Peculiarities of change in number and composition of winter wheat rhizosphere microbiome in the process of ontogenesis

Abstract

In agroecosystems, microorganisms are the main factor in the soil formation process, plant nutrition and phytosanitary condition of the soil. Therefore, all measures aimed at restoring soil fertility and increasing productivity, environmental safety of agricultural production are closely linked to the activities of microorganisms. Increased local activity, biomass and diversity of microbiota are one of the most important characteristics that distinguish the rhizosphere from the total soil volume. The aim of the research was to study the number and composition of the microbial complex of the rhizosphere of cereals (winter wheat of different varieties of domestic selection) in the process of ontogenesis. To conduct a set of microbiological studies, soil samples were taken and prepared (typical chernozem) in compliance with the standard requirements for sample preparation and storage of samples in the laboratory. The analysis of rhizosphere soil samples was performed according to the variants of different varieties of winter wheat of domestic selection. The number of soil microorganisms was determined by the method of inoculation of suspensions on nutrient media according to generally accepted methods in microbiology. Determination of the total microbial biomass in the soil was carried out by the rehydration method, and the intensity of "respiration" of the soil, respectively, by the release of CO2 and O2 absorption by the manometric method (Warburg apparatus). It is established that varietal specificity is significantly related to the peculiarities of microbiome formation in different phases of plant growth and development, which is an integral indicator of functional and metabolic activity of soil microorganisms. The number and composition of the microbial complex of winter wheat rhizosphere in the process of ontogenesis changes significantly, especially in the ratio of the number of spore-forming and non-spore forms of microorganisms under the same conditions of crop cultivation. The total pool of saprotrophic microorganisms of the rhizosphere demonstrates the variability of biomass and changes in favor of ecoplastic Bacillus. An increase in the number of spore-forming bacteria to 4.2 x 107 CFU/g in the variants of growing certain varieties was found. It is shown that in the cultivation of different varieties of winter wheat there are stable indicators of the intensity of CO2 emissions - from 5.2 to 7.0. A similar trend can be traced to the absorption of O2 (not more than 5.3-6.8).