Geobotany, Regional and Environmental Sciences, University of Trier, Trier, Germany.
Analytical and Ecological Chemistry, Regional and Environmental Sciences, University of Trier, Trier, Germany.
PLoS One. 2022 Nov 21;17(11):e0277865. doi: 10.1371/journal.pone.0277865. eCollection 2022.
Formulations of macrocyclic lactone anthelmintics such as moxidectin are regularly administered to sheep to combat parasites. A disadvantage of these pharmaceuticals are their side effects on non-target organisms when entering the environment. Little is known about anthelmintic effects on plant reproduction and whether the effects depend on environmental factors. For ecological and methodological reasons, we aimed at testing whether temperature affects the efficacy of a common moxidectin-based formulation on seed germination. We carried out a germination experiment including three typical species of temperate European grasslands (Centaurea jacea, Galium mollugo, Plantago lanceolata). We applied three temperature regimes (15/5, 20/10, 30/20°C), and a four-level dilution series (1:100-1:800) of formulated moxidectin (i.e., Cydectin oral drench). These solutions represent seed-anthelmintic contacts in the digestive tract of sheep shortly after deworming. In addition, a control was carried out with purified water only. We regularly counted emerging seedlings and calculated final germination percentage, mean germination time and synchrony of germination. Formulated moxidectin significantly reduced percentage, speed and synchrony of germination. A 1:100 dilution of the formulation reduced germination percentage by a quarter and increased mean germination time by six days compared to the control. Temperature moderated effects of the anthelmintic drug on germination in all response variables and all species, but in different patterns and magnitudes (significant anthelmintic x temperature x species interactions). In all response variables, the two more extreme temperature regimes (15/5, 30/20°C) led to the strongest effects of formulated moxidectin. With respect to germination percentage, G. mollugo was more sensitive to formulated moxidectin at the warmest temperature regime, whereas P. lanceolata showed the highest sensitivity at the coldest regime. This study shows that it is important to consider temperature dependencies of the effects of pharmaceuticals on seed germination when conducting standardised germination experiments.
大环内酯类驱虫药（如莫昔克丁）的配方经常被用于绵羊以对抗寄生虫。这些药物的一个缺点是，当它们进入环境时，会对非目标生物产生副作用。关于驱虫药对植物繁殖的影响以及这些影响是否取决于环境因素，人们知之甚少。出于生态和方法学的原因，我们旨在测试温度是否会影响基于常见莫昔克丁配方对种子发芽的效果。我们进行了一项发芽实验，其中包括三种典型的温带欧洲草原物种（矢车菊、筋骨草、车前草）。我们应用了三个温度范围（15/5、20/10、30/20°C）和莫昔克丁配方（即赛特罗口服滴剂）的四级稀释系列（1:100-1:800）。这些溶液代表了绵羊驱虫后不久在消化道中接触到的种子和驱虫药。此外，还进行了仅用纯净水的对照实验。我们定期计数萌发的幼苗并计算最终发芽率、平均发芽时间和发芽同步性。配方莫昔克丁显著降低了发芽率、发芽速度和发芽同步性。与对照相比，配方的 1:100 稀释液使发芽率降低了四分之一，平均发芽时间延长了六天。温度调节了驱虫药对所有物种所有反应变量中发芽的影响，但模式和幅度不同（驱虫药 x 温度 x 物种的交互作用显著）。在所有反应变量中，两个更极端的温度范围（15/5、30/20°C）导致配方莫昔克丁的影响最强。就发芽率而言，筋骨草在最温暖的温度条件下对配方莫昔克丁更为敏感，而车前草在最冷的温度条件下表现出最高的敏感性。本研究表明，在进行标准化发芽实验时，考虑药物对种子发芽的影响的温度依赖性非常重要。
