Discuss the ascent of sap with the help of a neatly labelled diagram.

Ascent of sap in plants is described below:

1. Root hair cells absorb mineral salts mainly by active transport. The mineral salts then reach the root cortex.
2. Root hair cells also absorb water from the soil through osmosis.
3. As mineral salts get accumulated in the xylem, the water concentration gets reduced in it. This creates a concentration gradient that is strong enough to draw water and minerals to move towards the stem. The pressure developed in the roots due to the continuous inflow of water helps in pushing the plant sap upwards. It is called root pressure.
4. Further on, water moves through the xylem up the stem, then to the leaves. This happens due to a pull created by transpiration. It is called transpiration pull.
5. Water and minerals absorbed by roots are conducted upwards through xylem to other plant parts. This upward movement of cell sap, which contains water and minerals, is called ascent of sap.