All the components of the xylem except xylem parenchyma are dead. Hence xylem is non-living tissue.
Xylem is the complex tissue of plants, responsible for transporting water and other nutrients to the plants. It consists of dead cells (parenchyma is the only living cells present in the xylem). They comprise xylem vessels, fibre and tracheids. It is located in the centre of the vascular bundle, deep in the plant, and movement is unidirectional. Xylem is the dead tissue at maturity but no cell contents.
Xylem is composed of four different kinds of elements:
- Tracheids: Dead, tube-like cells with a tapering end.
- Vessels: They are present in angiosperms. These are long cylindrical structure having a tube-like appearance.
- Xylem Fibre: Dead cell with lignified walls and a central lumen. Involved in water transportation and providing mechanical support.
- Xylem Parenchyma: Only living cells of the xylem and store starch and fat. They assist in the short distance transportation of water.