Колонизация ризопланы корней огурцов микроорганизмами, входящими в состав микробного препарата «Эмбико®»

Abstract

The ability of microorganisms belonging to the microbiological preparation “Embiko®” to colonize the rhizoplanes and rhizospheres of the Competitor and Phoenix Plus types of cucumber (Cucumis sativus L.) in vitro was investigated. The objects of study were the cultures of the lactic homofermentative streptobacteria Lactobacillus plantarum 20 and L. casei 6 and the homofermentative lactic streptococcus Lactococcus lactis 4/6, the yeast Saccharomyces cerevisiae 75 and the microbiological preparation “Embiko®” which includes the above-mentioned microorganisms. Germinated seeds were placed aseptically in biological test-tubes with starvation agar, where a suspension of the microbiological consortium of microorganisms had been added before. The ability of bacteria to colonize the root zone of plants was assessed visually by the intensity of formation of bacterial microcolonies on the surface of the roots of the seedlings and on the crushed micropreparations. The strain of S. cerevisiae colonized the entire volume of the agar along the entire length of the root, in the apical part of the root colonization was shown to be less active. With increasing duration of cultivation the intensity of colonization of the root zone by microorganisms was increased – colonies became larger. In various areas of the root the diameter of the cloud colonies S. cerevisiae was different in size. The strains of L. casei 6 and L. plantarum 20 colonized all the root zones, forming a cloud of small colonies around them. The strain of L. lactis 4/6 did not form colonies in the starvation agar and didn’t colonize the root surface of the cucumber seedlings. The microbiological preparation “Embiko®” colonized the root throughout its length, gradually narrowing in the apical zone. When inoculated with a pure culture of isolated strains the cloud was composed of monotypic colonies and looked homogeneous. When inoculated with the microbial consortium the cloud of the colonies looked heterogeneous, colonies of different sizes and colors were clearly visible. Under microscopy the preparations of the roots of the cucumber seedlings inoculated with the microbial preparation “Embiko®” yeast cells and cells of the lactic acid bacteria were found. This study of the ability of microorganisms from the preparation “Embiko®” to colonize the rhizoplanes and rhizospheres of roots of cultivated plants in vitro showed that the different strains of microorganisms form clouds of colonies around the roots which were distinct in turbidity and size: the strain of L. plantarum – almost transparent, and S. cerevisiae – very dense. The lowest growth rate of microorganisms was observed at the apex of the root, the highest – in the zone of root hair. Clearly, root exudates of plants are the main source of carbon and energy for the inoculated bacteria. The results indicate that the investigated microbial consortium has a promising potential to inoculate plants in order to stimulate their growth and development.