Formation of the ligno-suberized barrier zone and wound periderm in four species of European broad-leaved trees

The development of wound periderm after mechanical wounding was examined in the barks of Acer pseudoplatanus, Betula pendula, Fagus sylvatica and Sorbus aucuparia. Following the initial necrosis of cells immediately surrounding the wounds, development of the ligno-suberized barrier zone was detected within 7 days. Suberin deposition was observed in this tissue in A. pseudoplatanus, S. aucuparia and B. pendula 7 days after wounding, but not in F. sylvatica until day 14. By 28 days after wounding, extensive thickening of the walls of these cells had occurred. Differentiation of the wound periderm was detected immediately abutting the ligno-suberized barrier-zone tissues in all species, with extensive development by 28 days. Fifty-six days after mounding, the wound periderm was fully formed and completely confluent with the original periderm. Development of the wound response was similar in all species, with differences only in the timing of first detection of suberin.