Metabolism of Indole-3-acetaldehyde.

Aerobic infiltration of synthetic indoleacetaldehyde (IAAld) in buffered medium of pH 4.55, into living tissues of lower and higher plants, leads in the majority of cases to the formation of both indoleacetic acid and tryptophol. This activity is evinced by etiolated as well as green tissues. Besides, all parts of higher plants tested — roots, cotyledons, hypocotyls and leaves possess this activity. Abolishment of this activity by boiling indicates its enzymic nature. Coupled with the established occurrence of indoleacetaldehyde, the widespread distribution of such activity, strengthens the probability that indoleacetaldehyde may be the normal and natural precursor in the biosynthesis of indoleacetic acid.