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 PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Ben-Aziz, A. Articles by Koren, E. Search for Related Content PubMed PubMed Citation Articles by Ben-Aziz, A. Articles by Koren, E. Agricola Articles by Ben-Aziz, A. Articles by Koren, E.

Articles

Interference in Carotenogenesis as a Mechanism of Action of the Pyridazinone Herbicide Sandoz 6706

Accumulation of C-40 Carotenoid Precursors Inhibition of -Carotene Synthesis and Enhancement of Phytoene Epoxidation ¹

^a Pesticide Chemistry and Residue Research Laboratory and Department of Weed Research, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel

The herbicide Sandoz 6706 (4-chloro-5-(dimethylamino)-2-,,, (trifluoro-m-tolyl)-3(2H)-pyridazinone), when applied as a preplant soil treatment at a concentration of 0.05 µg/g reduced the content of -carotene and chlorophylls in 21-day-old wheat seedlings (Triticum aestivum L.) by 55% and 29%, respectively, without affecting the fresh or dry matter of the seedlings. At 0.8 µg/g, the herbicide reduced the content of -carotene and chlorophyll by as much as 98%, while the fresh weight of the albino seedlings was reduced by only 24%. The effect of the herbicide on chlorophyll b was much stronger than on chlorophyll a. Time course studies of pigment synthesis in Sandoz 6706-treated seedlings showed that chlorophyll, -carotene, cyclic xanthophylls, phytoene, phytofluene, and -carotene were accumulating during the first 7 days after sowing. Later on, there was a sharp decline in the content of chlorophyll and -carotene and a gradual reduction in the content of phytofluene, -carotene, and cyclic xanthophylls; the content of phytoene remained essentially unchanged. Coinciding with the drop in content of -carotene and chlorophyll, there was a remarkable increase in the content of epoxy phytoene. It is suggested that Sandoz 6706 might act as an inhibitor of the cyclization reaction in the biosynthetic pathway of carotenoids and that other effects, such as the bleaching of chlorophyll, are a consequence of this inhibition.

³ Present address: Palimport Chemical Co. P. O. Box 13, Tel-Aviv, Israel.

¹ Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1973 Series No. 256-E.

This article has been cited by other articles:

				D. J. Thomas, T. J. Avenson, J. B. Thomas, and S. K. Herbert A Cyanobacterium Lacking Iron Superoxide Dismutase Is Sensitized to Oxidative Stress Induced with Methyl Viologen but Is Not Sensitized to Oxidative Stress Induced with Norflurazon Plant Physiology, April 1, 1998; 116(4): 1593 - 1602. [Abstract] [Full Text]