Question

A leafy twig of mesophytic plant dipped in water would demonstrate
(a) Photosynthesis
(b) Transpiration
(c) Respiration
(d) Guttation

Answer 1

Hint: The process by which water vapour leaves the living plants body and enters the atmosphere is a very useful procedure for plants. It creates a negative pressure gradient that helps draw water and minerals up through the plant from its roots, which occurs highest in leaves.

Complete step by step answer:
When a leafy twig of a mesophytic plant dipped in water shows transpiration by the suction pressure developed by the leafy twig. The leafy twig is used to measure the rate of transpiration by using Ganong’s potometer under the sunlight.

Additional Information: Demonstration of transpiration by a leafy twig:
- This demonstration consists of the graduated capillary tube.
- One end of the apparatus is dilated to form the shoot chamber in which leafy twig is introduced into the one- holed rubber cork and the other end is bent with a small hole through which the air bubble is introduced.
- The reservoir is connected to the capillary tube with a stop clock.
- The apparatus is filled with water without any air bubble.
- The leafy twig is introduced into the one-holed rubber cork and is fitted with the shoot chamber.
An air bubble is introduced into the capillary tube through the hole and the initial level is marked.
- The bent tube is immersed in a small beaker containing water.
- The apparatus is made airtight by applying vaseline.
- The set-up is kept direct sunlight as well as in the diffused sunlight.
So, the correct answer is ‘transpiration.’

Note: Conclusion of demonstration of transpiration by leafy twig:
- The suction pressure developed by leafy twigs causes water to move in the capillary tube along with the air bubble.
- The distance travelled by the air bubble was more in the direct sunlight than the diffused sunlight indicates that the rate of transpiration was found to be greater in the direct sunlight than the diffused sunlight.