Specific features of soil microbial communities under Lavandula angustifolia Mill. introduced plants
Authors: Yunosheva O. P. , Ellanska N. E. 
Published: February 2020

In article the results of microbiological studies of Lavandula angustifolia Mill introductive plants soil are presented. The purpose of this study was to investigate the influence of hydrothermal and soil conditions of forest steppe zone on the microbial cenosis formation and dynamics of taxonomic and ecology-trophic groups of microorganisms. 9–10 years age plants L. angustifolia (Yuzhnoberezhnaja and Record varieties) have been studied during two years on the experimental fields of the National Botanical Garden. Rhizosphere and rows-space soil were taken for experimental researches. Investigations were carried out by conventional microbiology methods – seeding of certain dilutions of soil suspension on selective culture medium. The comparative characteristic of microbial groups was investigated in dynamic according to the lavenders development phases. The decreasing of quantity of soil micromycetes were found during flowering phase in parallel with increasing of their species diversity. It should be noted that compared to control, the lavenders’ rhizosphere differ wider range of micromycetes species that belongs to Trichoderma, Penicillium and, especially, Aspergillus genus. The largest quantity of actinomicetes was observed at the beginning of vegetation. The development of actinomycetes and nitrogen transforming microorganisms depended on soil hydrothermal conditions. We observe decreasing of their quantity during deficiency of soil moisture. The numbers of spore-forming bacteria were significantly increased during the flowering period. Compared to control, the number of cellulozolytic microorganisms increased during intensive vegetation, whereas its highest activity was observed at the end of vegetation. Lavandula angustifolia exametabolites positively influenced to the development of heterotrophic bacteria in the beginning of vegetation, as well as during the flowering, whereas at the end of vegetation we observe the decreasing of its quantity. In opposite, the number of oligonitrophylus microorganisms decreased during the active vegetation, especially during dry period. The correlation between organic nitrogen and non-organic nitrogen consumption microorganisms define process of humus formation. We observed that the processes of organic matter development were fairly balanced. The accumulation of soil organic matter dominated during active vegetation, whereas activation of mineralization processes occurred at the end of vegetation period. Microorganisms’ content was higher in rows-spacing of plants, where concentration of exometabolites was lower. The dynamic of microbial cenosis and direction of microbiological processes have been similar in soil of two researched varieties, but the total number of microorganisms was higher in near-root soil of Yuzhnoberezhnaya variety. The Lavandula angustifolia soil microbial cenosis forms under influence of its plants excretions, in particular essential oils, that have a specific effect on the microflora and cause a quantity decrease of basic groups of microorganisms. The concentration of lavender exometabolites decrease in parallel with increasing of soil moisture and accordingly inhibitory effect of essential oil changes on stimulation. The understanding of soil microbial coenosis formation features will promote prognostication of interrelations between microbiota and plants. It will help to create sustainable landscape compositions and rational use them in making healthy ecosystems and other practical aspects.