The Mitotic Activity of Embryonic Tissues During Gastrulation and Nevrulation in Triturus Vulgaris L. Embryos

ABSTRACT

The mitotic indices were measured on serial transverse section in ectoderm and mesoderm of different dorsoventral zones of the T. vulgaris embryos from the late blastula stage till the end of neurulation. The mitotic indices were shown to fall simultaneously in mesoderm of all zones during the transition from middle to late gastrula and in ectoderm of all zones at the late gastrula stage and rise synchronously in dorsal and lateral ectoderm and lateral mesoderm during neurulation. In the most cases the rise of mitotic indices coincided with the periods of active morphogenetic movements of the given area and fall of mitotic indices with the cessation of these movements.

Keywords:

• gastrulation
• ectoderm
• mitotic index
• mesoderm
• Triturus