[Structure of Epiphytic Bacterial Communities of Weeds].

Dynamics of the taxonomic structure of epiphytic bacterial communities of the rhizosphere and phyllosphere of seven weed species was studied. The major types of isolated organisms were identified using phenotypic and molecular biological approaches. Dispersion analysis revealed that the ontogenesis stage and plant organ were the factors with the greatest effect on the taxonomic structure of the communities. The dominant microorganisms of weeds were similar to those of cultivated plants. The minor components revealed in the spectra of bacterial communities of weeds belonged to poorly studied genera of chemolithotrophic proteobacteria.

[Effect of mechanical grinding of Sphagnum on the structure and physiological state of bacterial communities].

The microcosm method was used to demonstrate an increase in bacterial numbers and drastic changes in the taxonomic structure of saprotrophic bacteria as a result of mechanical grinding of Sphagnum moss. Ekkrisotrophic agrobacteria predominant in untreated moss were replaced by hydrolytic bacteria. Molecular biological approaches revealed such specific hydrolytic bacteria as Janthinobacterium agaricum and Streptomyces purpurascens among the dominant taxa. The application of kinetic technique for determination of the physiological state of bacteria in situ revealed higher functional diversity of hydrolytic bacteria in ground moss than in untreated samples. A considerable decrease of the C/N ratio in ground samples of living Sphagnum incubated using the microcosm technique indicated decomposition of this substrate.