Vascular cambium

In herbaceous plants, it occurs in the vascular bundles which are often arranged like beads on a necklace forming an interrupted ring inside the stem.

In woody plants, it forms a cylinder of unspecialized meristem cells, as a continuous ring from which the new tissues are grown.

Vascular cambia are found in all seed plants except for five angiosperm lineages which have independently lost it; Nymphaeales, Ceratophyllum, Nelumbo, Podostemaceae, and monocots.

[2] The phytohormones that are involved in the vascular cambial activity are auxins, ethylene, gibberellins, cytokinins, abscisic acid and probably more to be discovered.

It has been shown that mutants without auxin will exhibit increased spacing between the interfascicular cambiums and reduced growth of the vascular bundles.

Regulation of these initials ensures the connection and communication between xylem and phloem is maintained for the translocation of nourishment and sugars are safely being stored as an energy resource.

Differentiation is an essential process that changes these tissues into a more specialized type, leading to an important role in maintaining the life form of a plant.

Helianthus stem in section. The cells of the vascular cambium (F) divide to form phloem on the outside, located beneath the bundle cap (E), and xylem (D) on the inside. Most of the vascular cambium is here in vascular bundles (ovals of phloem and xylem together) but it is starting to join these up as at point F between the bundles.