The well-known phenomenon of 'fairy rings' can be explained in terms of the radial growth of fungi. As the underground mycelium of certain members of the Basid-iomycota extends outwards, it releases enzymes into the soil, degrading organic matter ahead of it and releasing nutrients such as soluble nitrogen for the grass, whose growth becomes more lush at this point, and forms the familiar ring. Further back, the branching mycelium outcompetes the overlying grass and deprives it of minerals. Fairy rings are more likely to be found on cultivated land such as lawns and golf courses, because in order to spread uniformly they require a relatively homogeneous medium from the tip do not become any longer during hyphal extension, however hyphae in this region may develop into aerial reproductive structures. Older hyphae at some distance from the tip may become completely empty of cytoplasm.
Cell counts and turbidometric measurements are not appropriate to estimate growth of fungi; however total mycelial mass can be measured and its change plotted against time. A fungal growth cycle shows roughly the same phases of growth as described above for bacteria.
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