Horseweed （Conyza canadensis）, an invasive alien weed, is one of the main weeds in orchards in China. Although glyphosate has been used for control of horseweed and many other weeds in orchards for more than 25 year...Horseweed （Conyza canadensis）, an invasive alien weed, is one of the main weeds in orchards in China. Although glyphosate has been used for control of horseweed and many other weeds in orchards for more than 25 years in China, a case of glyphosate-resistant horseweed has not been identified in orchard in China so far despite glyphosate-resistant horseweed cases have been reported in some other countries. Seeds of 25 horseweed populations were collected from different orchards with different glyphosate application history. Potted seedlings with 11-13-leaf growth stage were treated with glyphosate at 0.035, 0.07, 0.14, 0.28, 0.56, 1.12, 2.24, 4.48, and 8.96 kg a.i. ha-1. The dosage dependence response curve of each population was constructed with Log-logistic dose response regression equations. The ED50 value of each population was calculated and compared with the susceptible population from China. Different populations had different relative glyphosate-resistant levels which increased with the number of years of glyphosate application. Two populations with the highest resistance levels, 8.28 and 7.95 times, were found in Ningbo, Zhejiang Province, China, where glyphosate was used for weed control in orchards twice each year for 15 yr. The two resistant populations accumulated approximately two to four times less shikimic acid than the two susceptible populations 48 h after glyphosate application.展开更多
目的:研究加拿大蓬中总黄酮提取方法及最佳工艺。方法:采用超声提取法,通过单因素试验和正交试验筛选最佳工艺条件。结果:最佳提取条件为60%乙醇、料液比1∶20、60 kW下超声45 m in。得率为31.076 mg/g。结论:该方法提取提取总黄酮快速...目的:研究加拿大蓬中总黄酮提取方法及最佳工艺。方法:采用超声提取法,通过单因素试验和正交试验筛选最佳工艺条件。结果:最佳提取条件为60%乙醇、料液比1∶20、60 kW下超声45 m in。得率为31.076 mg/g。结论:该方法提取提取总黄酮快速、简便,可适用于生产中加拿大蓬总黄酮类物质的检测。该方法是提取加拿大蓬总黄酮类物质的有效途径。展开更多
基金supported by the National Basic Research and Development Program of China (2007CB109202)the National Natural Science Foundation of China (30400059)the National Specific Program on Environmental Protection for Public-welfare Industry of China (200709017)
文摘Horseweed （Conyza canadensis）, an invasive alien weed, is one of the main weeds in orchards in China. Although glyphosate has been used for control of horseweed and many other weeds in orchards for more than 25 years in China, a case of glyphosate-resistant horseweed has not been identified in orchard in China so far despite glyphosate-resistant horseweed cases have been reported in some other countries. Seeds of 25 horseweed populations were collected from different orchards with different glyphosate application history. Potted seedlings with 11-13-leaf growth stage were treated with glyphosate at 0.035, 0.07, 0.14, 0.28, 0.56, 1.12, 2.24, 4.48, and 8.96 kg a.i. ha-1. The dosage dependence response curve of each population was constructed with Log-logistic dose response regression equations. The ED50 value of each population was calculated and compared with the susceptible population from China. Different populations had different relative glyphosate-resistant levels which increased with the number of years of glyphosate application. Two populations with the highest resistance levels, 8.28 and 7.95 times, were found in Ningbo, Zhejiang Province, China, where glyphosate was used for weed control in orchards twice each year for 15 yr. The two resistant populations accumulated approximately two to four times less shikimic acid than the two susceptible populations 48 h after glyphosate application.
文摘目的:研究加拿大蓬中总黄酮提取方法及最佳工艺。方法:采用超声提取法,通过单因素试验和正交试验筛选最佳工艺条件。结果:最佳提取条件为60%乙醇、料液比1∶20、60 kW下超声45 m in。得率为31.076 mg/g。结论:该方法提取提取总黄酮快速、简便,可适用于生产中加拿大蓬总黄酮类物质的检测。该方法是提取加拿大蓬总黄酮类物质的有效途径。
