STUDIES ON THE DEVELOPMENT OF RHIZOMORPH OF ARMILLARIA MELLEA
蜜环菌索发育的研究

The development and structural differntiation of rhizomorph of Armil- laria mellea were studied systematically with light and electron microscope.The meristema- tic region was located at the apical center of rhizomorph,from which primary structure was derived.The primary structure included the young epiderm,cortex,and primary medulla which was composed of some large elliptic hyphae.Synchronous nuclear division usually took place in the primary medullary cell and formed cells with abundant nuclei.Then the narrow hyphae will be generated with one or several nuclei by streching out of the wall of parent cells. Both thin wall and thick wall of narrow hyphae could be produced in one parent cell.The wall of parent cells will break down to form a hollow center in mature rhizomorph,which was called medulla.Both of narrow hyphae distributed in it.The structure of mature rhi- zomorph and the branching process of rhizomorph were observed.New brbnches were derived from the cortical cells of parent rhizomorph.The cortical cells divided in cross direction to form the primordia of branch first,and then they protruded though the epiderm of parent rhi- zomorph to form a new apex of young rhizomorph.The infection ways of A.mellea in diffe- rent hosts were also discussed in this paper.