How do leaves adapt to their surroundings?

To the Aquatic plants or Hydrophytes (Greek hydor = water; phytos = plant) include those plants whose habitat is under water, on the water, on the bank or in swamps. Hydrophytes are specially adapted to their habitat:

root: are only found in a reduced form in most aquatic plants, because a pronounced root system to absorb water is not necessary in the water itself. Depending on the species, aquatic plants do not get nutrients from their roots, but from the leaves. In contrast to land-living plants, underwater plants in particular can absorb nutrients from the surrounding water through their leaves. Therefore, roots essentially only have a fixation function for an aquatic plant.

Stem axis: consists of the so-called aerenchymal tissue, which is used for gas exchange within the plant. This means that the carbon dioxide required by the aquatic plant (for photosynthesis) can also reach submerged parts of the plant.

leaves: also consist of the aerenchymal tissue. Air can be stored in this tissue, which leads to the leaves being lifted. Free-swimming aquatic plants usually form large floating leaves (e.g. water lilies). Their stomata are on the upper side of the leaf, which facilitates gas exchange. If the stomata were on the underside, the aquatic plant could not get any carbon dioxide from the air. Underwater leaves, on the other hand, are small (e.g. waterweed) and free of a cuticle, which normally protects plants from water loss (but superfluous in underwater habitats).