Occurrence Of Azotobacter Research Articles

Биогеохимическая характеристика корнеобитаемого слоя травянистых растений на рекультивированных участках техногенных отходов

The introduction of the work substantiates the relevance of studying the biogeochemistry of the root layer of herbaceous plants growing on man-made waste from coal mining and iron ore enrichment after 40 years of reclamation. The main part of the report is devoted to the results of determining the gross content of heavy metals and metalloids, Sorg., residual toxicity, occurrence and growth characteristics of the bacterium Azotobacter chroococcum in embryos and background soil under similar plants. It is shown that during the long-term development of embryosems on waste of different origin, a high pool of heavy metals and metals is preserved in them, and Sorghum accumulates. In the area of coal mining around the roots of the clover, the maximum concentrations of Pb are detected, while cereals - Br. On the forested tails of the iron ore agglomeration, the trend is different: Ca, Ni, Cu, Mn, Zn are concentrated around the roots of cereals, and As is near the roots of the clover. However, the residual toxicity is manifested only on the tailings of the iron ore agglomeration. It has been established that the occurrence of azotobacter in the root layer of different plants is ubiquitous, but in the embryos of the forested tailings pond, the bacterial populations are heterogeneous, they contain donkey strains showing luminescence, rhizoid growth type and antagonism. Around the roots of the clover, conditions were formed that were less favorable for reproduction than under cereals. The data obtained expand knowledge about the role of phytobiomes in the migration of chemical elements at man-made facilities, can be taken into account when developing toxicity neutralization and in predicting the effectiveness of biological reclamation.

Occurrence of Azotobacter spp. in cultivated soils in Poland

Azotobacter spp. are soil bacteria capable of fixing atmospheric nitrogen and making it available to plants. This makes them microorganisms of hight importance to the agriculture. The distribution of these bacteria is a complicated subject and is correlated with diverse factors, witch determine the presence or absence of the bacteria in a specific soil. The soil properties as soil and fertility and climate conditions affect the abundance of diazotrophs. Research material consisted of 182 soil samples taken in 2015 from agricultural land in various voivodeships. The number of Azotobacter spp. was determined based on plate method. The presented study evaluated the abundance of Azotobacter spp. in various Polish soils and confirmed the relationship between soil properties and the presence of these bacteria. The studied bacteria were present in 37% of soil samples and numbers of these bacteria varied widely, from 3 to 10801 cfu g-1 of the soil. In the case of Azotobacter spp., soil acidity was also an important factor restricting the occurrence of these bacteria in soils.

The molecular marker-based comparison of Azotobacter spp. populations isolated from industrial soils of Cracow-Nowa Huta steelworks (southern Poland) and the adjacent agricultural soils

The occurrence of Azotobacter spp., which has beneficial effects on plant development, is related to various soil properties, such as pH and fertility. This study evaluated the prevalence of Azotobacter spp. in industrial (H) and agricultural soils (P) in Nowa Huta, Cracow and determined the phenotypic and genetic diversity of these bacteria. The examined bacteria were present in 40% of H and in 50% of P soils. Taxonomic identification of the bacterial isolates indicated the presence of three species—A. salinestris, A. chroococcum and A. vinelandii. The genetic diversity, determined using two fingerprinting methods—Random Analysis of Polymorphic DNA (RAPD) and Rep-PCR (BOX) revealed high level of population diversity. In AMOVA analysis most of diversity was attributed to within-population variation (76–85%), and only 3.78–6.18% was associated with among-group H and P variation. Global test of differences revealed distinct population structure within bacterial strains isolated from H and P areas only for BOX markers (Fst = 0.05732, P = 0.00275). Phenetic analyses: UPGMA and DCA better discriminated H and P groups based on RAPD data. Both BOX and RAPD methods provided an insight into the genetic complexity of Azotobacter spp. variation in soils of different land-use types.

Studies on the occurrence of Azotobacter and Azomonas species in the soils and rhizosphere of plants in Egypt

Summary The occurrence of Azotobacter in the rhizosphere of 16 crop plants, grown in different types of soil, at two stages of growth and in root-free (control) soil, was studied. Azotobacter counts varied with kind and age of the plant and with the type of soil. An increased population in the rhizosphere is more common with leguminous plants than in other plant species, and is greatest with young plants. The properties of the soil also influence the number of Azotobacter cells, found in the rhizosphere. 320 strains of Azotobacter were isolated and studied of their morphological, cultural, and biochemical characteristics. Azotobacter chroococcum was found to be the most predominant species, while Azotobacter vinelandii, though found occasionally, was less numerous. Azomonas agilis was isolated from the rhizosphere of some rice plants for the first time.

Nitrogen-fixing Bacteria in various Tissue Cells of Cyperus rotundus

Summary The bacterium, identified as Azotobacter chroococcum, was present within the cortical cells of the various organs of Cyperus rotundus, suggesting the possibility of symbiotic associations in grasses similar to legumes. Azotobacter was shown by Iswaran and Sen (1959) to occur in the rhizosphere of Cyperus rotundus. Dobereiner and Day (1976) have shown that Spirillum lipoferum occurs within the root cells of Digitaria decumbens. Bhide and Puran Dare (1979) reported the occurrence of Azotobacter within the root cells of the grass Cynodon dactylon. Since Cyperus rotundus is another widely distributed grass, it was thought worthwhile to find out whether a similar association occurs in this plant as well, and the method by Bhide and Puran Dare (1979) was followed.

The Azotobacter flora of some Czechoslovakian watercourses.

The occurrence of Azotobacter in some Szechoslovakian watercourses has been investigated. Several strains belonging to A. chroococcum and A. beijerinckii were isolated from 7 out of 18 samples. A. insignis has been isolated from the flowing water of Lake Machovo at Doksy. This is first report of this strictly aquatic Azotobacter species in Czechoslovakian watercourses. The taxonomy of the genus Azotobacter was discussed against the background of the existing knowledge resulting mainly from other taxonomic techniques than those based on the phenotypically expressed characters.

Studies on the interaction of plants and free-living nitrogen-fixing microorganisms. I. Occurrence of Azotobacter in the rhizosphere of crop plants.

The occurrence of Azotobacter in the rhizosphere of 17 crop plants grown in different types of soil in the field and in the greenhouse has been studied as part of a program of work on the interaction of plants and free-living nitrogen-fixing microorganisms. Azotobacter counts were very low in both rhizosphere and non-rhizosphere soil from the field; they varied with the type and age of the plant and with the type of soil. The organism was usually absent from acidic and poor soils. I n the greenhouse experiments, soil counts of these bacteria were found to be somewhat higher than in the corresponding soil in the field (Granby sandy loam). The root effect was greater with both radish and wheat in the poor soil (Upland sand) than in the fertile Granby soil. Onion exerted no obvious influence on the Azotobacter population in either soil. However, even under optimum conditions of plant growth, numbers of these organisms were very low in comparison with those of other bacteria normally present in soil and in the root zone.

The effects of induced soil aggregation on the occurrence of Azotobacter and Streptomyces.

1. The effect of soil aggregation produced by synthetic soil conditioners on the occurrence ofAzotobacter andStreptomyces in a highly fertile Belgian loess soil was investigated by various methods. 2. Wide differences in levels of soil aggregation introduced technical problems which made impossible the obtaining of strictly comparable results. 3. In general increased soil aggregation tended to favour an augmentation ofAzotobacter andStreptomyces in the soil used and under the environmental conditions prevailing. 4. However, it seemed clear that in such investigations straight-line relationships cannot be obtained reliably because other soil micro-organisms also are favoured by such treatments and competitive effects may be emphazised from time to time. 5. No evidence was found of any inherent toxicity in the soil aggregating products used when they were employed within commercially practical limits.

Some observations on the occurrence of azotobacter in Finnish soils

In the present paper some observations upon the occurence of Azotobacter chroococcum in Finnish soils are reported. Without enrichment Azotobacter could be cultivated on the agar plates only from 5 soils out of the 72 samples tested. The enrichment procedure markedly increased the number of soils that gave positive results in the test. Azotobacter could not be found in soils with a pH value lower than 5.8. On the basis of the results it is concluded that Azotobacter probably is present in a large amount of our less acid soils, although generally, in very low numbers. The phosphorus status of the soil exerted some influence upon the development of inoculated Azotobacter in soil plaques. In soil tests the phosphorus requirement of Azotobacter appeared to be markedly higher than that of the crop plants, in general. It was supposed that in some cases this fact could be explained not only on the basis of the phosphorus need of the bacteria but on the basis of the high sensitivity of the organism to the effects of soil aluminium and iron prevented by phosphates. The cultivation of Azotobacter indicum from the soils failed, but Clostridium species could be found in all the samples tested. The increase in the nitrogen content of the mannitol solution cultures during incubation was highest when the soil contained Azotobacter chroococcum. But also in several cultures of soils from which no Azotobacter could be found by the agar plate method, a considerable increase in nitrogen was observed. This was connected with the formation of a thick membrane of fungi and bacteria on the surface of the liquid. The possibility of nitrogen fixation by the associations of soil microorganisms is discussed.

The Occurrence ofAzotobacterin Cranberry Soils

The Occurrence of<i>Azotobacter</i>in Cranberry Soils