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Wound Healing by Exposed Secondary Xylem in Adansonia (Bombacaceae)

1981; Brill; Volume: 2; Issue: 4 Linguagem: Inglês

10.1163/22941932-90000732

0928-1541

Jack B. Fisher,

Soil erosion and sediment transport

After large branches of Adansonia digitata were transversely cut, the entire surface of secondary xylem and pith responded by producing wound tissue.Eight days after cutting, the surface 1-3 cm of xylem cells died and xylem parenchyma cells beneath expanded, divided, and deposited tannin-like compounds.After 56 days, xylem and pith parenchyma, especially the wide zones of terminal parenchyma, proliferated further as did the exposed cambial zone.Transversely cut roots showed more proliferation than stems.A new cambium regenerated across the xylem surface of the proliferation of root xylem (= callus).Large branches (approximately 16-21 years old at the time of cutting) continued to produce an uninterrupted surface zone of wound parenchyma, similar in structure to normal bark, derived from pith, ray and axial parenchyma.A thin surface periderm covered the wound tissue, and a wound cambium was not formed 15 years after wounding.The proliferation of aged parenchyma cells in response to wounding is related to normal wood structure in the Bombacaceae.However, a similar response to branch cutting was not observed in two other species of this family.