Microscopic Tracing Study On Cell Fate During Early Embryonic Development In Planocera Riticulata

Planarian is the typical representative of the flatworms, with three germ layers andbilaterally symmetrical mechanism. As an early branching of bilateral animals, planariansappeared the mesoderm, central nervous and sensitive eyes and other important structures. Asa result of mesoderm, planarians have well-developed musculature, greatly enhancing theexercise capacity; nervous central system, strengthen the adaptability of them in the complexenvironment to draw on the advantages and avoid disadvantages. The structure not onlymakes them change their life styles from floating or fixed to crawl freely, but provides thebasis for animal landing in the evolutionary history, which belongs to an important new stageof the evolution. Therefore, planarian is good material for the research on the origins of life andevolution, the evolutionary history of mesoderm formation and evolution of the neurological. Sometaxa of planarians have spiral cleavage in early cleavage.,which is very similar to the higheranimals.Therefore, research of the embryo development on the planarian embryos, can alsocontributes to the study of many scientific problems in the origin and evolutions of piral cleavage.In this study the use of artificial insemination on planocera riticulata can produce eggs outside ofthe plastic membrane. In laboratory conditions to explore related culture conditions, the normalcleavage and develop into larvae, thereby providing experimental materials for planocera riticulataembryogenesis studies. and obtain early cleavage embryos in different periods. Then usingmicroinjection techniques, in different period of embryo on embryo cell microinjection and labeling,recording injection conditions (including the injection and dosages, periods of the receptor cell,embryonic development after injection such as time, survival rate and distortion rate). Using thismethod is simple, rapid, and has no toxic effects on experimental materials for the process of tissuedifferentiation and organogenesis during embryonic development of different periods. In order tobetter observation, this paper adopts DiI fluorescent markers, through the ordinary light microscopeand fluorescence observation, successful obtain comparatively accurate embryonic developmentpicture.The experimental results show that:(1) Artificial insemination to the planocera riticulata andembryo culture conditions were improved so as to get no outer rubber film eggs.(2) After theplanocera riticulata were fluorescent labed by DiI,labeling results of living donor embryos werepositive in100%, with red fluorescence.(3) In the two-cell stage embryos may have potential differentiation.(4) Developmental asynchrony appears in embryonic cells at4-cell stage, which to acertain extent, illustrate the potential cellular differentiation.Application of embryo microinjection technique, fluorescence labeling technique on the exposedembryos for research, can be more finely to observe morphological changes in early developmentalprocesses of multiple intestinal of planarian, Which has important reference value for furtherdevelopment of developmental research in multiple intestinal planarian embryos and studies on themolecular mechanism of cell fate.