Question

Identify the part that controls the closing and opening of the stomatal pore in leaves of plants. Select the correct option.

• A. Stomata
• B. Epidermal cells
• C. Guard cells
• D. Chloroplasts

Hint:

Stomatal control = Guard cells. Turgor change → Pore opens or closes.

Answer 1

The Correct Option is C

Concept: Stomata are tiny pores present on the surface of leaves that help in gas exchange and transpiration. The opening and closing of these pores are regulated by specialized cells. Explanation:

• Each stomatal pore is surrounded by two kidney-shaped cells called guard cells.
• Guard cells control the opening and closing of stomata by changing their turgor pressure.
• When guard cells absorb water, they swell and the pore opens.
• When they lose water, they shrink and the pore closes.

Why Other Options Are Incorrect:

• (A) Stomata → The pore itself, not the controlling structure.
• (B) Epidermal cells → General surface cells, not specialized for control.
• (D) Chloroplasts → Organelles for photosynthesis.

Conclusion: Guard cells regulate the opening and closing of stomatal pores by controlling their turgor pressure.