There are 4 elements of xylem viz. Tracheids, vessels, xylem parwnchyma and xylem fibres.
1. Tracheids provide mechanical support to the plants. They contain lignin. Help in conduction of minerals and water.
2. Vessels are similar to tracheids and perform the same function.
3. Xylem parenchyma stores water and food.
4. Xylem fibres are lignified with reduced lumen. They provide mechanical support.