The two primary functions of stomata in plants are gas exchange (specifically carbon dioxide intake and oxygen release during photosynthesis) and transpiration (the release of water vapor).
Here's a more detailed breakdown:
1. Gas Exchange:
- Carbon Dioxide (CO2) Intake: Stomata allow carbon dioxide from the atmosphere to enter the leaf. CO2 is essential for photosynthesis, the process by which plants convert light energy into chemical energy in the form of sugars. Without stomata opening to allow CO2 in, photosynthesis could not occur.
- Oxygen (O2) Release: As a byproduct of photosynthesis, oxygen is produced. Stomata provide a pathway for this oxygen to exit the leaf and enter the atmosphere.
2. Transpiration:
- Water Vapor Release: Stomata are the primary sites for transpiration, the process by which water evaporates from the leaf surface. This water loss creates a "pull" that helps draw water and nutrients up from the roots through the plant's vascular system (xylem). While vital, transpiration also needs to be carefully regulated, as excessive water loss can lead to dehydration and wilting. Stomata closing helps reduce transpiration.
In essence, stomata function as tiny, controllable pores that regulate the balance between gas exchange for photosynthesis and water loss through transpiration. Guard cells surrounding each stoma control the opening and closing of these pores in response to environmental conditions like light intensity, humidity, and carbon dioxide concentration.
