Aquatic non-targeted organisms are more likely to be exposed to herbicides in multiple pulse events then long continuous exposure. The potential of an organism to recover between exposures has an important role in the overall effects of the toxicant. Common duckweeds show high potential for recovery after a single exposure to isoproturon. To evaluate the growth patterns and recovery potential between multiple exposures, L. minor plants were exposed to isoproturon in three repetitive 7-day treatment cycles in three time-variable exposure scenarios with equivalent time-weighted average concentrations. The growth was significantly inhibited during each exposure phase with significant cumulative effects in every subsequent treatment cycle resulting in a cumulative decrease in biomass production. However, inhibitory effects were reversible upon transferring plants to a herbicide-free nutrient solution. These results indicate that L. minor plants have a high recovery potential even after multiple exposures to isoproturon. Observed cumulative decrease in biomass production, as well as the potential for fast and efficient recovery from repeated herbicide exposure, might affect the competitiveness of L. minor in surface water communities. The observations made during each exposure period, recovery patterns, and the resulting cumulative effects over time may contribute to further development, calibration and validation of mechanistic toxicokinetic/toxicodynamic models for simulating the effects of pesticides on aquatic plants populations in the laboratory and environmental conditions.

水生非靶向生物更有可能在多次脉冲事件中接触除草剂，然后长时间连续接触。有机体在两次接触之间恢复的潜力在有毒物质的总体影响中具有重要作用。普通浮萍一次暴露于异丙隆后显示出很高的恢复潜力。要评估多次暴露之间的生长模式和恢复潜力，小L.在三个时间可变的暴露场景中，以相等的时间加权平均浓度，在三个重复的7天处理周期中，将植物暴露于异丙隆。在每个暴露阶段都明显抑制了生长，并在随后的每个处理周期中产生了明显的累积效应，从而导致生物量产量的累积下降。但是，将植物转移至无除草剂的营养液后，抑制作用是可逆的。这些结果表明，即使多次暴露于异丙隆中，小L.植物也具有较高的恢复潜力。观察到生物量生产的累积减少，以及反复除草剂暴露后快速有效回收的潜力，可能会影响小L.的竞争力。在地表水社区。在每个暴露时间，恢复模式以及随时间推移所产生的累积效应中进行的观察，可能有助于进一步开发，校准和验证用于模拟农药在实验室和环境条件下对水生植物种群的影响的机制的动力学和毒物动力学模型。