Question

Describe the exchange of gases which takes place in the leaves of a plant at night.

Answer 1

• At night, photosynthesis does not occur because sunlight is absent.
• However, respiration continues in plant cells.
• During respiration, the plant takes in oxygen (O₂) from the atmosphere through the stomata.
• Oxygen diffuses into the leaf cells and is used to release energy from food.
• Carbon dioxide (CO₂) produced during respiration diffuses out of the leaf through the stomata into the atmosphere.
• Thus, at night, plants absorb oxygen and release carbon dioxide.