Bioassay Test for Detection of Plant Growth Promoting Substance in Bacillus polymyxa Isolated from Rhizosphere of Brinjal

Rhizosphere, phylloplane and caulosphere is the region where a complex community of microbes, mainly bacteria and fungi are present. The microbe plant interaction in these regions can be beneficial, neutral, variable, or deleterious for plant growth. Among the possible mechanisms, proposed to explain the growth promotion by rhizobacteria are the enhancement of mineral availability and uptake and production of phytohormones, which stimulate plant growth. Many rhizobacteria produce phytohormones, this evidence has been primarily from analysis by bioassay, usually on chemically defined media, always in a system containing a single microorganism.