[Physiological and biochemical activity of bacteria during germination of cucumber seeds and impact of ciliates Colpoda steinii on this process].

It is shown that the bacteria Bacillus subtilis B-7023 IMV produce indole-3-acetic acid and amino acids in the liquid medium Knoop. Processing cucumber seed suspension containing 10(7) cfu/ml as bacilli, and Azotobacter vinelandii IMV V-7076, resulted in a decrease in the length of the roots of plants. Reduction of bacterial load bacilli to 10(6) cfu/ml followed by reduction of indole-3-acetic acid in the medium, and to an increase in the length of roots, shoots and total plant mass. During the cultivation of Bacillus subtilis IMV V-7023 with ciliates Colpoda steinii reduced the amount of free forms of auxin in the medium to 5.5 times, and the related--to trace amounts. The content of histidine, phenylalanine, tyrosine, methionine and lysine significantly reduced.

[Interrelations of infusoria with Azotobacter and their influence on plants].

Symbiotic coexistence of infusoria Colpoda steinii with bacteria of Azotobacter genus has been investigated. It is shown that when infusoria are incubated during 3 days with the cells of A. vinelandii IMV D-7076 selected in the logarithmic phase of growth, the number of colpods increased 19 times, and with A. chrooccum 20--only 1.8 times. After 6 days of incubation with bacteria selected in the phase of stationary growth the number of infusoria increased with A. vinelandii 10 times, and with A. chrooccum 20 - 9.2 times. Treatment of seeds by the bacterial mix of A. vinelandii and C. stenii stimulates their germination, growth of roots and sprouts at early stages of plants development as compared with the use of cultures of monobacteria. It is evident that infusoria Colpoda steinii as well as the bacteria of Azotobacter genus secrete biologically active substances which accelerate growth and development of plants.

[Relationship of bacteria of Bacillus genus with ciliate Colpoda steinii and their impact on germination of plant seeds].

Features of symbiotic coexistence of bacteria of the genus Bacillus with ciliates Colpoda steinii have been studied. In their mutual cultivation during 10 days the number of bacteria B. subtilis IMV V-7023 was reduced 4.4 times, B. pumilus 3 - 3.4 times, B. megaterium 12 - 2.5 times. In the mixed culture with B. pumilus 3 the number of the ciliates increased gradualluy while under availability of the other two bacilli strains the number of protozoan increased in the first two days, after that their amount decreased. Treatment of some plants seeds by suspension of B. subtilis IMV V-7023 with the protozoan increased their germination and stimulated the growth of plants at the early stages of development.

[Chemotactic and adhesive properties of Azotobacter vinelandii and Bacillus subtilis].

The effects of some factors on the chemotaxis of Azotobacter vinelandii IMV V-7076 and Bacillus subtilis IMV V-7023 and on their adhesion to cucumber roots have been studied. Glucose chemotaxis and adhesion to roots reach peak values in pH ranges characteristic of each strain. These ranges are 7.0-8.0 for A. vinelandii IMV V-7076 and 6.0-7.0 for B. subtilis IMV V-7023. The adhesion values of each species decrease significantly in their mixed suspension. The interaction of each of the strains with the clay mineral montmorillonite improves their adhesion to cucumber roots. The clay mineral palygorskite improves the adhesion of A. vinelandii but reduces that of B. subtilis.

[Production of biologically active substances of indol nature by bacteria of Azotobacter genus].

A stimulating effect of Azotobacter vinelandii IMB B-7076 bacteria on germination of seeds and formation of germs of different plants has been shown. One of the factors, which determines such phenomenon is the accumulation of biologically active substances in culture medium. The researched bacteria of Azotobacter genus accumulate indoleacetic acid (IAA) in the culture medium. Other substances of indol nature have been identified in the culture medium of these bacteria. It has been shown, using the computer's program PASS that these substances cannot take part in the regulation of plants growth. However 1H-indole-3carboxaldehyde can be characterized by antagonistic activity.

[Adhesion of Azotobacter vinelandii IMV V-7076 and Bacillus subtilis IMV V-7023 on different surfaces].

The dependence of Azotobacter vinelandii IMV V-7076 and Bacillus subtilis IMV V-7023 adhesion on some parameters of dispersion media (pH, Ca 2+ ions presence) has been investigated. It has been determined that a decrease of bacteria negative charge determines an increase of the degree of their attachment to abiotic surface (glass) that corresponds to physicochemical regularities of the given process. The adhesion of bacteria on the biotic surface (cucumber roots) is not subordinated to generally accepted ideas, according to which the electrostatic repulsion between the interacting objects is one of factors that determines the adhesion effectiveness.

[The effect of Azotobacter vinelandii on plant seed germination and adhesion of these bacteria to cucumber roots].

Bacterization of seeds of several plant species with Azotobacter vinelandii suspension stimulates their germination to different degrees. This demonstrates that seeds of different species display different sensitivity to the biologically active substances accumulating in the culture liquid of these bacteria. The adhesion patterns of these bacteria to cucumber roots were studied. The maximal number of cells adhered to the root surface at the phase of culture logarithmic growth (24 h), when they were motile. The loss of motility in the stationary growth phase (72 h) decreased the number of cells adhered to roots by 80%.

[Effect of argillaceous minerals on the growth of phosphate-mobilizing bacteria Bacillus subtilis].

It was shown that the argillaceous minerals montmorillonite and palygorskite at concentrations within 0.2-1.0% considerably accelerate the growth of phosphate-mobilizing bacteria Bacillus subtilis grown in media with hardly soluble Ca3(PO4)2 as the sole source of phosphorus. The most notable effect of these minerals was recorded at concentrations within 0.5-1.0%. The effect of argillaceous minerals in the colloidal form on bacterial growth was more pronounced than that of the powdered ones. An increase in montmorillonite or palygorskite concentrations to 2% is accompanied by the inhibition of the growth of the phosphate-mobilizing strain. At such concentrations the minerals adsorb ca. 22% of the glucose and 11.3% of the phosphate added to the nutrition medium.

[The effects of several factors on the growth of pure and mixed cultures of Azotobacter chroococcum and Bacillus subtilis].

We studied the effect of a clay mineral, palygorskite, on the physiological activity of Azotobacter chroococcum and the phosphate-mobilizing bacterium Bacillus subtilis, as well as their mixed cultures, under various oxygen supply conditions during the utilization of phosphorus from readily and poorly soluble compounds (K2HPO4 x 3H2O) and (Ca3(PO4)2), respectively. During cultivation of the bacteria in a nutrient medium with Ca3(PO4)2, the number of microorganisms was higher than that observed in a medium with K2HPO4. An increase in oxygen mass transfer in the nutrient medium was followed by a rise in the number of Bacillus subtilis cells and an inhibition of Azotobacter chroococcum growth. An addition of palygorskite (5 g/l) into the nutrient medium stimulated the growth of both bacteria and stopped the decreasing growth of Azotobacter chroococcum at high values of oxygen mass transfer. The number of Bacillus and, particularly, Azotobacter cells was two to five times lower in a mixed culture than in a monoculture. These differences were less significant during the cultivation of mixed cultures in medium with palygorskite.