xylem Tissue in the vascular system of plants that moves water and dissolved nutrients from the roots to the leaves and also provides mechanical support. Xylem is of two kinds: primary, formed by differentiation from procambium and consisting of protoxylem and metaxylem, and secondary, additional xylem produced by activity of cambium. Xylem is characterized by the presence of tracheids and/or vessels, fibers, and parenchyma. In mature woody plants, xylem makes up the bulk of vascular tissue itself and of the entire structure of stems and roots. Related category • BOTANY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |