Aquatic Plants

Aquatic plants — also called hydrophytic plants or hydrophytes — are plants that have adapted to living in or on aquatic environments. more...

Because living on or under water surface requires numerous special adaptations, aquatic plants can only grow in water or permanently saturated soil. Aquatic vascular plants can be ferns or angiosperms (from both monocot and dicot families). Seaweeds are not vascular plants but multicellular marine algae, and therefore not typically included in the category of aquatic plants. As opposed to plants types such as mesophytes and xerophytes, hydrophytes do not have a problem in retaining water due to the abundance of water in its environment. This means the plant has less need to regulate transpiration (indeed, the regulation of transpiration would require more energy than the possible benefits incurred.)

Hydrophytes share several survival characteristics:

1. A thin cuticle. Cuticles primarily prevent water loss, thus most hydrophytes have no need for cuticles.
2. Stomata that are open most of time: so water is (abundant). This means that guard cells on the stomata are generally inactive.
3. An increased number of stomata, that can be on either side of leaves.
4. A less rigid structure: water pressure supports them.
5. Large flat leaves on surface plants for flotation.
6. Air sacs for flotation.
7. Smaller roots: water can diffuse directly into leaves.
8. Feathery roots: no need to support the plant.
9. Specialized roots designed to take in oxygen.

For example, some species of buttercup (genus Ranunculus) float slightly submerged in water; only the flowers extend above the water. Their leaves and roots are long and thin and almost hair-like; this helps spread the mass of the plant over a wide area, making it more buoyant. Long roots and thin leaves also provide a greater surface area for uptake of mineral solutes and oxygen.

Wide flat leaves in water lilies (family Nymphaeaceae) help distribute weight over a large area, thus helping them float near surface.

Many fish keepers keep aquatic plants in their tanks to control phytoplankton and moss by removing metabolites.

Many species of aquatic plant are invasive species in different parts of the world. Aquatic plants make particularly good weeds because they reproduce vegetatively from fragments.

Adaptations

• Free Plants: In a pond community, they receive more sunlight than submerged plants. But they also have to compete with one another for sunlight
• Submerged Plants: Submerged leaves receive low levels of sunlight because light energy diminishes while passing through a water column.

All floating Plants

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