ADVENTITIOUS ROOT FORMATION IN RELATION TO THE UPTAKE AND DISTRIBUTION OF SUPPLIED AUXIN

SUMMARY Triiodobenzoic acid (TIBA) or morphactin (chlorfluorenol), applied to the base of the epicotyl of mung bean cuttings, inhibit root formation in the hypocotyl. Such inhibition occurs even when cuttings are supplied with auxin at the same time. Both treatments reduce the accumulation of radioactivity in the hypocotyl when [ 14 C]IAA is supplied to the primary leaves. Morphactin does not influence the uptake of [ 14 C]IAA supplied basally to cuttings, nor does it have any apparent influence on the distribution of radioactivity within the cutting. However, the extent to which [ 14 C]IAA moves from leaves to hypocotyl is influenced by the basal supply of auxin in which cuttings are placed. These observations are discussed in terms of the role of the leaves in auxin‐induced adventitious root formation.