[Cytogenetic studies on submerged plants from the Yenisei river area in the zone of radioactive contamination].

Cytogenetic studies on three species of submerged plants from different parts of the Yenisei river area subjected to radioactive impact of the Krasnoyarsk Mining-and-Chemical Plant and the Electrochemical Factory have been conducted. A high level of irregularities in anatelophase and metaphase of mitoses has been revealed in test samples compared to the control: agglutination and fragmentation of chromosomes, lagging chromosomes, bridges, fragments, misdivisions, and others. The natuie of the disorders indicates that they are related in part to the direct damage to the chromosome structure and in part to damage to the spindle.

[Karyological characteristics of Abies sibirica in the Middle Siberia].

Data on Abies sibirica karyotype structure have been obtained in five populations of Middle Siberia. Chromosome set (2n = 24) consists of 7 pairs of metacentric (I--VII), 4 pairs of submetacentric (VIII, X-XII) and a pair of intercentric (IX) chromosomes. Morphometric parameters of chromosome groups are similar in the populations studied. Variation of Abies sibirica chromosome characteristics is low. Intraspecific chromosome polymorphism of A. sibirica is substantially connected with variation of the number of NOR-chromosome in the karyotype and with location of NOR in chromosome arms. Mixoploidy, somatic reduction of chromosomes, and a triploid seedling of A. sibirica have been registered on the territory with antropogenic press.

[Microsporogenesis and pollen formation in Scotch pine (Pinus sylvestris L.)].

The prolongation of a warm season during autumn, typical for the Siberia in recent 5-6 years, caused changes in the terms of reproductive processes in microsporangia of Scotch pine in the Krasnoyarsk region. The meiosis started in the autumn of the year, preceding the pollination, and comes to the end in next spring, whereas usually this process occurs in the spring of the year of pollination. In such conditions the division of microsporocytes accompanied with different abnormalities, causing various anomalies and the incomplete development of pollen grains.

[Meiosis in the Siberian fir during microsporogenesis in conditions of arboretum].

Meiosis was studied in the Siberian fir (Abies sibirica Ledeb.) at the arboretum of the Sukachev Institute of Forest. Specific features of meiosis in planted trees have been described. Both general and specific types of irregularities have been identified. The range of irregularities under the arboretum conditions was much wider than in natural ecosystems.

[Radioecological monitoring of the Yenisei River and citological characterization of a submerged aquatic plant Elodea canadensis].

The study was devoted to investigation of the contents of radionuclides and of heavy metals and to evaluate the frequency of chromosomal aberrations in samples of Elodea canadensis, a submerged plant, collected in different parts of the Yenisei River. The samples were collected in the area subjected to radioactive impact of the Mining-and-Chemical Combine (MCC) at Zheleznogorsk and in the control area, upstream of the MCC. The investigations shown that elodea biomass in the area affected by MCC operation contained a long inventory of artificial radionuclides typical for the MCC discharges. The upstream of the MCC, in the control sampling area, the sediments and the elodea biomass contained only one artificial radionuclide--137Cs. Thus, the exposure doses to elodea shoots and roots upstream of the MCC are small (not more than 8 microGy/d) and the main contribution info the dose is made by natural radionuclides. At the MCC discharge site (the village of Atamanovo) and at the downstream of it, the total dose rate increases almost an order of magnitude, reaching its maximal values--72 microGy/d for elodea shoots and 58 microGy/d for its roots. Cytogenetic investigations of elodea roots shown that at the MCC discharge site (the village of Atamanovo) and at downstream of it the occurrence of chromosomal aberrations in ana-telophase and in metaphase cells of elodea was considerably higher than in the control area. It is highly probable that this simultaneous dramatic increase in the total exposure rate and the occurrence of chromosomal aberrations in elodea is associated with the radiation factor. It is suggested that elodea is affected not only by the radiation factor but also by the chemical factor--toxicity of heavy metals.

[Karyological studies of two populations of Juniperus communis L. in west Siberia].

Results of a karyological study of Juniperus communis L. populations under swamp and dry conditions are presented. The chromosome number of J. communis are 2n = 22. Analysis of morphological chromosome parameters showed a similarity between karyotypes of both populations. It is possible to identify one pair of asymmetric chromosomes (VIII pair); this chromosome pair is close to submetacentric type. Three pairs of chromosomes (I, VII, VIII) have secondary constrictions. Other metacentric chromosomes form groups of five long (II--VI) and three short (IX-XI) pairs. Differences between two populations in absolute chromosomal length are observed.

[Karyological studies on Picea ajanensis (Lindl. et Gord.) Fisch. ex Carr. from different regions]. / Kariologicheskoe izuchenie Picea ajanensis (Lindl. et Gord.) Fisch. ex Carr. raznogo proiskhozhdeniia.

Results of karyological study of Picea ajanensis (Lindl. et Gord.) Fisch. ex Carr examined from 13 provenances are presented. In addition to the cytotypes with typical chromosome number (2n = 24), P. ajanensis displays cytotypes with one or two B-chromosomes (2n = 24 + 1 - 2B). Among A-chromosomes, there are 8 pairs of long metacentrics and 4 pairs of shorter meta- or submetacentrics. Among B-chromosomes there are two types of chromosomes: metacentric (B1) and submetacentric (B2) ones. There are many nucleolar chromosomes. Several chromosomes have secondary constrictions. Patterns of B-chromosome distribution within P. ajanensis are have been discussed.

[Supernumerary chromosomes in the karyotype of the Siberian spruce, P. obovata]. / Dobavochnye khromosomy kariotipa eli Sibirskoi P. obovata.

Results of karyological study of ornamental forms of Picea obovata Ledeb. are presented. Typical chromosome number (2n) is 24, but some trees have one or two additional chromosomes (2n = 24 + 1B; 2n = 24 + 2B). Heritability of additional chromosomes, pollen fertility, morphological features of cones, and seed quality in trees with and without additional chromosomes were studied. System of B-chromosomes is of importance for population and species adaptation and possibly plays a role in adaptation of P. obovata under introduction.