Metal ion adsorption by pseudosclerotial plates of Phellinus weirii

Abstract

Melanized pseudosclerotial plates, commonly referred to as zone lines, form at colony boundaries of Phellinus weirii and other white-rot fungi in response to various stimuli. Pseudosclerotial plates of P. weirii produced in the laboratory can sequester metal ions from contact with soil in concentrations up to fifteen times greater than found in the soil. Phellinus weirii accumulated greater ion concentrations for 11 of 13 elements assayed than did Fomitopsis pinicola, a brown rot fungus that produces thick mycelial mats but does not produce melanized pseudosclerotial plates. Ion concentrations for 10 of 13 elements were significantly greater in soil-treated pseudosclerotial plates of P. weirii than in controls. Aluminum and iron concentrations for soil-treated pseudosclerotial plates of P. weirii were 162 and 117 times greater, respectively, than that of controls. Ion concentration for untreated mats of P. weirii and F. pinicola were not significantly different in 12 of 13 elements assayed. The metal ion-rich outer layer of the pseudosclerotial plates of P. weirii may help in protecting the fungus from combative antagonistic organisms and enhance long-term saprophytic survival of this fungus.