Name: Carbon Dioxide: Vital Raw Material of Photosynthesis
Uploaded: 2019-07-19
Duration: 3 min 37 s
Description: Plants fix carbon dioxide during photosynthesis to produce sugar. Hence, carbon dioxide is a vital raw material for photosynthesis. Let's establish this fact...

Question

How transpiration pull helps in ascent of sap?

Accepted Answer

Transpiration is the process by which plants loose water in the form of water vapour from the leaves into the atmosphere. This takes place through stomata present in the leaves.

Due to loss of water partial vacuum is created in the plant body. This creates a pull in the water column, which is called as transpiration pull. This pull leads to the upward movement of water in plants.

The solution containing water along with minerals is called as sap. The upward movement of sap in the plant body is called as ascent of sap.

The upward movement of sap in water column is carried out by cohesion of water molecules together. Due to transpiration pull the water molecules are pulled upwards and by cohesion of water molecules the water column remains intact.

Water molecules also adhere to the surface of xylem vessels, this also helps in maintaining the continuity of the water column. Root pressure also helps in pushing the water column upwards.

Hence, ascent of sap is the combined effort of transpiration pull, cohesion, adhesion and root pressure.

How transpiration pull helps in ascent of sap?

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