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

To answer the question of which part controls the opening and closing of the stomatal pore in leaves, let's review relevant biological concepts regarding plant leaf anatomy:

Understanding Stomatal Function:

• Stomata: These are tiny openings or pores in the epidermis of leaves. Their primary function is to facilitate gas exchange, allowing carbon dioxide to enter the plant for photosynthesis and oxygen to exit.
• Epidermal Cells: These cells form the outermost layer of the plant leaves, providing protection and aiding in reducing water loss. However, they do not directly control the opening and closing of stomatal pores.
• Guard Cells: Positioned around each stomatal pore, guard cells are responsible for the opening and closing of these pores. They achieve this by changing shape, which is controlled by the movement of water and ions in and out of the cells.
• Chloroplasts: While involved in photosynthesis, chloroplasts do not play a direct role in the functioning of stomatal pores.

Reasoning:

The function of opening and closing stomata is essential for regulating water loss via transpiration and facilitating gas exchange for photosynthesis. This mechanism is primarily controlled by guard cells. When these cells become turgid, the stomatal pore opens to allow gas exchange; conversely, when guard cells lose turgidity, the stomatal pores close.

Conclusion:

Based on the explanation and the mechanism of stomatal function, the correct option is:

Guard cells