Tryptamine in Zinc-Deficient Barley

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Abstract
Several Ehrlich-positive spots were detected on the thin layer chromatogram (TLC) of the zinc-deficient barley extract developed with n-butanol : acetic acid: water (4 : 1 : 2) as the solvent. Spot 1, a dominant spot in the basic fraction of the zinc-deficient extract gave the same Rf value as the authentic tryptamine on the TLC. No differences were found in chromogenic reactions such as Ehrlich, Salkowsky and ninhydrin reactions. The UV absorption spectrum of the purified spot 1 coincided completely with that of the authentic tryptamine. The purified spot 1 and the authentic tryptamine were compared by GC-MS. The mass spectra observed were identical within the limits of experimental error. Based on these results, it is concluded that a very large amount of tryptamine is present in zincdeficient barley. Tryptamine content was higher in barley shoots, which developed symptoms of zinc deficiency (16 μg/F.W. g). With an adequate zinc nutrition (Zn 50 ppb), tryptamine was also detected in barley seedlings, but the amounts (1.0 μg/F.W. g) was small in contrast to that in the zinc-deficient plant.