The plant that is completely submerged in water for living in the aquatic environment is known as a hydrophytic plant. They usually live in the region where plenty of water is available, like a pool, river lake or wet soil. Their body parts will remain under the water like traps, lotus etc. They are sometimes referred to as macrophytes and said to be the common component of wetland.
The hydrophyte plant bodies adapt to survive in an aquatic ecosystem by modifying their leaves, stems and roots and modifying their cellular components. This aquatic plant belongs to the base of the trophic level, i.e. producer. This macrophyte is divided into three based on relation to air and water. They are submerged, floating and emergent hydrophytic plants. Here are some detailed explanations of these categories
Classification of Hydrophytes
- Floating hydrophytes
These plants are rooted in the mud, but their leaves and flowering shoots float on the water surface. E.g. Victoria, Regia, Nymphaea, Nelumbium and Marsilea. Floating itself has two kinds. Free-floating and rooted floating where the former floats on water and the latter are attached to the muddy substrate.
- Submerged Hydrophytes
Submerged is again classified into two. They are floating submerged and rooted submerged. Species like Utricularia sp, Ceratophyllum sp etc., are examples of floating type without contact in air, and Hydrilla sp, Vallisneria sp, Isoetes sp, Aponogeton sp etc. are examples of rooted submerged that are saturated in the water.
- Emergent Hydrophytes
They are also known as amphibious. These plants grow in shallow waters. Their roots, some parts of stems and leaves are submerged in water. But some flowering shoots spring well above the water surface. Typha sp, Sagittaria sp, Ranunculus sp etc., are some examples of this type category.
- Water retention
- Flat leaves
- Feathery roots
- Air sacs
The aquatic plants require a water surrounded environment to survive. They will have the ability to absorb and retain moisture to keep the plant alive between watering cycles. They are constantly submerged in the water, so there is no need for aquatic plants to expend energy to regulate transpiration.
The flat leaves of aquatic plants enable them to float on the water quickly. Some aquatic plants float on the water surface like water lilies (Nymphaea Attraction) with 12-inch diameter leaves. Thus, it increases the rate of water and mineral diffusion into the plant cells.
The aquatic macrophytes have small feathery roots that are specifically designed to take in oxygen from the water. They don’t need a long and thick root structure because the plant will permanently be submerged in water.
The distinguishing factor of the air sac helps them float on the surface of the water, Some plants will fully be submerged into the water, and some types will float top on the surface since their leaves distribute the weight across the surface of the water.
Ecological adaptations in hydrophytes
- As the aquatic plants are constantly immersed in the water, the root system has minor importance.
- Roots absent in Wolffia, Ceratophyllum.
- In plant-like hydrilla, the roots are poorly developed
- Root caps are absent in hydrophytes
- Balancing roots are present in Pistia, Eichornia.
- The stems are flexible and long slender in plants like hydrilla
- In Eichornia, the branch appears thick, short and spongy
- In Nymphaea and Nelumbo, the branch is a rhizome in rooted plants with free-floating leaves
- Leaves will be in the form of long and ribbon-like structures
- Leaves that are floating are large and flat with a coating of wax
- In victoria Regia, the largest simple leaves are seen
- Petioles are swollen and spongy in Eg: Eichornia, Trapa.
The hydrophytic plants can live in diverse habitats like marine, lentic and lotic water sources. This macrophyte is divided into three based on relation to air and water. They are submerged, floating and emergent hydrophytic plants. Here are some detailed explanations of these categories. The hydrophytes plants undergo certain modifications to adapt according to their surroundings or thrive in an aquatic environment.