Involvement of the chloroplast plastoquinone pool in the Mehler reaction

2017 ◽  
Vol 161 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Daria V. Vetoshkina ◽  
Boris N. Ivanov ◽  
Sergey A. Khorobrykh ◽  
Ivan I. Proskuryakov ◽  
Maria M. Borisova-Mubarakshina
Keyword(s):  
Mehler Reaction ◽  
Plastoquinone Pool

Diethyldithiocarbamate, a New Photosystem I Electron Donor of Mehler-Type Hill Reactions

1986 ◽  
Vol 41 (9-10) ◽  
pp. 861-866 ◽  
Author(s):  
Brad L. Upham ◽  
Kriton K. Hatzios
Keyword(s):  
Superoxide Dismutase ◽  
Electron Transport ◽  
Electron Donor ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Mehler Reaction ◽  
Plastoquinone Pool ◽  
Electron Donation

Abstract 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. There 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.

Light-Adaptation of Photosystem II Is Mediated by the Plastoquinone Pool†

Biochemistry ◽  
2003 ◽  
Vol 42 (25) ◽  
pp. 7655-7662 ◽  
Author(s):  
Karin A. Åhrling ◽  
Sindra Peterson
Keyword(s):  
Photosystem Ii ◽  
Light Adaptation ◽  
Plastoquinone Pool

Mechanism of Action of the Herbicide 4,6-Dinitro-o-cresol in Photosynthesis

1979 ◽  
Vol 34 (11) ◽  
pp. 1021-1023 ◽  
Author(s):  
J. J. S. van Rensen ◽  
J. H. Hobé
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Mechanism Of Action ◽  
Chemical Structure ◽  
Methyl Viologen ◽  
Primary Electron ◽  
Reaction Centers ◽  
Mehler Reaction ◽  
Cyclic Photophosphorylation ◽  
Primary Electron Acceptor

Abstract The herbicide 4,6-dinitro-o-cresol inhibits electron transport to ferricyanide and non-cyclic photophosphorylation for 50% at about 15 μm. At higher concentrations the photosystem I depen­dent Mehler reaction ascorbate/dichlorophenolindophenol to methyl viologen is stimulated, while cyclic photophosphorylation is inhibited. The herbicide thus is an inhibitory uncoupler. Although the chemical structure of 4,6-dinitro-o-cresol is different from that of the diuron-type herbicides, its site and mechanism of action is similar. Both 4,6-dinitro-o-cresol and diuron inhibit electron transport between the primary electron acceptor of Photosystem II and the plastoquinone pool. This causes a closing of the reaction centers of Photosystem II. The interaction with the inhibited molecule however is different for the two herbicides.

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