Abstract
Cultural conditions that stimulate Agaricus blazei basidiospore germination were examined using four heterokaryotic strains. Spore germination rates on water agar medium were very low (below 0.5 %), and spores failed to germinate on potato-dextrose agar or glucose-malt-yeast agar media. Significantly higher spore germination was observed on agar medium containing hot water extracts of bark compost (BA medium), indicating that the extracts contain compounds that stimulate spore germination. The main materials that stimulate spore germination of A. blazei in the extracts are polar compounds of high molecular weight. Heat pre-treatment of spores at 30-50℃ was effective for increasing germination rates, particularly for 5-10 min at 50℃. Co-culturing with living mycelium of A. blazei stimulated spore germination. The optimum pH value of BA germination medium was 5, and the addition of oxalic and succinic acids stimulated spore germination. A combination of optimum conditions determined from individual experiments gave the highest values of germination rates, ranging from 3.1% to 4.8%.
