Question

In submerged hydrophytes/Vallisneria the functional stomata are found
A. On the upper leaf surface
B. On the lower leaf surface
C. Both leaf surfaces
D. Nowhere on the plant

Answer 1

Stomata are the small pores or openings in the plant tissue. Stomata are mostly found in the leaves of plants but some may be found in the stem of plants. Stomata are surrounded by guard cells.

Complete answer: Stomata also known as stoma is a tiny pore found in the epidermis of plant leaves, stem, and other organs. Stomata regulate the exchange of gases. The pore is surrounded by a pair of parenchyma cells called guard cells. The guard cells regulate the size of the stomatal opening.
The entire stomatal complex consists of guard cells and pores and the pore is known as the stomatal aperture. Air enters the opening through this aperture and carbon dioxide is used in the process of photosynthesis and oxygen is used for respiration. In dicotyledons, stomata are present on the lower surface of the plant than the upper surface of the plant. Aquatic plants living under the surface of the water are mainly devoid of stomata. Some aquatic plants have stomata and some do not contain stomata in them. For example, Hydrophytes: Hydrophytes (ex. water ferns) are submerging aquatic plants that do not have stomata. At the place of stomata, the surface cells of plants regulate some functions like absorbing water, nutrients, and dissolved gases in the water. Submerged leaves of aquatic plants are astomatic. Stomata are either absent or vestigial.
So, the correct option is option D

Note: Stomata are responsive to light such as blue light being almost 10 times more effective as the red light in causing a stomatal response. Research suggests this is because the light response of stomata to blue light is independent of other leaf components like chlorophyll.