Zs. P. Komáromy szerk.: Studia Botanica Hungarica 15. 1981 (Budapest, 1981)

Bohus, Gábor: Some results of systematical and ecological research on Agaricales, VIII

S T U D I A XV. BOTANICA HUNGARICA (Antea: Fragmenta Botanica) 1981 p. 25-30 Some results of systematical and ecological research on Agaricales, VIII. By G. BOHUS (Received July 15, 1980) Abstract: Experimental investigations were carried out to study the. effect of carbon dioxide on Agaricus macroBporoides. It can be Btated that the mycelium growth, the fruit body formation and the development of this fungus is undisturbed even in a rather high concentration of CO2. The dispersion in the fructification of the mycelium thalli was also examined. The C0

2 concentration of the air and fruit body formation of Agaricus macrosporoidea On the baais of literature data and their own extensive research material, HINTIKKA & KORHONEN (1970) made the following statements: "Carbon dioxide seems to play a considerable regulatory role in the ecology of the higher basidiomycetes

... However, the inhibition of growth seems to appear only at low oxygen tensions and evidently the inhibitory effect of carbon dioxide sets in earlier, at least for Utterdecomposing species... When a fungus attacks wood, its hyphae must grow in veaaela and small cavities where the ventilation is much more restricted than it is in the leaves of the litter layer and CO2 may accumulate. The carbon dioxide tolerance of a fungus probably reflects UB ability to grow in such atmospheres, which consequently have a selective effect of carbon dioxide on the fungal growth has been known about for 40 years... One of the factors regarded as responsible for this effect is the heterotrophic assimilation of carbon dioxide... The formative effects of carbon dioxide on mycelium morphology have been also studied... The formation of basidiocarps of Schlzophyllum commune - and of some other fungi (Agaricus bisporus

, Flammulina velutlpes, Pleurotus ostreatus) - is a process very sensitive to excessive amounts of carbon dioxide... Ecologically, it is easy to understand the advantages of the changes in mycelium morphology brought about by carbon dioxide." Our experimental investigations were carried out with such an Agaricus species about which it turned out during the experiments that its fruit body formation is much less sensitive to excessive amount of carbon dioxide than that of the cultivated mushroom, Agaricus bisporus, at which a little as 0.1-0.18% CO2 retards the formation of the fruit bodies and their number (TSCHIERPE & SINDEN 1964). For the cultivation of Agaricus macrosporoides in laboratory such conditions were created (BOHUS 1978) that it can be considered as more or less closed system. About two thirds of glass vessels were filled with culture medium and one third of the vessels was air-space. The glass vessels were covered with Petridishes, ventilation took place through paper wadding (see the photo). Fruit bodies were formed on the surface of culture medium as it has been regarded in several hundreds of cases. In the course of their growth they either lifted up the cover or if it was tight they developed even while closed, only they became bent, filling up almost the