Studies on the fungus Flammulina velutipes

Abstract

Local ligninocellulosic waste materials were examined as substrates for growing Flammulina velutipes mushrooms. Mushroom production was favoured by substrate moisture content in the range of 125-150%, (substrate supplementation with wheat bran) and a vegetative run temperature of 25°C for 2-3 weeks. Cropping time was 34-49 days and Biological Efficiency (B.E.) with wheat bran supplemented aspen sawdust and pulp waste mixtures was close to 100 percent. There was significant increase in yield when the amount of wheat bran in the substrate was doubled. Spruce sawdust gave significantly lower yields than aspen sawdust and yield with pulp waste equaled the best yields obtained with aspen sawdust. Bark and inner bark fibres delayed cropping time as compared to other substrates. Cytological examination revealed irregularities in the nuclear cycle. The oidia were uninucleate, freshly shed basidiospores were binucleate, clamped mycelia were mostly dikaryotic and some cells were multinucleate, and simple septate mycelia were usually multinucleate, trama and basidia were binucleate and stipe hyphae were multinucleate (3-12 nuclei per hyphal cell). Nuclei stained with 4', 6 diamidino'-2-phenylindole (DAPI), a DNA specific dye, fluoresced pale blue. Some cells contained fluorescing yellow particles in the cytoplasm. During meiosis, spindle orientation was hemichiastobasidial. A post-meiotic mitotic division in the basidiospores resulted in binucleate basidiospores. Examination of the hymenial layer of the gill with SEM revealed a variation in basidiospore numbers and size. Preliminary elemental analyses of pulp wastes and of mushrooms growing on the pulp wastes indicated that lower than expected levels of heavy metals were present in both the materials.