Question

Ganong’s Potometer is not so accurate because
(a)It measures less in weight by the plant due to transpiration.
(b)It measures the amount of water test lost due to guttation.
(c)It measures the water absorbed by the plant.
(d)It measures the extent and duration of transpiration.

Answer 1

Hint: A device that is used to measure the rate of transpiration in the plant’s parts by measuring the traveling of water in the capillary tube in a given time.

Complete answer:
A device that is used in measuring the amount of uptake of water by the shoot during the process of transpiration is known as the Ganong’s Potometer. It may also be known as a transpirometer. The rate of transpiration cannot be measured accurately by the potometer because in the [process of transpiration all the water is not taken by the plant.

Additional Information: -A potometer is used in measuring the rate of transpiration which is found to be proportional to the uptake of water.
-It is observed that some of the water is utilized during the process of photosynthesis thus the transpiration cannot be directly measured.
-The calculation of the rate of transpiration can be done by measuring the distance which is traveled by an air bubble inside a capillary tube in a given time.
-The air bubble helps in keeping track of the transpiration rate and also the amount of water absorbed in the case of the twig which is recently cut and does not contain roots.
-It is found that the amount of water uptake is greater when the air bubbles move faster which will result in the increased rate of transpiration.
-The reservoir in the potometer helps the air bubble to travel back to the start of the measuring scale when the experiment is repeated.
So, the correct answer is ‘It measures the water absorbed by the plants’.

Note: Potometer is designed as a lengthy capillary tube, a reservoir, and a tube for holding the shoot. There are different types of potometer, they are – Bubble potometer, Mass potometer, Ganong’s Potometer, and Darwin’s Potometer.