Thiocarbamates as plant growth regulators

The findings of van der Kerk and his coworkers (10) that carboxymethyl (limietlhyldithiocarbamate (1) caused epinastic curvature ancl leaf deformations as well as some elongation of Avena coleoptile tissue related its action as a growth regulator to that of indole-3-acetic acid and other aromatic structures. However, there are several unusual aspects of this compound and its activity. It is the only such regulator without an unsaturated ring system. It is an extremely polar compound, whereas the other regulators have a large nonpolar structure as a part of the molecule. Only a very few of its analogues have activity. Its activity is shown only at relatively high concentrations. In an attempt to rationalize the activity of the clithiocarbamates in terms used for the indoleacetic and phenoxyacetic acids by Veldstra (12), van der Kerk and his coworkers (10) suggested that the resonance in the thioamide group would tend to hold the two alkyl groups attached to the nitrogen in the same S