Ultrastructural Studies on the Cultivation Processes and Growth and Development of the Cultivated Mushroom Agaricus Bisporus

Scanning electron microscopy (SEM) , transmission electron microscopy and light microscopy have been used to study various processes in the cultivation of the edible mushroom Agaricus bisporus . Mushrooms are cultured on composted wheat straw. The microbial degradation processes during composting have been visualised by TEM and SEM and correlated with microbiological studies . Various modes of attack by the microorganisms on the plant cell walls can be seen. Most rapid degradation occurred on the cuticle and phloem and spread to other cell types. Microbial attack was found to be nonuniform between tissue types and individual cells. The mycelium of Agaricus bisporus colonised the compost straw surface and the lumen of straw cells, and also degraded microbial cells therein. The cellular organisation and ultrastructure of the rhizomorphs and of the developing stipe and gill tissue were examined. The development and branching patterns of the hyphae generating the sub-hymenium and hymenium l ayer s of the gill tissue were examined . Light and electron microscope autoradiography were used to locate the site of synthesis of cell wall chitin and to demonstrate evidence for cell division in the upper stipe region