THE ORTHO EFFECT IN PLANT GROWTH-REGULATORS

Abstract

The elongation of sections of Avena coleoptiles in solns. of 5 selected organic compounds was detd. An ortho effect in their activity as growth-regulators is indicated. Those derivatives of gamma-phenylbutyric acid, phenoxyacetic acid and indoleacetic acid which do not have an unsubstituted position ortho to the position of attachment of the side chain do not induce elongation. Methods for the prepn. of 2,6-dibromophe-noxyacetic acid, 2,5-dichlorophenylhydrazone of ethyl levulinate and 4,7-dichloro-2-methylindoleacetic acid are descr. for the first time.