Gibberellin Induced Changes in Diffusible Auxins from Savoy Cabbage

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Abstract
Diffusates from apices of young plants of savoy cabbage treated with gibberellie acid (GA) and apices of control plants have been examined with respect to their content of Indole auxins. Three indole Compounds were detected and identified on the basis of their chromatographic characteristics in several systems. These compounds were: glucoubrassicin, indole‐3‐acetic acid (IAA) and indole‐3‐acetonitrile (IAN).An effect of GA on the total auxin activity of the diffusate was noted 90 hours after treatment, while an increase in stem height occurred 48 hours later. This increase in auxin effect of the entire diffusates was shown bv chromogenic development and bioassay of chromatograms of diffusates to be a result of an increase in level of the IAA content. A concomitant decrease in I the glucobrassicin content was indicated.Since GA was found to have no effect on the enzymatic conversion of tryptophan or tryptamine to IAA, it is proposed that the effect of GA is on the conversion of glucobrassicin to IAA.