In Australia, glyphosate is widely used in glyphosate-tolerant crops and fallows to control weeds such as common sowthistle (Sonchus oleraceus L.). It has been hypothesized that glyphosate at sublethal doses, as a consequence of herbicide drift, may have a stimulatory effect on S. oleraceus growth. In 2017, pot trials were conducted to evaluate the effect of low doses of glyphosate on growth and seed production of this weed at the Weed Science Screenhouse Facility at the University of Queensland, Australia. At the 4- to 5-leaf stage (3-wk-old rosette), plants were treated with low doses of glyphosate (0 [control], 5, 10, 20, 40, 80, and 800 g ae ha−1), and their responses were recorded until plant maturity. The study was repeated after completion of the first experimental run. An additional glyphosate dose (2.5 g ha−1) was added in the second run. The low doses of glyphosate (<40 g ha−1) caused a significant increase in S. oleraceus plant height and number of leaves compared with the no-glyphosate treatment. The highest stimulatory effect was observed at 5 g ha−1. At 5 g ha−1 glyphosate, S. oleraceus seed production increased by 154% and 101% in the first and second experimental runs, respectively, compared with the no-glyphosate treatment. The results of this study suggest that the sublethal doses of glyphosate produced hormetic effects on growth and seed production of S. oleraceus that changed the dynamics of weed–crop competition.

中文翻译：

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草甘膦引起的兴奋：对普通苦蓟 (Sonchus oleraceus) 幼苗生长和繁殖潜力的影响

在澳大利亚，草甘膦被广泛用于耐草甘膦作物和休耕以控制杂草，如常见的水飞蓟（苦参L.)。据推测，由于除草剂漂移，亚致死剂量的草甘膦可能对苦苣菜生长。2017 年，在澳大利亚昆士兰大学的杂草科学筛选设施进行了盆栽试验，以评估低剂量草甘膦对这种杂草生长和种子生产的影响。在 4 至 5 叶阶段（3 周龄莲座丛），植物用低剂量的草甘膦（0 [对照]、5、10、20、40、80 和 800 g ae ha-1)，并记录他们的反应，直到植物成熟。在完成第一次实验运行后重复该研究。额外的草甘膦剂量（2.5 g ha-1) 在第二次运行中添加。低剂量草甘膦（<40 g ha-1) 导致显着增加苦苣菜与无草甘膦处理相比的株高和叶片数。在 5 g ha 时观察到最高的刺激效果-1. 5 克公顷-1草甘膦，苦苣菜与无草甘膦处理相比，第一轮和第二轮试验的种子产量分别增加了 154% 和 101%。这项研究的结果表明，亚致死剂量的草甘膦对植物的生长和种子生产产生了兴奋作用。苦苣菜这改变了杂草作物竞争的动态。