Diphenamid Metabolism in Tomato: Time Course of an Ozone Fumigation Effect

Abstract

The time course of diphenamid (N,N-dimethyl-2,2-diphenylacetamide) metabolism in tomato (Lycopersicon esculentumMill. ‘Sheyenne’) was altered by fumigation with 30 pphm (parts per hundred million) of O3. After 2 days 70% of the absorbed diphenamid was metabolized in controls compared with 83% in fumigated plants. Concentrations ofN-methyl-2,2-diphenylacetamide (MMDA) were equivalent in both fumigated and control plants. Less glucoside conjugate (MDAG) was present in fumigated plants 2 to 4 days after treatment than in the control plants. Gentiobioside conjugate (MDAGB) increased rapidly in fumigated plants after 0.5 day but not in control plants until after 2 days. Loss of diphenamid from aerated solution was demonstrated. A scheme for diphenamid metabolism is proposed.