Indoleacetic Acid Metabolism in Cuttings of Plum (Prunus cerasifera × P. munsoniana cv. Marianna 2624)1

Abstract

Abstract Treatment of ‘Marianna 2624’ plum cuttings for 7 days with 1-14C-IAA with or without a pretreatment with 4000 ppm indolebutyric acid (IBA) for 5 sec revealed that the synthetic hormone inhibited IAA oxidase activity as measured by the decreased rate of 14CO2 evolution. KOH hydrolysis of different radioactive zones on paper chromatograms derived from alcoholic extractives of cuttings yielded presumptive IAA upon re-chromatography. Likewise, KOH and peptidase treatment of the alcohol insoluble residue yielded a radioactive substance with chromatographic properties characteristic of IAA. The presence of presumptive IAA and ninhydrin-positive substances in the peptidase hydrolyzate indicate that IAA was bound to protein(s). Appreciable radioactivity still remained in the alcohol insoluble residue after protein hydrolysis.