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Main Organ for Transpiration

 
2.3 Main Organ for Transpiration
 
The Necessity of Transpiration in Plants
  • Transpiration is the loss of water as water vapour from plants especially from leaves to surrounding through evaporation.
  • Leaves serve as the main organ to ensure transpiration takes place in plants
  • The importance of transpiration:
    • Ensures water and mineral salts can be transported continuosly within vascular tissues.
    • Supplies water to spongy mesophyll cells for photosynthesis.
    • Supplies water and mineral salts for cell development and growth.
    • Gives cooling effect to plants.
 
This image is an infographic titled The Environmental Factors That Affect the Rate of Transpiration. It features four main factors, each within an oval shape: 1. Light Intensity 2. Temperature 3. Air Movement 4. Relative Air Humidity Each factor is numbered and positioned in a vertical column. The background is light, and the text is in a contrasting color for clarity. The infographic is branded with the Pandai logo at the bottom.
 
The Environmental Factors that Affect the Rate of Transpiration
Light Intensity
  • In daylight, light intensity is high, this wil stimulate opening of stomata and then increases the rate of transpiration.
  • At a light intensity where the rate of transpiration is maximum, the increasing in light intensity does not increase the rate of transpiration because all stomata are opened.
  • The opening of stomata due to high light intensity is to uptake more carbon dioxide for photosynthesis.
Temperature
  • Kinetic energy of water molecules increses when the surrounding temperature increases.
  • When the surrounding temperature increases,water vapour in air spaces diffuse rapidly into surrounding through osmosis.
  • The rate of transpiration increases.
  • When the surrounding temperature too high,the rate of transpiration decreases due to closing of stomata to conserve water in plants.
Air Movement
  • A rapid movement of air remove water vapour from leaves rapidly.
  • The water vapour in air spaces diffuses out rapidly.
  • The rate of transpiration decreases.
Relative Air Humidity
  • When the relative humidity of surrounding air is lower than those in air spaces within leaves, the water vapour within air spaces diffuses out rapidly.
  • Thus, the rate of transpiration is high
  • As the relative humidity of surrounding air increases, the water vapour within the air spaces diffuses out is slower.
  • Thus,the rate of transpiration decreases.
 

 

 

 

 

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Chapter : Structure and Leaf Function
Topic : Main Organ of Transpiration
Form 5 Biology
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