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  • Effect of acidity on growth rate and stroma formation of Monilia fructigena and M. polystroma isolates

    The effect of acidity (pH) ranges on the mycelial growth and stroma formation of Monilia fructigena Pers: Fr. and of M. polystroma van Leeuwen was determined on agar plates and apple fruits. Four isolates of each of the brown rot fungi and two apple cultivars, `James Grieve' and 'Cox's Orange Pippin', were used for the study. For the agar plate study, a range of the initial pH was prepared from 2.5 to 6.5. The dishes were inoculated with a 4 mm plug of each isolate and incubated at 23 °C in darkness. The mycelial growth was measured after 1.5, 4, 7, 10 and 20 days of incubation. After a 30-day incubation, stroma formation was determined by image analysis and weighing of mature stroma. In the fruit experiment, both cultivars were inoculated with one isolate of M. fructigena and of M. polystroma. The pH changes were determined after 7, 14, 28 and 35 days of incubation in both healthy and inoculated fruits. The fastest mycelial growth was at pH 4.5 for M. polystroma and at pH 3.5 for M. fructigena. After a 30-day incubation, M. polystroma isolates produced twice or three times more stroma compared to M. fructigena isolates. For both brown rot fungi, the amount of mature stroma increased from pH 3.5 to 5.5, and then decreased at pH 6.5. Results of the.fruit experiment showed that healthy fruits were quite acidic (pH < 3.5), but pH rapidly increased in the inoculated fruits for both cultivars, reaching pH 4.6-5.4 depending on cultivar and fungus isolate. On both cultivars, the stroma developed at a significantly higher pH for M. polystroma than for M. fructigena. Biological and practical implications of the results are discussed.

  • Impact of substrate supplemented with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of black poplar mushroom Agrocybe cylindracea (DC.) Marie.

    Black poplar mushroom, Agrocybe cylindracea deserves special attention, due to its medicinal properties. Water and alcohol extracts from fruiting bodies of the fungus have an anti-oxidant, anti-cancer, anti-fungal, cholesterol and triglycerides blood level lowering abilities. This mushroom is rich in proteins and vitamins, mineral elements and low in fat. The aim of the experiments was to determine effect of a substrate supplementation with CaCO3 on mycelial growth, yield, morphological features and storability of fruiting bodies of four strains of A. cylindracea (DC.) Marie. The amount of additive to sawdust substrate affects rate of mycelial growth and yield of investigated strains. A. cylindracea mycelial growth was not affected by addition of CaCO3 to substrate, however a significant effect of this additive was found on yield, which was the highest with CaCO3 addition in an amount of 8 g/100 g of substrate. Carpophores characterized with the largest caps diameter, and the largest individual mass obtained of substrate enriched with CaCO3 addition of 8 g/100 g of substrate. In addition, it was found that supplementation with CaCO3 affect storability of A. cylindracea. The lowest weight loss of fruiting bodies after 3 and 7 days of storage was found with addition of CaCO3 to substrate in an amount of 4 g/100 g of substrate.