Xylem is transport tissue found in vascular plants. The function xylem is to transport water from the roots to shoots. It is also used to replace the water loss during transpiration and photosynthesis. The xylem sap has water and inorganic ions . The transport of water is done true passive process. Transporting water to the top of the tree becomes difficult that is why xylem is also condsidered to limit the height of trees