Oxindole-3-acetic Acid: Physical Properties and Lack of Influence on Growth

The auxin activity of OAA was studied. The assays used were the Avena coleoptile curvature and section tests, and the first internode test. OAA was completely inactive to these assays. Physical tests indicated no color reaction with modified Salkowski reagent (Gordon-Weber) and no activity of any of the biochromatograms run with OAA. These data indicate that OAA is inactive as an auxin due to its characteristics of structural difference from IAA and further lends some speculation as to the site of activity of IAA as an auxin.