Aquatic plants in agricultural landscapes play a vital role in maintaining the ecological integrity within the aquatic systems while facing an array of disturbances. Among them, information on herbicide exposure on non-target aquatic plants is scarce. The present study was designed to fill this information gap by detecting the impacts of 2-methyl-4-chlorophenoxyacetic acid (MCPA) on Hydrilla verticillata using morpho-anatomical and physiological biomarkers and assessing the environmental risk of MCPA to the non-target environment. H. verticillata was exposed to different MCPA concentrations (10, 100, 500, 1000 μg/L) and control (0 μg/L) for 7 days. At the end of the experiment, plant growth, pigments, H2O2 content, peroxidase activity (POD) and plant anatomy were compared. The environmental risk was assessed using predicted environmental concentration/predicted no effect concentration (PEC:PNEC) ratio, hazard quotient (HQ) and hazard index (HI). Control plants exhibited the highest growth, and a growth decline was noted in parallel to MCPA exposure, where a similar trend was detected for the plant pigment contents. MCPA induced chlorosis and oxidative stress in H. verticillata. Risk analysis detected high values for PEC:PNEC ratios (3-9), HQ (1.92-5.79) and HI (28.15). MCPA-exposed H. verticillata could recover once those plants received natural conditions. Overall, present findings showed the negative impacts of MCPA on non-target aquatic plant H. verticillata. These findings will be useful to clarify the interaction between agrochemicals and non-target aquatic plants. Such information would benefit to decide the criteria in aquatic ecosystem management.

中文翻译：

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2-甲基-4-氯苯氧基乙酸（MCPA）对非目标水生植物绿藻Hydrilla verticillata的毒性评估和环境风险评估。

农业景观中的水生植物在面临一系列干扰的同时，在维持水生系统内生态完整性方面发挥着至关重要的作用。其中，关于非目标水生植物接触除草剂的信息很少。本研究旨在通过使用形态解剖学和生理生物标记物检测2-甲基-4-氯苯氧基乙酸（MCPA）对网纹霉的影响并评估MCPA对非目标环境的环境风险，从而填补这一信息空白。将黄褐紫苏暴露于不同的MCPA浓度（10、100、500、1000μg/ L）和对照（0μg/ L）下7天。在实验结束时，比较了植物生长，色素，H2O2含量，过氧化物酶活性（POD）和植物解剖结构。使用预测的环境浓度/预测的无作用浓度（PEC：PNEC）比，危险商（HQ）和危险指数（HI）评估环境风险。对照植物表现出最高的生长，并且与MCPA暴露平行地注意到生长下降，其中检测到植物色素含量的相似趋势。MCPA诱导黄萎病菌发生绿化和氧化应激。风险分析发现PEC：PNEC比率（3-9），总部（1.92-5.79）和HI（28.15）较高。一旦那些植物受到自然条件的影响，暴露于MCPA的黄萎病菌就可以恢复。总体而言，目前的发现表明，MCPA对非目标水生植物H. verticillata有负面影响。这些发现将有助于阐明农药和非目标水生植物之间的相互作用。