Research Article

Genotypic Characterization of Azotobacteria Isolated from Argentinean Soils and Plant-Growth-Promoting Traits of Selected Strains with Prospects for Biofertilizer Production

Figure 3

Phytohormone production and nitrogenase activity by the selected Azotobacter strains. (a) Indole-3-acetic acid (IAA) production; (b) gibberellic acid (GA3) production; (c) zeatin (Z) production, and (d) nitrogenase activity. IAA and GA3 were identified and quantified by gas chromatography-mass spectrometry, Z was identified and quantified by HPLC-UV, and nitrogenase activity (acetylene-ethylene reduction) was determined by gas chromatography. Bars are means of three replicates. The same letters indicate no significant differences between means as determined by the DGC test ( ).