list the constituents of the xylem. what would happen if the xylem of root of a plant is blocked? code example

Example: list the constituents of the xylem. what would happen if the xylem of root of a plant is blocked?

constituents of xylem are tracheids,vessels,xylem parenchyma,xylem fibres.
if xylem root is blocked then the plant would not able to perform activities like transportation of water through out the plant, and etc.