Gibberellin-like Substances in the Sporophores ofAgaricus bisporus(Lange) Imbach

Abstract

Sporophores of cultivated Agaricus bisporus (Lange) Imbach, were shown to contain a gibberellin-like substance active in the dwarf maize (d-5), «-amylase and other bioassays. Ethyl-acetate extraction followed by paper, column, and thin-layer chromatography revealed the presence of one major active substance. Ficin hydrolysis of dried sporophore powder, after the complete removal of free substances, released more gibberellin-like substances, one of which appeared identical to the free compound. The free substance was predominantly in the lamellae and residual pileus tissue. The major active substance released by ficin occurred mostly in the lamellae but also in substantial equal amounts in both stipes and pilei. No activity was found in extracts of dikaryotic vegetative mycelium on malt agar. The level of activity in extracts from sporophores stored at — 20 °C fell sharply after 7 d, and then remained constant over a period of 6 weeks. The content of gibberellin-like substances in young and old whole sporophores showed wide variation between experiments. In most cases young 2-d tissue had higher levels than old, 11-d tissue on a fresh weight basis. Purified sporophore extracts and authentic gibberellins had no stimulating effect on growth of sporophores or of cultured vegetative mycelium. The inhibitors of diterpene biosynthesis, CCC, and AMO-1618 induced a small increase in mycelial growth rate. Ethyl acetate extraction of horse-straw compost prior to inoculation with Agaricus bisporus showed the presence of gibberellin-like activity in significant amounts.