[Studying of microbial potential agrocenoses for increase of efficiency and tolerance plants by methods of biotechnology]
2007
Shirokikh, I.G. | Shirokikh, A.A. | Ashikhmina, T.Ya.
The microbial complexes of the crop rhizosphere were studied under pot and field experiments on acid soddy-podzolic soils. Different varieties of barley, oat, winter rye and red clover were used as test subjects. It was experimentally shown that positive effect of plants - soil microorganisms interaction is enhanced under edaphic stress. Biomass of eucaryote microorganisms increased as affected by higher soil acidity. The percent of fungal mycelium rises more rapidly than the percent of spores. The indices of abundance and percentage of eucariotic microorganisms are influenced by plant development phase and plant genotype. Under acid stress and aluminum toxic effect the amount of bacterium decreases in rhizosphere and rises in roots surface. The elevation of bacterial cells adsorbed by roots is regarded as coadaptation of plants and bacteria to edaphic stress. Light acid stress induces first rhizobial-legumes symbiosis, but these systems are strongly suppressed by the achievement of some toxic limits. The varietal and specific specificity of rhizospheric actinomicetes is expressed more in acid soils as compared in the optimal conditions. There was fixed bright antifungal activity of actinomicete rhizosphere isolates. It is supposed to realize plant selection in the line to accumulation at roots surface of actinomicetes, which will be able to show some antagonistic activity and to enhance plant resistance against root infections. The ability of natural isolates of Methylobacterium to stimulate plant growth and morphogenesis was demonstrated. Three selected Methylobacterium strains were used for inoculation plants micropropagated or from callus cultivated. This effect was especially expressed by using of media deprived of phytohormones and vitamins. The combination of traditional plant tissues cultures and Methylobacterium inoculation makes it possible to develop new in vitro plant cultivation methods including these for plants of low regeneration ability.
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