As the Volume of Secondary Xylem increases, the older Phloem is crushed. This is partly due to the presence of extraxylary fibers in the Cortex and the absence of fibers in the Phloem. The active secondary phloem is located adjacent to the Vascular Cambium. |
|
| The same pressure leads to the disruption of the extraxylary fiber ring. The gap contains Parenchyma which is produced by the mitosis of adjacent cells. |
|
| The pressure generated by the increase in xylem volume also leads to the collapse of parenchyma cells in the central Pith. |
|
