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Phenology provides intimate insights into ongoing changes in nature and seasonality with respect to humans. In this study, the most complete volunteer observer phenological data set for the territory of Latvia from 1970 to 2018 was evaluated. The data set includes observations of 159 phases of eight taxonomical groups, as well as abiotic phenomena such as the first snow, last spring frost, and agrarian activities. With reducing dimensionality, a hierarchical cluster analysis was used to group the 66 phenological phases of most observations into 7 clusters. The largest changes were observed in the early spring phenological phases of the pioneer species such as the start of flowering of Corylus avellana (hazel), Alnus incana (grey alder) and Populus tremula (aspen), noted as -8 days/decade. The trend of the spring emergence of insects and spring migratory birds also showed a negative tendency. The phenology of crops and agrarian activities has not changed significantly. The trends of the autumn phases were heterogeneous-leaf colouration and fall for some species (Populus tremula) and (Acer platanoides, Norway maple) was recorded on average later; for other species, there was a slightly earlier trend (Betula pendula, silver birch; Tilia cordata, linden). Earlier onset of the spring phases affects the changes in the length of the growing season (for Acer platanoides + 7.7 days/decade; Betula pendula + 3.3 days/decade). Since 1990, it has been common that many phases have begun sooner (particularly spring phases), whilst abiotic autumn phases have been characterised by late years. This study has shown that significant seasonal changes have taken place across the Latvian landscape due to climate change.

The fatty acid composition (FAC) of fractions of organic compounds isolated from total lipids (TL) by successive solvents—chloroform, acetone, and methanol, taken as neutral lipids (NL), glycolipids (GL), and phospholipids (PL)—was studied by the phases of the opening of buds in plants of the Betula L. genus [1]. It was found that the FAC of the TL fractions of opening buds of trees with morphological features of Betula pubescens Ehrh., Betula pendula Roth, and Betula pendula Roth var. carelica (Mercklin) Hamet-Ahti is represented mainly by unsaturated fatty acids (USFAs) (up to 88% of the total fatty acids). Linolenic and linoleic acids (up to 55 and 47% of the total fatty acids, respectively) constituted the main share of USFAs. Palmitic acid predominated quantitatively among saturated fatty acids (SFAs) (up to 42%). The content of linoleic acid in all SL fractions decreased with the development of buds in all three birches, while the content of linolenic acid in the composition of the GL and PL fractions increased. In birches differing in morphological characteristics, the specific features of the FAC from the SL fractions of the buds were studied by the opening phases.

In this article, the functional group composition of the spruce (Picea abies) and birch (Betula pendula) phloem lignin is described. The features of the chemical structure were studied by analyzing dioxane lignin using the elemental analysis, UV-Vis, FT-IR, and 1D NMR spectroscopy. For comparison, samples of xylem dioxane lignin isolated from the corresponding wood species were also analyzed. FT-IR spectroscopy data suggest that the lignins of birch phloem and xylem are similar in chemical structure. However, there are differences in absorption bands in the spectra of spruce dioxane lignin, which indicate the opposite. Quantitative analysis of the functional group composition was performed using 13C and 31P NMR data. It was found that free phenolic hydroxyl groups of catechol and p-hydroxyphenyl types are dominated in the composition of spruce phloem lignin. Birch phloem lignin has a qualitative and quantitative composition of functional groups characteristic of hardwood lignins. However, the content of G-units is greater than S-units, in contrast to the birch xylem lignin, where S-units predominate. The revealed differences are relevant from the point of view of plant physiology. The practical significance of the study is connected with understanding the reactivity of lignins when considering the chemical processing of tree bark.

Plant SABATH family members catalyze the methylation of many hormones, signaling molecules, and floral scent metabolites, including salicylic acid (SA), jasmonic acid (JA), and indol-3 acetic acid (IAA). Demethylation of resulting methyl esters was executed by members of the MES family. Members of both families are significantly involved in plant developmental processes. Here, using different bioinformatics tools, we studied the evolutionary relationship and characterized the putative functions of the family members in silver birch (Betula pendula). It is a socio-ecologically important tree species and plays a vital role in reforestation. Ten and twelve members of the SABATH (BpSABATH1-10) and MES (BpMES1-12) family were identified in silver birch, respectively at the gene and enzyme levels. The BpSABATH and BpMES genes were distributed on seven of fourteen chromosomes, indicating the occurrence of moderate duplication events important for the expansion of both families. Phylogenetic clustering and the gene ontology database suggest, BpSA-BATH8 is involved in the methylation of indole-3-acetic acid (IAA), while BpSABATH5, BpSABATH6, and BpSABATH7 methylate JA to methyl jasmonate (MeJA). BpSABATH9 was alone in the phylogenetic functional group 1 and prefers SA as a substrate to synthesize methyl salicylate (MeSA). Likewise, BpMES5 and BpMES12 are possibly involved in the demethylation of the methyl ester of IAA, while BpMES6, BpMES7, and BpMES8 are responsible for the demethylation of MeJA. BpMES9 clustered with MES and prefers MeSA as a substrate. The current analysis helped to select candidate genes that could be subjected to further molecular breeding of birch varieties adapted to biotic and abiotic stress conditions.

The article discusses the morphological changes of birch trees (Betula pendula Roth.) due to bacterial cancer that grow in the artificial forest «Green Belt» surrounding the city of Nur — Sultan. Kernel samples were taken from diseased tree trunks, isolated bacterial cultures were grown in nutrient medium and given cultural and morphological characteristics. Extraction of cores from diseased birch trunks, isolation of pure strains of the pathogen, molecular identification of ribosomal RNA 16S nucleotide chains and comparison of these results with relevant data from the international database Gene Bank are carried out using modern methods in the field of bacteriology and botany. The molecular characteristics of the isolated bacterial strains corresponded to 96.72 % of the typical strain Dickeya dadantii based on the international Gene Bank.

The study of bioelectric resistance (impedance) of woody plants by electrometric method under the influence of adverse factors, including oil sludge, is one of the adequate methodological approaches to assessing the state of forest biogeocenoses. The aim of the study is to study the peculiarities of the influ-ence of oil sludge pollution of soils on the duration of changes in the bioelectric resistance of the precam-bial tissue complex of birch trunks. The object of the study is the trees of the hanging birch (Betula pendu-la Roth.) growing in the basin of buffer ponds of JSC «Gazpromneft - ONPZ» (Omsk). The research area is the Central forest-steppe of the South of Western Siberia. The results of the studies were processed by standard methods of variational statistics, correla-tion, regression and variance one-factor analysis using the package Statistica 10. Comparisons of experience variants were carried out according to student and Fisher criteria. The dependence of elec-trical resistance of birch trunk PCT (precompiling complex tissues) on the level of oil sludge pollution of soils was studied. A recommendation for rapid assessment of the condition of birch trees in the con-ditions of oil sludge pollution by electrometric meth-od was developed. According to the results of our long-term studies, it can be noted that the duration of a significant negative impact of oil sludge on the electrical resistance precompiling complex tissues of birch trees in the forest-steppe zone of Western Sibe-ria is manifested within six years, and in the seventh year these differences are not reliable and already in the ninth year-these differences disappear (τfact > τ0.5). The results obtained can be used in screening studies of forest biogeocenoses and in the planning and or-ganization of bioreculture activities on the territory of sanitary protection zones of oil refineries and in areas of oil production and oil transportation.

The influence of temperature and water availability on seed germination can vary across the geographic range of species with a large distribution.Betula pendulais a widely spread European tree that has differentiated into two narrowly distributed taxa, endemic to Mediterranean mountains:Betula aetnensisin Sicily andB. fontqueriin Spain and Morocco. We tested the hypothesis that the regeneration niche, expressed by temperature and water potential thresholds, varies across these species and is influenced by the local climate. Seeds were collected from six populations ofB. pendula, one ofB. fontqueriand two ofB. aetnensis. Germination tests were conducted between 5 and 30°C. The thermal thresholds were calculated before and after cold stratification. The osmotic potential tested ranged from 0 to −1.5 MPa. Time to reach 30 and 50% of germination was calculated by fitting non-linear models. Germination was promoted by high temperatures, but the response to stratification was heterogeneous.Tband Ψbdiffered between and within species.Tbranged between 2.22 and 8.94°C for unstratified seeds. Mediterranean species had higher drought tolerance, whileB. pendulashowed contrasting responses to low water potential. Ψbreached a minimum value of −1.15 MPa inB. fontqueri. High temperatures influenced theTbof unstratified seeds negatively, while, after stratification, theTbincreased with precipitation in the driest month. The heterogeneity observed could reflect higher genetic variability in marginal populations of silver birch. Knowledge of their germination ecology may be useful to mitigate future impacts of climate change on core populations ofB. pendula.

The purpose of the research was to determine the water regime and identify the nature of dust retention capacity of assimilation apparatus in artificial birch stands in green zone of Nur-Sultan (Northern Kazakhstan). The objects of the research were 16-year-old Betula pendula Roth. forest crops, some of which were transplanted at the age of 8 into the interrow space. Some water regime features of forest crops were considered to determine their adaptive ability to soil and climatic conditions. The intensity of leaf transpiration, relative water content in leaves, and water deficiency were studied. When making observations, it was found that there was no reliable difference between the water regime indicators in the sample areas in transplanted and non-transplanted crops. So, the results of the research are presented without taking into account peculiarities of the sample area location. A high water-holding capacity of the plant leaves was revealed, it amounted 96.98 %. The average transpiration rate during the growing season was 176 mg/g ∙ h, with the highest average transpiration rate (229 mg/g ∙ h) detected in July, and the lowest in August (162 mg/g ∙ h). The data obtained showed weak intensity of moisture evaporation by leaves. This indicates a low water deficit of the plants, which was 8.96 % after leaf was fully saturated with moisture. Ratio of retained dust and leaf area of silver birch showed that 1 cm2 of assimilation apparatus accumulated on average 0.1 mg of particulate matter. The amount of dust revealed that at a high location, more particulate matter is accumulated per unit area of assimilation apparatus than at a low location. The largest amount of dust (0.117 mg cm2) was deposited at a distance of 1000 meters from the highway, and the smallest amount (0.091 mg/cm2) - at a distance of 200 meters. Topographic features and presence of protective birch strip influenced this fact. The research revealed that a large leaf area is not a guarantee of high dust retention capacity.

Ash dumps occupy significant areas around the world and make a negative influence on the environment. This effect is decreased by their natural colonisation determined by the bioclimatic conditions of the area. The purpose of the current study was to identify the structure of the forest communities and the initial stages of soil formation on the ash dump in southern taiga. This study was carried out on three sites in the forest phytocoenosis formed in the process of revegetation of the Verkhniy Tagil Power Station ash dump over 50 years, as well as on two background forest sites in the Middle Urals. Complex geobotanical and soil studies were carried out. The results of the study show that forest phytocoenoses with a predominance of hardwood species (Betula pendula Roth and Populus tremula L.) and a small admixture of coniferous species can form on the non-recultivated ash dump within 50 years in a boreal zone. In total, the studied mixed forest phytocoenoses are similar in composition to zonal secondary forests, but differ by having lower height and diameter of the stand, as well as herb–shrub layer coverage. Their species density and floristic richness are also lesser. The study proved that the process of soil formation is also proceeding according to the zonal type in the ash substrate under forest communities. The results of the study can be applied to justifying the forecasts of ecosystem restoration on the technogenic substrate, as well as for the species selecting for their recultivation in the studied area and similar to it.

Proportions of 13C/12C and 15N/14N isotopes were identified in different woody compartments of birch (Betula pendula Roth), pine (Pinus sylvestris L.) and aspen (Populus tremula L.) trunks in preforest-steppe and pine-birch forests of the Middle Urals using mass spectrometry. The data were analyzed and interpreted from the perspective of the biochemical processes of carbon and nitrogen metabolism in leaves, cambial tissue, trunk wood, branches, roots, and soil. A lighter isotopic composition of carbon is characteristic of the leaves and trunk cambium. The trunk wood is characterized by a basal trend for 13C enrichment. The 13C/12C ratio corresponds to the nitrogen content in the trunk wood tissues, indicating metabolic control of carbon fractionation in woody plants. The isotope composition of nitrogen in the trunk cambium was significantly depleted in 15N (δ15N varies from –1.5 to –3.5‰) and δ13C (δ13C varies from –28.3 to –25.8‰). Meanwhile the sapwood (δ15N varies from –2.6 to 1‰ and δ13C varies from –27.5 to –27.1‰) and heartwood (δ15N varies from –2.5 to –3.5‰ and δ13C varies from –26 to –24.5‰) were more enriched in 15N and 13C. The significant difference between the values of 13C and 15N isotope discrimination consequently in the different woody compartments of trunk should be taken into account when interpreting data of wood organic matter in the context of paleoclimate.

The goal of the study was to develop a complex technique for the extraction and purification of polysaccharides from the leaves of birch (Betula pendula Roth., Betula pubescens Ehrh., family Betulaceae) (PSfB). The following characteristics have been used as criteria for estimating the effect of the parameters studied on the production of target compounds: the yield of PSfB (the gravimetric method), the protein content (spectrophotometry), the molecular weight distribution (high performance size-exclusion chromatography), and the degree of purification from low-molecular-weight impurities (LMWI). The following optimal parameters have been determined in experiments at different stages of PSfB production: the degree of grinding of a raw material 1.2–3 mm; the pH value of the extractant (purified water with the pH value of 6.5–7.0); the raw material : extractant ratio 1 : 20; the extraction temperature 50°C; the temperature and the degree of evaporation 50°C, four times; the concentrate : ethanol ratio 1 : 3; and the method of purification from LMWI by ultrafiltration. As a result of the work, an optimized method for obtaining PSfB has been developed, which affords a high yield without the loss of quality of the product (minimal admissible content of LMWI with the maximum content of high-molecular-weight fractions). The method is the basis for the development of laboratory regulations for obtaining an active pharmaceutical substance based on polysaccharides from birch leaves.

The influence of plant material fixation methods on the index of fluctuating asymmetry of Betula pendula Roth leaves is determined. The methods used were herbarization under pressure and leaves fixation in a solution of ethyl alcohol (45%). Biological material was collected in natural phytocenoses of the Pritalskaya zone of the Middle Urals and in technogenically formed territories, including soil contamination with heavy metals. The FA level of Betula pendula Roth leaf blades obtained on freshly harvested material increases in the gradient of toxic load and reflects a natural increase in soil contamination with heavy metals (Zn, Cu, Pb, Cd, etc.). The smallest deviation from the actual FA values obtained on freshly harvested material is given by a method of herbarization of leaves. The correlation coefficients are 0,940,99. Plant material fixation in an alcohol solution leads to more than 10-fold deviation of FA values from the real ones. The correlation between the studied morphological parameters of fresh and alcoholic leaf blades is 0,170,70. The signs distance between the bases of the first and second veins of the second order from the base of the leaf and angle between the main vein and the second vein of the second order from the base of the leaf are more distorted. Correction coefficients are proposed that allow to level out the differences in the FA level between the results obtained on freshly collected material and recorded by different methods. For the herbarization method, regardless of where the plant material is collected, the correction factor to be entered for the FA values of the fixed leaf blades is () 0,0004. For the method of leaves fixation in an alcohol solution, the coefficient value is () 0,00075 for material collected in undisturbed communities, and (+) 0,0045 for technogenically disturbed communities.

A significant role in the pathogenesis of diseases of woody plants belongs to phytopathogenic bacteria and fungi. It has been scientifically confirmed that the organs and tissues of woody plants have a certain myco- and microbiota, the components of which are systematically interconnected both with each other and with the plant. The species composition and quantitative ratio are constantly changing both in the process of ontogenesis of the tree and with changes in its physiology. The aim of the work was to study the species composition and the formation of diversity and systemic interactions of microbiota associated with bacterial dropsy in the pathology of Betula pendula Roth. Methods. Classical microbiological, phytopathological, biochemical, statistical methods were used in the work. Combined diagnostic methods were also used, in particular careful microscopic examination of the affected parts of plants, isolation and identification of the pathogen. Results. Bacterial origin of wet wood in the trunk of birches was detected. Samples of wood and exudate were taken for laboratory studies from plants that had pronounced signs of pathology (cracks, swellings). It has been experimentally proved that the causative agent of bacterial dropsy of silver birch is the phytopathogenic polybiotrophic bacterium Lelliottia nimipressuralis, which causes dropsy of coniferous and deciduous woody plants and experimentally found pathogenic properties to B. pendula. Xanthomonas campestris, Pantoea agglomerans and Bacillus subtilis are associated with bacterial dropsy pathology of B. pendula. The pathogenic properties of P. agglomerans and X. campestris on B. pendula are variable, which indicates the possibility of the expansion of the circle of plants sensitive for these species of bacteria. It was established that L. nimipressuralis both during spring and autumn inoculation showed high pathogenicity to B. pendula. In only one case, on isolated on the border of healthy and affected wood from young B. pendula (bast part) the results of artificial injury were less pronounced. Other bacteria isolated from bacterial dropsy, in particular X. campestris, were non-pathogenic for B. pendula. At the same time, we noted traces of artificial infection with X. campestris in the samples isolated on the border of healthy and affected wood from middle-age B. pendula (cambial part). This may indicate an expansion of the circle of sensitive plants or the increased sensitivity of certain forms of birch for the mentioned bacteria, which is quite likely, since the bacteria have a significant forms variety. In 10 places of inoculation no pathology caused by B. subtilis was found. Bacteria of the Bacillus genus were non-pathogenic for B. pendula in all experiment. Our studies have shown that they can be a regulatory factor in the development of bacterial dropsy. Conclusions. A certain variability of isolated strains in the assimilation of some carbohydrates and alcohols can be explained by the specific conditions of the existence of bacteria, including the influence of environmental factors on their biochemical properties. It is known that the ecological niche affects even the antigenic composition of bacteria; therefore, such an effect should also be expected on other properties. Our studies confirmed that causative agent of bacterial dropsy is L. nimipressuralis and clarified the information about this bacteria cells size.

The paper presents the results of research to assess the quality of the urban environment in the areas we have identified by the functional and economic significance of Cheboksary using a method of fluctuating asymmetry of Betula pendula Roth leaves and a scale of gas resistance of tree and shrub plants. The studies have showed that the integral indices of fluctuating asymmetry of Betula pendula leaf plates of all surveyed green planting objects vary from 0,038 to 0,054. The highest levels of asymmetry were found in the eastern and southern parts of the city, where the values of leaf asymmetry fluctuations range from 0,050 to 0,054. Based on an assessment of the quality of the urban environment the authors have developed recommendations to improve and expand the range of resistant woody plants to anthropogenic stress of Cheboksary. Depending on the nature of the urban environment and the degree of woody plants resistance to anthropogenic pollution, we offer a range of woody and shrub plants for landscaping, it contains 73 species. The recommended range of trees and shrubs for landscaping in the Central zone of Cheboksary is 68 species (asymmetry coefficient 0,040 to 0,044), in the Coastal and Suburban areas 62 species (asymmetry coefficient 0,046 to 0,049), in the Industrial zone 29 species (asymmetry coefficient 0,050 to 0,053).

We studied the impact of fly ash produced by the thermal power station in the Middle Urals (Russia) on functional traits of two Betula species naturally colonizing ash dump lagoons. The main limiting factors for tree growth on fly ash deposits were nitrogen deficiency, high alkalinity, and unfavorable mechanical composition of substrate. Leaf area ratio (LAR) and leaf mass ratio (LMR) per tree, leaf area (LA), leaf shape coefficient (LSh), leaf thickness (LT), leaf mass per area (LMA), photosynthesis (Amax) and transpiration rates, chlorophyll (Chl), carotenoid (Car), and nitrogen (N) content were measured in Betula pendula Roth and Betula pubescens Ehrh. growing on the ash dump and in the forest near the dump. Both Betula species showed similar functional response to adverse conditions of the fly ash. We found a 1.5–2-fold increase in LAR and LMR in trees growing on fly ash deposits compared with trees in the forest. In both species, the most significant differences across leaf morphological traits were shown for LT. Higher LT provided an increase in Chl and N content per leaf area that caused the rise in Amax and photosynthetic water use efficiency in the trees on the ash deposit. At the same time, Betula species preserved interspecific differences in values of LA and LT which were larger in B. pubescens whiles B. pendula differed by higher LSh. We concluded that the increase in assimilation activity at both whole-plant and leaf levels provides plant adjustment to edaphic and nutrient stress that allow Betula species to colonize technogenic substrates as fly ash deposits.

Aims Pioneer tree species such as Betula pendula and Pinus sylvestris encroach soils contaminated with heavy metals (HMs). This is facilitated by ectomycorrhizal fungi colonizing tree roots. Thus, we evaluated the ectomycorrhizal fungal (EMF) communities of B. pendula and P. sylvestris growing in HM-contaminated soils compared to non-contaminated soils. We also studied the effect of HMs and soil properties on EMF communities and soil fungal biomass. Methods Roots of B. pendula and P. sylvestris were collected from three HM-contaminated sites and from two non-contaminated sites located in Poland. EMF species were identified using DNA barcoding. Soil fungal biomass was determined by soil ergosterol. Results B. pendula and P. sylvestris growing in HM-contaminated soils had similar EMF communities, where Scleroderma, Rhizopogon and Russula as well as ectomycorrhizae of the long-distance exploration type dominated. Among all of the examined soil factors studied, toxicity index (TITotal) was the most significant factor shaping the composition of EMF communities. Despite significant differences in the structure of the EMF communities of trees growing in HM-contaminated sites compared to control sites, no differences in overall diversity were observed. Conclusions Only well-adapted EMF species can survive toxic conditions and form ectomycorrhizal symbiosis with encroaching trees facilitating the forest succession on contaminated soils.

The effects of different climatic conditions on growth and chemical composition of Betula pendula in geographically different European regions, Lithuania and Romania, were compared. Birch species in the entire area have a wide natural distribution, but B. pendula is commercially more important in Lithuania than in Romania. Here we evaluated tree ring width, wood density and foliar chemical composition of mature birch trees in two European regions. Trees at the Lithuanian sites had greater radial growth and wood density with no clear changes in foliar chemistry than those at the Romanian sites. Mean wood density was 600–700 kg m−3 at Lithuanian and 350–450 kg m−3 at Romanian sites. Mean width of wood ring, earlywood and latewood for Lithuanian birch trees were several times higher than the means for Romanian birch trees. We hypothesized that the main differences in birch radial growth and wood density were due to the different climatic conditions in the studied regions. Ca, K and Mg concentrations were significantly higher and Fe and Mn were lower in the birch foliage at the Lithuanian sites compared those at the Romanian sites. Overall assessment of growth showed that silver birch cultivation is more appropriate for colder climate regions and that birch growth may change in the context of a warming climate.

Palinoindication of 6 parks of the urban ecosystem of Kiev using Taraxacum officinale (L.) Weber ex F.H. Wigg. population, was carried out. There is a general trend towards an increase in the amount of nonviable pollen with an increase in anthropogenic load. In the example of T. officinale, this is manifested in a gradual increase to 27% of non-viable pollen on the pollution gradient. With the deterioration of the ecological situation in the studied test polygons, an increase in the number of teratomorphic pollen grains up to 41.10% in Babin Yar tract was recorded. According to the level of palynotoxic action (PE, %), only 2 gradations were revealed in the parks under study: initial and effective. The sublethal effect (highly toxic) has not been established, since the level of pollen sterility in our studies did not exceed 45,2%. The largest number of pollen grains with developmental pathologies (teratomorphic) – 41.10% – was recorded in the Babin Yar tract, the state of which, according to the anthropogenic load index (Jal), is characterized as poor. At the same time, the percentage of teratomorphic pollen grains in T. officinale plants in more favorable environmental conditions (control) does not exceed 16.50%. For the bioindication assessment of the park ecosystems state in the megalopolis, the most indicative were the index of sterility, palynotoxic effect and the content of teratomorphic pollen grains, which increases with the gradient of anthropogenic load. Keywords: Anthropogenic load; Pollen sterility; Fertility; Palynotoxic effect; Teratomorphic pollen; Urbanization References Azzazy, M. (2016) Environmental impacts of industrial pollution on pollen morphology of Eucalyptus globulus Labill. (Myrtaceae). App. Biol. Biotech. 4, 57–62. Balichieva, D.V., Ibragimova, E.E., Emirova, D.V. 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DOI: 10.24411/2073-1035-2018-10133. Morozova, T.V., Khrutba, V.O., Kobzista, O.P. (2019) Screening of palynomorphological and palynotoxic effect of motor vehicle emissions. Bulletin of the National Transport University. "Technical Sciences" series. 1(43), 116–126. Pausheva, Z.P. (1980) Workshop on plant cytology (Moscow: Kolos). 271 ??. http://booksshare.net/index.php?id1=4&category=biol&author=pausheva-zp&book=1988 Soldatova, V.Y., Samsonova, A.P. (2019) Influence of urban environment on variability of pollen grains of hanging birch (Betula pendula Roth) (on the example of Yakutsk). Samara Scientific Bulletin. 8/3(28), 80–84. DOI 10.24411/2309-4370-2019-13113. The main indicators of environmental protection of Kyiv. Statistical collection 2017. (Kyiv Main Department of Statistics in Kyiv; for order. O.I. Nastoyashcheho). 75 ??.

Mesophyll resistance to CO2 diffusion (rm) and the maximum carboxylation rate of Rubisco (Vcmax) affect photosynthetic rates, and can potentially also influence the percentage of respiratory and photorespiratory CO2 being refixated (Pr) by mesophyll cells. Here we investigated how various leaf anatomical traits (e.g. leaf mass per area [LMA] and leaf dry matter content [LDMC]) influenced rm in leaves of mature forest trees. We further explored how rm and Vcmax in turn affected Pr, and if these traits varied among species and leaves along a light gradient. Photosynthetic CO2 response of leaves grown in high-, medium-, and low-light environments was measured, from Pinus sylvestris [Scots pine], Picea abies [Norway spruce], Quercus robur [English oak], and Betula pendula [Silver birch] in southern Sweden. A modified version of the Farquhar-von Caemmerer-Berry model was fitted to the leaf gas exchange data to estimate Vcmax, rm and Pr. We found that of all leaf traits measured, only LMA for Q. robur was significantly higher in leaves from high-light environments. When comparing species, both rm and LMA were significantly higher in the conifers, and rm had a negative correlation with Vcmax. We found that Pr was similar between different species and functional groups, with an average of 73.2% (and SD of ±10.4) across all species. There was a strong, positive correlation between Pr and Vcmax in broadleaves, and we hypothesise that this effect might derive from a higher CO2 drawdown near Rubisco in leaves with high Vcmax.

Проаналізовано фітосанітарний стан зелених насаджень міста Херсон, багатий видовий склад дерев і кущів якого зумовили широкий спектр патогенних організмів та шкідників, що їх уражають. З'ясовано, що підвищення техногенного навантаження в урбанізованих екосистемах призвели до зниження життєздатності деревних рослин-едифікаторів Херсона. Встановлено, що патогенними організмами уражаються 45 видів досліджених деревних рослин міста. Виявлено, що найбільш вразливими до патогенних організмів є Acer negundo L., A. platanoides L., A. saccharinum L., Quercus robur L., Tilia cordata Mill., Aesculus hippocastanum L., Juglans regia L., Fraxinus excelsior L. За інтенсивністю пошкодження, яке впливає на життєвий стан рослин та їх декоративність, найбільш вразливими до дії фітопатогенів та ентомошкідників виявились Aesculus hippocastanum L., Buxus sempervirens L., Buxus sempervirens (Du Roi) Moench, Prunus divaricata Ledeb., Rosa canina L., Pinus pallasiana D. Don, Picea pungens Engelm., Juniperus virginiana L. З'ясовано, що низка дерев і кущів (Quercus rubra L., Betula pendula Roth, Betula pubescens Ehrh., Cotinus coggyria Scop., Sophora japonica L., Gymnocladus dioicus (L.) Koch, Mahonia aquifolium (Purh.) Nutt., Maclura acuminata L., Populus simonii Carr., Eucomia ulmoides Oliv., Albizia julibrissin Durazz, Symphoricarpos albus (L.) Blake, Ginkgo biloba L., Taxus baccata L.) є стійкими до дії шкідників та хвороб. Дослідження показали, що різні типи насаджень відрізняються за видовим складом патогенних організмів, а також за інтенсивністю пошкодження рослин-господарів. У паркових насадженнях частіше трапляються хвороби та шкідники листя або хвої деревних рослин. У вуличних насадженнях деревні рослини частіше пошкоджуються збудниками стовбурових і кореневих гнилей, листя рослин пошкоджуються американським білим метеликом та комахами-мінерами. Появі уражень та захворювань сприяють перестиглий вік насаджень, велике рекреаційне навантаження на зелені зони, а також відсутність регулярного кваліфікованого догляду за насадженнями. Тому на території дослідження рекомендовано проведення рубок формування та вибіркових санітарних рубок, а також регулярне та своєчасне здійснення агротехнічних заходів.

The article is focused on microbiological and silvicultural properties of bacterial wetwood of silver birch (Betula pendula), also known as European white birch. During the active phase of the disease, bacterial wetwood (i.e. bacterial dropsy, vascular parenchymatous bacteriosis or flux slime) is characterised by crust and periderm bloating, necrotic wet stains and abundance of exudate. The disease is more likely to occur in older (r = 0.56, p < 0.01) and less-dense (r = −0.29, p < 0.01) stands. The statistical model showed that the chance of bacterial wetwood increases with birch age by 0.36% per year. The stands with birch proportion of over 70% demonstrated 15.3% lower infection rate compared to the stands with lower birch presence. The stands with lower stocking demonstrated a higher proportion of infected tree distribution by 7.5% compared to the stands with higher birch representation. The most vulnerable were larger, older B. pendula trees with longitudinally fissured bark that grow on poorer soils and experience frequent water stress. Birch associations with Pteridium aquilinum and Vaccinium myrtillus were more susceptible to infection (31.6% and 44.3%, respectively), whereas associations with Brachypodium sylvaticum, Sphagnum palustre and Calluna vulgaris were at lower risk. Strong ecological and trophic association of bacterial wetwood was present between silver birch and Tremex spp., particularly Tremex fuscicornis. Mycobiota was represented by Rhizopus microsporus, Mucor mucedo, Penicillium aurantiogriseum, Penicillium purpurogenum and Acremonium strictum. Enterobacter, Xanthomonas, Pantoea and Bacillus spp. associated with bacterial wetwood of silver birch were isolated. Enterobacter nimipressuralis was found to be the primary causative agent through means of artificial infection, while other bacteria were found to be either weak pathogens or concomitant. E. nimipressuralis formed the largest number of colony-forming units (CFU) for bark and cambium (164 and 127 CFU, respectively) and was also found in a small amount as a vital obligate in the automicrobiota in healthy birch trees.

Key message Sustainability and safety aspects of plant cell cultures as food are presented. Applicability of dairy side streams as carbon source and use of natural growth enhancers in cultivation are shown. Abstract Biotechnologically produced cellular products are currently emerging to replace and add into the portfolio of agriculturally derived commodities. Plant cell cultures used for food could supplement current food production. However, still many aspects need to be resolved before this new food concept can enter the market. Issues related to sustainability and safety for human consumption are relevant for both consumers and regulators. In this study, two plant cell cultures, deriving from arctic bramble (Rubus arcticus) and birch (Betula pendula), were cultivated using lactose-rich dairy side streams as alternative carbon sources to replace sucrose. Biomasses were comparable to those of original plant cell culture media when up to 83% and 75% of the original sucrose was replaced by these side streams for arctic bramble and birch cell cultures, respectively. Furthermore, nutritional composition or sensory properties were not compromised. Synthetic plant growth regulators were replaced by natural components, such as coconut water and IAA for several subculture cycles. Finally, it was shown that only trace amounts of free growth regulators are present in the cells at the harvesting point and assessment by freshwater crustaceans assay indicated that toxicity of the cells was not exceeding that of traditionally consumed bilberry fruit.

Aboveground dead wood has a range of important ecological functions, including carbon (C) storage. According to the Intergovernmental Panel on Climate Change guidelines for National Greenhouse Gas Inventories established on the basis of the United Nations Framework Convention on Climate Change and the Kyoto Protocol, Lithuania is encouraged to quantify C pools in forests, including C in living biomass, soil and dead wood. The aim of this study was to assess species-specific dead wood density (DWD) and carbon content (CC) per decay class for Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), silver birch or downy birch (Betula pendula Roth or Betula pubescens Ehrh.), European aspen (Populus tremula L.), grey alder (Alnus incana (L.) Moench), black alder (Alnus glutinosa (L.) Gaertn.), common oak (Quercus robur L.) and European ash (Fraxinus excelsior L.), as the main representative hemiboreal forest tree species. The study findings revealed that mean DWD significantly decreased, while mean CC slightly increased during the wood decomposition process, which led to carbon density (CD) reduction over five decay classes. The mean CC showed little variation among the eight tree species and ranged between 47 and 54%. The lower CDs in the dead wood of decay classes 1 and 2 were more associated with coniferous than deciduous species. The estimated CD significantly decreased in all species with increasing decay class. Dead wood at decay class 5 of Scots pine, silver or downy birch, European ash and common oak had the highest CD, followed by Norway spruce and grey alder, and the lowest CDs were obtained for European aspen and black alder.

A sequence of changes of three stages over 10 years is reported during the formation of the phytocenosis of the pyrogenic formation of Betula pendula. The change of stages is due to the introduction of new plants of different phytocenotypes, the appearance of consortia and the complexity of its composition and structure. The account of abundance was performed according to O. Drude. The content of readily soluble phosphates and exchange potassium was performed according to Chirikov. After pyrogenic exposure, there was an increase in the content of P2O5 and K2O in the 0-10 cm layer, due to their increased content in the ash formed after the pyrogenic exposure. In 2014, the content of P2O5 in the soil in the territory of Betula pendula formation increased by 9.15% compared to the background. In 2018, the content of P2O5 decreased by 11% compared with the second year of the study after the 2010 forest fire and gradually approached the background value. In 2014, the K2O content in the 0-10 cm layer of sod-eluvial glue clay-illuviated soil increased by 6.86% compared to the background area. From 2014 to 2018, the K2O content decreased by 5.39% in the area of Betula pendula formation. Phyto-diversity decreased in 2015 and amounted to 13 species, compared to 2014 (47 species), 2016 - 18 species, 2018 - 22 species and in 2019 - 23 species. The work describes anthropotolerant groups

The allelopathic effect of extracts from leaf litter of Betula pendula on the initial stages of ontogenesis (seed germination and growth and development of seedlings) of Rumex aquaticus has been studied in laboratory conditions. A significant decrease in laboratory germination by 1.5–36.3 times, depending on the concentration of the extract, is found. The change in the coefficient of inhibition confirmed the phytotoxicity of the investigated extract. The inhibitory effect on the seedlings at a concentration ≥50% of control is manifested in a decrease in the morphometric parameters of both the underground (root system and hypocotyl) and aboveground (cotyledon) parts of the seedlings.