Colchicine-Like Action on Plants of Some Amide Derivatives of 3,5- Dichlorophenoxyacetic Acid

Abstract

1. Some N-alkyl substituted amides of 3,5-dichlorophenoxyacetic acid (3,5-D), namely, N-methyl-, N-ethyl-, and N-butyl-3,5-dichlorophenoxyacetamide, caused swellings on different parts of seedlings of the majority of the twenty-two species tested when applied over a concentration range of 0.1-1000 p.p.m. The degree to which these swellings occurred (with the exception of a few species) increased as follows: methyl amide < ethyl amide < butyl amide. 2. Root tips of barley, which exhibited swellings, and onion, which did not, were examined cytologically. Swelling was accompanied by typical cmitoses, and weak c-mitotic activity could be observed even in onion where tumors were absent. The most active compound, N-butyl-3,5-dichlorophenoxyacetamide, was similar to colchicine in its polyploidizing efficiency: in barley polyploid cells up to 32n were observed. 3. The swellings observed are considered to be c-tumors and the N-alkyl substituted amides studied to be colchicine-type agents. The significance of the d...