Difference Between Transpiration And Evaporation

What Is Transpiration?

Transpiration is the process by which plants lose water in the form of vapor to the atmosphere through the stomata. Transpiration cools the plant, changes osmotic pressure of cells and enables mass flow of mineral nutrients and water from roots to shoots. Two major factors influence the rate of water flow from the soil to the roots: the hydraulic conductivity of the soil and the magnitude of pressure gradient through the soil. Both of these factors influence the rate of bulk flow of water moving from the roots to the stomatal pores in leaves via the xylem.

Factors Affecting Transpiration

  • Number of leaves
  • Number of stomata
  • Size of the leaf
  • Presence of plant cuticle
  • Temperature
  • Relative humidity
  • Content of water in the soil

 What You Need To Know About Transpiration

  • Transpiration is the loss of water in gaseous state from the surface of living cells.
  • Transpiration is a controlled process and is dependent on factors such as osmotic pressure and water potential.
  • Transpiration is a relatively slow process and occurs through special pores referred to as stomata present in the living cells of the plant.
  • Occurs through stomata, cuticle or lenticel.
  • Transpiration process is controlled and depends on the availability of water for absorption by the plants.
  • Transpiration happens only from living bodies and not from non living things.
  • Transpiration happens only in the presence of light and no in dark.
  • Transpiration is a physiological process.
  • Plants can control transpiration from leaves by opening and closing the stomata.
  • Transpiration makes the surface of leaves and young stems wet and protects them from sun burn.

What Is Evaporation?

Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gaseous state due to an increase in temperature and/or pressure. In evaporation, the particles at the surface gain enough energy to overcome the forces of attraction and convert themselves into vapors. Water boils at 212oF (100oC), but it actually begins to evaporate at 32oC, it just occurs extremely slowly. As the temperature increases, the rate of evaporation also increases.

Evaporation is one of the three main steps in global water cycle. As water vapor rises higher in the atmosphere, it begins to cool back. When it is cool enough, the water vapor condenses and returns to liquid water. These water droplets eventually gather to form clouds and precipitation.

Factors affecting evaporation

The rate of evaporation is affected by the following factors:

  • Temperature
  • Surface area
  • Humidity
  • Wind speed

What You Need To Know About Evaporation

  • Evaporation is a type of vaporization that occurs on the surface of a liquid in gaseous state.
  • Evaporation is not a controlled process and it stops when air in the surrounding atmosphere is saturated.
  • Evaporation is relatively faster process.
  • It occurs from the entire surface of the water.
  • Evaporation is a continuous process as long as there is water on the surface.
  • Evaporation can happen from any surface either living or non living.
  • Evaporation can happen in warm condition without sunlight.
  • Evaporation is a surface level process i.e occurs on the surface of a body.
  • Evaporation can be control by any mechanism.
  • Evaporation provides dryness to the free surface.

Also Read: Difference Between Active And Passive Transport

Difference Between Transpiration And Evaporation In Tabular Form

BASIS OF COMPARISON TRANSPIRATION EVAPORATION
Description It is the loss of water in gaseous state from the surface of living cells.   It is a type of vaporization that occurs on the surface of a liquid in gaseous state.  
Control It is a controlled process and is dependent on factors such as osmotic pressure and water potential.   It is not a controlled process and it stops when air in the surrounding atmosphere is saturated.  
Evaporation It is a relatively slow process and occurs through special pores referred to as stomata present in the living cells of the plant.   It is relatively faster process.  
Occurrence Occurs through stomata, cuticle or lenticel.   It occurs from the entire surface of the water.  
Nature Of The Process It process is controlled and depends on the availability of water for absorption by the plants.   It is a continuous process as long as there is water on the surface.  
Occurrence It happens only from living bodies and not from non living things.   It can happen from any surface either living or non living.  
Effect Of Sunlight It happens only in the presence of light and no in dark.   It can happen in warm condition without sunlight.  
Nature Of Process It is a physiological process.   It is a surface level process i.e occurs on the surface of a body.  
Process Control Plants can control transpiration from leaves by opening and closing the stomata.   It can be control by any mechanism.  
Importance It makes the surface of leaves and young stems wet and protects them from sun burn.   It provides dryness to the free surface.  

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