ORIGIN AND DEVELOPMENT OF CRYSTAL AND THICK-WALLED CELLS IN SCLEROTIA OF GRIFOLA UMBELLATA

Crystal cells of sclerotia of Grifola umbellata exist in the mildle or apex of hyphae,the cells usualy are large in volume and rich in protoplasm.A great deal of very small grains in protoplasm accumulated into the vacuole to form crystals.Mitochondria distributed in the outside of the vacuole.As the crystals devtloped to maturity in crystal cells,the cell wall was broken to release the crystals.Smalt crystals could accumulated into a large prismatic cry- stals in the sclerotia of G.umbellata.Thick-walled cells of sclerotia formed at the middle of hyphae and were separated by cross septa with adjacent cells of hyphae,the cell wall was thickened as its protoplasm contracted.The thick walled cells were separated from adjacent cells of hyphae when cell cavity became very narrow or completely blocked.The development of thick-walled cells of Grifola umbellata was similar to that of chlamydospores of other fungi, but they differed from chlamydospores in their size.