METABOLISM OF THE BISETHYLENEGLYCOLESTERS OF 2,4-D AND MCPA IN EXCISED PLANTS AND CELL-SUSPENSION CULTURES OF TOMATO

The metabolism of bisethyleneglycolesters of [2-C-14]2,4-dichloropheno xyacetic acid (2,4-D) and [2-C-14]2-methyl-4-chlorophenoxyacetic acid (MCPA) was studied in excised seedlings and cell suspension cultures o f tomato. Both in plants and cultured cells, ester hydrolysis yielding the corresponding phenoxyacetic acids was the initial step of the met abolism. Carbohydrate conjugates, mainly with diglucose moieties, were shown to be the predominant metabolites in plants and cell cultures. The pattern of carbohydrate conjugates, including ester conjugates wit h mono-, di-, and higher carbohydrates, was more complex in cultured c ells than in excised plants. The bisethyleneglycolester of MCPA was me tabolized to a greater extent than the bis eater of 2,4-D.