In determining the quality of surface waters and, first of all, rivers, along with physical and chemical pollution, the analysis of the hydrobiological component of river ecosystems is becoming increasingly important. The aim of the work was to assess the ecological quality of the river ecosystems from the impact of wastewater discharge from the cities of Vitebsk, Polotsk and Novopolotsk on the Western Dvina River based on the macrozoobenthos community. The studied river sections are inhabited by rare for Belarus and protected in Europe species of aquatic organisms. A relatively high abundance (from 30 to 80 %) of the group of rheophilic species Plecoptera, Ephemeroptera, and Trichoptera was noted, which represent the three highest priority indicator groups of aquatic organisms. Biotic indices and the water purity class of the r. Western Dvina were determined. In accordance with the EU Water Framework Directive, the water purity class at the studied stations has a good and high value. It is concluded that the negative impact of wastewater from the cities of Vitebsk, Polotsk and Novopolotsk has a very local significance and weakly affects the biota and the ecological quality of the water of the Western Dvina River already at a distance of 18 km. below the discharge of water from the treatment facilities of the Novopolotsk refinery.

Red band needle blight, or Dothistroma needle blight is one of the most common and harmful diseases of pine. The causative agents of the disease are pathogenic micromycetes Dothistroma septosporum (Dorogin) M. Morelet and Dothistroma pini Hulbary. Dothistroma needle blight was firstly detected in Belarus in 2012 year, but till now information about this disease in the republic is fragmentary. The article presents the results of a survey of different pine trees, carried out in the period 2016–2020 years in botanical and dendrological gardens, forest nurseries and mini-arboretums at forestry enterprises, urban stands, nurseries of decorative plants, garden centers, for the presence of Dothistroma needle blight. The species identification of the causative agent of the disease was carried out by mycological and molecular genetic methods. In this study, Dothistroma needle blight was revealed on individual trees of Pinus mugo, P. nigra and P. ponderosa in the stands of the Central Botanical Garden of the NAS of Belarus, the dendrological garden of the Glubokoe experimental forestry enterprise, in the nurseries of decorative plants in the Grodno and Minsk regions. In the collected samples of needles, the invasive species Dothistroma septosporum was identified. The frequency of occurrence of the pathogen was 4.8–7.2 %, the proportion of observation sites in which this disease was detected at 60 %. The detection of Dothistroma needle blight on pine trees, mainly on planting material imported from abroad, indicates a transboundary route of D. septosporum entering the country. Analysis of literature data indicates the potential danger of Dothistroma needle blight for pine stands in the republic, which in turn requires the organization of regular monitoring of the disease and the development of methods to limit the spread of D. septosporum in the republic.

The content of reactive oxygen species, the activity of key antioxidant enzymes ‒ ascorbate peroxidase and glutathione reductase, the level of expression of the hypersensitive response marker gene (HSR) as well as potato virus X particles content in cv. Uladar seedlings grown on an ion-exchange substrate in the presence of a complex preparation containing chitosan, Bacillus subtilis bacteria-based preparation and salicylic acid, when infected potato virus X. Accumulation of the reactive oxygen species, increase in ascorbate peroxidase activity, a lower level of HSR gene expression and a lower content of virus X particles in potato plants under such conditions are shown. An increase in both the number of potato minitubers and dry matter content in them was also registered when plants were grown on an ion-exchange substrate in the presence of a complex preparation.

The article provides information on the phenological rhythms of representatives of the genus Abies Mill. and their decorative forms growing on the territory of the Central Botanical Garden. The purpose of this study was to determine the degree of adaptability of introduced species to local conditions and to establish from the possible potential use in landscaping the country. Studies have shown that in all studied species of fir, biological rhythms coincide with the climatic rhythms of Belarus, which indicates a sufficient degree of their adaptation to new conditions. At the same time, A. alba and A. nordmanniana are less winter-hardy and are damaged by spring frosts, while A. sibirica, A. concolor, A. fraseri, and A. nephrolepis are annually damaged by diseases and pests. A. holophylla, A. veitchii and A. koreana are potentially suitable for use in the country’s green building. Among the ornamental forms, A. nordmanniana ‘Lennartz’ and A. alba ‘Belopestraya’ are annually damaged by frosts. The rest of the forms of fir have successfully passed the initial test under the conditions of introduction, adapted to local conditions and are suitable for use in landscaping the territory of Belarus.

Russian dereza (Lycium ruthenicum Murr.) is a shrub plant that spreads on the territory of the dried Aral Sea in conditions of high soil salinity, dry and sharply continental climate. The fruits were collected and the features of germination of seeds of the russian dereza halophyte (Lycium ruthenicum Murr.) Under sterile and non-sterile conditions were studied. The optimal temperature and illumination regime for the germination of annual seeds of this species is a 16-hour photoperiod and a temperature of 25 °C, the germination of seeds in nonsterile conditions was: 4-year-old – 46 %; 2-year – 83; one-year – 96 %. It has been shown that L. ruthenicum plants remain viable for up to 4 years or more, on this basis, we attributed the seeds of this species to truly orthodox. When introduced into culture in vitro, it has been shown that multi-stage sterilization significantly reduces the viability of seeds and seedlings of Lycium ruthenicum Murr., which leads to a decrease in seed germination by up to 40 %. The optimal nutrient medium for the stable development of microshoots without anomalies, callus formation and initiation of root formation was MS with the addition of 1.0 mg/l 6-BAP to the nutrient medium, without sucrose. Maintaining the samples in the in vitro collection is carried out on a half-MS medium without hormones, without sucrose at a low positive temperature of 4 °C, illumination of ~500 lx and a photoperiod of 8 hours. The samples of L. ruthenicum in vitro can be used to develop methods of clonal micropropagation; for genotyping of samples and identification of molecular biomarkers of plant resistance to soil salinity; in the ex vitro morpho-biological study of plants resistant to salt stress.

The dependence of the action of lactone-structure brassinosteroids in composition with a growth-inhibiting dose of glyphosate on the root system and the aerial part of fiber flax (Linum usitatissimum L.) and spring barley (Hordeum vulgare L.) seedlings was determined. The species specificity of growth responses to seed incrustation by such mixtures was identified. The concentration ranges of brassinosteroids, in which their interaction with the herbicide is most pronounced, were detected. In this case, there is an increase (on spring barley seedlings) or weakening (on fiber flax seedlings) of the inhibitory effect of glyphosate on the root system.

The species composition of zoobenthos in the heated and non-heated zones of the cooling lake Lukoml State District Power Station was studied. 80 taxa of bottom animals have been registered, and two new species of chironomid larvae have been identified. The bottom fauna includes a protected relict species of Pallaseopsis qudrispinosa, which is preserved in the conditions of warming.it is listed in the Red book of Belarus and the alien species – freshwater shrimp Macrobrachium nipponense. The high taxonomic diversity indicates that the Lukoml State District Power Station operation has little impact on the bottom community throughout the lake’s water area. However, species richness is reduced locally by half in the zone of influence of heated water discharge, especially in summer. Under the influence of heating, the taxonomic structure and spatial distribution at different depths change.

The tree peony, which is considered a traditional ornamental plant in China, Japan, America and Europe, is also widely used as a medicinal plant. The collection of tree peonies in the State Scientific Institution “Central Botanical Garden of the National Academy of Sciences of Belarus” is represented by four taxa. The aim of our work was to assess the quantitative composition of the sum of phenolic compounds and hydroxylcinnamic acids in the leaves of the genus Paeonia, as well as to assess the antioxidant status of these samples depending on the phase of ontogenesis. As a result of the studies, a high content of phenolic compounds and hydroxycinnamic acids in the leaves of the studied taxa of the genus Paeonia was established, including the content exceeding the threshold of 65 mg/g in the leaves of Paeonia suffruticosa in all observed phases of ontogenesis. In the studied varieties, the proportion of hydroxycinnamic acids in the composition of phenolic compounds ranged from 25 to 50 %. Extracts of leaves of the Paeonia genus collected during the flowering period had the maximum antioxidant activity. Thus, the above data indicate that the aerial part of the Paeonia genus can be considered as a promising raw material for the creation of herbal remedies with antioxidant action.

In this work, the genetic diversity of the modern gene pool of the winter rye (S. cereal L.) of the Republic of Belarus from 20 actual breeding samples was investigated using 15 microsatellite (SSR) markers to develop divergent crossing combinations in breeding for heterosis. It was shown that the formed set of SSR markers is highly effective – the informational content index (PIC) varied from 0.50 to 0.83 and averaged 0.72. The most effective microsatellite markers (SCM28, SCM43, SCM101 and SCM102) were identified and can be successfully used to study the genetic diversity of rye. It has been established that the modern gene pool of the winter rye of the Republic of Belarus is generally characterized by fairly wide genetic diversity (interpopulation variability) – all collection samples are characterized by a unique allelic composition of the studied microsatellite loci. Based on investigation results, a hierarchical clustering dendrogram was constructed, which made it possible to determine the most genetically divergent combinations of crosses. The information obtained can be used for the development of an effective scheme allowing to develop new varieties and hybrids in the practical breeding of rye for heterosis.

An analysis of genetic heterogeneity was performed for two populations of Ophrys insectifera L. located in the Berezinsky Biosphere Reserve and the Verkudy village. The species are critically endangered (CR). The analysis of data obtained using iPBS markers detected the higher risk of extinction of the population in the Berezinsky Biosphere Reserve than the population from the Verkudy village, since the level of population genetic heterogeneity from the Verkudy is higher compared to the Berezinsky Biosphere Reserve. Molecular variance analysis (AMOVA) and other parameters of genetic variation showed the major fraction of intrapopulation variation (64 %, Gst = 0.26). Principal Coordinates Analysis (PCoA) revealed two groups that coincided with natural populations, and confirmed a larger genetic heterogeneity in the population from the Verkudy.

Conducted electron microscopic investigation of the primary remex fine structure of thirteen species of Owls (Strigiformes), using a scanning electron microscope (SEM). It is shown that Owls (Strigiformes) have a number of specific primary remex microstructural characteristics. First of all, these are the features of the structure of the pennaceous barb: a cross section configuration, a pith architectonics on the cross section and longitudinal sections, a cuticular structur of the barb. A number of the unique features in the microstructure of the vanules of the pennaceous barb have been found for the first time (at the scanning electron microscope level, at a large SEM magnification). First of all, these are the structural features of the distal barbules and the structure of the apical portion of the barb with the elongated proximal barbules and the distal barbules tightly contiguous to the ramus and closed with each other. Mentioned characteristics make for the thick velvet-like dorsal surface of the vane and the presence of a complex of peculiar “bunches” (fringes) forming the cleft edge (a fringed edge) of the inner vane – exceptionally specific adaptive characteristics in Strigiformes. Рresentenced original research results suggest that Owls (Strigiformes) have a number specific microstructural characteristics of the primary remex and also a number of the unique features in the microstructure of the primary remex which reflecting the ecological and morphological adaptations conditioned by the flight specificity.

The main goal was primary comprehensive assessment of the biological and decorative indicators of varieties of chrysanthemum (Chrysanthemum coreanum (H. Lèv. & Vaniot) Nakai ex T. Mori), ukrainian selection of National Botanical Garden named after N. N. Grishko, for definition the possibility of their using for flower decoration of cities and other settlements of Belarus. Phenological observations were carried out during all vegetation periods from 2010 to 2020. The types of inflorescences of chrysanthemums were classified according to the generally accepted classification, which was developed for the chrysanthemum by the Dresden Institute of Horticulture (Clauss, 1960). Primary comprehensive assessment of chrysanthemum varieties was carried out according to the modified method of varietal assessment of the Central Scientific Center of the National Academy of Sciences of Belarus, which based on 11 biological and decorative indicators: color stability of the inflorescence, number of inflorescences on one shoot, height and shape of the plant, leafiness of the shoot (stem), winter hardiness, resistance to diseases and pests , vegetative mobility, annual stability of flowering, duration of flowering, longevity in culture. In article are given the results of the introduction of varieties of chrysanthemum breeding NBG named after N. N. Grishko collection of the Central Botanical Garden of the National Academy of Sciences of Belarus. Primary comprehensive assessment of 76 varieties of Korean chrysanthemum. The 31 varieties of chrysanthemums were selected, which can be recommended for flower decoration of cities and towns of Belarus. Thus, investigated varieties of Korean chrysanthemum, breeding NBS named after N. N. Grishko, characterized by a steady rhythm of seasonal growth and development. The majority varieties is going through all stages of seasonal development during the growing season, which indicates their successful adaptation to the climatic conditions of Belarus.

The article describes the results of a study of the impact of biohumus alkaline extract on growth and development of woody plants seedlings. A positive impact has been found out. When biohumus alkaline extract is used, the height of Thuja occidentalis seedlings surpasses the target by 19.0 %, the length of root systems – by 13.3 %. These indexes for Spiraea x cinerea are 18.6 and 50.0 %, and for Taxus baccata – 9.0 and 23.1 % correspondingly.