Concentration of Indole-3-acetic Acid and Its Derivatives in Plants

Seeds of oat, coconut, soybean, sunflower, rice, millet, kidney bean, buckwheat, wheat, and corn and vegetative tissue of oat, pea, and corn were assayed for free indole-3-acetic acid (IAA), esterified IAA, and peptidyl IAA. Three conclusions were drawn: (a) all plant tissues examined contained most of their IAA as derivatives, either esterified or as a peptide; (b) the cereal grains examined contained mainly ester IAA; (c) the legume seeds examined contained mainly peptidyl IAA. Errors in analysis of free and bound IAA are discussed.