Manganese Accumulation in Wood Decayed by White Rot Fungi

Abstract

Black regions and flecks in wood decayed by several white rot fungi (Cerrena unicolor, Dichomitus squalens, Ganoderma applanatum, G. tsugae, Heteroblasidion annosum, Ischnoderma resinosum and Perenniporia medulla-panis) contained large concentrations of Mn. Two types of decay patterns occurred in wood degraded by these fungi: a selective delignification resulting in the removal of lignin and hemicellulose and a typical white rot causing simultaneous removal of all cell wall components. Atomic emission spectrometry and X-ray microanalyses detected Mn and determined its spatial relationship within selectively delignified wood. Black regions in eastern hemlock wood decayed by G. tsugae showed over a 100-fold increase of Mn when compared with sound wood. When black regions were compared with surrounding delignified wood and adjacent white-rotted wood, the increases of Mn were 24- and 51-fold, respectively. In contrast to the other decays examined, Mn deposits were found in white-rotted wood attacked by Fomes fomentarius. Micromorphological characteristics of decayed wood and Mn deposits were observed with scanning electron microscopy. Leucoberbelin blue reagent confirmed the presence of manganese oxides within the black regions.