The impact of different sources of basic nutrients containing carbon, nitrogen and phosphorus on mycelial mass production of white rot fungus Stereum hirsutum (Wild. ex Fr.) S.F. Gray.

Wood decaying fungi can utilize cellulose, lignin and hemicelluloses, causing brown-, soft- or white rot. Among this group extremely important are the species with both parasitic and saprophytic mode of nutrition. Their deteriorating activities can start in stems and continue (or start) in felled timber. The content of available and easy - assimilable nutrients inside xylem sap, for sure plays the most important role in the very first stage of fungal attack. The fungus Stereum hirsutum can behave as facultative parasites or parasites of weakened trees, but after felling, and during storing of logs in forest or industrial plots, it behaves as a saprophyt. This fungus is widespread and represents the one of the most frequent fungus in forests and storages, playing very important role in wood deterioration. Physiological requirements of fungi are of the highest importance in understanding of mechanism of decaying processes in the wood. The most important factors as like main nutrients as sources of carbon, nitrogen and phosphorus can affect the behaviour of wood decaying fungi. Nutrition of fungi is the main reason for appearance of wood decay, since rotting fungi utilize wood as source of carbon (C), nitrogen (N) and phosphorus (P). Different sources of these elements are important not only for the decaying process but also in the state of mycelial colonisation of the wood before appearance of active decay. Different seasonal status of nutrients in alive plant sap is important in this phase when fungi behave as weakened – tree parasites. The impacts of different sources of C, N and P on production of mycelial mass of Stereum hirsutum (Willd. ex Fr.) S. F. Gray., have been investigated in vitro. This fungus is one of the most frequent appearing on the Oak weakened trees or felled logs. As a causer of Oak sapwood white rot S. hirsutum causes significant damages of wood in forest stands as well as at industrial storages. Among the tested monosaccharides the best carbon source for S. hirsutum was mannose, while disaccharide mannitol was the most convenient for Strain 1. and starch for Strain 2. Generally, malt as a complex nutritive substance has been appropriate source of carbon for the both strains of tested fungus. In N - test Strain 1. mainly produced higher amount of mycelia in accordance with incubation period, except in the cases of control group, L – glutamic acid and peptone. Peptone has been the most convenient nitrogen source for Strain 2. Mycelial yield in all tested series containing phosphorus showed lower amount than in the cases of carbon and nitrogen. That means that phosphorus is not extremely necessary for vegetative fungal growth in comparison with carbon and nitrogen which are of major importance. Higher concentration of phosphorus in substrate could inhibit vegetative growth of fungi.