DECAY POTENTIAL OF FOUR WHITE-ROT FUNGI ON BETULA ALNOIDES AND QUERCUS DEALBATA WOODBLOCKS

摘要

Four white-rot fungi viz., Armillaria mellea, Heterdbasidion perplexa, Schizophyllum commune and Trichaptumfuscoviolaceum were selected for the study of decay potential on woodblocks of two common host tree species viz., Betula alnoides and Quercus dealbata. Samplings were done at 30 days time interval for the estimation of wood weight loss, wood moisture content, pH, lignin and cellulose contents. Enzyme activity assays for laccase and cellulase enzyme was also done accordingly. The results showed that H. perplexa caused maximum weight loss and moisture content in B. alnoides woodblocks. The best lignin degrader was H. perplexa followed by T. fuscoviolaceum, S. commune and A. mellea. In Q. dealbata wood blocks, T. fuscoviolaceum caused maximum weight loss and moisture content. The better lignin degrader was T. fuscoviolaceum followed by H. perplexa, A. mellea and S. commune. In both the wood blocks it was found that H. perplexa and T. fuscoviolaceum were better cellulose degraders as compared to A. mellea and S. commune. The pH of the wood blocks was acidic throughout the incubation period. Laccase was detected as the main oxidative enzyme in the extracts of the fungal mycelia of H. perplexa and T. fuscoviolaceum colonizing both the woodblocks. Laccase activity was low in both S. commune and A. mellea. No correlation was observed between cellulase activity and cellulose degradation and only few correlations of lignin degradation and laccase activity were seen in the present study. It is, therefore, evident that other enzyme systems are involved in cellulose and lignin degradation by the 4 selected white-rot fungi and an intricate relationship exists between the enzyme activity and the wood decaying ability of these fungi.