Transpiration in Plants

Definition

• Transpiration: The process by which plants lose excess water through evaporation from aerial parts, especially through stomata on the underside of leaves.
• Transpiration Pull: Suction force generated by water evaporation from leaves, pulling water up the xylem vessels.
• Transpiration Stream: The upward movement of water and mineral salts through a plant.

Importance

• Essential for transporting water and minerals against gravity.
• Helps in cooling the plant and preventing leaf scorch.

Factors Affecting Transpiration Rate

1. Humidity

• Dry Air: Increases transpiration as water vapor diffuses more rapidly out of the leaf.
• Humid Air: Slows down transpiration as evaporation is limited.

2. Temperature

• Higher temperatures increase the rate of evaporation and thus transpiration.

3. Wind

• Strong Wind: Removes humid air around leaves, increasing transpiration.
• Very Strong Wind: May cause stomata to close due to water loss, potentially decreasing transpiration.

4. Light

• Light intensity affects stomatal opening.
  • Night/ Shade: Stomata close, reducing transpiration.
  • Sunny Day: Stomata open wide, increasing transpiration.

Conclusion

• Transpiration is crucial for plant water regulation and nutrient transport.
• It involves a delicate balance influenced by environmental conditions such as humidity, temperature, wind, and light.