The production of indole-3-acetic acid (IAA) by these bacteria
was determined using the Salper’s reagent (Gordon and Paleg,
1957). Three milliliters of fresh Salper’s reagent (1 mL 0.5 M FeCl3
in 50 mL 37% HClO4) was added to free-cell supernatant and keptin
complete darkness for 30 min at room temperature, and the optical
density at 535 nm was measured in each treatment (Wöhler,1997).
A standard curve was also prepared for IAA determination.