A t first sight, light might have no significance for fungi, because fungi are carbon-heterotrophic. The vegetative mycelium including the rhizomorphs of Armillaria species and the strands of house-rot fungi grow in nature in the absence of light, namely in the soil and within trees or timber (substrate mycelium), or in buildings hidden behind wall coverings and in the subfloor area. The growth within the substrate might be rather due to hygro-, hydro-, geo- and chemotropisms than to negative phototropism (Muller and Loeffler 1992). Surface and aerial mycelia also grow in the dark like during the routine fungal culturing in the laboratory or at low light intensity like in the indoor polypores and Serpula lacrymans in buildings. A requirement for light occurs particularly with respect to the initiation of reproduction and the ripening of the fruit bodies. Light is the signal that the mycelium has reached the (irradiated) surface, where there the spores can be produced in an
All about Ecology