part_of part of part of portion of ground tissue sporangium wall tapetum plant_anatomy PO_GIT:357 絨毯組織、タペート組織 (Japanese, exact) A portion of ground tissue (PO:0025059) that is the inner-most layer of a sporangium wall (PO:0025306). tapeto (Spanish, exact) rwalls May function in providing nutrition to developing sporocytes or pollen. May have one or more layers of cells. May break down as spores mature. A tapetum does not develop in some plants, such as Psilotum. In angiosperms, the tapetum develops from one of the parietal layers. In non-seed plants, the tapetum may develop from the outer cells of archesporium or from the inner-most layer of the sporangium wall. The tapetum may be one of two types ameboid or secretory/glandular. PO:0025313 2011-05-03T11:59:24Z