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Potometer works on the principle of -
A
Potential difference between the tip of the tube and that of the plant
B
Amount of water absorbed equals the amount transpired
C
Osmotic pressure
D
Root pressure
Detailed Solution
A potometer is an apparatus used to measure the rate of transpiration of a leafy shoot.
The cut shoot is fixed in an air-tight water-filled apparatus with a graduated capillary tube; an air bubble introduced into the tube moves as the shoot takes up water.
What the potometer actually measures is the rate of absorption (uptake) of water by the shoot.
It is assumed that the amount of water absorbed is equal to the amount of water lost by transpiration.
So the potometer works on the principle that the amount of water absorbed equals the amount transpired.
(In reality a small part of the absorbed water is used in photosynthesis and growth, so the value is only an approximation.)
The cut shoot is fixed in an air-tight water-filled apparatus with a graduated capillary tube; an air bubble introduced into the tube moves as the shoot takes up water.
What the potometer actually measures is the rate of absorption (uptake) of water by the shoot.
It is assumed that the amount of water absorbed is equal to the amount of water lost by transpiration.
So the potometer works on the principle that the amount of water absorbed equals the amount transpired.
(In reality a small part of the absorbed water is used in photosynthesis and growth, so the value is only an approximation.)