Question

Sunken stomata can be traced in
A) Nerium
B) Musa
C) Allium cepa
D) All of the above

Answer 1

Hint: Sunken stomata are characteristic features of the xerophytes.

Complete Answer:
Let us first know a little about xerophytes. Plants which are adapted to survive in an environment with very less amount of water are known as xerophytes.

Option A: Nerium belongs to the family Apocynaceae and is also known as oleander. It is also an example of xerophytes and thus presence of sunken stomata is seen in them.

Option B: Musa includes plants like bananas and there is presence of sunken stomata as seen in them.

Option C: Allium cepa is commonly known as onion and presence of sunken stomata is seen in them.

Option D: Being characteristic features of the xerophytes, the sunken stomata are present sunken in the leaf surface and usually surrounded by cuticles and hairs often referred to as trichomes. Hailing from the arid environment, photosynthesis makes use and waste a disproportionate quantity of water.
- It is here where your sunken stomata stem the flow of water. Later, the drying winds shield the open sunken stomata.
- Further, the hair-like trichomes present in the plants helps in maintaining a moist atmosphere which further leads to reduction in the loss of excessive water quantity. This low level of water can thereby aid in the process of gaseous exchange.
- As the water loss is quite less, the stomata remain open for a longer duration thereby replenishing the carbon dioxide levels within the leaf so that the photosynthetic process may proceed with ease. Thus, sunken stomata are found in all the options mentioned above. Therefore, this is the correct option.

Thus, the correct option is D) All of the above.

Note: The presence of stomata in the plants modifies their survival ability in extreme conditions like droughts. The advantage of sunken stomata are,
- They trap moist air which in turn reduces diffusion, thereby by reducing water loss.
- They help in reducing the rate of transpiration.
- They help in reducing deficiency of water.