Xylem parenchyma
Explanation
Xylem is a complex permanent tissue in plants primarily responsible for the conduction of water and minerals from roots to the stem and leaves. It also provides mechanical strength to the plant parts. Xylem is composed of four different types of elements: tracheids, vessels, xylem fibres, and xylem parenchyma.
- Tracheids: These are elongated or tube-like cells with thick and lignified walls and tapering ends. They are dead and are without protoplasm.
- Vessels: A vessel is a long cylindrical tube-like structure made up of many cells called vessel members, each with lignified walls and a large central cavity. The vessel cells are also devoid of protoplasm (dead).
- Xylem Fibres: These have highly thickened walls and obliterated central lumens. They may either be septate or aseptate and are dead at maturity.
- Xylem Parenchyma: These cells are living and thin-walled, and their cell walls are made up of cellulose. They store food materials in the form of starch or fat and other substances like tannins. The radial conduction of water takes place by the ray parenchymatous cells.
Key Takeaway: In xylem tissue, xylem parenchyma is the only living component, whereas tracheids, vessels, and xylem fibres are dead at maturity.