SPORULATION IN COPRINUS-CINEREUS - USE OF AN INVITRO ASSAY TO ESTABLISH THE MAJOR LANDMARKS IN DIFFERENTIATION

Basidia of Coprinus cinereus continue differentiation when explanted to water agar. Inclusion of various compounds in the explantation medium can inhibit basidium differentiation. Growth is not inhibited but vegetative hyphal tips grow from regions of the basidium expected to produce sterigmata. Ammonium, glutamine and alkali metal salts were effective in tissues exposed at any time after meiotic division I; whereas ionophores, cAMP and wall synthesis inhibitors were effective only if applied during meiosis. This implies that the cell is prepared for sporulation during meiosis so that by the end of the nuclear division sporulation can proceed despite the presence of some metabolic inhibitors. On the other hand, the sporulation process must involve essential components that are sensitive to excess metal ions, ammonium and glutamine, but which do not contribute to the nuclear division. Since both types of inhibitor cause hyphae to grow from positions corresponding to sterigmata, these sites must be specified early in differentiation, and in a way which survives treatment with many different inhibitors. © 1990, British Mycological Society. All rights reserved.