Physiological and biochemical studies of adventitious root formation. Extractible rooting cofactors from Hedera helix

Abstract

Physiological and biochemical studies were made of the extractible rooting cofactors from juvenile and mature growth phases of Hedera helix, English ivy. An extraction procedure involving 100, 95, 80, and 60% ethyl alcohol was adopted for general use. The number and concentration of rooting cofactors in the leaves, stems, and roots were determined. Elution of cofactor 4 (oxygenated terpenoids) from a silica gel column, with increasing amounts of ethyl acetate in hexane, resulted in five major fractions and several minor ones. High levels of chlorogenic and isochlorogenic acids were found in all tissues, while traces of caffeic and ferulic acids were detected only in the roots. The decreasing order of plant parts from both growth phases for total chlorogenic and isochlorogenic acids was leaves, roots, and stems; this pattern also applied to total phenol content of the plant parts. Chlorogenic acid was a component of rooting cofactor 2. Rooting cofactor 3 had at least three constituents: chlorogenic and isochlorogenic acids, and an unknown promoter (P-257). The effects of caffeic, chlorogenic, isochlorogenic, and quinic acids with indoleacetic acid in the rooting bioassay were similar and not very large at a concentration of 5 × 10−4 M or lower. No active component of rooting cofactor 1 was identified.