Question

Name the following:

Development of negative pressure due to transpiration.

Answer 1

Transpiration pull

1. Ascent of sap from the roots to the shoot occurs to supply water and minerals to the shoot system.
2. The most widely accepted theory for the accepted mechanism of the ascent of sap is the transpiration pull or the cohesion tension theory.
3. Tension or negative pressure in the water column of xylem channels results in this upward pull.
4. Since it develops due to transpiration, it is called transpiration pull.
5. This mechanism was proposed by Dixon and Joly in 1894.

So, the development of negative pressure due to transpiration is called ‘transpiration pull’.