Abstract: The effects of substrate composition and temperature on mycelial growth and sclerotium production in Grifola umbellate (Pers.) Pilát were investigated in the present study. The induction of sclerotia of G. umbellate was affected greatly by the type of medium, as well as the type of carbon source. Malt-extract agar was able to induce the production of sclerotia. The production of sclerotia was also observed when the carbon source in the GPC agar medium (glucose 20 g/L, peptone 6 g/L, corn steep liquor 10 g/L, and agar 15 g/L) was replaced with glycerol or mannitol. Altering the composition of the GPC medium with milk powder, thiamine hydrochloride, extract of Armillaria mellea, active clay, diatomite, kaolin, or arginine did not induce the production of sclerotia. A temperature range of 18–25 °C was suitable for both mycelial growth and sclerotium formation. Glycerol significantly induced slerotium formation on nutrient supplemented with sawdust substrates in bottle culture. 24S-Polyporusterone A and polyporusterone B were assayed in samples of natural and cultured sclerotia. Both natural and cultured sclerotia contained 24S-polyporusterone A and polyporusterone B.(Author for correspondence. Tel: +86 (0)10 6282 9619; Fax: +86 (0)10 6289 5120; E-mail: sxguo2006@yahoo.com.cn)

Key words: carbon sources, glycerol, Grifola umbellate, mannitol, polyporusterone, sclerotia.