RESPIRATION OF WHEAT ROOT CELLS UNDER SIMULTANEOUS INHIBITION OF PARTS I AND III OF THE ELECTRON TRANSPORT CHAIN OF
MITOCHONDRIA BY ROTENONE AND ANTIMYCINE A
D. F. Rakhmatullina,1 L. H. Gordon, T, I. Ogorodnikova
Kazan' Institute of Biochemistry and Biophysics, Kazan' Research Center, RAS, Russia;
1 e-mail: rahmatullina@mail.knc.ru
Respiration of excised roots of 5 day old wheat seedlings with blocked mitochondrial oxidation under simultaneous
action of rotenone and antimycine A was studied. A reduced rate of oxygen uptake was observed within the first hour of root treatment
inhibitors. However, after a 5 h exposure there was an increase in oxygen uptake, which was prevented by KCN but amplified by malate
and ascorbate. The application of inhibitors caused a considerable increase in the respiratory coefficient (RC) up to 2.1, that
suggests a significant CO2 release, when the initial sites of mitochondrial electron transport chain were inhibited.
RC did not raise, when ascorbate was added in the presence of inhibitors. We assume that inhibition of mitochondria! oxidation
at I and III sites of electron transport chain facilitates switching on the alternative paths of reductant translocation to oxygen.
Participation of ATPases and redox system of plasma membrane in the response reactions of respiration directed to the restoration of
ion, particularly, proton homeostasis in conditions of inhibited mitochondrial oxidation is discussed.
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