THE RELATIONSHIP BETWEEN ARMILLARIELLA MELLEA AND GRIFOLA UMBELLATA

Armillariella mellea invaded sclerotia of Grifola umbellata by its rhizomorphs, which activated immunocompetence of G. umbellata against other invasion. The xyloid cells of hyphae of G. umbellata formed the wall of dividing cavity which resembled epidermal tissue of sclerotia. The rhizomorph of A. mellea and a part of hyphae of G. umbellata were surroundtd by dividing cavity. The hyphae of G. umbellata were digested by A. mellea in the dividing cavity. Some thin-walled hyphae of G. umbtllata in the wall of dividing cavity invaded the cortical or infection bands of A. mellea to obtain nutrition. Hyphae of G. umbellata could still get nutrition by adhering on the surface of A. mellea cells to absorb secondary metabolite of A. mellea. G. umbellata can germinate new one. When the hyphae of G. umbellata in the dividing cavity were digested completely. The hyphae of A. mellea disintegrated and were absorbed by G. umbellata. The dividing cavity became an empty cavity. The relation between A. mellea and G. umbellata can be regarded as a mutualistic symbiosis in broad sense.