Study Notes
Transpiration is the process by which water is lost from the plant through evaporation and diffusion, primarily from the leaves. This process is crucial for transporting minerals, maintaining plant structure, and cooling the plant.
- Transpiration — the loss of water vapor from plant leaves through evaporation and diffusion. Example: Water evaporates from the mesophyll cells and diffuses out through the stomata.
- Transpiration Pull — the tension created by transpiration that pulls water upward through the plant. Example: Water molecules are pulled up the xylem vessels due to cohesive forces.
- Cohesion — the attraction between water molecules that helps maintain a continuous column of water in the plant. Example: Water molecules stick together as they move up the plant.
- Stomata — small openings on the leaf surface that allow gas exchange and water vapor to exit. Example: Stomata open to release water vapor and take in carbon dioxide.
Exam Tips
Key Definitions to Remember
- Transpiration: The loss of water vapor from the leaves.
- Transpiration Pull: The tension created by water loss that pulls water up the plant.
- Cohesion: The attraction between water molecules.
- Stomata: Openings on leaves for gas exchange.
Common Confusions
- Confusing transpiration with photosynthesis.
- Thinking transpiration only occurs during the day.
Typical Exam Questions
- What is transpiration? The loss of water vapor from plant leaves.
- How does transpiration help in nutrient transport? It creates a pull that moves water and minerals up the plant.
- What factors affect the rate of transpiration? Temperature, humidity, air movement, and light intensity.
What Examiners Usually Test
- Understanding of the transpiration process and its importance.
- Factors affecting the rate of transpiration.
- The role of stomata in transpiration and gas exchange.