Alla Vladimirovna Golovchenko
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Bacterial communities structure of the main types of bog plantsMoscow University Bulletin. Series 17. Soil science. 2019. N 1. p.42-46read more914
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This research based on both direct and seeding methods revealed high bacteria concentration on bogs plants: Carex nigra, Eriophorum vaginatum, Drosera rotundifolia, Ledum palustre. There was identified a correlation between bacteria number and investigated plants’ organs. Proteobacteria dominated in phyllosphere, bacilli and actinomycetes - in rizoplane and rhizospheric soil. Representatives of the genus Pseudomonas and Erwinia dominated in phyllosphere. Nitrogenase activity of bacterial populations in rhizosphere soil was high and reached the maximum in Drosera rhizospheric soil.
Keywords: bog; plants; bacteria; number; taxonomical composition; nitrogenase activity
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Taxonomic structure of bacterial communities of rhizospheric soil under bog plantsMoscow University Bulletin. Series 17. Soil science. 2020. N 2. p.45-52read more1135
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For the first time, the ratio of large taxa and the genera spectrum in the prokaryotic complex of the rhizosphere soil under typical plants of bogs were revealed by high-performance sequencing. The dominance of acidobatheria and alpha-proteobacteria was established with a low proportion of other taxa (less than 10%). Among the 24 bacterial genera found, representatives of the phylums Acidobacteria and Actinobacteria, as well as the Alphaproteobacteria class, predominate. Common bacterial genera were identified in rhizosphere soil under plants and surface layers of peat. Representatives of most of these bacteria are adapted to grow in an acidic environment and at low temperatures. Their functioning is determined by the use of various sugars, polysaccharides, aromatic compounds, organic and amino acids. Bacteria of the genera Cytophaga and Acidothermus are capable of cellulose destruction, Occallatibacter - chitin, Nocardia - humic substances and lignin.
Keywords: bogs; plants; rhizospheric soil; bacterial communities; phylums; spectrum of genera; bacterial functions; high-performance pyrosequencing; metabarcoding of gen 16S rRNA
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Bacterial complexes in the fens of Tomsk region: abundance, taxonomic structure, activityMoscow University Bulletin. Series 17. Soil science. N 4. p.43-51read more988
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This article provides an analysis of structural and functional indicators of bacterial complexes taken for examination from the complete profile of the fens that form part of “Klukvennoye” and “Karbyshevskoye” wetland systems in the Tomsk Region. In the fens bacteria was found throughout all the profile. The number of bacteria was high and varied from 27 to 78 ´ 109 cells/g of dry peat. This data was obtained by direct method using fluorescence microscopy. The high count of the saprotrophic bacteria (reaching up to 108-109 CFU/g of dry peat) was found by the plate method. Those results allowed to identify a trend, showing that the number of saprotrophic bacteria increased down the fen profile. The results of this study give an opportunity to state for the first time that the index k ( k is a dimensionless universal characteristic of natural prokaryotic communities, k stands for microscopy/plate) in fen profiles does not increase, but decreases with depth. The following bacterial cultures were identified and isolated from the fens studied (those cultures were attributed to 10 taxa): Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Pedobacter, Flavobacterium, Dyadobacter, Janthinobacterium, Myxobacteriales. Bacterial cultures, representing Bacillus and Streptomyces genera, were dominant in the acrotelm. At the same time Pseudo-monas, Dyadobacter and Arthrobacter dominated in the catotelm. The functions of bacterial genera and species, identified by molecular biological methods, were described. A study of nitogen fixation, nitrogen decline and methanogenesis showed that bacteria were in a viable state and were able to remain active throughout the entire peat profile.
Keywords: fens; Sapric Histosols; bacteria; abundance; taxonomic structure; nitrogen fixation; denitrification; methanogenesis
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The influence of erodibility degree of sod-podzolic soil on the abundance and diversity of fungi and actinomycetesMoscow University Bulletin. Series 17. Soil science. 2024. N 3. p.28-37Valery V. Demidov Tatyana A. Gracheva Polina M. Perebasova Alla V. Golovchenko Alexey L. Stepanov Oleg A. Makarovread more748
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The paper presents the results of assessing the eff ect of the degree of soil erodibility on the abundance and diversity of cultivated fungi and actinomycetes in diff erent seasons of the annual cycle. The objects of the study are sod—podzolic soils (Umbric Retisols (Abruptic)) of diff erent degrees of washout, located on the slope of the southeastern exposure (Moscow region, Solnechnogorsk district), used for a long time for the cultivation of agricultural crops. The indicators of microbial abundance were determined by the cup method, identifi cation was carried out on the basis of phenotypic characters. It is shown that the decline in physical and agrochemical parameters of the soil, which is a result of erosion processes, leads to a change in microbiological parameters. A decrease in the abundance and species diversity of fungi and actinomycetes was found with an increase in the degree of soil erosion. Significant diff erences were found in the taxonomic composition of microbial communities of non-eroded and washed away soils (the Sorensen species similarity coeffi cient does not exceed 0.42 for fungi and 0.30 for actinomycetes). Taxonomic units of mycelial microorganisms have been identifi ed. Among the fungi are representatives of the species Aspergillus, Cladosporium and Scopulariopsis, among the actinomycetes are Streptomyces malachitospinus, S. candidus and Micromonospora aurantiaca.Keywords: water erosion; erodibility; abundance; indicator species
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The influence of the degree of washout on the agrochemical properties and biological activity of agro-gray soilMoscow University Bulletin. Series 17. Soil science. 2025. N 4.
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The paper evaluates the effect of erosion processes on the agrochemical and microbiological properties of the soil in different seasons of the annual cycle. The objects of the study are agro-gray soil of varying degrees of water erosion (uneroded, slightly and moderately eroded) and gray soil under woody forest plantations (south of the Moscow region). It was found that the content of alkaline hydrolyzable nitrogen, exchangeable potassium and mobile forms of phosphorus in the soil depended both on the degree of soil erosion and on seasonal fluctuations. Analysis of the chemical composition of soil organic matter showed that in the summer there was an increase in carboxylic, carbonyl and aromatic components, and in other periods – carbohydrate fractions. In the agro-gray soil, bacterial biomass stocks ranged from 27 to 96 kgha‒1, fungal biomass – from 10 to 357 kgha‒1, their dynamics were determined to a greater extent by the degree of washout and to a lesser extent by the season. With an increase in the degree of washing, both fungal and bacterial biomass decreased in the series unwashed>slightly washed>medium washed. Washed-away soils lost an average of 50% of bacterial and 59% of fungal biomass relative to non-washed soils. In the gray soil, bacterial biomass stocks varied seasonally from 43 to 107 kgha‒1, and fungal biomass from 171 to 621 kgha‒1. The gray soil under forest was superior in microbial pool to all variants of agro-gray soil, and was also characterized by a high content of mycelium, both actinomycete and fungal. In the studied soils, the level of potential respiration (SIR) exceeded the level of actual respiration (BR) by 2‒33 times. Microbial biomass reacted most actively to the introduction of glucose in the average washed soil in the spring and summer periods.Keywords: soil erosion status; soil agrochemical properties; soil organic matter composition; microbial biomass; bacteria; fungi; microbial respiration
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