Question

Given is the diagram of an apparatus used to study a particular phenomenon in plants:

Name the apparatus
What is it used for?
What is the role played by the air-bubble in this experiment ?
What is the use of the reservoir?
What happens to the movement of the air - bubble if apparatus is kept:
(i) in the dark ; (ii) in sunlight ; (iii) in front of a fan?

Answer 1

A . The name of the apparatus is Potometer .

B . This is used to measure the uptake of water by the shoot of the plant .

C . The air bubble in the potometer moves with the uptake of water by the plant and the distance travelled by the bubble in a given time gives the rate of the transpiration .

D . The reservoir plays an important role in this apparatus as it is useful in bringing the air bubble to the start position

E . i) In the dark room the plant transpiration is reduced as a result of which the air bubble will not move much

ii) In the sunlight the plant transpires the most as a result of which the air bubble moves to a greater amount towards the plant

iii) The effect of wind on the plant is that as the wind rate increases the rate of transpiration also increases ,hence the plant placed in front of the fan will show more transpiration rate thus the movement of air bubble will be more towards the plant