Although cover crops are widely used for weed suppression in the agroecosystem, little research is available regarding the possibility that the decomposed weed solution may control weeds. In this study, we tested the allelopathic effect of decomposed weed solution on barnyardgrass (Echinochloa crus-galli). In two separate tests, we found that the solution of decomposed Myosoton aquaticum completely suppressed the germination of barnyardgrass seeds at a concentration of 20 g l-1. We then isolated and identified the predominant inhibitory substance in the decomposed M. aquaticum solution. The solution was subjected to organic solvent extraction and then separated on a silica gel column before the final identification of its components by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Dihydrocoumarin was isolated from the M2 and M3 fractions using a bioassay-guided method and was found to be the most active of eleven candidate allelochemical compounds. Dihydrocoumarin is typically used as a food additive. In this study, barnyardgrass germination was completely inhibited when treated with dihydrocoumarin at 1 g l-1, and its root and shoot growth were significantly inhibited at an application rate of 0.005 g l-1. Dihydrocoumarin showed highly efficient inhibition of root and shoot growth in barnyardgrass at low concentrations compared with coumarin. These findings show that weeds may be used as cover crops to provide allelochemicals for weed suppression and that dihydrocoumarin has the potential to be used as a bioherbicide.

中文翻译：

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Myosoton Aquaticum 提取物和化合物控制稗草 (Echinochloa crus-galli) 的潜力

尽管覆盖作物被广泛用于农业生态系统中的杂草抑制，但关于分解的杂草溶液可能控制杂草的可能性的研究很少。在这项研究中，我们测试了分解杂草溶液对稗草( Echinochloa crus-galli )的化感作用。在两个单独的测试中，我们发现分解的Myosoton 水生植物的溶液在 20 g l-1 的浓度下完全抑制了稗草种子的萌发。然后我们分离并鉴定了分解的水生 M.aquaticum 中的主要抑制物质解决方案。将溶液进行有机溶剂萃取，然后在硅胶柱上进行分离，然后通过高效液相色谱-串联质谱 (HPLC-MS/MS) 对其成分进行最终鉴定。使用生物测定指导的方法从 M2 和 M3 级分中分离出二氢香豆素，发现二氢香豆素是 11 种候选化感化合物中活性最高的。二氢香豆素通常用作食品添加剂。在本研究中，稗草的萌发在用 1 g l-1 的二氢香豆素处理时被完全抑制，在 0.005 g l-1 的施用量下其根和芽的生长被显着抑制。与香豆素相比，二氢香豆素在低浓度下表现出对稗草根和芽生长的高效抑制作用。