Environment and Climate Change Canada, Science and Technology Branch, Carleton University, Ottawa, Ontario, Canada.
Department of Agroecology, Aarhus University, Slagelse, Denmark.
Environ Toxicol Chem. 2020 May;39(6):1244-1256. doi: 10.1002/etc.4712. Epub 2020 Apr 29.
Herbicides have been shown to reduce flower production and to delay flowering, with results varying among herbicides and tested plant species. We investigated the effects of herbicides on flowering in an extensive greenhouse study conducted in Canada and Denmark. The effects of low doses of 5 different herbicides (bromoxynil, ioxynil + bromoxynil, metsulfuron-methyl, clopyralid, and glyphosate), simulating realistic drift scenarios (1 and 5% recommended field rates), on plant flowering were examined using 9 wild plant species exposed at either the seedling (6- to 8-leaf) or flower bud stage. Following herbicide exposure, initial flowering date as well as flower production over time were recorded over the growing period. The effect of herbicides on cumulative flower numbers and flowering time were modeled using Gompertz growth models. Significant delays to peak flowering and/or reductions in flower production were observed in at least one plant species for all tested herbicides, with glyphosate often exhibiting the greatest negative effects, that is, plant death. Except for ioxynil + bromoxynil, there was no clear evidence of either the seedling or the flower bud stage being more sensitive. Overall, 58% of all species × life stage × herbicide treatments resulted in either a statistically significant or a strong decline in flower production with herbicide application rates up to 5% of recommended field rates, whereas significant or strong delays in peak flowering were also detected but were slightly less common. Effects at 1% label rates were minimal. Simultaneous delays to peak flowering and reductions in total flower production occurred in approximately 25% of all cases, indicating that herbicide application rates simulating realistic drift scenarios would likely have negative effects on wild floral communities. Environ Toxicol Chem 2020;39:1244-1256. © 2020 SETAC.
除草剂已被证明会减少花的产量并延迟开花，而且不同的除草剂和被测试的植物物种之间的结果也不同。我们在加拿大和丹麦进行的一项广泛的温室研究中调查了除草剂对开花的影响。使用 9 种野生植物，在幼苗（6-8 叶）或花蕾期暴露于低剂量的 5 种不同除草剂（溴苯腈、溴苯腈+碘苯腈、甲磺隆甲酯、氯吡嘧磺隆和草甘膦）下，模拟实际漂移情况（推荐田间用量的 1%和 5%），考察了这些除草剂对植物开花的影响。在生长期间，记录了除草剂暴露后的初始开花日期以及随时间推移的花产量。使用 Gompertz 生长模型对除草剂对累积花数和开花时间的影响进行建模。所有测试的除草剂都至少在一种植物中观察到对开花高峰期的明显延迟和/或花产量的降低，草甘膦通常表现出最大的负面影响，即植物死亡。除了碘苯腈+溴苯腈之外，幼苗期或花蕾期都没有明显的证据表明更敏感。总体而言，在所有物种×生命阶段×除草剂处理中，有 58%的处理导致花产量的显著或强烈下降，而在推荐田间用量的 5%的除草剂应用率下，开花高峰期的显著或强烈延迟也被检测到，但稍微不太常见。在 1%的标签用量下，效果最小。在大约 25%的情况下，同时出现开花高峰期延迟和总花产量减少的情况，表明模拟实际漂移情况的除草剂应用率可能对野生花卉群落产生负面影响。环境毒理化学 2020；39:1244-1256。版权所有 2020 SETAC。
