metaxylem plant_anatomy PO_GIT:434 後生木部 (Japanese, exact) Metaxylem has larger tracheary elements (PO:0000290) than the protoxylem (PO:0000272), and develops after the formation of the protoxylem, once elongation of the plant axis (PO:0025004) has completed. A portion of primary xylem (PO:0005849) tissue that has as part one or more metaxylem tracheary elements (PO:0025576) embedded in parenchyma (PO:0005421) tissue and may contain xylem fiber cells (PO:0000274). metaxilema (Spanish, exact) portion of metaxylem tissue (exact) PO:0000372 primary xylem