Studies On Microstructure And Development Regularity In Different Life Cycle Stage Of Several Myxomycetes

As research material in this experiment, the plasmodial slime molds, Physarum melleum, Physarum globuliferum belong to Physarales, Physaraceae, Physarum; and Diderma effusum belongs to Physarales, Didymiaceae, Diderma. The life cycle of three species are endospore general type. The myxomycetes had become firmly establishd as an important experimental material in cell biology for their unique biological characteristics.Futher studies on life cycle, included microstructure and development regularity in differentlife cycle stage of several myxomycetes by use of sterile feeding culture, microscopic photography technology and the tissue slice method in this experiment. The three typical veins at same situation in plasmodium of P. melleum, P. globuliferum and D. effusum were selected, observed on cytoplasmic streaming for368s, compared the time forward and backward, provided the quantitative datas of shuttle streaming; measured the velocity of vesicles moving in cytoplasmic flow by use of micrometer, provided new method to estimate the velocity of cytoplasmic flow. Multifactor analysis was used to screen the fructification and sclerotium development condition, included the state of plasmodium and mature degree, for the study of ontogeny, ensure species continuity, and ecology research of myxomycetes. Comparsion on the different display of microstructure during sporulation with safranin-fast green, iron alum-hematoxylin and safranin-cresyl violet-orange dyeing for the study the changes during the fructification and sclerotium development, further get some information about sporophores as traditionally classified on, for taxonomy research of myxomycetes.The results showed:The swarm cell of P. melleum was tadpoles with a small head and a long tail, which swimming rapidly by way of rotation and turnover. The swarm cell of P. globuliferum was pupa-shape bearing one flagellum located at the pointed anterior end, which swimming slowly by way of rotation and turnover. The more myxamoeba of P. globuliferum and the less myxamoebae of P. melleum under optical microscope, crawled by way of pseudopodia. The myxamoeba pseudopodia of P. melleum with translucent ectoplasm, obtuse-round leading edge, crawled faster than P. globuliferum without translucent ectoplasm.The plasmodia of three myxomycetes were generally regarded as essentially simlar in form, like typical phaneroplasmodium. The plasmodium of P. globulferum consists of more secondary branches(which donot connect to others).The plasmodium growth of P. melleum rely on mainly merging others.Each vein of plasmodium consists of fluid components that exhibits rhythmic, reversible streaming, and colloidal compositions that flow with cytoplasmic streaming finally. The time of streaming forward is longer than backward in368s. Extremely significant difference, P<0.01, between the time of forward and backward; No different between the time forward or backward of two by two in three plasmodium, P>0.05. There are9flow patterns in shuttle streaming of P.melleum in368s,11patterns in P. globuliferum, for more branches veins in pladmodium, and7patterns in D.effusum that less branches in. The moving vesicles in shuttle streaming of P. melleum, was negatively relationship between the moving velocity with it’s diameter, indicates the velocity of cytoplasmic streaming by use of micrometer. The pigment granules flowed with cytoplasmic streaming. There was positive relationship between the protoplasmic flow and material transportation.Multifactor analysis indicated that it was necessary for mature plasmodium was under condition of hunger, wet,20-25℃to induce sporephores. Scattering light was rather necessary for the sporephores morphological construction of P. melleum than maturity, Wet and drying alternation was necessary for the formation of of sporephores:wet was necessary for morphological formation of sporephores, and drying was necessary for maturity. The plasmodium of D.effusum which was cultured for a long time, lose it’s ability to sporulation. The morphological change for three species, five stages in the pattern of sporulation were recognized:the advancing front aggregation and veins merging,hemisphere round group heap,papillas; ball round (cushion)sporangium, mature sporangium.The fructification of P.melleum and P.globuliferum were sporangium, the fructification of D.effusum was sporangium to plasmodiocarp. Six stages in the structure of sporangium of P.melleum and P.globuliferum, the original sporangium, peridium appearing, ball sporangium, plasmodium cleavage, primary spore, mature spore. The best tissue slice dyeing for sporulation was safranin-fast green, the subculture plasmodium (The plasmodium just climbed down from old agar block)of P.melleum was better maerials to study the structure changes in sporulation.The complete, thick fan-like plasmodium under wet, dark, hunger condition was necessary for the sclerotium development of P.melleum. The requirements on the temperature range of sclerotium development was over a wide range (9-25℃). The plasmodium of P.globuliferum and D.effusum cound not be induced to develop the sclerotium under same conditions. The sclerotium development conditions of myxomycete had a characteristic of species. The culture plasmodium (The plasmodium was fed for a period of time)of P.melleum was good material to screen the conditions of the sclerotium development. Five stages during the sclerotium development of P. melleum:the plasmodia shrink, the mass connection, the mass separation (initial yellow sclerotium), the orange sclerotium; the dark brown sclerotium. The plasmodia thick and shrink was a prerequisite for the sclerotial development. The yellow sclerotium were able to regenerate into viable plasmodia, while the orange sclerotium and dark brown sclerotium cound not. The plasmodia develop to the sclerotia:the cytoplasm thicken,the plasmodium cleavage, the original spherule,2-5connected spherules, the mature sclerotium. The subculture plasmodium of P.melleum was good material to study the structural changes during the sclerotium development of plasmodium. The best tissue slice dyeing for sclerotia development was safranin-cresyl violet-orange dyeing.