Production of IAA hormone in rhizosphere bacterial isolates of community forest stands

Abstract

The rhizosphere is the soil around plant roots, which is directly affected by soil microbes, and exudation of plant roots have an essential role in plant health and soil fertility. The IAA (Indole Acetic Acid) hormone or known as the auxin hormone, is a major member of the auxin group that controls important physiological processes, including cell enlargement and division, tissue differentiation, and responding light and gravity. The purpose of this study was to determine the ability of rhizosphere bacteria isolates to produce IAA hormone associated with tree roots at community forest stand. This study comprised rejuvenating bacterial isolates to obtain pure and uncontaminated isolates and testing IAA concentrations. The results showed that rhizosphere bacterial isolates around the roots in community forest stands could produce IAA hormones. The BR 2 (Bacillus) bacteria isolates produced the highest IAA, which indicated with the color change of isolates to pink, while BB 3 and JS 1 isolates produced the lowest IAA.