The Mechanisms of Wound Response in Acacia Mangium

Branches of 8-year-old trees of Acacia mangium Willd. from a plantation in Malaysia were wounded. After response periods from 1 to 4 weeks wound-adjacent xylem was investigated by electron microscopy. Wounding induced the synthesis of dark-stained material in parenchyma cells with subsequent secretion through the pits into vessels and fibres. After four weeks many of them contained wall-attached layers of this material. Entirely filled vessels and fibres were not observed. As a second wound-associated process suberization of parenchyma cells contributes to the separation of wound-adjacent xylem tissue. Fungal degradation frequently occurred around the wound already three weeks after wounding. The effectivity of early wound responses in A. mangium appears low