Question

List three events that occur during the process of photosynthesis. State in brief the role of stomata in this process.

Answer 1

• Three events that occur during the process of photosynthesis are

(i) Absorption of light by chlorophyll pigment molecules and splitting of water molecules.
(ii) Light energy is converted into chemical energy
(iii) And Carbon dioxide is reduced to carbohydrates.

• Stomata are the minute pores present on the epidermal surface of the leaves which allows the movement of gases in and out of the intercellular spaces.
• During the day, when air temperatures rise and carbon dioxide levels are normal or above normal, the stomata open, allowing carbon dioxide to enter and photosynthesis to take place.
• Oxygen, a poisonous (to the plant) byproduct of photosynthesis, is released to the environment by stomata. The excess water exits through the stomata in a process called transpiration.

• So, stomata do not directly participate in photosynthesis. However, the stomata control the influx of carbon dioxide, a critical component of photosynthesis, and allow the excess oxygen to exit.
• Stomata also control the flow of water vapor out of the leaf, limiting water loss during drought and allowing excess water to exit.