cell death stage of secondary xylem 2012-03-14T02:07:50Z A cell differentiation stage of secondary xylem (PO:0025469) that occurs during the interval between the first cell death of a tracheary element (PO:0000290) or non-septate xylem fiber cell (PO:0000274) and the death of the last secondary xylem parenchyma cell (PO:0004525) or septate fiber cell (PO:0004521) in a portion of secondary xylem (PO:0005848). During this stage, the cells of a portion of secondary xylem are undergoing cell death (GO:0008219), sometimes called apoptosis. Death of the tracheary elements and non-septate xylem fiber cells generally precedes the death of secondary parenchyma cells and septate fiber cells. Once all cells in portion of secondary xylem are dead, it transitions from sapwood (PO:0004513) to heartwood (PO:0004512), and secondary xylem development ends. PO:0025466 PO_GIT:447 etapa de muerte celular del xilema secundario (Spanish, exact) plant_structure_development_stage rwalls transition to heartwood stage (exact) 二次木部の細胞死段階 (Japanese, exact) cell differentiation stage of secondary xylem