Final answer:
Halophytes adapt to estuarine environments through specialized root filters that remove salt and mechanisms to pump oxygen into their roots. They may also have pneumatophores and aerenchyma to facilitate gas exchange in flooded, oxygen-poor conditions.
Step-by-step explanation:
Some plants are adapted to live in estuarine environments where there is a mix of fresh water and salt water, resulting in conditions that are sometimes flooded and sometimes salty. These plants are known as halophytes, and they have developed specific adaptations to thrive in such demanding conditions. One key adaptation is having specialized root filters that remove the salt from the water absorbed by the plant.
Additionally, these plants evolve to have mechanisms to pump oxygen into their roots, ensuring their survival during flooding when oxygen levels in the water are low. While some adaptations mentioned in the question, such as forming deep root systems and succulent stems, are relevant, it's the halophytic nature of some plants that primarily enables them to adapt to both flooding and salinity.
For instance, certain species can produce pneumatophores, which are specialized root structures that facilitate gas exchange in oxygen-poor soils. Others have aerenchyma, which are air spaces in tissues that help transport oxygen to submerged roots.