Clonal integration increases growth performance and expansion of Eichhornia crassipes in littoral zones: A simulation study

Clonal integration can improve the spread and growth of invasive plants in response to various disturbances. However, little is known about its role in floating aquatic clonal plants that expand from aquatic into terrestrial habitats in littoral zones. Thus, in this study, we simulated the expansion of the invasive clonal aquatic plant Eichhornia crassipes from aquatic to terrestrial habitats through two modes of clonal integration. We subjected E. crassipes parent plants and offspring ramets to three levels of natural light in terrestrial habitats: 100%, 60%, and 10%. The stolon connections were either severed or kept intact. Our findings showed that clonal integration had positive effects on plants exposed to shade in the terrestrial habitats and produced negative effects on plants in the aquatic habitats. Overall, clonal integration significantly increased whole-plant growth performance. Parent plants and offspring ramets in the terrestrial environments can enhance their adaptability to shade by increasing the maximum quantum yield of photosystem II and chlorophyll content. Clonal integration can support the expansion of E. crassipes from aquatic into terrestrial habitats with limited light conditions through significantly elevated growth traits. Thus, E. crassipes has a high ability for clonal integration and may be a potential threat to littoral zone ecosystems.