Vascular Cambium

Abstract

The vascular cambium generates the xylem and phloem of the vascular system, which are used for transport and support. It is a single layer of meristematic cells that undergoes an expansion during the transition from primary to secondary growth. The two cell types, fusiform initials and ray initials, generate the axial and radial xylem and phloem derivatives. Different patterns of fusiform initials are reflected in the resulting axial xylem and phloem generated. The “normal” vascular cambium is a single ring that surrounds the stem. “Anomalous” variations, found in vines, lianas, and storage tissues, generate a variety of other forms that deviate from the standard transport and support functions found in a “normal” stem. In grafting, the vascular cambium of the root stock and that of the scion are encouraged to grow together and make a function vascular connection. Parasitic plants do the same thing, by growing into and fusing their vascular system with that of the host.