• Melia azedarach;
  • vascular rays;
  • vessels;
  • wound effects;
  • xylem differentiation


The axial and radial derivatives of the cambium showed contrasting wound responses in Melia azedarach L. The vascular rays became larger, less spaced, and their shapes were modified following wounding. As the wound effects vanished with time, ray size, spacing and shape returned to normal patterns. On the other hand, following wounding, vessels became smaller, and fibres were not formed. Vessels returned to normal size, and vessels and fibres reverted to their normal pattern when wound effects vanished. These changes in the patterns of vascular rays, vessels and fibres reflect the nature of the regulatory mechanisms of their formation: axial signal flows, and the involvement of wound effects.