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Is xylem tissue alive or dead ? >DEAD
In flowering plants, the xylem is made up from vessel elements, trachieds, fibres and parenchyma cells.
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The vessel elements and trachieds > These are the actual cells that transport water. They are dead.
Fibres > These are elongated cells with lignified walls and are dead too. They are important in providing support for the plant.
The Parenchyma cells > Standard, living plant cells with conventional plant-cell features although rarely chloroplasts as they are not exposed to light.
Xylem Vessels and Tracheids
Xylem vessels are made from many elongated vessel elements joined end to end. Each began as a normal cell, but laid down the waterproof substance lignin in its cellulose wall- resulting in cell death. They have pits in their walls where there used to be plasmodesmata, and these are gaps in the lignin wall, allowing water to move out of the vessel. The end walls of neighbouring vessels break down completely, forming a long continuous tube called a xylem vessel.
Tracheids
Tracheids are like vessel elements in that they are dead. They do not have completely open ends, but water moves through pits from tracheid to tracheid. Tracheids are very common in evolutionarily primitive plants like ferns and conifers, but more advanced plants (like the angiosperms or folowering plants ) rely mostly on vesels.