How does a potometer measure plant transpiration?
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How does a potometer measure plant transpiration?
The basic design of a potometer As water is taken up by the plant, the bubble moves and its length of movement is measured by the scale attached with capillary tube . The distance the bubble travels in a given time is determined by the rate of transpiration by the plant.
What is the potometer experiment?
A Potometer experiment is performed to estimate the transpiration rate in different plants. A potometer is an apparatus used to determine the transpiration rate of the cut shoot at the desired time. It is also called a transpirometer. Using the potometer, we can record the readings of water uptaken by the cut shoot.
What is the experiment to demonstrate transpiration?
Water drops appear inside the walls of the bell jar containing potted plant whereas no water drops appear in the bell jar without a plant. This demonstrates that water is evaporated from the surface of leaves in presence of sunlight.
What is the independent variable in a potometer experiment?
Variables. Independent variable – time. Dependent variable – the distance moved by the bubble along the capillary tube. Control variables – temperature, air flow or draughts, adequate supply of water.
What is the function of potometer?
A potometer can measure the amount of water taken up by a leafy shoot but cannot provide an accurate value for the amount of water transpired, because some water will be used in photosynthesis and to provide turgor.
What is a potometer and how does it work?
A potometer’ (from Greek ποτό = drunken, and μέτρο = measure), sometimes known as transpirometer, is a device used for measuring the rate of water uptake of a leafy shoot which is almost equal to the water lost through transpiration. The causes of water uptake are photosynthesis and transpiration.
Why is a potometer used?
Water uptake is due to transpiration and photosynthesis. Potometer or transpirometer is an apparatus or instrument using which the rate of transpiration can be measured. There are several types of potometers – Farmer’s potometer, simple potometer, Ganong’s potometer.
Why mercury is used in transpiration experiment?
Mercury is used in the experiments o demonstrate anaerobic respiration because: It is the only metal which occurs in liquid state and is a good conductor of heat. It does stick to the walls of the capillary and hence, gives accurate results.
How does light intensity affect the rate of transpiration experiment?
Light Intensity: Increasing the light intensity to which a plant is exposed is predicted to cause an increase in the rate of transpiration. Increasing light exposure will cause more stomata to open in order to facilitate photosynthetic gas exchange.
What are the steps to set up a potometer?
Method
- Cut a shoot underwater.
- Place the shoot in the tube.
- Set up the apparatus as shown in the diagram.
- Make sure it is airtight, using vaseline to seal any gaps.
- Dry the leaves of the shoot.
- Remove the capillary tube from the beaker of water to allow a single air bubble to form and place the tube back into the water.
Why is a potometer useful?
A potometer is a device used for measuring the rate of water uptake of a leafy shoot. The reasons for water uptake are for photosynthesis and transpiration. Potometers are often difficult to set up, as measurement-altering air bubbles in the xylem of the plant or in the apparatus must be eliminated.
Why is a potometer important?
What unit is used by potometer?
Unsourced material may be challenged and removed. A potometer’ (from Greek ποτό = drunken, and μέτρο = measure), sometimes known as transpirometer, is a device used for measuring the rate of water uptake of a leafy shoot which is almost equal to the water lost through transpiration.
What is suction due to transpiration?
Transpiration develops a pull/upward suction force because of the presence of a continuous water column (formed due to cohesive and adhesive properties) that starts from the mesophyll cells of leaves (from where water is lost) to the root hairs (from where water enters the plants). This is called transpiration pull.
Why is Potometer not accurate?
The potometer does not measure the rate of transpiration accurately because not all of the water that is taken by the plant is used for transpiration (water taken might be used for photosynthesis or by the cells to maintain turgidity).
Why is capillary tube used in potometer?
It consists of one glass (Capillary) tube and is mounted on a strong white backing plate. The potometer is used to investigate the uptake of water and transpiration of small plant shoots. By submerging the apparatus in a basin of water the freshly cut stem can be placed in the tube.
How do you create a transpiration experiment?
Procedure
- Get six small plants, three with wide leaves and three with narrow leaves. Use the masking tape and pen to give each one a number.
- Water the plants until water comes out of the bottom of the pot. If the plants are really dry when you start, water them thoroughly and wait a few minutes. Then, water them again.
Who invented potometer?
The Potometer was invented by Ganong. The phenomenon which is measured using a potometer was first observed by scientist Stephen Hales who was an English botanist. Complete answer: Potometer is a device also known as transpirometer is used for measuring transpiration by measuring the rate of water absorption by plants.
