Question

How does transpiration pull water upwards?

Answer 1

Transpiration:

1. Transpiration is the process by which water molecules evaporate and escape from the aerial parts of the plants in the form of water vapor.
2. The evaporation of water during transpiration creates a negative pressure in the leaves.
3. This, in turn, creates a suctional pull.
4. This suctional pull is referred to as the transpirational pull and helps water flow towards the stem from the roots and the roots absorb more water.
5. Transpiration is said to be the main force behind water movement in the xylem according to the cohesion-tension theory.
6. Cohesion and adhesion forces draw water up the xylem vessel and draw water molecules from through the stomatal openings.
7. Evaporation of water creates a negative water potential that causes water to move upwards towards the leaves via the xylem.