Fig. 5

Plant growth-promoting traits of Stenotrophomonas rhizophila FT₂. a: The supernatant was mixed with Salkowski’s reagent; the appearance of red indicated IAA production (tube 1: un-inoculated strains; tube 2: S. rhizophila FT₂); b: Yellow-orange halos in CAS agar medium indicated siderophore production; c: growth on Ashby nitrogen-free solid medium proved the ability to fix nitrogen; d: Nessler’s reagent was added in peptone water, and the development of brown to yellow color was the evidence of NH₃ production; e, f, g: clear zone formation around the colony in inorganic phosphorus, organic phosphate and potassium agar medium indicated the ability of solubilize inorganic phosphorus, organic phosphate and potassium; h: capacity to use ACC as a sole nitrogen source was the presence of bacterial growth in the DF salt minimal medium; and i, j: capacity to product protease and cellulase was evident as a clearing zone on Skim Milk Agar medium and CMC agar medium