Accumulation of C-radiolabel in leaves and fruits after injection of [C]tryptophan into seeds of soybean.

Injection of [(14)C]tryptophan into one seed in a soybean fruit resulted in recovery of radiolabel in a fraction that cochromatographed with indoleacetic acid (IAA) through three successive high performance liquid chromatography separations. Label was found in the putative IAA fraction in all of the fruit tissues sampled and in the blade of the leaf subtending the pod into which the radiolabeled tryptophan had been injected. This suggested that IAA or an IAA precursor was transported from seeds to other parts of the fruit and to subtending leaves.