xylem (zī`ləm): see stem stem, supporting structure of a plant, serving also to conduct and to store food materials. The stems of herbaceous and of woody plants differ: those of herbaceous plants are usually green and pliant and are covered by a thin epidermis instead of by the bark of woody
..... Click the link for more information. ; wood wood, botanically, the xylem tissue that forms the bulk of the stem of a woody plant. Xylem conducts sap upward from the roots to the leaves, stores food in the form of complex carbohydrates, and provides support; it is made up of various types of cells specialized
..... Click the link for more information. .

xylem

Cross section of oak xylem

(credit: 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.

xylem (redirected from protoxylem)

xylem

xylem
(redirected from protoxylem)