Myxomycetes means fungus with mucus or fungus with slimy nature . They are also known as slime molds . Molds mean fungus made up of hyphae . So slime molds mean fungus made up of hyphae and slimy in nature . They share characters of both animals and fungi . They have holozoic nutrition like animals and bear fruiting stage like fungus . Myxomycetes are called true slime molds . The plant body is a free-living true plasmodium . Plasmodium is multinucleated , irregularly shaped slimy mass of protoplasm . Plasmodium may be of three types -
1. Protoplasmodium-It is simple and primitive type . At fruiting time it gets converted into a single sporangium .
2. Aphanoplasmodium- It shows network of protoplasmic strings .
3. Phaneroplasmodium- It is fan shaped and shows vein like structures .
Slime molds are found on moist decaying wood , dung , soil etc . Physarales is one of the order under myxomycetes .
Physarum
Class - Myxomycetes
Order - Physarales
Family - Physaraceae
Genus - Physarum
They are found all over the world . P. polycephalum is regarded as good study material for genetic , physiological and biochemical studies . Plant body is phanerolasmodium type ( fan shaped ) . Under unfavourable conditions plasmodia are cleaved into spherules which are then packed as thick walled sclerotia . Under favourable conditions fruiting bodies called sporangia are produced . Sporangia are covered by non-cellular slimy layer called peridium . Capillitium are sterile threads in sporangia for dispersal of spores . Spores germinate to form myxamoebae or swarm cells . These motile cells function as gametes and fuse to form zygote which ultimately form plasmodium .
Physarum
Class - Myxomycetes
Order - Physarales
Family - Physaraceae
Genus - Physarum
They are found all over the world . P. polycephalum is regarded as good study material for genetic , physiological and biochemical studies . Plant body is phanerolasmodium type ( fan shaped ) . Under unfavourable conditions plasmodia are cleaved into spherules which are then packed as thick walled sclerotia . Under favourable conditions fruiting bodies called sporangia are produced . Sporangia are covered by non-cellular slimy layer called peridium . Capillitium are sterile threads in sporangia for dispersal of spores . Spores germinate to form myxamoebae or swarm cells . These motile cells function as gametes and fuse to form zygote which ultimately form plasmodium .