Aims The incidence of herbicide-resistant blackgrass is escalating in wheat fields; the development of alternatives to traditional herbicides is crucial. Allelopathic wheat can suppress blackgrass. Herein, we investigated the influence of allelopathic wheat on herbicide-resistant blackgrass. Methods Mesosulfuron-methyl-resistant and -susceptible blackgrass were used. We examined i) root interactions between allelopathic wheat and both blackgrass biotypes, ii) allelochemical 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) production by allelopathic wheat in a root segregation experiment, and iii) responses of allelopathic wheat to root exudates. Signal chemicals in the root exudates of both blackgrass biotypes were characterised. Results Allelopathic wheat inhibited the growth of roots more than shoots for resistant and susceptible blackgrass. Allelopathic wheat inhibited roots of resistant blackgrass more than those of susceptible blackgrass. Allelopathic wheat significantly shaped blackgrass root behaviour. Resistant blackgrass caused a lower relative increase in DIMBOA production by allelopathic wheat. Root segregation with 30 μm nylon led to greater growth inhibition of blackgrass and a relative increase in allelochemical DIMBOA. Root exudates from blackgrass induced DIMBOA production, but more so for susceptible blackgrass. The concentration of (−)-loliolide, a potential signal chemical, was much lower in the root exudates from resistant than susceptible blackgrass. Conclusions Allelopathic wheat can interfere with the growth of mesosulfuron-methyl-resistant blackgrass through allelochemical-mediated root interactions. Such allelopathic interference can provide insight into weed management.

中文翻译：

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耐甲基磺隆的黑草对化感小麦的生长反应降低是由地下化学相互作用驱动的

目的 麦田中抗除草剂黑草的发病率正在上升；开发传统除草剂的替代品至关重要。化感小麦可以抑制黑草。在此，我们研究了化感小麦对抗除草剂黑草的影响。方法选用耐甲磺隆和易感黑草。我们检查了 i) 化感小麦与两种黑草生物型之间的根相互作用，ii) 化感小麦在根分离实验中产生的化感化学 2,4-二羟基-7-甲氧基-1,4-苯并恶嗪-3-one (DIMBOA)，以及iii) 化感小麦对根系分泌物的反应。表征了两种黑草生物型根系分泌物中的信号化学物质。结果化感小麦对抗病黑草和易感黑草的根系生长抑制作用大于地上部。化感小麦对抗病黑草根系的抑制作用大于对感病黑草根系的抑制作用。化感小麦显着塑造了黑草根的行为。抗性黑草导致化感小麦 DIMBOA 产量的相对增加较低。用 30 μm 尼龙进行根分离导致对黑草的生长抑制更大，并且化感化学 DIMBOA 相对增加。黑草根系分泌物诱导 DIMBOA 产生，但对易感黑草更是如此。(-)-loliolide 是一种潜在的信号化学物质，在抗性黑草根系分泌物中的浓度比易感黑草低得多。结论 化感小麦可通过化感化学介导的根系相互作用干扰耐甲基磺草胺的黑草生长。