Traumatic Vertical Lysigenous Canals in Cacao in Papua and New Guinea.

Abstract

The occurrence of tangential series of traumatic vertical lysigenous canals or pseudo growth rings is recorded in some cacao wood specimens from three areas in Papua and New Guinea. The traumatic canals replace xylem and fibres and constitute a zone of weakness in the wood when it is cut from the tree. Normal and traumatic lysigenous cavities of cacao are clearly distinguished with excitation with ultra violet light after treatment with acridine orange, the mucilage appearing brilliant red. The cause of the traumatic canals is not known but was probably injury to the cambium.