Question

Guard cells are present in
A)Stomata
B)Vascular bundle
C)Cork
D)Suberin

Answer 1

Guard cells are the specialised type of cells present at the epidermis of the leaf and stem in some plants. The main function of the guard cell is exchange of gases. Plants undergo photosynthesis when the guard cells are open.

Complete answer:
The guard cells are the specialised structure present in the plants. It is present in the leaf, stem and other organs of the plant. The guard cell is kidney shaped and is present in pairs.

The gap between the two cells is called the stomatal pore. The main function of a guard cell is to regulate transpiration (by opening and closing) and facilitate the exchange of gases required for photosynthesis. The carbon dioxide diffuses in through the pore and oxygen diffuses out.

Vascular bundle- The vascular bundles in a plant are made up of xylem and phloem whose main function is to transport water and minerals and processed food to different parts of the plant. The cells present in vascular bundles are parenchyma, tracheids, vessels etc.

Cork- A cork is the outermost covering of the stem of the plants. It is composed of dead cells which protects the older parts of the plant.

Suberin- It is a complex biopolymer present in the cell wall of the epidermal cells in the stem.
Its main function is insulation and protection from the surrounding.

Hence, the correct answer is option (A)

Note: The opening and closing of stomata is regulated by the guard cells. When the guard cells are charged with water or in a turgid state, the cells move apart as a result of which the stomata open and the photosynthesis takes place. When the cell is in a flaccid state, the stomata closes. The stomata open during the day and closes at night.