presence of tryptophan as it is a precursor for IAA biosynthesis. The
significant enhancement in the production of IAA recorded with
concentration of tryptophan is in agreement with those of Ahmad
et al. (2005) who found 1.47 to 32.8 g ml−1 of IAA in presence of
1–5 mg ml−1 tryptophan. Similar results were obtained for Bacillus
isolates by Srinivasan et al. (1996). The reason being l-tryptophan
acting as suitable precursor for auxin synthesis. The phytohormone,
IAA has been directly correlated with growth promotion of plants
(Noel et al., 1996; Tsavkelova et al., 2006). The release of this phytohormone
during the study evidently suggests the plant growth
promoting ability of the test strain.
Characterization of multifaceted Bacillus sp. RM-2 for its use as plant growth
promoting bioinoculant for crops grown in semi arid deserts