Resumo

LARA MANTILLA, Cecilia; OVIEDO ZUMAQUE, Luis E  e  BETANCUR HURTADO, César A. Strain native with potential in the acetic acid production indol to improve the grass. Zootecnia Trop. [online]. 2011, vol.29, n.2, pp.187-194. ISSN 0798-7269.

In order to find efficient strains in the production of phytohormone from genera Azotobacter sp and Azospirillum sp native to the Zone of the Sinu in the Department of Cordoba, Colombia, 90 microorganisms of the strains were isolated, from grounds of the rizosfera of cultures of banana, maize, grass, yucca, cotton and field of stubble. The populations were evaluated in presence of Tryptophan and the production of indolacético acid (AIA) was obtained a ranging from 3,0 to 45, 0 ppm; the determination was realised by colorimetric technique using Salkowski`s reagent. The technique was modified, adapted and standardized. One of the isolates of the Azotobacter found in zones of left-overs concentrated the greater ampunt of the auxin: 44,726 ppm. A preliminary test was realized inoculating seeds of Angleton grass (Dychanthium aristatum) with different bacterial concentrations: 10⁶, 10⁷ y 10⁸ UFC and were compared with a witness without inoculate. The results showed to a greater average of the length of the stem and length of leaves of the sampled plants

Palavras-chave : Azotobacter sp; Azospirillum sp; Auxin; AIA; reagent of Salkowski; grass; Dychanthium aristatum.