Question

Given below is an apparatus used to study a particular process
in plants. Study the same and answer the questions that follo

(i)Name the apparatus.
(ii)Mention one limitation of this apparatus.
(iii) Which phenomenon is studied with the help of this apparati
(iv)What is the function of the part marked reservoir?
(v)What is the role of the air bubble in the experiment?​

Answer 1

Required Answers:

(I) The picture shows a device named 'Ganong's potometer' which measures the rate of water intake by the plant which is almost equal to the rate of water lost by the plant through transpiration.

(II) Limitations:

It is asked for only one limitation, but I am providing three. You can choose according to your ease$.$

• The Air bubble is difficult to introduce.
• And, the twig or small branch taken may die after some time.
• Sometimes due to temperature fluctuations in the environment may affect the position of air bubble in the capillary tube (shown).

(III) The Transpiration is the phenomenon for which the potometer is used. But, it do not measures the amount of water lost by the plant but the amount of water intake by the plant. [ They are almost same ]

(IV) Reservoir helps in bringing back the air bubble to its original position and this can be done by releasing some water from the Reservoir (which contains water) into the capillary tube (Just open the stop clock).

(V) Basically, the movement of the air bubble along the capillary tube determines the volume of water lost by the plant. When, transpiration occurs, it creates a suction force which pulls the water to intake. Here, the air bubble also moves along with water.

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