Nuclear cell cycle analysis via flow cytometer was assayed on explants from different node positions, plant ages, green house pot-grown and in vitro grown plantlets. It is found that patterns of nuclear cell cycle phases in the leaf explants from different sources vary. Plant cultural ages, leaf sizes as well as leaf position along the shoot have some effects on percents of G0/G1, S and G2/M nuclei distributions. In general, young explants have a relative lower percent of G0/G1 and relative higher percents of S and G2 nuclei than the old explants. There was also a tendency of increase percent of G0/G1 nuclei as the leaf explants sampled from the node positions downward the shoot tip. In average, plant age of 6 to 8 week-old had a relative lower percent of G0/G1 nuclei than the post 12 week-old materials. On the contrary, the total percent of S and G2 nuclei was generally higher in the former than the latter. This phenomenon is especially distinct in leaf explants from the upper parts of shoots than from the lower parts. Small (young) leaves in comparison with the large(old) leaves from the same nodes of the upper portion shoots show the same tendency. Association between nuclear cell phase distribution and plant regeneration ability was also noted. Negative correlation(r = -0.9934) between the percent of G0/G1 nuclei distribution in expants and regeneration frequency was found, while positive correlation (r = 0.9931) between percent of S together with G2 nuclei and regeneration frequency was exhibited. Explants with a relatively higher in total percent is S and G2 nuclei generally have a more stable and higher regeneration ability in this study.