Vallisneria denotes the genus, which includes a lot of freshwater plants like Vallisneria americana, Vallisneria spiralis, etc. They are long, slender, tape-like grasses usually present in freshwaters. Also, they are most commonly preferred for aquariums.
Vallisneria are submerged water plants and are monocots. They are completely submerged underwater, and their roots are anchored to the soil. Most of their vegetative parts are also submerged underwater.
Distribution
They are common aquatic plants that are widely distributed across Africa, Europe, Asia as well as America.
Also Read: Aquatic Ecosystem
Reproduction in Vallisneria
Vallisneria are dioecious. Thus, they produce both female and male plants separately. Male Vallisneria produces gametes (pollen), which reach the female flower for fertilisation. The gametes are dispersed in water through water pollinators.
Adaptations
- The roots of hydrophytes do not have any significant role in absorption. Their main duty is anchorage. Hence, they are fibrous and have reduced structures.
- Their leaves are thin and long tape-like structures. This helps the plant to withstand the water current. Also, their large surface area helps in the maximum absorption of sunlight.
- Their leaves are devoid of stomata. This is due to the lack of transpiration in aquatic plants.
- The plant consists of aerenchyma cells. These cells are huge open spaces that are present in between the cells. Thus, they help in buoyancy.
- Their mechanical tissues are absent.
Also see: Transportation in plants
Frequently Asked Questions
How does pollination happen in Vallisneria?
In Vallisneria, pollination and fertilisation happen through the water current. This is termed hydrophilly. The female Vallisneria shows up on the outer layer of the water as it has a long tail. The pollen grains delivered by the male plant reach the female for fertilisation.
Extended Reading:Pollination by water
What is seagrass?
Seagrass is a type of marine grass. Here, the female flowers are submerged underwater. Thus, pollination also happens inside the water body. Whereas, in Vallisneria, the female flower is seen on the surface of the water. Sometimes, both Seagrass and Vallisneria are together termed as ‘eelgrass’.
What are halophytes?
Halophytes are plants that can grow in extreme salinity. The plants surviving in marshes and swamps are usually halophytes. Examples are sea lavender, mangrove trees and rice grass.
How do aquatic plants acquire oxygen?
The oxygen dissolved in the water body acts as the main source for the respiration process. The submerged plants and planktons also release oxygen during photosynthesis. Moreover, aquatic plants can also respire anaerobically for a short period of time.
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