Fungal Decomposition of Bracken Petioles

Frankland (1966) described a succession of fungi on decaying petioles of bracken (Pteridium aquilinum (L.) Kuhn) in six habitats and tentatively ascribed chemical changes in the bracken to the action of certain predominant fungi. In the present investigation, some individual members of the fungal succession were grown on sterile bracken and changes in the chemical composition (carbon, nitrogen, ash, soluble carbohydrates, holocellulose, a-cellulose and lignin), dry weight and pH were followed. The aim was to evaluate the potential role of these fungi in bracken decomposition. Previous investigators of the fungal decomposition of plant material have used similar laboratory cultures of sterile litter (Lindeberg 1944, 1947; Mikola 1954; Saito 1960; Chastukhin 1962). In this investigation gamma radiation was used to sterilize the braclten instead of the more conventional methods, which involve drastic heat treatment or the inconvenience of gaseous chemicals and difficulties in moisture regulation. Major physical or chemical changes in bracken petioles after irradiation were not detected.