【摘要】 本研究以移植细胞核的方法,探讨黑眶蟾蜍胚胎发育过程中胚胎层细胞核的早期分化。以囊胚期动物半球细胞核的移植为对照:当原肠早期囊胚腔底内胚层细胞核,与原肠晚期原肠腔底内胚层细胞核,移入去核的未受精卵后;移核卵发育到各期胚胎的百分率,与对照组基本相似。这表明以上两个时期的内胚层细胞核与囊胚期动物半球的细胞核一样,是尚未分化的,它们仍有发育的全能性。在以神经板期内胚层细胞核为供体的移植过程中,虽有一半以上的全囊胚发育到原肠期,但是胚胎进一步发育的能力受到较明显的阻抑。由此得出结论:黑眶蟾蜍内胚层细胞核从神经期开始,出现了较明显的分化,使卵子发育到游泳蝌蚪的能力显著下降。这结果表明黑眶蟾蜍内胚层细胞核的功能变化迟于豹蛙,而与非洲爪蟾相似。更多还原

【Abstract】 In the present paper the early differentiation of the endodermal nuclei of Bufo melanostictus during development were studied by nuclear transplantation. The trans-plantation of blastula nuclei which were taken from the animal hemisphere into the enucleated eggs was used as control. When the endodermalnuclei which were taken from the floor of blastocoele in early gastrula and of archenteron lumen in late gas-trula were transplanted to enucleated eggs, the percentage of the developmental stages of recipient eggs were about the same as that of the control. The result shows that the endodermal nuclei in these two developmental stages as well as the blastula nuclei remained undifferentiated. They still possess the capacity of promoting normal development when transplanted to enucleated eggs. But when the endodermal nuclei of neural-plate cells were transplanted into enucleated eggs, only half of the blastulae underwent gastrulation and tten the development was arrested. The result shows that the endodermal nuclei started to differentiate at the beginning of neurula stage in Bufo Melanostictus.By comparing the above results with those of Rana pipiens and Xenopus laevis,it shows that the endodermal nuclei differentiation of Bufo melanostictus is similar to that of Xenopus,更多还原