[High-priority research directions in genetics, and the breeding of the sugar beet (Beta vulgaris L.) in the 21st century].

High-priority research directions for the genetics and breeding of the sugar beet in the 21st century were developed with consideration of the available scientific achievements of domestic and foreign scholars. These directions unite the classical and molecular approaches to solving the problems of increasing the effectiveness of sugar beet breeding carried out on a genetic basis, and they correspond to the contemporary level of scientific research. Seven such directions are proposed.

[Karelian birch (Betula pendula Roth. var. carelica Merkl.) as a model for studying genetic and epigenetic variation related to the formation of patterned wood].

The results of long-term pioneering studies on in vitro micropropagation of Karelian birch patterned forms and simultaneous cytological analysis of plants multiplied using different periods of in vitro culturing are published for the first time. The patterned wood character has been shown to be correlated with the degree of mixoploidy of its somatic tissue, which is higher in the plants obtained from callus cultures during the first years of culturing. Subsequent intracellular selection leads to a decrease in mixoploidy and, hence, in a later expression and lower expressivity of the patterned wood character in regenerant plants. It is also known that extreme growth conditions stimulate the formation of patterned wood. Thus, Karelian birch may serve as a model object for studying the forms of variability (both genetic and epigenetic) that result in patterned wood. The genetic variability is expressed in the variation of the degree of mixoploidy of somatic tissue as a result of various mitotic aberrations. The epigenetic variability is not related to changes in the DNA structure; it is caused by different phenotypic effects of genes located in cells with different ploidy/aneuploidy levels, the ratio between which varies depending on the environmental conditions. The expression of genes, in particular, rRNA genes, is affected by extreme conditions. The appearance of a residual nucleolus at the mitotic metaphase-telophase stages is a cytological expression of this phenomenon.

[Molecular genetic investigation of sugar beet (Beta vulgaris L.)].

Molecular genetic studies of sugar beet (Beta vulgaris L.) are reviewed as a basis for the development of genomics of this species. The methods used to study structural and functional genomics are considered. The results and their application to increase the efficiency of sugar beet breeding are discussed.

[The rhythms of daily mitotic activity in Vigna radiata (L.) R. Wilczek].

The daily mitotic activity (MA) in Vigna radiata (L.) R. Wilczek. has been studied using local cultivar for Vietnam No I 176. It has been shown that the curve of mitotic activity has five peaks. Maximum mitotic index (MI) was observed at 04:00 (5.93 %) and the other peaks were at 02:00 (5.58 %), 08:00 (4.70 %), 12:00 (4.60 %) and at 22:00 (4.60 %). If we took into account that duration of the mitotic cycle in Vigna radiata makes up ten hours, we can propose that there are two peaks of MA within each cycle. It may be due to the presence of two meristematic cell subpopulations which enter mitosis at different time and have nearly equal duration of the cell cycle.

[Cytogenetic monitoring of the Usmansky and Hrenovskoy autochtonic pine stands].

The data on the cytogenetic monitoring of the Usmansky and Khrenovskoy autochthonic pine stands (Voronezh Region) allow their status to be rated satisfactory. The indices of the mitotic and nucleolar activity as well as of abnormal mitosis were within the normal variation range for Scotch pine. However, the occurrence of micronuclei (less than 1%) points to pathological processes starting in the stands, which necessitates urgent measures for the conservation of the Usmansky and Khrenovskoy Forests as valuable gene sources.

[Cytogenetic responses of birch to stress factors].

The following range of changes in response to anthropogenic stress has been revealed in experimental birch seedlings relative to control: increased mitotic index, the range and frequency of abnormal mitoses, number of cells with persistent nucleoli, and number of cells in prophase. Cells with vacuolated cytoplasm were also observed. The mutagenic pressure on the organisms in the industrial areas of Voronezh demonstrated a trend to increase, which points to their high environmental pollution.

[Variability of the cytological parameters of Pinus sylvestris L. seeds from the unique Hrenovskoy pine forest].

Hrenovskoy pine forest is a unique island stand at the boundary of the species range of Scots pine Pinus sylvestris L. This object is of exceptional economic value, because it serves as a forest-seed base for the Voronezh oblast and some other regions of Russia; therefore, the stand and seed qualities have to be monitored constantly. The results of the first cytogenetic study of the seed progeny of P. sylvestris from the Morozov Grove, a high-quality stand in a reserved site within the Hrenovskoy pine forest, are reported. The studies have been performed in order to obtain a more correct assessment of seed quality based not only on their germination and energy of germination (traditionally used by forest breeders), but also on their genomic stability. The latter may be estimated by the stability of chromosome number in the somatic cells of seedlings and the regularity of mitotic divisions, because they also characterize the state of the generative system of parental forms and may serve as an integrated estimate of the stand development homeostasis. Therefore, the chromosome number, mitotic and nucleolar activities, and the number and spectrum of pathological mitoses (PMs) have been determined. Seedlings have been obtained from 240 seeds (collected from 12 trees) that resulted from free pollination. The cytological analysis of the rootlets of these seedlings has not detected any deviations from the chromosome number typical of the species P. sylvestris L. (2n = 24). However, considerable variation has been found in each family with respect to the mitotic index (MI) (from 4.2 +/- 0.36 to 8.1 +/- 0.39%) and the number of PMs (from 0.5 to 2.1%); micronuclei have also been found in each family (from 0.01 to 0.05%). In general, the phenotypic characteristics and the variation pattern of cytological parameters of the progeny of the trees studied in the Hrenovskoy pine forest, together with the high germination rate of seeds (90-98%), indicate that the current state of pines in the Hrenovskoy pine forest can be considered to be satisfactory. However, the presence of micronuclei in all variants and the decrease in MI in some individual plants (which was, on average, 6.1 +/- 0.03% in the sample studied, i.e., significantly lower than that of P. sylvestris from the Usmanskii pine forest (7.3 +/- 1.2%), where the conditions are optimal for this species) may serve as the bioindicators of the deterioration of both the state of trees themselves and the ecological conditions in the Hrenovskoy pine forest. Therefore, the population structure of this valuable autochtonic stand should be reproduced urgently.

[Investigation of daily mitotic activity of the birch, Betula pendula Roth]. / Izuchenie sutochnoi mitoticheskoi aktivnosti u berezy povisloi.

A study was made of the daily mitotic activity in the seedling root meristem of birch trees growing in an ecologically clear area--the biological station of Voronezh State University "Venevitinovo". The peak of mitotic activity was exposed at 9 a. m. (according to winter time). The rise of mitotic index was noted at 9 and 12 p. m. due to an increase in the share of cells being in the prophase stage, and to a high number of dividing cells with persistent nucleoli. A possibility of prolongation of the mitotic cycle time is supposed to be due to cell delay in prophase stage, which may be associated with anthropogenic and nature-climatic influences on the original trees themselves and on their seed progeny. This makes it possible to consider the investigated region as only conventionally clear, because of the availability of a high recreative pressure upon the trees.

[The function of leaf meristematic cells in Cotinus coggygria Scop]. / Funktsionirovanie kletok meristemy list'ev u skumpii kozhevennoi Cotinus coggygria Scop.

Proliferation of leaf meristem cells and formation of multicellular glands and unicellular hairs in Cotinus coggygria were studied under conditions of complex stressors exerting influence on this species when introduced and grown in such a big industrial city as Voronezh. Variability in the length of dividing meristematic cells (from 7.5 to 30.0 microns) was detected. The chromosome number was calculated, and the mean length of chromosomes (1 micron) was determined. The modal chromosome number in the leaf meristem cells in 2 n = 30. However, along with these cells, aneuploid (2.7%), uninucleate polypoid (1.9%), binuclear (10%), and polynuclear (3%) cells were also observed. The length of trichomes initials, formed in the epidermis, was near 40 microns. These have a large nucleus and may have, presumably, a polyploid nature. It is assumed that a heterogeneous meristematic cell population, at the expense of selection into such a population, is able to provide an optimum combination of cells with different level ploidy and aneuploidy for more effective realization of gene function in the extremal environment conditions.

[Genetic engineering of forest woody plants]. / Geneticheskaia inzheneriia lesnykh drevesnykh rastenii.

The present state of genetic engineering (GE) of forest woody plants is considered with special reference to the materials of the International Conference "Wood, Breeding, Biotechnology and Industrial Expectations" held in France in June, 2001. Main tree species subjected to GE are listed, aims of constructing transgenic plants discussed, and methods described. Major achievements in the field are considered along with the problems associated with the employment of GE in the breeding of forest woody plants.

[Peculiarities of mitosis and nucleolar characteristics of the birch plantlets under antropogenous pollution]. / Osobennosti protekania mitoza i iadryshkovye kharakteristiki semennogo potomstva berezy povisloi v usloviiakh antropogennogo zagriazneniia.

A study was made of some cytogenetic characteristics (mitotic activity, the level and spectrum of pathological mitosis, nucleolar features in root tip cells) in birch plantlets. The seeds were collected in four districts of Voronezh and in the ecologically clean territory. The index of mitotic activity has a considerable resistance to anthropogenous pollution. In the experimental areas, the level and spectrum of pathological mitosis increase. In contaminated areas we observed changes of nucleolar characteristics (the increased surface area of nucleoli and their higher number in cells, the increased number of cells with highly active types of nucleoli, the appearance of residual nucleoli). These changes can be considered as possible mechanisms of adaptation to stress due to antropogenous pollution. It is suggested that the use of such indices as single nucleolar surface area or the level of pathological mitosis may be perspective for cytogenetic monitoring of the environment, and for prognostification of environmental conditions suitable or unsuitable for the human health.

[Activity of nucleoli in cells of different type in early embryogenesis of Pinus sylvestris L]. / Kharakteristika iadryshkovoi aktivnosti kletok razlichnykh tipov v rannem émbriogeneze Pinus sylvestris L.

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.

[Adaptive significance and possible origin of B-chromosomes in Picea Glauca (moench.) voss = P.canadensis B.S.P]. / Adaptivnoe znachenie i vozmozhnoe proiskhozhdenie B-khromosom u eli koliuchei.

The karyotype (2n = 24 + 1B) was detected in 8 trees of Picea glauca (Moench.) Voss. = P. canadensis B.S.P., and the karyotype (2n = 24) was detected in 2 trees of spruce from the same stand in the centre of Voronezh. The majority of seeds, collected from these trees, were empty. From 150 selected seeds, which were full, four plantlets were obtained. One of them died, another one had no mitotic figures, and the third and fourth plantlets had karyotypes (2n = 24 + 1B, and 2n = 24, respectively). A possible mechanism of formation of B-chromosomes and their adaptive role are discussed.

[Cytogenetic study of certain Tilia species]. / Tsitogeneticheskoe izuchenie nekotorykh vidov roda Tilia L.

The number of chromosomes, and mitosis and microsporogenesis were studied in Tilia europaea, T. tomentosa, T. cordata and T. platyphyllos under natural conditions of Voronezh region. Significant mixoploidy of meristematic tissue cells in seedling root tips, mitotic activity and meiosis have been demonstrated for the first time. The number of chromosomes in somatic cells varied from 28 to 140-146. The number 2n = 82 was modal for all the studied species. The number of chromosomes in T. europaea has been determined for the first time. The numbers of chromosomes in the genus Tilia are analysed on the basis of the literature and our own data. The peak of mitotic activity in seedlings and juvenile leaves (8-10%) fell on the night: 0-1 a.m. according to the winter time. Microsporogenesis is simultaneous and asynchronous. In some individual trees various abnormalities of meiosis were found: lagging in time in 1 to 5-6 chromosomes, bridges, fusions of spindles. Variations in pollen dimensions, shape and pore number were detected in many trees.

[Cytogenetic characteristics of seed progeny of trees under condition of antropogenic contamination in Voronezh town]. / Tsitogeneticheskaia kharakteristika semennogo potomstva nekotorykh vidov drevesnykh rastenii v usloviiakh antropogennogo zagriazneniia g.Voronezha.

It has been shown that in seed progeny of Quercus robur L., Pinus sylvestris L. and Betula pendula Roth. some cytogenetical characteristics vary under conditions of contamination. Such changes may be common or specific type. Thus, the frequency of pathological mitosis increases under such conditions in all the investigated species of trees. Inhibition of mitosis was found in the progeny of the pine, and variability in the number of nucleoli was detected in the pine and oak. However, in some cases the level of pathological mitosis in the oak progeny did not differ from the control, but the mitotic activity was higher due to the presence of much more cells being at the prophase stage. In the birch progeny under conditions of contamination the mitotic index increased, with a simultaneous shifts in the peaks of mitotic activity. The possibility of using these cytological characteristics for the aims of cytogenetical monitoring is considered.