Phenotypic plasticity can determine the performance of exotic plants in environmental disturbance. Aquatic plants can adapt to the stress caused by water level fluctuations in the water level, water depth, or substrate nutrients through phenotypic plasticity. The high-potential invasiveness of Myriophyllum aquaticum in riparian wetlands may be associated with its growth and phenotypic plasticity. The interactive effects of fluctuations in the water level, water depth, and substrate nutrients on the growth performance of M. aquaticum were evaluated. We performed two two-factorial experiments to evaluate the effects of (i) frequency and amplitude of water level fluctuations and (ii) water depth and substrate nutrients on the performance of M. aquaticum. The results indicated that in the first experiment, low fluctuation frequency with a ± 20 cm amplitude significantly increased the value of all growth traits (except for total length of lateral branches). Regardless of fluctuation frequency, relative to a ± 60 cm amplitude and a static water level, the maximum values of total biomass, plant height, relative growth rate, and total length of lateral branches existed in moderate fluctuation amplitudes (± 20 cm, ± 40 cm). In the second experiment, the growth performance of M. aquaticum decreased with increasing water depth from 25 cm to 75 cm. High nutrient substrate significantly increased all growth traits (except for chlorophyll content) in water depths of 25 and 50 cm. Above all, M. aquaticum has optimal growth performance in response to low fluctuation frequency, moderate fluctuation amplitudes (± 20 cm, ± 40 cm), and high nutrient substrate in shallow water (water depth lower than 75 cm). These results indicate that M. aquaticum has a high-potential invasiveness in shallow water and with low disturbance of freshwater habitats.

中文翻译：

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适度水文扰动和高营养基质提高水生狐尾藻的生长性能

表型可塑性可以决定外来植物在环境干扰中的表现。水生植物可以通过表型可塑性适应水位、水深或基质养分等水位波动引起的胁迫。河岸湿地狐尾藻的高潜在侵袭性可能与其生长和表型可塑性有关。评价了水位、水深和底物养分波动对水生植物生长性能的交互作用。我们进行了两个双因素实验，以评估 (i) 水位波动的频率和幅度以及 (ii) 水深和基质养分对水生分枝杆菌性能的影响。结果表明，在第一个实验中，± 20 cm 幅度的低波动频率显着增加了所有生长性状的值（侧枝总长度除外）。不考虑波动频率，相对于±60 cm幅度和静态水位，总生物量、株高、相对生长速率和侧枝总长度的最大值存在中等波动幅度（±20 cm，±40厘米）。在第二个实验中，M.aquaticum 的生长性能随着水深从 25 cm 增加到 75 cm 而下降。高营养基质显着增加了 25 和 50 厘米水深的所有生长性状（叶绿素含量除外）。最重要的是，M.aquaticum 在低波动频率、中等波动幅度（± 20 cm、± 40 cm）、浅水（水深低于75厘米）的高营养基质。这些结果表明，M.aquaticum 在浅水区具有很高的入侵性，对淡水栖息地的干扰很小。