Basipetally polarised transport of [(3)H]gibberellin A 1 and [ (14)C]gibberellin A 3, and acropetal polarity of [ (14)C]indole-3-acetic acid transport, in stelar tissues of Phaseolus coccineus roots.

Movement of both [(3)H]GA1 and [(14)C]GA3 through root segments from P. coccineus seedlings was basipetally polarised. The basipetal/acropetal ratio of radioactivity from [(3)H]GA1 in agar receiver blocks was 9.2 for apical, elongating segments, and 4.0 for more basal, non-elongating segments. Polarity of gibberellin transport was restricted to the stele, and absent from cortical tissues. Transport of [(14)C]IAA through root segments to agar receivers was preferentially acropetal, particularly so in the stele. Despite the existence of basipetal polarity of gibberellin transport in the root, [(3)H]GA1 injected into cotyledons moved into and acropetally along the seedling root.