Gaseous Exchange in Plants
Gaseous exchange in plants occurs mainly through stomata and lenticels.
Stomata are tiny openings primarily found on the leaves. They are surrounded by guard cells that regulate their opening and closing. During the day, stomata open to allow carbon dioxide (CO2) to enter for photosynthesis, while oxygen (O2) and water vapor exit. At night, stomata generally close to minimize water loss.
Lenticels are small pores found on the stems and woody parts of plants. They facilitate gas exchange when stomata are closed, allowing oxygen to enter and carbon dioxide to exit. Lenticels are essential for the respiration of plant tissues, especially in woody plants.
In summary, stomata and lenticels play crucial roles in maintaining gas exchange, ensuring that plants can perform photosynthesis and respiration effectively.
Key points to remember
- Stomata are openings on leaves regulated by guard cells.
- Stomata allow CO2 in and O2 out during photosynthesis.
- Lenticels are pores on stems for gas exchange.
- Lenticels facilitate respiration when stomata are closed.
- Both structures are vital for plant survival.
Worked example
Describe how stomata and lenticels contribute to gaseous exchange in plants.
- Stomata open to take in CO2 for photosynthesis.
- They also release O2 and water vapor.
- Lenticels allow gas exchange in stems, especially when stomata are closed.