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.
Department of Biological Sciences, Washington-Singer Laboratories, Exeter University, EX4 4QG, Exeter, UK.
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Hartung
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Phillips