Strongly Acidic Auxin Indole-3-Methanesulfonic Acid

Abstract

A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. The utility of both Fourier transform IR spectometry and fast atom bombardment mass spectrometry for analysis of IMS was demonstrated. IMS was an active auxin, stimulating soybean [Glycine max] hypocotyl elongation, bean [Phaseolus vulgaris] 1st internode curvature and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 .mu.M concentration, IMS exhibited a basipetal polarity in its transport in both corn [Zea mays] coleoptile and soybean hypocotyl sections. [14C]IMS should be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles.