Give an account of structure and function of xylem.

Xylem is a complex vescular tissue which is composed of several types of cells. Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.

The cells of this tissue have thick walls and many of them are non-living.

(i) Tracheids: These are long elongated tubular cells. Tracheids cells are dead. Its main function is conduction of water and minerals from root to stem.

(ii) Vessels: These are pipe-like structure. Vessels are dead and have lignified cell wall. They also participate conduction of water and minerals.

(iii) Xylem parenchyma: These are living cells which store food material.

(iv) Xylem fibres: These are dead cells provide mechanical support to the plant.