Figure 4.

Results were obtained from in vitro preparations of orange pericarp seedlings of maize. Conditions are as described for Figure 1. A1 to A3 are three replicated reactions using [¹⁴C]indole in the reaction mixture, and for replicates C1 to C3 the radiolabeled substrate was [¹⁴C]Trp. Trp does not partition into ethyl acetate from the aqueous phase, so it is not shown on these chromatograms. Quantification of radioactivity at the R_F of IAA (obtained by software analysis of the scanned image and correction for counting efficiency) is shown in the bar-graph inset (data from A1–A3 and C1–C3 were averaged).