Structural and photosynthetic improvement of Myriophyllum aquaticum plant traits through artificial adjustments

Plant height is a key quantitative trait in plant ecology, linked with leaf area and stem diameter, affecting photosynthesis and water transport. Taller plants typically access lighte and resources, enhancing their competitive ability. However, the invasive aquatic plant Myriophyllum aquaticum usually reaches around 20 cm above the water surface. Despite its shorter stature, this species demonstrates rapid growth and efficient resource utilization, which contributes to its competitive success in various aquatic environments. This study aims to explore how altering its height impacts photosynthesis and water transport, providing insights into its growth adaptation mechanisms. We conducted an experiment with M. aquaticum, adjusting its height artificially (H) and comparing it to naturally maintained height (CK). We measured plant traits related to photosynthesis and water transport, including stem diameter, root pressure, and photosynthetic pigments (chlorophyll-a, chlorophyll-b, and carotenoids). Observations of guttation were also recorded. Under height-adjusted treatments, M. aquaticum exhibited positive significant growth responses with increased stem diameter and root pressure compared to the CK. Photosynthetic pigments were significantly higher in H than in CK. Notably, guttation was observed in CK but absent in H. Artificially increasing the height of M. aquaticum enhances its photosynthetic and hydraulic traits. However, this adjustment may lead to water deficiency issues, particularly during sunny conditions. This study contributes to understanding the ecological significance of plant height in aquatic species, highlighting the complex interplay between growth adaptations and environmental conditions.