Question

The figure given below is a diagrammatic representation of a part of the cross section of the root in the root hair zone. Study the same and then answer the questions that follow:

(i) Name the parts indicated by the guidelines 1 to 4.

(ii) Which is the process that enables the passage of water from the soil into the root hair?

(iii) Name the pressure that is responsible for the movement of water in the direction indicated by the arrows. Define it.

Answer 1

(i) Name the parts 1-4:

1. Part 1: Root hairs- These are hair-like structures of the root that absorbs water from the soil through osmosis.
2. Part 2: Water particles of the soil- These water molecules from the soil enters the root hair cells by osmosis.
3. Part 3: Xylem- It is a vascular tissue of a plant that conveys water from the roots to the rest of the plant.
4. Part 4: Cortex- It is an outer layer of the root.

(ii) Process of the passage of water from the soil to root hairs:

1. The osmotic concentration of cell sap in root hair cells is higher than that of the soil.
2. As a result, water from the soil moves into the root hair cells by the process of osmosis.
3. This helps in water absorption of water by plant roots.

(iii) Pressure responsible for the movement of water inside the roots:

1. Pressure responsible for the movement of water in the direction indicated by the arrows is known as root pressure.
2. It is the pressure developed in plant roots due to the inward movement of water from the soil by the process called osmosis and later into the xylem from where the sap ascends to the stem.