Influence of Indole-3-Acetic Acid on Incorporation of14C-Uridine by Adventitious Root Primordia of Brittle Willow

Abstract

Accumulation of label was measured autoradiographically in "preformed" adventitious root primordia of brittle willow (Salix fragilis L) nodes which were incubated with uridine-2-14C In untreated (control) plants, accumulation of label was about the same during initiation and early growth of the primordia Surgical treatment of stems to limit the supply of indole-3-acetic acid (IAA) to root primordia resulted in decreased accumulation of label only during the initiation stage Replenishment of auxin in surgically treated plants by applying IAA increased accumulation of label (in comparison to surgical treatment alone) by about 25% during primordium initiation and by about 100% during the early growth phase. The data are interpreted to mean that some factor in addition to auxin, possibly an auxin synergist, is required to initiate ribonucleic acid synthesis during the initiation of root primordium cells