Question

The stomata are sunken in
A) Hydrophytes
B) Mesophytes
C) Heliophytes
D) Xerophytes

Answer 1

Hint:Stomata are minute pore like epidermal structures which help in gaseous exchange between the plants and the environment. Plants perform stomatal transpiration i.e loss of water in form of water vapour through stomata. Sunken stomata are usually present in plants found in dry environments to prevent water loss.

Complete answer:
Let us analyse the options to find the correct answer.
>Option A: Hydrophytes are plants that usually live in moist environments. They may be partially or fully submerged in water. Since, there is no need to save a lot of water, fewer stomata are present in hydrophytes. Also, their stomata are mostly open. Examples include Lotus and White water Lily. Hence, this is an incorrect option.
>Option B: Mesophytes are plants which are adapted to live in average environment conditions i.e neither too wet nor too dry. Stomata are present on the lower epidermis of the mesophyte plant leaves and close and open depending on the weather. Examples include Goldenrod and Clover. Hence, this is an incorrect option.
>Option C: Halophytes are sun loving plants and have stomata present on their leaves and shoots.Examples include Thyme and White clover. Hence, this is an incorrect option.
>Option D: Xerophytes are the plants which are found in extreme dry conditions. They have very less number stomata present in sunken pits and therefore called sunken stomata. Their stomata being present in grooves keep the area around moist to tackle the water shortage. An example of xerophyte is the Cactus plant. Hence, this is the correct option.

Thus, the correct answer is option (D) Xerophytes.

Note:Sunken stomata is an adaptation used by Xerophytes to sustain in extremely harsh and dry conditions. Such stomata are present in the pits or grooves of lower epidermis thus preventing excessive water escape from the leaves of the plants.