caa a22 4500 445890002 CHVBK 20180317145613.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11120-011-9697-2 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9697-2 The size of the lumenal proton pool in leaves during induction and steady-state photosynthesis [Elektronische Daten] [Vello Oja, Hillar Eichelmann, Agu Laisk] This report describes a new method to measure the chloroplastic lumenal proton pool in leaves (tobacco and sunflower). The method is based on measurement of CO2 outbursts from leaves caused by the shift in the CO2+H2O↔HCO3 −+H+ equilibrium in the chloroplast stroma as protons return from the lumen after darkening. Protons did not accumulate in the lumen to a significant extent when photosynthesis was light-limited, but a large pool of >100μmolH+m−2 accumulated in the lumen as photosynthesis became light-saturated. During thylakoid energization in the light, large amounts of protons are moved from binding sites in the stroma to binding sites in the lumen. The transthylakoidal difference in the chemical potential of free protons (ΔpH) is largely based on the difference in the chemical potential of bound protons in the lumenal and stromal compartments (pK). Over the course of the dark-light induction of photosynthesis protons accumulate in the lumen during reduction of 3-phosphoglycerate. The accumulation of electrons in reduced compounds of the stroma and cytosol is the natural cause for accumulation of a stoichiometric pool of lumenal protons during this transient event. Springer Science+Business Media B.V., 2011 Leaves nationallicence Photosynthesis nationallicence Thylakoid nationallicence Protons nationallicence BPGA : Bisphosphoglycerate nationallicence CET : Cyclic electron transport nationallicence CRC : Carbon reduction cycle nationallicence ECS : Electrochromic shift nationallicence ETR : Electron transport rate nationallicence Fd : Ferredoxin nationallicence FNR : Ferredoxin-NADP reductase nationallicence GAP : Glyceraldehyde phosphate nationallicence LED : Light-emitting diode nationallicence NPQ : Non-photochemical excitation quenching nationallicence PC : Plastocyanin nationallicence PAD, PFD : Photon flux density, absorbed and incident nationallicence PGA : 3-Phosphoglyceric acid nationallicence pmf : Proton motive force nationallicence PQ : Plastoquinone nationallicence RuBP : Ribulose-1,5-bisphosphate nationallicence T3P : Triose 3-phosphates nationallicence ΔpH : Osmotic component of pmf nationallicence ΔΨ : Field component of pmf nationallicence Oja Vello Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut Eichelmann Hillar Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut Laisk Agu Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut Photosynthesis Research Springer Netherlands 110/2(2011-12-01), 73-88 0166-8595 110:2<73 2011 110 11120 https://doi.org/10.1007/s11120-011-9697-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9697-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Oja Vello Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut NATIONALLICENCE 700 1- Eichelmann Hillar Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut NATIONALLICENCE 700 1- Laisk Agu Institute of Molecular and Cellular Biology, University of Tartu, Riia St. 23, 51010, Tartu, Estonia aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 110/2(2011-12-01), 73-88 0166-8595 110:2<73 2011 110 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer