Question

Study the diagram given below and answer the questions that follow:

 

1. Name the process being studied in the above experiment.
2. Explain the process mentioned in (a) above
3. Why is oil placed over water?
4. What do we observe with regard to the level of water when this set-up is placed in (1) bright sunlight, (2) humid conditions and (3) windy days?
5. Mention any three adaptations found in plants to foster the process mentioned in (a) above

Answer 1

1. Transpiration
2. The loss of water from aerial sections of the plant in the form of water vapour.
3. Oil is poured on water to stop evaporation-induced water loss.
4. When the configuration is set,
   1. Transpiration causes the amount of water to drop in strong sunlight quickly.
   2. In humid conditions, the water level doesn't change much as the rate of transpiration decreases.
   3. The water level drops quickly during transpiration on a windy day.
5. Leaves have morphological adaptations to control their transpiration rate, as follows:
   1. Thick cuticle: A quite thick cuticle could cover the leaves, e.g., banyan.
   2. Loss of leaves: As in cactus, some plants have leaves lost or absent.
   3. Narrow leaves: In order to decrease the surface area for transpiration, certain plants, such as Nerium, develop narrower leaves.