Related Experiment Video
Updated: Aug 8, 2026

Scalable, Flexible, and Cost-Effective Seedling Grafting
Published on: January 6, 2023
Gibberellin-auxin interaction in pea stem elongation
1Department of Biology, Yale University, New Haven, Connecticut 06520.
Abstract:
Joint application of gibberellic acid and indole-3-acetic acid to excised stem sections, terminal cuttings, and decapitated plants of a green dwarf pea results in a markedly synergistic growth response to these hormones. Synergism in green tall pea stem sections is comparatively small, although growth is kinetically indistinguishable from similarly treated dwarf sections.Gibberellin-induced growth does not appear to be mediated through its effect on auxin synthesis, since gibberellin pretreatment of dwarf cuttings fails to elicit an enhanced tryptophan-induced growth response of sections, whereas auxin-induced growth is strongly enhanced. Also, tryptophan-gibberellin synergism is not significant in sections and cuttings of green dwarf peas, while auxin-gibberellin synergism is.Administration of gibberellic acid prior to indole-3-acetic acid results in greatly increased growth. In reversed order, the application fails to produce any synergistic interaction. This indicates that gibberellin action must precede auxin action in growth regulation.
Related Concept Videos
Plant Hormones
Cell Signaling in Plants
Meristems and Plant Growth
Primary and Secondary Growth in Roots and Shoots
Responses to Gravity and Touch
Stringent Response in E. coli

