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The polar movement of IAA has been examined in 5-mm root segments of Brassica oleracea and Helianthus annuus. The movement was studied partly with IAA-1-14C and partly with IAA-5-³H In both plants a slight acropetal flux of 14C and IAA-³H was found through the segments. The recovered radioactivity in the agar receiver blocks and in the receiver end of the segments increased as a function of time. A large portion of the applied IAA was converted on the cut surfaces and in the tissues of the segments. Chromatographic analysis indicated different destruction products when estimated by scintillation counting and by spraying with indole reagent (DMCA). Chromatograms run in isopropanol : ammonia : water, 8 : 1 : 1, yielded three different substances, one spot near the starting line and one near the front, neither of which has been identified. Finally there was a spot with Rf 0.4-0.6, probably representing IAA.

The formation of certain indole compounds in Acetobacter xylinum was investigated by paper chromatographic methods supplemented with preliminary bioassays. The results indicate the production of indole-3-acetic acid (IAA) and tryptophol (Tr-ol) when the bacterium is cultivated on a medium containing peptone. IAA and Tr-ol were also produced when washed bacterial cells were in- cubated for 24 hours with DL-tryptophan (1 g. pr L). The yield of IAA was of the order of 5 % of the tryptophan. When sodium hydrosulphite was present in the incubation medium, the yields of IAA and Tr-ol were considerably reduced, but under these circumstances the formation of small amounts of indole-3-acetaldehyde (IAAId) could be demonstrated. These results are in agreement with the view that IAAId is the immediate precursor of IAA and Tr-ol. [ABSTRACT FROM AUTHOR]

A spectrophotometric method for the identification of tryptophol, indole-3- acetic acid (IAA), and indole-3-acetonitrile (IAN) is described. The method can probably also be applied to other indole derivatives. If the components of a mixture of indolic compounds are to be identified, these must first be separated by chromatographic methods. Procedure. Eluate containing approximately 100 μg. of the indole compound is dissolved in 2.75 ml. of methanol. Ehrlich's reagent (l.5 ml.) is O added. The mixture is heated at 95°C for 2 min., after which 0.25 ml. 1 % NaNO2 in water are added. The mixture is cooled for 30 min. at room temperature. The volume is adjusted to 4.5 ml. with methanol, and the optical density at wavelengths between 470 and 700 mμ is read on a spectrophotometer. Absorption spectra for the reaction products of tryptophol, IAA, and IAN are presented. The method can be used for quantitative determinations of tryptophol in the range 10 to 100 μg. and for IAA between 100 and 500 μg. Supporting evidence for the occurrence of tryptophol in the culture medium from Acetobacter xylinum was provided by using this method. [ABSTRACT FROM AUTHOR]