Question

Plants like Nymphaea which are attached emerged hydrophytes float on the surface of water with the help of
A. Chlorenchyma
B. Sclerenchyma
C. Aerenchyma
D. collenchyma.

Answer 1

Hint: It is the changed structure of parenchyma. Its cells are organized with regular air chambers in among to facilitate diffusion of gases in and out. This shape is in general present in aquatic plants.

Complete answer:
To answer this question, first, we need to know about the Nymphaea species. Nymphaea is a genus of hardy and tender aquatic plants that belongs to the family Nymphaeaceae. The genus has a cosmopolitan distribution. Many species are cultivated as decorative flowers, and many cultivars were bred. Some taxa arise as brought by species in which they are not local and a few are weeds. Plants of this genus are recognised normally as water lilies.
Now, let us find the solution from the option. Chlorenchyma cells bring out photosynthesis and manufacture food. It does not help the plant to waft on water.
Sclerenchyma is the tissue which makes the plant tough and stiff. It also does not involve floating the purpose of plants on the water surface. The hydrophytes have aerenchyma cells that are changed to the shape of parenchyma cells within the leaf of the Nymphaea plant. These cells have air areas which permit the glide of air among the leaf tissues. The presence of air makes the leaves lighter and they could waft at the floor of the water. This form of cells is found inside the leaves and floating systems of the aquatic plants. Collenchymas include live, commonly elongated cells with inconsistently thickened barriers or walls and acts as aid specifically in regions of main growth. So it is also not involved in the floating activity of aquatic plants.

Hence, the correct answer is option(C)

Note: Nymphaea are aquatic, rhizomatous perennial herbs, occasionally with stolons, as well. The stem is angular and erect. The leaves develop from the rhizome on long petioles (stalks that attach the leaf blade to the stem). Floating spherical leaves of water lily develop till 12 inches across. The disc formed leaves are notched and separate to the stem in a V-form on the centre, and are frequently purple underneath. Most of them flow at the surface of the water due to the presence of aerenchyma.