A Potent Auxin with Unique Chemical Structure-4-Amino-3,5,6- Trichloropicolinic Acid

The compound 4-amino-3,5,6-trichloropicolinic acid was found to act as an auxin, and in most cases as a strong auxin, in its effects upon the extension of wheat and oat coleoptile sections, pea stem internode sections, pea root tips, the roots of wheat seedlings from normal and γ-irradiated grains; upon the growth of fruits from emasculated tomato flowers; and upon the induction of cell division in tobacco stem pith cells. This compound represents a new chemical class of auxin, and its effects support a theory published in 1959 on the relationship between chemical structure and auxin activity.