title: [Growth and survival of Azospirillum in roots and maize rhizospheres with different levels of acidity].
abstract: An experiment was carried out in order to evaluate the effect of pH on Azospirillum sp. growth and survival in maize rhizosphere. Sterilized maize seeds were sown in a perlite substratum with addition of a nutritive medium. The pots were buffered at two different pHs: 5.8 (group one) and 7.0 (group two). Each group was divided in two treatments: inoculated with Azospirillum sp. Az-39 and non-inoculated. Experimental pots were incubated at 20 degrees C with a 14 hour photoperiod. Growth of non-inoculated roots was negligible. Inoculated roots showed a better response at pH 5.8 than at 7.0. Several accompanying bacteria were found. Azospirillum grew in both groups with a low penetration into roots. A set of nutritive relationships among microorganisms and maize roots was observed; Xanthomonas is a maize pathogenic bacteria, and it is a NO3- consumer, and uses this anion as hydrogen acceptor. The Gram (-) Diplococcus is a nitrate producer . Cytophaga and Flavobacterium are related with roots decomposition. It is concluded that Azospirillum improves the root growth, mainly at pH 5.8.
authors.affiliation: Departamento de Ciencias Básicas, Universidad Nacional de Luján, Argentina.
authors.forename: V J
authors.initials: VJ
authors.lastname: Eöry
authors.forename: F R
authors.initials: FR
authors.lastname: Momo
authors.forename: M
authors.initials: M
authors.lastname: Alvarez
mesh_terms: D016949:Azospirillum / Q000254:growth & development*; D003589:Cytophaga / Q000378:metabolism; D005417:Flavobacterium / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology; D012988:Soil Microbiology; D013559:Symbiosis; D014974:Xanthomonas / Q000378:metabolism; D003313:Zea mays / Q000382:microbiology*
chemical_list: D009566:Nitrates
vernacular_title: Crecimiento y supervivencia de Azospirillum en raíces y rizosfera de maíz con diferentes niveles de acidez.