Study On The Life Cycle Of Important Taxa In Dictyosteliaceae

The dictyostelid cellular slime molds are a special biocoenosis which are difficult to be observed by naked eyes for their very small, transitory presence sorocarps in the nature. The dictyostelids maily fed on the bacteria where lived in the forest soil, litter, decayed substratum and rot animal dug. Unlike the large-fungi which are easy to be found,it is very difficult to get the sorocarps from the wild, so in order to obtain more dictyostelids, need us to extensively collect the substratum, meanwhile isolate and culture the samples as soon as possible. More and more biololgists, cytologists, geneticists pay attention to the special organism, because their unique macroscopic characteristics and simple life cycle.At present, the most studies are relation to the taxonomic and the molecular biology, but no more than one person systematically studied a species, from taxonomy, the whole process of the life cycle and the molecular biology, especially about the whole process of the life cycle. Now in China,39 dictyostelid species were found, including 31 species of Dictyostelium,7 species of Polysphondylium and 1 species of Acytostelium.Therefore, selecting 11 species of dictyostelids, the whole process of the life cycle of them were observed and recorded by the microtechnique on the bi-concavity slide and the water agar, recorded the characteristics and time of each phage in the life cycle. Including Dictyostelium homostipes, Dictyostelium recurvusbasicus, Dictyostelium tenuistipes, Dictyostelium globosisporum;Dictyostelium antarcticum, Polysphondylium tenuissimun;Polysphondylium candidum;Dictyostelium sphaero-cephalum, Dictyostelium implicatum, Dictyostelium magnum, Dictyostelium tenue.The life cycle of some species in Dictyosteliaceae need 2-3d.Spores start germinating after inoculating 9-13h, the time of germinating in Dictyostelium homostipes and Dictyostelium magnum is 20h; From germination to aggregation needs 8-12h,but Dictyostelium tenuistipes only needs 4h; From aggregation to pseudoplasmodia needs 7-15h,the time of Dictyostelium recurvusbasicus reaches to 20h;Because pseudoplasmodia migration of different species need different time, the time of forming sorogen is different, less than 7h for Dictyostelium antarcticum,more than 24h for Dictyostelium implicatum; From sorogen to maturation needs 7-15h, however the time of maturation reach to more than 16h in some species of Polysphondylium. This is the first report of the characteristics and time of each phage in the life cycle of the dictyostelid cellular slime molds.