title: [Activity of nucleoli in cells of different type in early embryogenesis of Pinus sylvestris L].
abstract: Early embryogeny of Pinus silvestris L. is characterized by suspensory system formation consisting of several cell generation formed by apical cell fissions. A comparative analysis was made of quantitative characteristics of nucleoli of two functionally different cell types: the apical cells of meristematic nature, and specialized cells resulting from mitotic cycle of suspensory cells. We determined the number of nucleoli and their diameters, the character of distribution and variability of these indices for cells of different types. It has been shown that in the cell cycle, changes of qualitative parameters of nucleoli in cells of secondary suspensors are most dynamic. A conclusion is made that in P. sylvestris L. early embryogeny differences in nucleolar activity and mechanisms of its regulation occur in suspensory cells of different generations. On the basis of differences in nucleolar activity observed in suspensory cells of the same generation, certain mechanisms of competition between cleavage polyembryos of this species are suggested.
authors.affiliation: Research Institute of Forest Genetics and Breeding, Voronezh State University.
authors.forename: V S
authors.initials: VS
authors.lastname: Svintsova
authors.forename: A K
authors.initials: AK
authors.lastname: Butorina
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D002466:Cell Nucleolus / Q000648:ultrastructure*; D008854:Microscopy, Electron; D028223:Pinus / Q000196:embryology* / Q000648:ultrastructure; D041605:Pinus sylvestris; D012639:Seeds / Q000648:ultrastructure