三种杂草对草甘膦的敏感性及处理后植株体内莽草酸积累量差异

Sensitivity to glyphosate and dynamics of shikimate accumulation in three weed species following glyphosate application

为明确不同杂草对草甘膦的敏感性,以稗Echinochloa crusgalli、马唐Digitaria sanguinalis、藜Chenopodium album为供试材料,采用生物测定法和吸光光度法分别测定了草甘膦对3种杂草的抑制中浓度(GR50),以及不同剂量处理后杂草体内莽草酸积累量的变化。经410 g/hm2(有效成分)的草甘膦处理后,稗体内莽草酸积累量呈上升-下降-上升趋势,而马唐和藜则表现为缓慢上升,根据此剂量处理下莽草酸积累趋势得出,3种杂草对草甘膦的敏感性由高到低依次为稗、藜和马唐,与生测法的结果一致。经820～3 280 g/hm2(有效成分)的草甘膦处理后,3种杂草体内莽草酸积累量从第2 d开始急剧升高,增长速率随着草甘膦处理剂量的增加而加大;处理后稗、马唐和藜体内莽草酸积累量最高值差异显著,分别为1 137.9、4 989.7和2 084.2μg/g,为各自对照水平的16.7、23.7和82.9倍。该研究结果可为系统检测杂草对草甘膦的敏感性提供依据。

The GR50 value and shikimate accumulation in three problematic weed species were determined by whole plant bioassay and spectrophotometric assay,respectively,after treated by glyphosate.After treated by glyphosate at 410 g（a.i.）/ha,shikimate accumulation in Echinochloa crusgalli was first increased,then declined,increased slightly finally.However,it kept increasing in Chenopodium album and Digitaria sanguinalis.Based on the accumulation of shikimate by glyphosate treated within this dosage,the order of sensitivity to glyphosate from high to low was E.crusgalli,C.album and D.sanguinalis,which was similar to the result of whole plant bioassay.Shikimate accumulation was increased rapidly in all three weeds after treated 2 days by glyphosate within the dose range of 820 to 3 280 g（a.i.）/ha,and the accumulation rate showed positive relationship to the treatment dosage.The highest shikimate accumulation in E.crusgalli,D.sanguinalis and C.album were 1 137.9 μg/g,4 989.7 μg/g and 2 084.2 μg/g,which were 16.7-,23.7-and 82.9-fold compared to that of the untreated control,respectively.The knowledge obtained in this study will provide basis for developing method to detect the sensitivity of weeds to glyphosate.