Scanning Electron Microscope Studies on Fruitbody Primordium Formation in Agaricus Bisporus

ABSTRACT

To obtain specimens suitable for viewing the early stages of development in Agaricus bisporus, we modified the Halbschalen test method. A plastic foam, impregnated with peat moss, enabled examination of the mycelium throughout its entire depth by scanning electron microscopy. Early in the developmental sequence, single hyphae with infrequent branches appeared. As development progressed, the hyphae were consolidated into strands by adhesive, mucilaginous substances. These substances formed electron-lucent sheets which were especially obvious after the mycelium was watered. The initial stage of primordium formation was marked by appearance of hyphae which were turgid and tended to curve sharply and branch frequently. These hyphae were found in both initial and later stages of primordium development. Primordia that continued to increase in size appeared to recruit hyphae and strands from surrounding mycelium.

Key Words:

• mushroom
• basidiocarp
• development
• mycelium
• primordium formation