Question

How do the pollen grains of Vallisneria protect themselves?

Answer 1

Pollination is the transfer of pollen grains from the stamen to the ovule themselves or the transfer of pollen grains from the anther to the stigma of a pistil. Pollination in Vallisneria is achieved by the assistance of water. It is a type of aquatic cross-pollination.

Complete answer:
Pollination in Vallisneria is accomplished by epihydrophily which happens outside the surface of the water. The female blossoms are submerged in the water and the male blossoms are delivered onto the surface of the water. Water helps in the interaction of pollen grains with the female blossoms. The pollen grains are delivered inside water.
But since Vallisneria is a water pollinated species, there are high chances of the pollen grains getting destroyed by water. So, to protect the pollen grains of the male Vallisneria plant, the pollen grains are covered with a mucilaginous coat. This coat prevents pollen grains from getting wet in the water.

Additional information:
Hydrophily is a unique form of pollination where pollen grains are spread by water currents in rivers or streams. Hygrophilous species have two categories-
The first consists of plants that distribute pollen on top of the water.
The second consists of plants that distribute the pollen under the surface of the water.

Note:
Vallisneria spirals are evergreen perennial also known as eelgrass or tape grass. The characteristics of species are dioecious which means individual flowers are either male or female. This means that there is only one sex in one plant. Mostly it is used as an aquarium plant that requires plentiful nutrition and sufficient light to grow properly.