Occurrence of Endogenous Indol-3yl-Aspartic Acid in Light and Dark-Grown Bean Seedlings (Phaseolus vulgaris).

An acid ether-soluble, strongly growth-stimulating substance revealed by the Avena coleoptile straight-growth test in methanol extracts from bean seedlings (Phaseolus vulgaris L.) was identified as indol-3yl-aspartic acid (IAAsp). Points of agreement between synthetic IAAsp and the investigated growth stimulator were indicated by chromatographic behavior, elution stimulator were indicated by chromatographic behavior, elution volume in gel filtration, mobility in paper electrophoresis, "colour reaction" with DMCA reagent, ability to form indol-3yl-acetic acid (IAA) and aspartic acid after hydrolysis and, finally, biological activity in the Avena test. Furthermore, some experiments demonstrated the occurrence of an inhibitor in extracts from light-grown tissue. This masked the stimulation of IAAsp in the Avena test when the extracts had been chromatographed in isopropanol: NH₃ : H₂O. A comparison of the levels of IAAsp between green and etiolated tissue did not reveal any distinct difference, demonstrating that the IAA conjugate IAAsp does not participate in the regulation of the photomorphogenesis. [ABSTRACT FROM AUTHOR]