Оценка техногенного загрязнения городской среды Читы по состоянию снежного покрова

The pollution of the snow cover in the city of Chita (Transbaikalia) with heavy metals (Zn, Cd, Pb, and Cu) is analyzed, and a level of its pollution is compared with similar characteristics in the cities of neighboring regions. The method of inversion voltammetery made possible to find that the content of water-soluble forms of toxic trace elements in the snow is several times greater than in other settlements outside Chita. However, the median values of these values (indicators) are close. Similar results (indicators) were also noted in the ecological and geochemical coefficients, according to which the city of Chita may be attributed to areas with the average level of pollution (ZC = 35.66). Trends in the accumulation of mobile forms of heavy metals in the snow cover of other cities were similar features as it follows from low values of the Saet coefficient (ZC < 32). The charge coefficient calculated for the liquid fraction of the snow cover was found to be high. Therefore, for safe use, melt water should be diluted with clean water 75.24 times for fishery purposes and 9.4 times for economic and drinking use. Rather low content of heavy metals was found in the dust fraction of the snow cover, but in the industrial zone and the zone of residential many-storeyed buildings concentrations of all trace elements exceeded the maximum permissible values (TLV - threshold limit value). At the same time, similar data for other settlements had still greater values, and the exceedings were tens and hundreds times greater the TLV values (the maximum permissible concentrations). The total pollution index (ZC = 72.5) with consideration for the toxicity of chemical elements (ZCT = 98.8) shows that the geochemical conditions in Chita is at the average level. For most other cities, values of the Saet coefficient were smaller 32 that corresponds to low and medium pollution levels. According to the level of dust load Chita is characterized by a high level of pollution (Pn ≥ 10 tons/km2), and it means that more than 8000 tons of dust fall to the snow cover. It has been found that by the total load index (Zp = 493.5) the dust fraction characterizes urbanized territory of Chita as highly polluted, and in this case cadmium (Cu = 255.47) is the main polluter. Comparison of our results with those of other researchers allows making the conclusion that during the period of the Soviet Union disintegration by the beginning of the XXI century pollution of a snow cover notably reduced.Анализируется загрязнённость снега города Читы цинком, кадмием, свинцом и медью в сравнении с соседними городами. В Чите содержание водорастворимых форм тяжёлых металлов в снегу в несколько раз больше, чем в других городах. Суммарный показатель загрязнённости (Zc = 72,5) с учётом токсичности (ZCT = 98,8) - средний, но пылевая нагрузка (Zp = 493,5) очень высока

Assessment of the diversity of vascular plants in phytocenoses with a share of Quercus mongolica on the territory of Relic Oaks State Reserve

In this paper, we assess the diversity of vascular plants in phytocenoses with Quercus mongolica (family Fagaceae) on the territory of the Relic Oaks State Reserve (Eastern Siberia, Transbaikal region), where Q. mongolica is located at the northwestern boundary of the areal. The descriptions of phytocenoses have been processed in the PAST3 application. The similarity of species composition has been determined using the Jaccard index. The resulting tree diagram shows two groups of descriptions at a similarity level of 0.14-0.15. The first group includes the descriptions of mixed forest quadrats, in which Q. mongolica is a co-edificator. The second group of descriptions presents the communities where Q. mongolica is the only species in the tree layer. The analysis of the tree diagram shows the dependence of species richness within the phytocenoses on the surface patterns and edaphoclimatic conditions. The phytocenoses located on steep southern slopes show less diversity

Молекулярно-генетическая характеристика образцов озимой мягкой пшеницы в связи с селекцией на устойчивость к полеганию

The objective of the study was to analyze the genomic structure and allelic composition of the dwarfing Rht-B1, Rht-D1 and Rht8 genes in 37 varieties and breeding samples of soft winter wheat in connection with breeding for lodging resistance in the Republic of Belarus. The molecular cytogenetic marking (C-banding) and DNA typing of genotypes were used. As a result, the analysis of the chromosomal composition of the breeding material showed that 21 winter wheat samples are characterized by the standard karyotype with the genomic structure AABBDD (2n = 42). Five variants of translocations affecting the chromosomes 1B, 3B, 5B, 6B, and 7B were revealed in the karyotypes of the remaining samples. It was found that the chromosomes of the 2nd and 4th homologous groups, in which the main dwarfing genes (Rht-B1, Rht-D1, and Rht8) are localized, did not undergo structural changes. Genotyping showed that 45.9 % of the samples contain one of the dwarfing alleles (Rht-B1b, Rht-D1b, Rht8c) in their genotype. A combination of two commercially significant alleles (Rht-B1b and Rht8c) in the genotype were identified in one of the winter wheat samples. The genotype with a combination of the Rht-B1a, Rht-D1a and Rht8b alleles occurred with the highest frequency (37.8 %) in the analysed breeding material. The Rht-B1b, Rht-D1a, Rht8b; Rht-B1a, Rht-D1a, Rht8a genotypes showed the frequency of 16.2 %. The Rht-B1a, Rht-D1a, Rht8c; Rht-B1a, Rht-D1b, Rht8b; Rht-B1a, Rht-D1b, Rht8j genotypes were identified in 5.4 % of the samples; the Rht-B1a, Rht-D1b, Rht8а genotypes – in 8.1 % of the samples. The analysis of the plant height, taking into account the karyotyping and genotyping data showed that the targeted selection of the most efficient allelic combinations of dwarfing genes is important for the cultivation region. The studies carried out allow us to suggest that the selection by the overwintering level can contribute to the fixation of the Rht8b allele in the breeding material, which is apparently associated with better winter hardiness in the conditions of Belarus.Цель – анализ геномной структуры и аллельного состава генов короткостебельности Rht-B1, Rht-D1 и Rht8 у 37 сортов и селекционных образцов озимой мягкой пшеницы в связи с селекцией на устойчивость к полеганию в Республике Беларусь. Методы. Молекулярно-цитогенетическое маркирование (С-бэндинг) и ДНК-типирование генотипов. Результаты. В ходе анализа хромосомного состава селекционного материала установлено, что 21 образец озимой пшеницы характеризуется стандартным кариотипом с геномной структурой AABBDD (2n = 42). В кариотипах остальных образцов выявлено пять вариантов транслокаций, затрагивающих хромосомы 1В, 3В, 5В, 6В и 7В. Установлено, что хромосомы 2-й и 4-й гомеологичных групп, в которых локализованы основные гены короткостебельности Rht-B1, Rht-D1 и Rht8, не подверглись структурным изменениям. В результате генотипирования показано, что 45,9 % образцов содержат в генотипе один из аллелей короткостебельности (Rht-B1b, Rht-D1b, Rht8с). Сочетание в генотипе двух коммерчески значимых аллелей короткостебельности Rht-B1b и Rht8с выявлено у одного образца озимой пшеницы. С наибольшей частотой (37,8 %) в проанализированном селекционном материале встречался генотип с комбинацией аллелей Rht-B1а, Rht-D1а и Rht8b. С частотой 16,2 % присутствовали генотипы Rht-B1b, Rht-D1а, Rht8b; Rht-B1а, Rht-D1а, Rht8а. Генотипы Rht-B1а, Rht-D1а, Rht8с; Rht-B1а, Rht-D1b, Rht8b; Rht-B1а, Rht-D1b, Rht8j выявлены у 5,4 % образцов, генотип Rht-B1а, Rht-D1b, Rht8а – у 8,1 % образцов. Заключение. Анализ высоты растения с учетом данных кариотипирования и генотипирования показал важность целенаправленного подбора наиболее эффективных для региона возделывания сочетаний аллелей генов короткостебельности. Проведенные исследования позволили предположить, что отбор по уровню перезимовки может способствовать закреплению в селекционном материале аллеля Rht8b, ассоциированного, по-видимому, с лучшей зимостойкостью в условиях Беларуси

Assessment of technogenic pollution of the urban environment in Chita by the snow cover state

The pollution of the snow cover in the city of Chita (Transbaikalia) with heavy metals (Zn, Cd, Pb, and Cu) is analyzed, and a level of its pollution is compared with similar characteristics in the cities of neighboring regions. The method of inversion voltammetery made possible to find that the content of water-soluble forms of toxic trace elements in the snow is several times greater than in other settlements outside Chita. However, the median values of these values (indicators) are close. Similar results (indicators) were also noted in the ecological and geochemical coefficients, according to which the city of Chita may be attributed to areas with the average level of pollution (ZC = 35.66). Trends in the accumulation of mobile forms of heavy metals in the snow cover of other cities were similar features as it follows from low values of the Saet coefficient (ZC < 32). The charge coefficient calculated for the liquid fraction of the snow cover was found to be high. Therefore, for safe use, melt water should be diluted with clean water 75.24 times for fishery purposes and 9.4 times for economic and drinking use. Rather low content of heavy metals was found in the dust fraction of the snow cover, but in the industrial zone and the zone of residential many-storeyed buildings concentrations of all trace elements exceeded the maximum permissible values (TLV - threshold limit value). At the same time, similar data for other settlements had still greater values, and the exceedings were tens and hundreds times greater the TLV values (the maximum permissible concentrations). The total pollution index (ZC = 72.5) with consideration for the toxicity of chemical elements (ZCT = 98.8) shows that the geochemical conditions in Chita is at the average level. For most other cities, values of the Saet coefficient were smaller 32 that corresponds to low and medium pollution levels. According to the level of dust load Chita is characterized by a high level of pollution (Pn ≥ 10 tons/km2), and it means that more than 8000 tons of dust fall to the snow cover. It has been found that by the total load index (Zp = 493.5) the dust fraction characterizes urbanized territory of Chita as highly polluted, and in this case cadmium (Cu = 255.47) is the main polluter. Comparison of our results with those of other researchers allows making the conclusion that during the period of the Soviet Union disintegration by the beginning of the XXI century pollution of a snow cover notably reduced

Особенности фитоценозов с участием Melica virgata Turcz. ex Trin. (Poaceae) Восточного Забайкалья в сравнении с сопредельными территориями

В работе рассмотрены особенности видового состава редких растительных сообществ с участием Melica virgata Turcz. ex Trin. (Poaceae). При сравнении с ранее известными данными по фитоценозам Монголии с участием этого вида выяснилось, что состав их значительно отличается. Также для фитоценозов из Восточного Забайкалья характерен уникальный видовой состав (заросли трех видов рода Rhamnus: R. davurica, R. erythroxylon, R. pissjaukovae + Ulmus pumila, с высоким проективным покрытием Melica virgata и участием крайне редкого вида для региона – Artemisia rutifolia), представленный на крайне ограниченной территории в бассейне реки Чикой (у с. Усть-Урлук). Сохранение комплекса видов требует создание охраняемой территории и включение в её состав нескольких наиболее ценных участков

Assessment of the diversity of vascular plants in phytocenoses with a share of Quercus mongolica on the territory of Relic Oaks State Reserve

In this paper, we assess the diversity of vascular plants in phytocenoses with Quercus mongolica (family Fagaceae) on the territory of the Relic Oaks State Reserve (Eastern Siberia, Transbaikal region), where Q. mongolica is located at the northwestern boundary of the areal. The descriptions of phytocenoses have been processed in the PAST3 application. The similarity of species composition has been determined using the Jaccard index. The resulting tree diagram shows two groups of descriptions at a similarity level of 0.14-0.15. The first group includes the descriptions of mixed forest quadrats, in which Q. mongolica is a co-edificator. The second group of descriptions presents the communities where Q. mongolica is the only species in the tree layer. The analysis of the tree diagram shows the dependence of species richness within the phytocenoses on the surface patterns and edaphoclimatic conditions. The phytocenoses located on steep southern slopes show less diversity

RYE CHROMATIN INTROGRESSION IN THE BREAD WHEAT GENOME: CYTOGENETIC ASPECTS

Alien chromatin introgression into the genome of common wheat Triticum aestivum L. is the most efficient way to enrich the gene pool of this crop. To improve the breeding value of wheat accessions, rye Secale cereale L is used as a donor of characters. Transfer of rye genetic material has certain specific features. The combination of the two cereal genomes in a single nucleus results in imbalance in all genetic systems. Fertility restoration in amphihaploids is the first step in the formation of introgression accessions. It is followed by the hybrid genome reorganization, which leads to cytological and genetic stability in the diploid progeny. In this paper, we present and analyze results that were obtained in the study of the two steps of wheat-rye hybrid genome reorganization: (1) breaching of F1 hybrid sterility (cytogenetic mechanisms of unreduced gamete formation) and (2) reorganization of wheat subgenomes during the introgression of single rye chromosomes