinam,difenoconazole,or propiconazole.The G143S mutation in Cyt b protein was detected in seven high-resistant mutants of C.truncatum(RF>100),and G137R occurred in four moderate-resistant mutants(RF<_(50)).Contrastingly,there were no point mutations in Cyt b of any C.gloeosporioides mutants.Molecular docking confirmed that two mutations conferred different resistance levels to picoxystrobin.Under greenhouse trials,picoxystrobin did not control mutants with the G143S mutation,those bearing G137R or no point mutation were somewhat controlled,but at a lower level compared to wild-type isolates.These results showed that integrated management strategies should be implemented to preserve fungicide effectiveness.展开更多
The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by ...The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by parallel-line bioassay with quantal responses. The LC50s for 40 day of exposure of aldrin, fenvalerate, captan and diazinon were 0.00036,0.0094, 0.5473 and 2.4186 ppm respectively. These values were lower than those obtained for an exposure of 96 hour. It shows the greater toxicity of the pesticides in a long-term exposure. The relative toxic potency of aldrin fenvalerate, captan and diazinon was in a ratio of 6807:241:4:1 respectively. Thus the chemically different groups of pesticides exhibit an order of toxicity as aldrin > fenvalerate >captan > diazinon for the freshwater catfish, Clarias batrachus. It infers that the catfish is most sensitive to aldrin and least sensitive to diazinon. The comparison of the sensitivity of various species tested against these pesticidal chemicals has also been done to review the available information.展开更多
文摘目的采用脉冲不分流进样气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定茶叶中百菌清、克菌丹残留量。方法样品经酸化后,用丙酮-正己烷混合溶剂提取,经石墨化碳黑固相萃取柱净化,以GC-MS/MS测定。结果本研究在0.05、0.10、1.00、10.00 mg/kg 4个添加水平时的2种农药的回收率为百菌清87.3%~105.0%、克菌丹76.3%~99.2%;相对标准偏差为百菌清1.5%~9.3%、克菌丹2.6%~11.7%;方法定量限均为0.05 mg/kg。该方法还通过了实验室间的协同性验证。结论该方法操作简便、快捷,方法灵敏度、准确度和精密度均满足农药残留检测要求,可在实际中应用和推广。
基金funded by the Natural Science Foundation of Fujian Province, China (2021J01476)East and West Cooperation Project of the Fujian Academy of Agricultural Sciences, China (DKBF2022-01)+2 种基金the Project of Department of Agriculture and Rural Affairs in Fujian Province (2021PZQS006)the “5511” Collaborative Innovation Project of High-quality Agricultural Development and Surpassment in Fujian Province (XTCXGC2021011)the Team Project Funding of Scientific Research Innovation of FAAS, China (CXTD2021002-1).
文摘Anthracnose,caused by Colletotrichum truncatum and C.gloeosporioides,is amongst the most serious diseases of soybean in China.Picoxystrobin,a quinone outside inhibitor fungicide,is commonly used for the control of anthracnose.Its resistance risk and mechanism in C.truncatum and C.gloeosporioides are unclear.In this study,the sensitivities of 128 C.truncatum and 121 C.gloeosporioides isolates to picoxystrobin were investigated,and unimodal distributions were observed with average EC_(50)values of 0.7740 and 1.1561μg mL^(-1),respectively.Eleven picoxystrobin-resistant mutants of C.truncatum and six mutants of C.gloeosporioides were acquired,with EC_(50)values varying from 5.40-152.96 and 13.53-28.30μg mL^(-1),respectively.Compared to the parental isolates,mutants showed similar or higher relative fitness in conidial production and germination,and pathogenicity.Collectively,the resistance risk of C.truncatum and C.gloeosporioides to picoxystrobin is moderate to high.There was positive cross-resistance between picoxystrobin and pyraclostrobin,but not between picoxystrobin and fluazinam,difenoconazole,or propiconazole.The G143S mutation in Cyt b protein was detected in seven high-resistant mutants of C.truncatum(RF>100),and G137R occurred in four moderate-resistant mutants(RF<_(50)).Contrastingly,there were no point mutations in Cyt b of any C.gloeosporioides mutants.Molecular docking confirmed that two mutations conferred different resistance levels to picoxystrobin.Under greenhouse trials,picoxystrobin did not control mutants with the G143S mutation,those bearing G137R or no point mutation were somewhat controlled,but at a lower level compared to wild-type isolates.These results showed that integrated management strategies should be implemented to preserve fungicide effectiveness.
文摘The median lethal concentrations (LC50s) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by parallel-line bioassay with quantal responses. The LC50s for 40 day of exposure of aldrin, fenvalerate, captan and diazinon were 0.00036,0.0094, 0.5473 and 2.4186 ppm respectively. These values were lower than those obtained for an exposure of 96 hour. It shows the greater toxicity of the pesticides in a long-term exposure. The relative toxic potency of aldrin fenvalerate, captan and diazinon was in a ratio of 6807:241:4:1 respectively. Thus the chemically different groups of pesticides exhibit an order of toxicity as aldrin > fenvalerate >captan > diazinon for the freshwater catfish, Clarias batrachus. It infers that the catfish is most sensitive to aldrin and least sensitive to diazinon. The comparison of the sensitivity of various species tested against these pesticidal chemicals has also been done to review the available information.
