Peerzada Arslan Masood, Williams Alwyn, O'Donnell Chris, Adkins Steve
School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD 4343, Australia.
Plants (Basel). 2021 Oct 29;10(11):2345. doi: 10.3390/plants10112345.
The glasshouse study was conducted with the objectives of (i) investigating the effect of soil moisture variations on the control efficiency of glyphosate on windmill grass ( R.Br.), common sowthistle ( L.), and flaxleaf fleabane [ (L.) Cronq.], (ii) evaluating the tolerance of tested weed species under soil moisture variations, and (iii) determining the morphological and physiological characteristics of these species to partially explain herbicide tolerance under periods of reduced soil moisture availability (RSM). The species' tolerance to glyphosate increased significantly under reduced soil moisture availability ( < 0.001). The lethal dose to cause herbicide injury or biomass reduction by 50% (LD) and 80% (LD) in relation to untreated control for water-stressed plants [i.e., moderate soil moisture availability (MSM) and RSM] was significantly higher than that of plants grown under high soil moisture availability (HSM). The tolerance factor (TF) for , , and , in terms of biomass reduction under RSM, was 2.6, 2.4, and 2.6, respectively, as compared to HSM. The results showed that the glyphosate sensitivity, especially at the sub-lethal rates, of the three weed species under study decreased as soil moisture availability reduced ( 0.01). Overall glyphosate efficacy, in relation to the recommended rate, was unaffected, except for ; the weed survived the highest tested glyphosate rate [750 g active ingredient (a.i.) ha] under RSM. There was significant interaction between weed species and soil moisture regimes for weed morpho-physiological traits ( < 0.001), with reduced soil moisture having a more influential impact on the growth of and compared to . Changes in the leaf characteristics, such as increased leaf thickness, higher leaf chlorophyll content, reduced leaf area, and limited stomatal activity for all the tested weed species under MSM and RSM in relation to HSM, partially explain the tolerance of species to glyphosate at sublethal rates.
（i）研究土壤水分变化对草甘膦防除风车草（R.Br.）、苣荬菜（L.）和亚麻叶斑鸠菊[（L.）Cronq.]的防治效果的影响；（ii）评估受试杂草物种在土壤水分变化条件下的耐受性；（iii）确定这些物种的形态和生理特征，以部分解释在土壤水分供应减少（RSM）时期的除草剂耐受性。在土壤水分供应减少的情况下（<0.001），这些物种对草甘膦的耐受性显著提高。与未处理对照相比，水分胁迫植物[即中等土壤水分供应（MSM）和RSM]造成除草剂伤害或生物量减少50%（LD）和80%（LD）的致死剂量显著高于高土壤水分供应（HSM）条件下生长的植物。就RSM下生物量减少而言，、和的耐受性因子（TF）分别为2.6、2.4和2.6，与HSM相比。结果表明，随着土壤水分供应减少（0.01），所研究的三种杂草物种对草甘膦的敏感性，尤其是在亚致死率下，降低了。总体而言，与推荐剂量相比，草甘膦的药效不受影响，除了；在RSM条件下，该杂草在测试的最高草甘膦剂量[750克活性成分（a.i.）/公顷]下存活。杂草形态生理特征在杂草物种和土壤水分状况之间存在显著交互作用（<0.001），与相比，土壤水分减少对和的生长影响更大。与HSM相比，在MSM和RSM条件下，所有受试杂草物种的叶片特征变化，如叶片厚度增加、叶片叶绿素含量升高、叶面积减小和气孔活性受限，部分解释了这些物种对亚致死率草甘膦的耐受性。
