Factors Affecting Transpiration Rate

Key Factors Influencing Transpiration

1. Temperature

   • Higher temperatures increase transpiration rate.
   • Water evaporates more from mesophyll cell walls.
   • Higher temperature increases kinetic energy of water vapor particles.
   • Increased kinetic energy leads to a higher diffusion rate, thus more water loss.

2. Light Intensity

   • Light intensity affects stomatal opening, independent of temperature.
   • Dark Conditions:
     • Stomata closed, no photosynthesis.
     • No CO2 intake, water vapor cannot diffuse out, reducing transpiration.
   • Low Light Intensity:
     • Stomata slightly open.
     • Slight photosynthesis occurs; some CO2 intake.
     • Limited water vapor diffusion, moderate transpiration.
   • High Light Intensity:
     • Stomata opens wider to intake more CO2 for photosynthesis.
     • More water vapor diffuses out, increasing transpiration.

3. Humidity

   • Humidity measures moisture or water vapor in the air.
   • Low Humidity:
     • Low moisture in the air (arid conditions).
     • Creates a steep concentration gradient between inside and outside the leaf.
     • Higher diffusion rate, thus higher transpiration.
   • High Humidity:
     • High moisture in the air (misty conditions).
     • Less steep concentration gradient.
     • Lower diffusion rate, reducing transpiration.

Conclusion

• Understanding these factors is crucial to predict and explain changes in transpiration rate.
• Remember: Temperature affects kinetic energy and diffusion rate, light intensity influences stomatal aperture, and humidity affects the concentration gradient of water vapor.