Metabolism of Piperazine in barley plants

The shoots of barley plants root‐treated with [2,5‐14C]piperazine were analysed 30 days after treatment. Methanol extraction left a solid residue which contained 31.9% of 14C (all percentages refer to the total of 14C incorporated into the shoots); further extraction with acidified methanol and dimethyl sulphoxide dissolved respectively 3.2% and 5.8% of 14C. The initial methanol extract contained radioactive piperazine (16.8%), iminodiacetic acid (8.6%), glycine (15.4%), oxalic acid (7.2%), and un‐identified compounds (20.1%). In barley, piperazine is the product of the most advanced metabolism so far identified of the fungicide triforine, 1,4‐bis(2,2,2‐trichloro‐1‐formamidoethyl)piperazine; the results obtained here show that piperazine is certainly not the end‐product of the metabolism of triforine in barley.