This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (86) Citing Articles via Google Scholar Google Scholar Articles by Burns, E. R. Articles by Carter, M. C. Search for Related Content PubMed PubMed Citation Articles by Burns, E. R. Articles by Carter, M. C. Agricola Articles by Burns, E. R. Articles by Carter, M. C.

Articles

Inhibition of Carotenoid Synthesis as a Mechanism of Action of Amitrole, Dichlormate, and Pyriclor ¹

^a Department of Agronomy and Soils, and Department of Forestry, Auburn University, Auburn, Alabama 36830

Amitrole (3-amino-s-triazole), dichlormate (3,4-dichlorobenzyl methylcarbamate), and pyriclor (2,3,5-trichloro-4-pyridinol) inhibited normal carotenogenesis in etiolated wheat (Triticum aestivum L. var. Coker 65-20) seedlings. Carotenoid precursors accumulated in treated plants. In dichlormate-treated plants, -carotene accumulated, whereas phytofluene, phytoene, and -carotene accumulated in amitrole- and pyriclor-treated plants. None of the herbicides interfered with protochlorophyllide synthesis or its conversion to chlorophyllide when etiolated plants were illuminated. Chlorophyll accumulated in treated plants exposed to light at 60 foot candles, but was unstable and partially destroyed by illumination at 4000 foot candles. These data suggest that the phytotoxicity of amitrole, pyriclor, and dichlormate is due to inhibition of the synthesis of carotenoids and to the consequent photodestruction of chlorophyll and chloroplast disruption.

¹ This work was supported by Grant ES-00189 from National Institutes of Health, to M. C. Carter.