Kravets E. Role of the cell selection in the mechanisms of the maintenance of tissue homeostasis in plants

The object of thesis is a tissue homeostasis; the goal is to elucidate the mechanisms of cell selection and its role in maintaining of tissue homeostasis in plants. We used morphometric, anatomical, cytological, cytogenetic, physiological, radiometric, genetic methods and standard methods of statistical analysis. For the first time the concept of cell selection and its role in maintaining tissue homeostasis in plants in the environment that cause genotoxic effects was developed. Using the wide experimental material the activities are demonstrated for the first time that by a cell selection in plants damaged cells are eliminated and mutagenesis is bounded, proliferation and dedifferentiation of cells is stimulated, the number of cell populations of both somatic and generative tissue is regulated, non-specific adaptation is formed. First it is shown the recovery of meristem is based on a combination of symplastic and intrusive growth of new cell rows. Promotion of inactivated cells to the elongation zone can be blocked through their replacement by new cells inside polycytes that limit the involvement of aberrant cells in the construction of specialized tissues of the root. For the first time found that the efficiency of the cell selection is indicated by the dynamics of the genetic load of elimination - a steady decline in level of aberration in early ontogeny of seedlings, reducing the level of pathology till the tetrad stage or single microspores and pollen quality improvement during the end of haplophase. The negative correlation between the levels of pathology at different stages of embryo selection confirms this trend. For the first time shown that cytomixis and haplontic selection regulate fertility of male germline. There is stated that the physiological nature of cytomixis implies switching of trophyc relations of the microsporocytes from tapetum cells to the surrounding cells and is accompanied by hypersecretion of callose. Overall, developed the concept of cell selection in plants is an important contribution to the development of the modern theory of cell selection and representations of tissue homeostasis. The practical significance of the results is very important for the development of measures to conserve species diversity and genetic stability of plant species under increasing anthropogenic impact on the environment. It is recommended testing of microsporangium condition, fluctuating asymmetry and leaf plate for monitoring of plant populations. To study different types of cell death should be used anther as a convenient and informative model system. The results of cross- adaptation to UV-radiation can be recommended for the development of measures to optimize the conditions for cultivation of plants with low resistance in artificial agrocenoses. In natural and cultivated plantations in the Chernobyl exclusion zone to reduce mutagenesis encouraged the cultivation of diploid mainly autogamous species with sexual reproduction. The studies are recommended for use in the learning process while preparing students for specialized "Cell biology and Bioengineering " NSC "Institute of Biology" Taras Shevchenko Kyiv National University