[Genesis of cells of apical meristems and realization of gametophytic apomixis in flowering plants].

Based on our own and literature data on peculiarities of caryotypical variability, we concluded that gametophytic apomixis is naturally accompanied with phenomena of poly-, aneu-, and mixoploidy and that apomicts have genome instability manifesting at the level of meristematic somatic cells. In this connection, a hypothesis is substantiated that realization of this mode of seed reproduction in flowering plants is caused by modification of systems of cell cycle control, following after acts of hybridogenesis and/or polyploidization. It is concluded that instability of the seed reproduction system by gametophytic apomixis manifests not only at the stage of choice of a seed reproduction pathway (apomeiosis-euspory; apozygosis-zygosis) but also in all the cycles of reproduction of the cells of a germ line in plant ontogenesis.