Soil yeasts and their role in seed germination

A collection of yeasts isolated from soils of different types (soddy-podzolic, gray forest, and chernozems) in European Russia was analyzed. Soil yeasts were found to accelerate the development of seeds of common crops (wheat, barley, and rye). Cultures of yeasts from different taxa (representatives of the Rhodotorula, Cystofilobasidium, Sporobolomyces, Metschnikowia, Saccharomyces, Aureobasidium, Debaryomyces, Cryptococcus genera) are shown to stimulate the seed germination. The impact of soil yeasts (and preparations made on their basis) on seed germination is determined by their penetration to seed endosperm (endophytic microflora) followed by the isolation of amylolytic enzymes and physiologically active substances stimulating seed germination. The method of seed treatment is shown to affect greatly the direction of the preparations' action. When soaking seeds in solutions with the preparation, microorganisms multiply on the seed surface, and when treating seeds using a semi-dry method, seeds themselves and endophytic microorganisms inside them begin to develop. This study can be considered one of the new directions of soil microbiology related to studying the participation of soil microorganisms in the formation of endophytic communities and their role in the germination of vascular plant seeds.