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Question
Given below 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 the apparatus is kept:
- in the dark
- in sunlight
- in front of a fan?
Give a reason in each case.
Solution
- Ganong’s potometer
- The rate of transpiration from a leafy shoot is measured using a potometer.
- As transpiration occurs, the air bubble added to the horizontally graded capillary tube goes along. A suction force is created as the water from the twig is lost from the beaker and the bubble in the capillary tube goes along.
- Opening the stopcock releases the water into the capillary tube from the reservoir.
- The movement of air bubbles is affected as follows:
- The stomata, tiny openings on leaves, will close in the absence of light, sometimes known as the dark, therefore preventing transpiration. Thus, the air bubble will remain stationary in one location.
- More transpiration results during the day when the stomata are open to let carbon dioxide enter for photosynthesis. Transpiration lessens at night as the stomata close. As a result of the higher water loss throughout the day, the air bubble travels more.
- Placing the equipment before the fan speeds up transpiration. This causes the air bubble to migrate more since the quicker air from the fan removes more water vapour, promoting more transpiration.
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RELATED QUESTIONS
Which of the following statements are true and which ones are false? Give reason in support of your answer.
Forest contribute in bringing rains.
The apparatus shown here is Ganong's photometer designed to demonstrate unequal transpiration from the two surfaces of a dorsiventral leaf. Before keeping the leaf in between the cups, anhydrous calcium chloride (CaCl2) contained in two small vials were weighted and placed in both the cups. The ends of the cups were weighted and with corks through which two mercury manometers were connected. After a few hours, CaCl2 vials were taken out and weighed again.
(i) What is the purpose of keeping CaCl2 vials inside the cup?
(ii) After a few hours, CaCl2 vials were taken out and weighed again.
will you except any difference in weight? If so, give reasons.
(iii) What was expect the purpose of using a manometer?
(iv) What do you mean by transpiration?
Given below is the diagram of an apparatus used to study a particular phenomenon in plants:
What is the role played by the air-bubble in this experiment?
Given below is the diagram of an apparatus used to study a particular phenomenon in plants:
What happens to the movement of the air-bubble if the apparatus is kept:
(i) In the dark
(ii) In sunlight
(iii) In front of a fan
Give a reason in each case.
The apparatus shown in the following diagram is Garreau’s potometer designed to demonstrate unequal transpiration from the two surfaces of a dorsiventral leaf. Before keeping the leaf in between the cups, anhydrous calcium chloride (CaCl2) contained in two small vials were weighed and placed in both the cups. The ends of the cups were closed with corks through which two mercury manometers were connected. After few hours, CaCl2 vials were taken out and weighed again.
After few hours CaCl2 vials were taken out and weighed again. Will you expect any difference in weight? If so, give reason.
Write any two limitations of using a Ganong's potometer to demonstrate the uptake of water.
The apparatus used to measure the rate of transpiration is ______.
Name four kinds of potometers on the basis of the names of the scientists who discovered them.
Define the following term:
Potometer
