xylem [
PO:0005352; plant anatomy term ]
A portion of vascular tissue (PO:0009015) that has as part one or more tracheary elements (PO:0000290).
More Synonyms: portion of xylem tissue, xilema (Spanish), 木質部 (Japanese)
Comments: Functions in the translocation of water and solutes from roots (PO:0009005) to the shoot system (PO:0009006) and in support. Tracheary elements have lignified cell walls with secondary thickening and are dead at maturity.
xylem fiber cell [
PO:0000274; plant anatomy term ]
A fiber cell (PO:0025407) that is part of a portion of xylem (PO:0005352) tissue.
More Synonyms: fibra del xilema (Spanish), 木部繊維細胞 (Japanese)
Comments: It may be difficult to distinguish xylem fiber cells, especially fiber tracheids (PO:0000355), from tracheary elements (PO:0000290). Fiber tracheids have bordered pits with smaller pit cavities than the vessel members (PO:0002003) or tracheids (PO:0000301) of the same wood and a distinct pit cavity leading to the cell lumen through the cell wall.
xylem pole pericycle cell [
PO:0000064; plant anatomy term ]
A pericycle cell that is adjacent to the protoxylem of a vascular bundle.
More Synonyms: célula del polo xilemático del periciclo (Spanish), 木質部孔鞘細胞 (Japanese)
Comments: Xylem pole pericycle cells are cells in the pericycle that are adjacent to the protoxylem pole of a vascular bundle. Pericycle cells that are adjacent to other xylem cells in the vascular bundle are not considered xylem pole pericycle cells. Xylem pole pericycle cells may retain some meristematic activity and are the site of lateral root initiation.
xylem sap [
PO:0025539; plant anatomy term ]
A plant sap (PO:0025538) that is an aqueous solution which may contain mineral elements, nutrients, and plant hormones, and is transported from the root system (PO:0025025) toward the leaves through the tracheary elements (PO:0000290) of the xylem.
More Synonyms: savia del xilema (Spanish), 木質部樹液 (Japanese)
Comments:
xylem vessel [
PO:0025417; plant anatomy term ]
A portion of xylem (PO:0005352) tissue that has as parts a tube-like series of vessel members (PO:0002003), the common walls of which have perforations.
More Synonyms: vaso xilem&$225tico (Spanish), vessel, 木質部導管 (Japanese)
Comments:
xylem vessel member [
PO:0002003; plant anatomy term ]
A tracheary element (PO:0000290) that is part of a xylem vessel (PO:0025417) and has as parts perforation plates.
More Synonyms: miembro de vaso (Spanish), vessel element, vessel member, vessel segment, 木質部道管状要素 (Japanese)
Comments: Commonly thick walled, with pointed ends and bordered pits that have lenticular to slit-like apertures. If both libriform fibers (PO:0004520) and fiber tracheids are present, the libriform fibers usually have thicker walls. Fiber tracheids have bordered pits with smaller pit cavities than the vessel members (PO:0002003) or tracheids (PO:0000301) of the same wood and a distinct pit cavity leading from the pit cavity to the cell lumen through the thick cell wall.