Diethyldithiocarbamate (DEDTC) does not accept electrons from the photosynthetic electron transport (PET) but can donate electrons to a photosystem I (PSI) Mehler reaction in the pres­ence of the following PET inhibitors: DCMU. DBMIB, and bathophenanthroline. It cannot photoreduce PSI in the presence of cyanide, a PET inhibitor. These data indicate that the site of electron donation is after the plastoquinone pool. Ascorbate is not required for the ability of DEDTC to donate electrons to PSI.

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... ere is no photoreductant activity by DEDTC inferredoxin/NADP Hill reactions. Superoxide dismutase inhibits DEDTC/DCMU or bathophenanthroline→methylviologen/O2 Mehler reaction. Catalase does not recover the consumed O2 from a DEDTC/DCMU→methylviologen/O2 Mehler reaction, indicating O2- has not been dismutating into H2O2. These results indicate that superoxide is required for DEDTC ability to donate electrons, therefore DEDTC is limited only to Mehler-type reactions.