Investigations into the influence of some synergists of 2,4-dioxo-hexahydro-1,3,5-triazine (DHT) on the formation of 14CO2 from [2,4-14C]DHT

Combined treatment with DHT and N-phenyl-N'-p-carboxyphenyl-thiourea reduced the formation of 14CO2 from [2,4-14C]DHT. Contrary to this, combined treatments with N-phenyl-N'-p-carboxyphenyl-urea, cyanoguanidine and, above all, guanidine carbonate increased the formation of 14CO2 from [2,4-14C]DHT. Thus, retardation of the breakdown of DHT and, beside this, maintenance of a high concentration of DHT, can only be the reason for the augmentation of the antiphytoviral activities of DHT by N-phenyl-N'-p-carboxyphenylthiourea, but not for that by the other 3 substances. An alternative hypothesis is discussed. (author)