The effect of temperature on the activity and metabolism of glyphosate applied to rhizome fragments of elymus repens (=Agropyron repens)

Abstract

AbstractThe effect of temperature on the activity and metabolism of glyphosate, as its mono(isopropylammonium) salt, in single‐node rhizome fragments of Elymus repens was investigated in controlled environment cabinets. Post‐treatment temperatures of 26/16° (day/night) reduced the activity of the herbicide compared with that at 10/6°, respectively. Under both temperature regimes and using [14C]glyphosatemono(isopropylammonium), more [14C]glyphosate accumulated in the node tissues and buds than in the internodes, but at teh higher temperature the rate of glyphosate metabolism was greater, and more 14C was lost as [14C]carbon dioxide. Evidence is presented to indicate that plant extracts contained at least two components which yielded glyphosate and aminomethylphosphonic acid after both acid or base treatment, but not on incubation with β‐glucosidase. It is therefore tentatively suggested that these metabolites are not β‐glycosides but perhaps are conjugates with other natural plant constituents involving the phosphonyl and/or amino groups of the herbicide.