[Production of auxins by the endophytic bacteria of winter rye].

The ability of the actinomycetes and coryneform bacteria isolated from the root tissues of winter rye to produce auxin in a liquid culture was studied. The isolates of coryneform bacteria produced indolyl-3-acetic acid (IAA) into the medium in the amount of 9.0-95.0 microg/ml and the isolates of actinomycetes in the amount of 39.5-83.0 microg/ml. The maximal IAA accumulation in culture liquid of actinomycetes coincided, in general, with the beginning of the stationary growth phase. The dependences of IAA synthesis by actinomycetes on the composition and pH of nutrient medium, tryptophan concentration, and aeration conditions were determined. Biological activity of the bacterial IAA was assessed. Treatment of winter rye seeds with coryneform auxin-producing bacteria increased the germination capacity and enhanced an intensive seedling growth in vitro.

[Number and structure of actinomycetes complexes in the rhizosphere winter rye, oat and red clover].

The actinomycetes complexes in the rhizosphere of three agricultural plants by using the methods of luminescense microscopy and cup sowing were investigated. It was established, that concentration of prokaryotic biomass and biomass of actinomycetes mycelium in rhizosphere of plants is higher than in free from the radicals to soil. Rhizosphera of the oat (Avena sativa L.) and red clover (Trifolium pratense L.) is colonized by Streptomyces, Micromonospora and olygospore species. Dominante actinomycetes of winter rye (Secale cereale L.) are classified into the genera Micromonospora. It was shown that numbers and biomass of actinomycetes mycelium were fond to decreased, diversity of actinomycetes in contrast is increased in the series: "winter rye--oat--red clover". In connection with ecological safety the capability of increase with prokaryotes naturally disease suppressive soil and stability of plants to pathogen is discussed.

[Colonization of plant rhizosphere by actinomycetes of different genera].

The survival of environmental isolates of actinomycetes introduced with the seeds of agricultural plants in the root-free soil and in the rhizosphere and rhizoplane was studied. Different strategies of colonization of the rhizosphere were revealed for the representatives of the genera Streptomyces, Micromonospora, and Streptosporangium, the organisms typical for the moderate climate rhizosphere. The plants of winter rye (Secale cereale L.) inoculated with actinomycetes were shown to have growth advantages, while the cow clover plants (Trifolium pratense L.) had no growth advantages compared to uninoculated plants. The role of the plant component in the interaction with mycelial prokaryotes is discussed.

[Actinomycete complexes in the rhizosphere of winter rye on soddy podzolic soil].

The structure of actinomycete complexes in the rhizosphere of winter rye (Secale cereale L.) varieties originating from different ecosystems and geographical zones was studied in field experiments on soddy podzolic soil. In addition to streptomycetes, the complexes studied contained actinomycetes of the genera Micromonospora and Streptosporangium, represented at high occurrence and comparable abundance rates. The rhizosphere of most of the studied rye varieties was dominated by micromonosporas. The antifungal potential of mycelial prokaryotes associated with winter rye was assessed. The taxonomic and functional structure of actinomycete complexes was shown to be similar in rye varieties originating from the nonchernozem zone of Russia. However, the actinomycete complex proved to be much different in the rye variety that developed in the steppe zone of the lower Volga region.