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5 in your experiments transpiration was observed by

Top 13 Experiments on Transpiration Plants Article Shared by The below mentioned article includes a collection of thirteen experiments on transpiration. Experiment to demonstrate the transpiration phenomenon with the bell jar method: Bell jar, well-watered potted plant, rubber sheet, glass plate, Vaseline.

Take a well-watered, healthy potted plant and cover the pot with the help of rubber sheet.

LabBench Activity

Only aerial parts of the plant should remain uncovered. Keep the potted plant on a glass plate and cover it with a bell jar Fig. Apply vaseline at the base of the bell jar to prevent the outer air to pass in the bell jar. Keep the whole apparatus in light and observe for some time. Set another experiment exactly in the same way except that the pot should be without any plant.

Top 13 Experiments on Transpiration | Plants

Water drops appear inside the wall of the bell jar containing a potted plant while there is no drop in the another bell jar which is without any plant. Because water drops appear only in the bell jar in which pot 5 in your experiments transpiration was observed by having a plant with its only aerial parts exposed, so it can be concluded that these drops appeared due to the process of transpiration from the aerial parts of the plant.

The same can also be concluded by the observations of the control apparatus, in which no water drop appears due to the absence of plant in the pot. Experiment to demonstration of Transpiration by Cobalt-Chloride Screen: Filter paper, cobalt-chloride solution, a potted plant, clip.

Some pieces of the filter paper are dipped in cobalt chloride solution and then dried off. They are blue coloured. Now, two such pieces of filter paper are taken and pressed on both the surfaces of the leaf of a potted plant with the help of a clip. This apparatus is kept for some time as such. After a few hours, when it is observed, the cobalt chloride paper of the lower surface of the leaf becomes pink coloured. The dried blue coloured cobalt chloride paper turns red as it becomes moist.

The stomata are confined mostly on the lower surface of the leaf, and therefore, the cobalt chloride paper of that surface becomes moist and turns red.

The paper of the upper side of the leaf may also become pink to some extent, as few stomata are found on this side. Experiment to demonstration of Transpiration by Four-Leaf Experiment: Four leaves, Vaseline and a string.

To demonstrate the transpiration from the leaf surface, four banyan leaves are taken. Both the 5 in your experiments transpiration was observed by of the A leaf, lower surface with stomata of B leaf, upper surface without stomata of C leaf are vaselined.

The Vaseline is not applied on the D leaf. Now, as shown in the figure the leaves are hanged so that they may transpire freely.

When the observations are taken after a day or two, they are as follows — the A leaf, which is vaselined on its both the surfaces, looks fresh and green, as no surface transpires.

The B leaf is vaselined on its lower surface with stomataand transpiration takes place only from the upper surface which is negligible. This leaf also remains turgid and green like the A leaf. If few stomata are present on the upper surface of the leaf, then it shrivels to some extent. The C 5 in your experiments transpiration was observed by is vaselined on its upper surface, which contains less number of stomata or no stomata.

The transpiration takes place from the lower stomatal surface, and the leaf shrivels to a large extent. The D leaf is not vaselined and both the surfaces transpire freely releasing much water. The leaf wilts completely in this case.

This experiment proves that the rate of stomatal transpiration is fairly higher than the cuticular transpiration. With the help of this apparatus, the comparative study of the transpiration from both the surfaces of the leaf is being done. This apparatus consists of two small bell-jars, which are kept together in close contact as shown in the figure. A leaf of a potted plant is kept in between these two bell-jars.

In each of these bell-jars a small test tube is kept. Each small test tube contains equal amount of anhydrous calcium chloride CaCl2. The apparatus is made air-tight, applying vaseline where they press the leaf in between. There are two manometers at the two ends of the bell-jars. They are partially filled with oil. These manometers, however, maintain the vapour of the bell-jars. If the surface of the oil, within the manometers changes, then it indicates that the apparatus is not airtight or the vapour released from the leaf surface is not completely absorbed by calcium chloride.

The complete apparatus is fitted upon a vertical stand. After few hours, the calcium chloride tubes are taken out and weighed again. This way, the water transpired from both the surfaces of the leaf may be known. The amount of water transpired from the lower surface stomatal surface of the leaf is always greater, as it bears large number of stomata.

The cuticular transpiration takes place from the upper surface of the leaf, which is very much less. Simple potometer, beaker, scale, water, cork, a freshly cut twig, grease, stop watch. It is made up of glass tube having a side limb. The mouth of the side tube is fitted with a cork having a hole, through which the twig is inserted in the tube. Upper end of the straight tube is closed by a cork and in its lower end a cork with a capillary tube is fitted. Lower part of the capillary tube is placed in beaker containing water.

A scale is fitted on the capillary tube Fig. Fill the potometer with water and insert a freshly cut twig in the hole of side limb in such a way that its lower end is in the water.

Transpiration Experiment

Cut the twig in the water. Make all the joints air-tight by applying grease. Insert a bubble in the capillary tube and place the whole apparatus in light.

  1. After a few hours, when it is observed, the cobalt chloride paper of the lower surface of the leaf becomes pink coloured.
  2. The difference between the initial and the final weight is equal to the amount of water evaporated under the process of transpiration.
  3. In each of these bell-jars a small test tube is kept.

Note the readings in shade, wind and also in darkness. The observations of above table indicate that the largest distance is travelled by the bubble in a given time when the apparatus is placed in front of a fan in sunlight and the distance travelled is least in the shade.

There is no change in the position of bubble when the apparatus is placed in darkens. Changes in all these conditions can be explained as follows: When the apparatus is placed in sunlight, the stomata will open and the temperature will also be high.

So the atmospheric humidity will be less. All these conditions favour the transpiration and so more water will be transpired, and nearly equal amount will be absorbed from the potometer. This can be observed by the movement of bubble in the capillary tube.

The atmospheric humidity is high in the shady conditions and so the atmosphere outside the apparatus is saturated with water vapours.

  1. There is no change in the position of bubble when the apparatus is placed in darkens.
  2. The observations of above table indicate that the largest distance is travelled by the bubble in a given time when the apparatus is placed in front of a fan in sunlight and the distance travelled is least in the shade. Now, as shown in the figure the leaves are hanged so that they may transpire freely.
  3. There are two manometers at the two ends of the bell-jars. Mercury level in the capillary tube rises.

In the high atmospheric humidity the temperature will also not be too high. All these conditions are unfavourable for the transpiration, and hence it will be too less. Stomata do not open in darkness. So, when the stomata, the chief apparatuses for transpiration, remain close, question does not arise of transpiration and hence there will be no change in the position of the inserted bubble.

When the apparatus is placed in front of fan in the sunlight: Sunlight is in itself sufficient for high transpiration because it increases the temperature, lowers the atmospheric humidity and opens the stomata, being all these conditions favourable for the process. If a fan is also placed in front of apparatus if will provide a continuous current of wind which also removes the water vapours and reduces the atmospheric humidity, and thus ultimately favouring more for the process of transpiration.

Thus, the transpiration process will be very high in these conditions. It consists of a wide-mouthed bottle fitted with a rubber cork having 3 holes. In one hole is fitted a thistle funnel provided with a 5 in your experiments transpiration was observed by cork; through the second hole is inserted a leafy twig; and in the third hole is fitted a bent tube of narrow bore provided with a scale.

The other end of the bent tube is placed in a beaker containing water Fig. Fill the whole apparatus with water and insert a freshly cut twig through one of the holes. Make all the joints air-tight by applying grease, thoroughly.

Insert one air bubble in the graduated tube, place it again in the beaker containing water and keep the whole apparatus in light. Note the initial and final readings of the bubble in a given time. Note the same readings in the same time in shade, darkness and by placing a fan in front of apparatus. It consists of a graduated tube dipped into the beaker containing water.

The graduated tube is connected with a vertical arm bearing a cork on its mouth. The cork contains one hole through which a twig is inserted in the water of the vertical arm.

Vertical arm is also attached with a stop cork connected with a water reservoir Fig. Fill the apparatus with water through the water reservoir. Insert a freshly cut twig in the water of the vertical arm through the hole of the cork.

Insert an air bubble in the graduated tube and keep the whole apparatus in sunlight. Note the initial and final readings of the bubble in given time in different conditions like sunlight, shade, darkness and by placing the plant in front of a fan in sunlight. It consists of a wide-mouthed bottle, the mouth of which is fitted with a two-holed cork. The bottle is filled with water.

A freshly cut twig is inserted in one of the hole. Through the another hole is fitted a bent tube having two bulbs.