Question

Write a note on types and functions of vascular tissues.

Answer 1

Vascular system

1. Plants have transport system which is also called as vascular system.
2. This system includes phloem and xylem tissue.
3. Phloem helps in transportation of food from the aerial parts of the plant to the other areas of the plant.
4. Xylem helps in transportation of water from the roots to the aerial parts of the plant.

Types of vascular system-

Xylem tissue:

1. This tissue plays a major role in transportation of water and mineral salts from the roots to the aerial parts of the plant.
2. It consists of four types of cells- xylem vessels, xylem tracheids, xylem fibres and xylem parenchyma.

• Xylem tracheids-

1. They are elongated cells with tapering ends.
2. Walls are thick with lateral pores.
3. They provide mechanical strength and support and conducts water to the aerial parts of the plant.

• Xylem vessels-

1. Tube-like structures open at both ends. they form along channels.
2. They provide mechanical support to the plant and conduct water upwards.

• Xylem parenchyma-

1. It is also called as wood parenchyma.
2. They have small, thick walled, living cells.
3. They help in storage of food along with conduction of water and mineral salts.

• Xylem sclerenchyma

1. It is also called as wood fibres.
2. They provide mechanical support to the plant.

Phloem tissue:

1. This tissue plays a major role in transportation of food from the the aerial parts of the plant to the other parts of the plant.
2. It consists of four types of cells-sieve tubes, companion cells, phloem fibres and phloem parenchyma.

• Sieve tubes-

1. They are formed of cylindrical cells devoid of nucleus.
2. End walls are perforated and are called sieve plates.
3. They conduct food from the aerial parts of the plant.

• Companion cells-.

1. Companion cells are living, thin walled and elongated cells.
2. They are attached to the sieve tubes.
3. They do not participate in translocation of food but it helps the sieve tubes in conduction of food.

• Phloem parenchyma-

1. It is also called as wood parenchyma.
2. They have thin walls.
3. They help in storage of food.

• Phloem sclerenchyma

1. They are dead sclerenchyma fibres.
2. They provide mechanical strength and support to the plant.