长江中下游棉田马唐(Digitaria sanguinalis)对草甘膦的抗药性初步研究

采用培养皿种子检测法和整株植物测定法的测定了从长江中下游3个省13个县棉田采集的18个马唐(Digitaria sanguinalis)种群,其草甘膦抗药性水平,并采用分光光度计测定了1个相对敏感种群和3个相对抗性种群在施用草甘膦后莽草酸积累量和谷胱甘肽S￣转移酶(glutathione S-transferase,GST)活力的变化情况。整株植物测定法结果表明:湖南常德安障乡地区马唐种群相对抗性水平最高,抗性指数为7.637,培养皿种子检测法与整株植物测定法测定的结果基本一致。测定的4个种群莽草酸积累量均随时间的变化而上升,其中3个抗性马唐种群的莽草酸积累量在9 d内始终低于相对敏感种群。4个种群GST活力变化无显著性差异,表明GST的代谢活力与马唐对草甘膦产生抗药性不相关。

Preliminary Study on the Resistance of Digitaria sanguinalis to Glyphosate in Cotton Fields in the Middle and Lower Reaches of the Yangtze River

Resistance levels of 18 Digitaria sanguinalis populations to glyphosate were assessed by seed bioassays and whole plant assays. Samples were collected from cotton fields in three provinces of the middle and lower reaches of the Yangtze River. Shikimic acid content and glutathione S-transferase (GST) activity of four selected populations, i.e. one relatively susceptible and three relatively resistant ones, were measured using ultraviolet spectrophotometry. The whole plant assays indicated populations from the collecting sites of Anzhang town, Hunan, had the highest resistance, with a resistance index of 7.367. The two detection methods showed the same resistance tendencies. In four of the samples, shikimic acid accumulation rose over time, however, the accumulation levels in three resistant populations were significantly lower than observed in the most susceptible population. There were no significant differences among the populations for GST activity, revealing that GST activity is irrelevant to glyphosate resistance in Digitaria sanguinalis.