Question

Explain cohesion tension theory

Answer 1

• Cohesion tension theory says that the movement of water in the upwards direction against gravity is guided by the attractive forces between the particles of water which is known as cohesion.

(1 mark)

• This gives rise to surface tension which pulls the water upwards from the root through the xylem and this is aided by Transpiration pull and capillary action of water. This is the main mechanism of transport of water in plants.

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• Transpiration pull causes a suction effect on the water column and water rises up, aided by its capillary action.

(1 mark)