ABSTRACT
This study evaluated 26 pigeonpea rhizobial isolates according to their cultural characteristics, intrinsic antibiotic resistance, salt and temperature tolerance, carbon source utilization and amylolytic activity. The cultural characterization showed that the majority of them presented the ability to acidify the YMA. Among the 27 isolates evaluated, 25 were able to grow when incubated at 42° C and 11 showed tolerance to 3% (w/v) of NaCl in YMA medium. The patterns of carbon sources utilization was very diverse among the isolates. It was observed the capacity of three strains to metabolize all the carbon sources evaluated and a total of 42% of the bacterial isolates was able to grow in the culture medium supplemented with at least, six carbon sources. The carbon sources mannitol (control) and sucrose were metabilized by all isolates evaluated. The profile of intrinsic resistance to antibiotics showed that the isolates were mostly resistant to streptomycin and ampicillin, but susceptible to kanamycin and chloranphenicol. High amylolytic activity of, at least, four isolates was also demonstrated, especially for isolated 47.3b, which showed the highest enzymatic index. These results indicate the metabolic versatility of the pigeonpea rhizobia, and indicates the isolate 47.3b to further studies regarding the amylase production and characterization.
Subject(s)
Anti-Bacterial Agents/analysis , Drug Resistance, Microbial , Streptomycin/isolation & purification , Genetic Variation , Nitrogen Fixation , Phenotype , Rhizobiaceae/physiology , Rhizobiaceae/isolation & purification , Biotechnology , Methodology as a SubjectABSTRACT
O cornichão (Lotus corniculatus L.) tem sido apontado como uma das forrageiras mais promissoras para o uso no Rio Grande do Sul. No entanto, pouco se conhece a respeito da interação dessas plantas com os rizóbios nativos em condições de campo. Este estudo visou a avaliar a eficiência das interações entre rizóbios e plantas de Lotus corniculatus cv. 'São Gabriel' em condições de campo. O experimento foi conduzido na Estação Experimental Agronômica da UFRGS com delineamento de blocos ao acaso com quatro repetições. Os tratamentos estudados foram: dois controles sem inoculação (um com a adição de 80kg ha-1 de nitrogênio na forma de uréia e outro sem a adição de nitrogênio); inoculação com rizóbios: estirpes SEMIA 816, recomendada no Brasil, U510, recomendada no Uruguai, U512, em estudo no Uruguai, e quatro isolados de rizóbios nativos (UFRGS Lc322, UFRGS Lc349, UFRGS Lc269 e Iso 7). O isolado UFRGS Lc322 e a estirpe U510 são mais eficientes do que a estirpe SEMIA 816, recomendada para cornichão no país. Além disso, a produção de forragem das plantas inoculadas com o isolado UFRGS Lc322 e a estirpe U510 superou a obtida com a adição de 80kg ha-1 de nitrogênio.
The bird's-foot trefoil (Lotus corniculatus L.) has been pointed as one of the most promising forage plants for use in Rio Grande do Sul. However, there is lack of information about the interaction of those plants with the native rhizobia in field conditions. This study aimed to evaluate the efficiency of interactions between rhizobia and plants of Lotus corniculatus cv. 'São Gabriel' in field conditions. The experiment was carried out in the Agronomic Experimental Station (EEA) of the Federal University of Rio Grande do Sul (UFRGS), using random block design with four replications. The treatments were: two controls without inoculation (one with the addition of urea corresponding to 80kg ha-1 of nitrogen and other without nitrogen addition); inoculation with rhizobia: strain SEMIA 816, recommended in Brazil, U150 recommended in Uruguay and U512, being studied in Uruguay, and four rhizobia isolates (UFRGS Lc322, UFRGS Lc349, UFRGS Lc269 e Iso 7). The rhizobia isolate Lc322 and the strain U510 are more efficient than the strain SEMIA 816, which is recommended for bird's-foot trefoil in the country. Furthermore, the forage production of plants inoculated with the isolate Lc322 and the strain U510 surpassed that, with the addition of 80kg ha-1 of nitrogen.
ABSTRACT
To solve separating problem of natural soda, fifty-seven strains screened from soil, floul water and activated mud were of flocculating activity. Two strains of bacteria, which were screened from above mentioned strains have higher activity and better steady than the whole culture liquid of bacteria was observed that its flocculating use to natural soda was strong and the mean flocculating rate of two strains were 79.80% and 87.% respectively.