Effect of Glyphosate on Protein and Nucleic Acid Synthesis and ATP Levels in Common Cocklebur (Xanthium pensylvanicum) Root Tissue

Common cocklebur ( Xanthium pensylvanicum Wallr.) root tissue was used to investigate the mechanism of action of glyphosate [ N - (phosphonomethyl)glycine]. Arrival of glyphosate in the root-tip was followed closely by a rise in ATP levels to 136% of control levels by 2 h after treatment. Incorporation, but not uptake, of 14 C-leucine was significantly decreased within 2 h after treatment. Incorporation declined steadily over a 32 -h time course. Uptake of 33 P by the roots was temporarily stimulated by glyphosate, and as a percent of the total 33 P taken up, there was decreased incorporation into RNA and DNA fractions by 8 h. Our results indicate that glyphosate may cause the rapid rise in ATP level primarily by inhibiting protein synthesis.