AS ANATOMICAL FEATURES OF THE XYLEM COULD INFLUENCE WOUND HEALING PROCESS IN TREES?

Since trees are continually at risk of damage from animals and adverse environmental conditions, their survival depends on wound healing capacity. Common physiological responses to injury are cell proliferation, regeneration of the vascular tissue and the formation of compounds to protect cells near the wound. The wood anatomy is important for understanding the mechanisms of wound healing, and hence tree survival. We studied twelve tropical tree species to understand how some wood characteristics contribute to the wound healing process. We made the quantitative analysis of wood characteristics and evaluated the rate of wound healing two years after the collection of samples. Species with a large amount of axial parenchyma, presented the highest wound healing rate, proving that axial parenchyma cell supply material for greater cell proliferation, acting to close the wound much faster. Species that have axial parenchyma and produce a network between vessels and rays through living tissue, recover and provide passage of hormones that stimulate cell division of tissue near the wound, promoting growth of callus tissue all around the wound area, accelerating wound closure. On the other hand, the absence of axial parenchyma hinders such recovery by disabling affected regions; both above and below the injury, from producing sufficient wound healing tissue. The presence of longer fibers is an indicative of a larger amount of gibberellin that is involved in cell division during wound healing; therefore, species with longer fibers had faster wound healing.