After a few days in culture, cell division was observed and small spherical cell colonies forming clusters begun to appear (Fig. 1A).
In contrast, in mature cuttings, although some cell divisions were observed, no primordia were formed during the time period of the experiment.
The ability of fast neutron and UV-B radiation to exert genotoxic action on PMCs DNA in 1st and 2nd meiotic divisions was observed in spite of long period of recovery (Table 1) and–(8)).
No significant difference in the number of basal cortical mitotic divisions was observed at E12.5 between control and Sall1 −/− mice (n=4, P=0.2; data not shown), which suggests that early cortical IPCs are not altered in the absence of Sall1.
Indeed, the A. thaliana stem cells divide much less frequently than the surrounding cells [4, 19], and most endodermis cortical initial divisions are observed a few days after germination, whereas the cortical layer, an outer cell layer, is established 1 week later [2, 73].
Interestingly, such a daily regulation of cell divisions is observed in certain types of tissues including tongue epithelium, intestinal epithelium, and skin [12] [14], implying that the temporal regulation of progenitor divisions seems to be important for animals living under day/night cycles.
Furthermore, in this strain background a high degree of polar divisions was observed, leading to consecutive minicelling.
Circadian gated cell divisions are observed in nearly all organisms.
Finally, as expected the vast majority of cell divisions was observed in the cambium.
