O₂ requirements for growth and survival of wood-decaying and sapwood-staining fungi

Abstract

Various experiments were conducted to examine O 2 requirements for growth and survival of a total of 48 wood-destroying basidiomycetes and 6 sapwood-staining fungi. An additional objective was to determine whether species that invade heartwood of living trees (heartrotters) are more tolerant of O 2 deficiencies than those that attack better-aerated wood (product rotters). Growth of cultures exposed to flowing mixtures of O 2 and N 2 was moderately retarded by an O 2 pressure of about 11 mm (1 mmHg = 133.322 Pa) and was severely retarded by a pressure near 2 mm. None of the fungi grew with 1.5 mm of O 2 . Comparable minimal O 2 pressures for growth were found by growing the fungi in a closed chamber (with an attached manometer) containing NaOH to absorb CO 2 , then regularly measuring growth and internal O 2 pressure. Fungi grown in a closed chamber consumed all of the available O 2 . Length of survival of species grown in sealed test tubes differed markedly, from less than 1 week to more than 2 years. The species surviving longest included more heartrotters than product rotters.