Decomposition of 14C‐Labeled Cell Wall and Cytoplasmic Fractions from Hyaline and Melanic Fungi

Abstract

AbstractA hyaline fungus, Aspergillus niger, and an unnamed melanic fungus isolated from a soil sclerotium were grown on 14C glucose, fractionated into cell wall and cytoplasmic components, and the fractions analyzed for C, H, N, OCH3, and specific activity. The cell wall fraction from the melanic fungus was higher in C and OCH3 content than that from the hyaline organism. The fractions were incorporated into soil samples and 14CO2 evolved was determined during 6 months. The rate of decomposition for cell wall material of both organisms was initially lower than that for cytoplasmic material. The hyaline cell wall decomposed at a relatively steady rate for a prolonged period, and after 6 months 70% of the C in this fraction had been lost as CO2 compared with 62% of the C in the cytoplasmic fraction. Cell wall and cytoplasmic fractions of the melanic species were strongly pigmented and resistant to decomposition with 35% and 48% of the C in these respective fractions evolved as CO2. The decomposition of complete, non‐fractionated tissue of additional fungi was also studied. Hyaline organisms (Penicillium sp., Schizophyllum commune, Polystictus versicolor, Lenzites sp.) had a lower C content and underwent rapid decomposition in comparison with melanic organisms (Mycoleptodiscus terrestris, Cladosporium sp., Cenococcum graniforme, Mycelium radicis‐atrovirens, Macrophomina phaseoli).