– 3-Indoleacetic acid sodium (Heteroauxin sodium salt) is a naturally occurring plant hormone of the auxin class. It can stimulate cell elongation and division, promoting plant growth and development. However, at high concentrations, it exhibits growth inhibiting effects, including epinasty and prevention of shoot and root growth. This latter effect formed the basis for which synthetic auxins were developed as herbicides and bioregulators in agriculture.