Which components of xylem are living and which ones are dead?

The xylem is one of the conductive tissues in plants. It is a complex tissue composed of many types of cells. The main function of xylem is to conduct water and minerals from roots to leaves.

There are 4 components of xylem:

Xylem parenchyma is the fourth component of xylem. It is the only living component in the xylem. The cells are with plenty of cytoplasm and prominent nucleus. They have thin cellulosic cell wall. Lignified secondary cell wall is absent in xylem parenchyma. Very rarely parenchyma cells in the secondary xylem undergo secondary growth. Parenchyma in the xylem can store starch, oil and other ergastic (non-protoplast materials found in a cell) substances. It is the only component of xylem that transfer movement of water from xylem to phloem and back.

Rest other components of xylem, tracheids and vessels are involved in water conduction throughout the plant and xylem fibers mainly make the outer dead bark of the plant for mechanical support.