What enables hydrilla to adapt to fluctuations in water levels?

Hydrilla's ability to adapt to fluctuations in water levels is primarily due to its various growth forms and structures. This aquatic plant demonstrates remarkable plasticity, meaning it can alter its growth characteristics based on environmental conditions. For instance, hydrilla can exhibit different growth forms such as submersed, emersed, and floating types depending on the water level. When water levels rise, hydrilla can grow taller to maximize light exposure, while lower water levels can trigger the plant to spread horizontally.

This adaptability is crucial in various aquatic ecosystems, allowing hydrilla to thrive in diverse conditions. Other characteristics, like a shallow root system, while beneficial for anchoring, do not provide the same level of adaptability to changing water conditions as the plant's growth forms. Similarly, reliance on aquatic animals or rapid seed dispersal does not directly contribute to its adaptability in the same way its structural flexibility does. Therefore, its growth forms and structures are key to surviving and flourishing amidst the challenges posed by fluctuating water levels.