Plants that can grow in water are collectively called aquatic plants. In order to absorb water and nutrients from the soil, terrestrial plants must have developed roots. In order to support the body and facilitate the transportation of nutrients and water, strong stems are necessary. Roots and stems are covered with thick epidermis to prevent water loss. Aquatic plants are surrounded by water, and they don't need a thick epidermis to reduce the loss of water, so the epidermis becomes extremely thin and can directly absorb water and nutrients from the water.
In this way, the roots will lose their original functions, making the roots of aquatic plants underdeveloped. The roots of some aquatic plants are not used to absorb water and nutrients. Submerged plants are rooted in mud, and the whole plant is immersed in water, which has developed ventilation tissue, which is conducive to gas exchange. Most of the leaves are long and narrow or filiform, which can absorb some nutrients in water and grow normally under underwater lighting conditions. There are certain requirements for water quality, because water turbidity will affect its photosynthesis.
Flowers are small and short-lived, and are mainly used for leaf viewing. Aquatic plants play the role of "oxygen generator" in water, providing dissolved oxygen necessary for the growth of other organisms in the pond; At the same time, they can also remove excess nutrients from the water, so keeping the water free of algae by controlling the growth of algae will lead to turbid and green water, and block the light necessary for the healthy growth of aquatic plants and pond creatures.