Question

Measure the rate of transpiration with the help of Ganong's potometer.

Answer 1

Transpiration is nothing but the loss of water from the plants as water vapor through the stomata which present on the surface of the leaves and the device which is used to measure the transpiration is Potometer, it measures the water uptake by the shoot during transpiration.

Complete answer:
Ganong's manometers are used to measure the transpiration in the laboratory.
Ganong's potometer consists of a glass tube that bends twice, and also has a glass cylinder with a wide mouth.
A capillary tube is inserted in a horizontal glass bar which attaches to the reservoir.
A wide-mouth glass cylinder is present towards the front end and the apparatus.
A rubber cork with a hole is fitted on the mouth of the glass cylinder.
Now a freshly cut twig should be placed in the hole, and the horizontal bar has graduated reading which is marked on it. And it also has a bent end with nozzle opening.
Now the beaker with colored water is placed below the horizontal bar, where the end of that bar should insert into it.
A reservoir is connected to a horizontal bar to store water, and the whole setup is placed on the flat surface.
Before the beginning, an air bubble should be kept at zero reading in the capillary tube of the horizontal glass rod, lifting the bent end that allows the air bubble to enter and to get trapped in the horizontal bar.
By the time the experiment begins, one should observe that the air bubble starts moving.
The rate of transpiration is calculated by taking a distance covered by the air bubble in a certain period, several readings should be taken, so that the average value tells about the transpiration rate.

Note: As we all know that transpiration mainly occurs by transpiration pull, which is created by the shoot to make up the water so that we can observe the bubble start moving toward the direction of the twig.