Question

Why are the leaves of Vallisneria thin and long?

• A. To minimize the damage by strong water currents
• B. To maximize the absorption of sunlight
• C. To help the leaves grow faster
• D. To help the leaves float in water

Answer 1

Answer: (A), (B)

To maximize the absorption of sunlight

Leaves in submerged hydrophytes like Vallisneria are generally thin, narrow and long. These leaves offer little resistance against the water currents. Thus plants are subjected to little mechanical stress of water and leaves are not easily damaged by water. Long leaves have a large surface area which allows for more sunlight absorption and hence photosynthesis. Thin leaves also facilitate the diffusion of gases inside the plant more easily.