xylem

xy·lem

noun \ˈzī-ləm, -ˌlem\

Definition of XYLEM

: a complex tissue in the vascular system of higher plants that consists of vessels, tracheids, or both usually together with wood fibers and parenchyma cells, functions chiefly in conduction of water and dissolved minerals but also in support and food storage, and typically constitutes the woody element (as of a plant stem) — compare phloem

Origin of XYLEM

German, from Greek xylon

First Known Use: 1873

Other Botany Terms

annual, burgeon, chloroplast, nomenclature, succulent, sylvan

Rhymes with XYLEM

hilum, phylum, whilom

xylem

noun    (Concise Encyclopedia)

Cross section of oak xylem—J.M. Langham

Part of a plant's vascular system that conveys water and dissolved minerals from the roots to the rest of the plant and furnishes mechanical support. Xylem constitutes the major part of a mature woody stem or root and the wood of a tree, and consists of specialized water-conducting tissues made up mostly of several types of narrow, elongate, hollow cells. Xylem formation begins when the actively dividing cells of growing root and shoot tips give rise to primary xylem. Eventually the primary xylem is covered by secondary xylem produced by the cambium. The primary xylem cells die, forming a hard skeleton that supports the plant but loses its conducting function. Thus, only the outer part of the wood (secondary xylem) serves in water conduction.