Question

Which among the following is the function of guard cells?

• A. Opening and closing of stomata
• B. Production of antioxidants
• C. Protection
• D. Transmission of spores

Answer 1

The correct option is A

Explanation of the correct answer:

1. Guard cells are kidney shaped cells that surrounds the stomata.
2. They control the opening and closing of the stomata.
3. When the plant has an excess of water, the guard cells swell and create an opening for the exchange of gases.
4. In dry conditions, the guard cells are flat and keep the stomata closed, inhibiting exchange of gases.

5. 
   

Explanation of the incorrect answers:

Option B:

• Plants synthesise low molecular weight antioxidants such as glutathione and ascorbate within the chloroplast stroma and cytosol.

Option C:

• Spores are transmitted by wind, water, insects, etc.

Option D:

• The protection in the plants is done by the dead schlerenchyma tissue.

Final answer: Opening and closing of stomata is the function of guard cells.