Fig. 13
Reprinted with permission from (Scientific Reports 2013; 3: 3447). Copyright (2013) Nature Publishing Group
Dark- and light-adapted C. reinhardtii are exposed to 100 nM of Cd(II). Time evolution of (a) the differential oxidation state coefficient Δϕ, b the H2O2 production and c the H2O2 production rate. After injection of Cd(II) the light-adapted algae under illumination start excreting H2O2 without delay, whereas there is a production delay under dark conditions. d ROS production for dark-adapted algae exposed to 100 nM of Cd(II) when the illumination is successively turned on and off during the measurement. e These data support the following action mechanism of Cd(II) on the photosynthetic apparatus of C. reinhardtii: Cd(II) binding to the plastoquinone pool disturbs the electron transport chain between PSII and PSI. Upstream, the light driven electron extraction from oxygen evolving complex (OEC) remains functional and generates light-dependant ROS at the PSII acceptor side.