A Note on the Manipulation of Flower Symmetry inAntirrhinum majus

Treatments consisting of maceration of the centre of the shoot apical meristem or localized application of the plant hormone, indoleacetic acid (IAA), to apical flower buds or the estimated centre of the shoot apex were made to test their effect, if any, on flower shape or symmetry. Both types of treatment affected flower symmetry. IAA treatment was most successful, but it also affected the completeness of the flower, producing a small number of reduced flowers. Alteration of symmetry was, however, the main response to treatment.