Abstract:Explants were obtained by excising cortical tissue from stems of precultured Nicotiana tabacurn in 3×10 mm strips, containing 3–4 cell layers, and thickness of which was 30–40 μm. Using modified microculture method, a successful experimental system that could be used for positioned sequential observation in vivo was established. Through continued observation in vivo and using microspectrophotometer technique, we found that, after 24 h culture of explants, nuclei in tabacco epidermal cells enlarged and their DNA contents increased, the density within the nuclei and cytoplasm also increased, cytoplasm and organelles in them moved faster. Thraugh these changes the cell dedifferentiation was completed, epidermal cells returned to interphase, ready for mitosis.