Progenitor cells of the human erythroid and granulocytic cell lineages are characterized by the presence of several nucleoli. One of these nucleoli is larger and possesses more fibrillar centres than others. Such nucleolus is apparently dominant in respect of both size and main nucleolar function such as nucleolar-ribosomal RNA transcription. Such nucleolus is also visible in specimens using conventional visualization procedures, in contrast to smaller nucleoli. In the terminal differentiation nucleated stages of the erythroid and granulocytic development, dominant nucleoli apparently disappeared, since these cells mostly contained very small nucleoli of a similar size with one fibrillar centre. Thus, the easily visible dominant nucleoli appear to be useful markers of the progenitor cell state, such as proliferation, and differentiation potential.
Photosynthetic and growth characteristics of Mosla chinensis and M. scabra were compared at three irradiances similar to shaded forest understory, forest edge, and open land. At 25 % full ambient irradiance, M. chinensis and M. scabra had similar photosynthetic characteristics, but saturation irradiance, compensation irradiance, and apparent quantum yield of M. chinensis were higher than those of M. scabra at full ambient irradiance and 70 % full ambient irradiance. At the same irradiance treatment, specific leaf area and leaf area ratio of M. chinensis were lower than those of M. scabra. Photon-saturated photosynthetic rate and water use efficiency of M. chinensis, however, were not significantly higher than those of M. scabra, and the leaf area and total biomass were lower than those of M. scabra. As a sun-acclimated plant, the not enough high photosynthetic capacity and lower biomass accumulation may cause that M. chinensis has weak capability to extend its population and hence be concomitant in the community. and J.-X. Liao ... [et al.].