AbstractThe growth‐regulating activity and metabolism, in pea and wheat tissues, ofy‐(chloro‐phenoxy)‐, y‐(2,4‐dichlorophenoxy)‐ andy‐(N, N‐diniethylthiocarbamoylthio)‐substituted butyric, β‐hydroxy‐butyric, crotonic and vinylacetic acids have been investigated. With the exception ofy‐(2,4‐dichlorophenoxy) vinylacetic acid in pea tissue, members of the two phenoxy series were degraded to the corresponding phenoxyacetic acid. Although members of the 2,4‐dichlorophenoxy series were less easily metabolised, both series exhibited similar activity. Other than with they‐phenoxyvinylacetic acids, there were no appreciable differences in metabolism or growth‐regulating activity between members within a series. No evidence for the metabolism ofy‐(2,4‐dichlorophenoxy)vinylacetic acid in pea tissue was found and this acid was also less active in the pea tests. Members of theN, N‐dimethyl‐thiocarbamoylthio series of acids, however, were less regular in their metabolic and growth‐regulating patterns. The substituted crotonic acid was inactive and unstable whilst pea tissue was found to metabolise the substituted acetic acid to inactiveN‐methylcarbamoylthioacetic acid. The results with all active acids fit th
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