Published online by Cambridge University Press: 12 June 2017
The sodium salt of 2,2–dichloropropionic acid (dalapon) at 4 lb per acre was applied as a foliar spray to sugar beets, a species tolerant of the herbicide, and yellow foxtail (Setaria glauca), a susceptible species. Shoots of treated and untreated plants were collected during three weeks after treatment and assayed. Dalapon appeared to cause protein degradation to amino acids in the shoots of both species. Striking increases in the concentration of amides (primarily glutamine in sugar beets and asparagine in yellow foxtail) were found. The free pantothenic acid in the shoots of both species rose greatly following treatment. In sugar beets, observed recovery of treated plants was accompanied by return of the concentrations of the constituents studied to levels near those in untreated plants. Yellow foxtail did not recover after treatment and concentrations of the constituents studied generally remained at a high level compared to the untreated plants. The similarity in initial biochemical responses of the two species and the fact that sugar beets recovered may indicate that some mechanism capable of inactivating dalapon was operating in sugar beets.