caa a22 4500 445840269 CHVBK 20180317145341.0 cr unu---uuuuu 170323e20110701xx s 000 0 eng 10.1007/s00709-010-0198-5 doi (NATIONALLICENCE)springer-10.1007/s00709-010-0198-5 Chlorophyll fluorescence images demonstrate variable pathways in the effects of plasma membrane excitation on electron flow in chloroplasts of Chara cells [Elektronische Daten] [Natalia Krupenina, Alexander Bulychev, Ulrich Schreiber] Chlorophyll fluorescence Imaging and Microscopy PAM fluorometry were applied to study spatial dynamics of photosystem II quantum yield $$ \left( {\Delta F/F_m^\prime } \right) $$ and non-photochemical quenching (NPQ) in resting and electrically stimulated Chara corallina cells in the absence and presence of the hydrophilic electron acceptor methyl viologen (MV) in the external medium. Electrical excitation of the plasma membrane temporarily enhanced the heterogeneity of photosynthetic patterns under physiological conditions (in the absence of MV), but irreversibly eliminated these patterns in the presence of MV. These findings suggest that the action potential (AP) of the excitable plant cell affects the spatial patterns of photosynthesis and chlorophyll fluorescence through different pathways operated in the absence and presence of MV. Based on the extent of NPQ as an indicator of MV-dependent electron flow, it is supposed that MV cannot permeate into the chloroplasts of photosynthetically active "acid cell regions” but gains an immediate access to the stroma of these chloroplasts after triggering of an AP. The AP-triggered MV-dependent non-photochemical quenching in the chloroplasts of acidic cell regions was routinely observed at 0.1mM Ca2+ in the medium but not at elevated (2mM) external Ca2+ concentration. The results are interpreted in terms of competition between two permeant divalent ion species, Ca2+ and MV2+, for their passage through the voltage-gated calcium channels of the plasma membrane. It is proposed that the herbicidal activity of MV in characean cells, here serving as model object, can be manipulated by triggering AP and varying Ca2+ concentration in the environmental medium. Springer-Verlag, 2010 Action potential nationallicence Chara corallina nationallicence Chlorophyll fluorescence imaging nationallicence Krupenina Natalia Faculty of Biology, Lomonosov Moscow State University, 119991, Moscow, Russia aut Bulychev Alexander Faculty of Biology, Lomonosov Moscow State University, 119991, Moscow, Russia aut Schreiber Ulrich Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs-Platz 2, 97082, Würzburg, Germany aut Protoplasma Springer Vienna 248/3(2011-07-01), 513-522 0033-183X 248:3<513 2011 248 709 https://doi.org/10.1007/s00709-010-0198-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00709-010-0198-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Krupenina Natalia Faculty of Biology, Lomonosov Moscow State University, 119991, Moscow, Russia aut NATIONALLICENCE 700 1- Bulychev Alexander Faculty of Biology, Lomonosov Moscow State University, 119991, Moscow, Russia aut NATIONALLICENCE 700 1- Schreiber Ulrich Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, Julius-von-Sachs-Platz 2, 97082, Würzburg, Germany aut NATIONALLICENCE 773 0- Protoplasma Springer Vienna 248/3(2011-07-01), 513-522 0033-183X 248:3<513 2011 248 709 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer