Abstract
Susceptibility to toxaphene, an extensively used organochlorine pesticide, was evident in five cereal types and was widespread in oat (
Avena spp.) and barley (
Hordeum spp.). In these cereals most of the varieties tested were susceptible, this being assessed biochemically from inhibition of the Hill reaction in chloroplasts from treated plants. Studies with the susceptible
Avena sativa variety Blyth showed two sites of inhibition ofphotosynthetic electron flow. The first site was on the oxidizing side of photosystem 2, and the second in the intermediate electron transport chain between the two photosystems. As a consequence of the latter, cyclic photophosphorylation was inhibited and toxaphene may additionally have some uncoupler activity.