title: Effect of glyphosate on carrot and tobacco cells.
abstract: The growth of suspension-cultured carrot (Daucus carota L.) and tobacco (Nicotiana tabacum L. cv. Xanthi) cells was inhibited by glyphosate (N-[phosphonomethyl]glycine). This inhibition was reversed by adding combinations of phenylalanine, tyrosine, and tryptophan or casein hydrolysate. Casein hydrolysate and phenylalanine + tyrosine + tryptophan were the most effective treatments. Reversal of glyphosate-induced inhibition occurred only if the aromatic amino acids were added during the first 8 days of glyphosate incubation. Glyphosate uptake was not reduced when the aromatic amino acids or casein hydrolysate were added.Even though phenylalanine biosynthesis is a suggested site for glyphosate action, inhibitory levels of glyphosate did not lower free phenylalanine concentrations in carrot cells within 10 days. (14)C-Phenylalanine studies indicated that the metabolic pool size was, likewise, not decreased.In carrot cells total free amino acids increased within 6 hours after glyphosate addition. Cell protein levels declined within 48 hours following glyphosate treatment.Studies on (14)C-thymidine and (14)C-uridine incorporation were complicated by rapid metabolism of these compounds to (14)CO(2).
authors: Department of Agronomy, University of Illinois, Urbana, Illinois 61801.
authors: L C
authors: LC
authors: Haderlie
authors: J M
authors: JM
authors: Widholm
authors: F W
authors: FW
authors: Slife