Uptake, Translocation, and Metabolism of IAA in the Olive (Olea europea)

Abstract

The uptake, translocation, and metabolic pathway of IAA degradation in detached ‘Manzanilla’ olive leaves were studied using [2–¹⁴C] IAA. The uptake of radioactivity was very rapid. With scraped leaves devoid of their peltate scales, it reached 80 percent of total applied radioactivity after 6 h. Translocation from the site of application in mature leaves was negligible. Limited transport was apparent only in young leaves. The absorbed label was initially ethanol-extractable but later half of the radioactivity could not be extracted in ethanol and had to be extracted with 1 N KOH. The first and major metabolite of the IAA in the olive leaves was identified as indolecarboxylic acid (ICA). Minor amounts of indoleacetylaspartic acid (IAsp) and indolealdehyde (IAld) were also detected. The identity of the KOH-extractable label was not determined.