Xylem tissue in plants serves both as a conduit for water and dissolved minerals and provides structural support. It is a specialized vascular tissue that transports water and dissolved minerals from the roots to the rest of the plant, including stems and leaves. 

Xylem tissue, particularly the wood, provides mechanical support and strength to the plant, helping it stand upright and resist deformation. Also, it consists of specialized cells, including tracheids and vessel elements, which are responsible for water conduction.