RESUMEN
Significant correlations exist between the ability of root-nodule bacteria to fix molecular nitrogen and some of their properties (accumulation of riboflavin, cobalamine, ATP, cell pyrolysis, effect on plant vegetation characteristics) which can be used for quickly assessing the activity of the process in individual strains of rhizobia.
Asunto(s)
Plantas/microbiología , Rhizobium/metabolismo , Microbiología del Suelo , Adenosina Trifosfato/biosíntesis , Técnicas Bacteriológicas , Técnicas de Cultivo/métodos , Calor , Nitrógeno/metabolismo , Nitrogenasa/metabolismo , Riboflavina/biosíntesis , Simbiosis , Vitamina B 12/biosíntesisRESUMEN
Deformation of lucerne root hairs caused by the action of beta-indolylacetic acid (IAA) and alpha-naphthylacetic acid (NAA) differs from deformation induced by Rhizobium meliloti. High concentrations of IAA brought about abnormal deformation of root hairs wherease the action of average concentrations of IAA resulted in corkscrew-like winding and wavy structures. No deformation was observed under the action of low IAA concentrations or the cultural broth of Rhizobium. Infective filaments in root hairs were found only upon infection with pure cultures of Rhizobium.
Asunto(s)
Sustancias de Crecimiento/farmacología , Medicago sativa/microbiología , Enfermedades de las Plantas , Rhizobium/patogenicidad , Acetatos/farmacología , Medios de CultivoRESUMEN
The nitrogen fixing activity of Rhizobium japonicum in symbiosis with soya grown in the sterile microvegetative conditions at an air humidity of 70%, at a temperature of 20 degrees C and a length of light day of 16 hours was assayed using the acetylene technique. The plants were cultivated in phytotron in glass tubes (245 cm3) illuminated with xenon lamps. This technique can be used, apparently, to determine the nitrogen fixing activity of other legumes and cereals.
Asunto(s)
Fijación del Nitrógeno , Rhizobium/metabolismo , Humedad , Luz , Glycine max , Temperatura , Factores de TiempoRESUMEN
As was shown using the acetylene technique, the nitrogenase activity of Rhizobium meliloti and Rhizobium vigna increased when they were cultivated with the root tissue cultures of legumes (lucerne, sweetclover) and non-legumes (tobacco, glasswort, carrot), particularly in the case of the former. The maximum activity of nitrogenase was found in R. meliloti. The tissue cultures of legumes had no effect on the growth of Rhizobium whereas the tissues of non-legumes stimulated their biomass accumulation though the activity of nitrogenase in both Rhizobium cultures was low in this case. Therefore, the metabolites of legumes produced a specific action on the nitrogenase of nodule bacteria.
Asunto(s)
Fabaceae , Nitrogenasa/metabolismo , Plantas Medicinales , Rhizobium/enzimología , Medios de Cultivo , Activación Enzimática , Factores de TiempoRESUMEN
The dependence of the nitrogenase activity of Rhizobium meliloti on the strain peculiarities of the cultures, the composition of the media used, and the metabolites of legume tissue cultures was demonstrated by the acetylene method. The nitrogenase activity is significantly higher in R. vigna than in R. meliloti, under the same experimental conditions. Enrichment of the Murashige-Skoog medium with arabinose (25 mM), succinate (25 mM), glutamine (2 mM nitrogen), and yeast extract (0.1%) substantially stimulated the nitrogenase activity of a pure culture of R. vigna. The maximum nitrogenase activity on this medium was noted when metabolites of sweet clover tissue were introduced.
Asunto(s)
Nitrogenasa/metabolismo , Rhizobium/enzimología , Etilenos , Factores de TiempoRESUMEN
Experiments were conducted with five clover varieties and six lucerne varieties infected with their specific strains of nodule bacteria with a high or low activity. The role of plants in active symbiosis with nodule bacteria was established. The nitrogen fixing activity of nodule bacteria varied within a wide range depending on the plant variety. Not only the activity of the strain, but the variety of the plant too, should be taken into account for industrial purposes.