Maximum H^+/hv_<PSI> Stoichiometry of Proton Transport during Cyclic Electron Flow in Intact Chloroplasts Is at Least Two, but Probably Higher than Two : MEMBRANES AND BIOENERGETICS

スポンサーリンク

概要

• 論文の詳細を見る

• Effects of antimycin A on 9-aminoacridine (9AA) fluorescence quenching by intact chloroplasts during light-dependent electron flow to different electron acceptors indicated that considerable cyclic electron flow occurs concurrently with linear electron transport already at low PFDs, when oxygen supported electron flow, but not, when nitrite or methylviologen (MV) were present. Quantum efficiencies of the use of 696 and 675 nm light were calculated for oxygen-, nitrite- and MV-dependent linear electron flows. Since H^+/e=3 during linear electron transport [Ivanov (1993) Photosynthesis, p. 111; Kobayashi et al. (1995) Plant Cell Physiol. 36: 1613] and comparable 9AA fluorescence quenching indicates comparable transthylakoid proton gradients, total proton transport could be calculated and part of it could be assigned to linear and the remainder to cyclic electron transport when oxygen was electron acceptor. Quanta of 696 nm light not used to support linear electron flow to oxygen at hv/e=2 were assumed to be available for coupled proton transport during cyclic electron flow. H^+/hv ratios for cyclic electron transport obtained on this basis were consistently higher than I and occasionally approached 3. No allowance was made in these calculations for oxidized P700 in the reaction center of PSI, which could not donate electrons to the cyclic pathway, and for reduced Q_A in the reaction center of PSII. It therefore appears likely that maximum H^+/hv ratios in cyclic electron transport are higher than values calculated in this work. Our observations with intact chloroplasts agree in principle with those of [Heath (1972) Biochim. Biophys. Acta 256: 645] with thylakoids, who also reported high H^+/e ratios in cyclic electron transport. These ratios are briefly discussed in relation to the H^+/ATP stoichiometry of ATP production during carbon assimilation of leaves and to protection of chloroplasts against photoinactivation.

• 日本植物生理学会の論文

著者

• HEBER Ulrich

  Julius-von-Sachs-Institut, Univ. Wurzburg

• Heber U

  Univ. Wuezburg Wuezburg Deu

• Heber Ulrich

  Julius-von-sachs Institut Fiir Bio Wissenschaften Universitat Wtirzburg

• Kobayashi Yuhko

  Laboratory Of Plant Pathology Faculty Of Bioresources Mie University

• Kobayashi Y

  Bioscience And Biotechnology Center Nagoya University

• BUKHOV Nikolai

  Julius-von-Sachs-Institut fur Biowissenschaften, Universitat Wurzburg

• NEIMANIS Spidola

  Julius-von-Sachs-Institut fur Biowissenschaften, Universitat Wurzburg

• KOBAYASHI Yoshichika

  Julius-von-Sachs-Institut fur Biowissenschaften, Universitat Wurzburg

• Bukhov Nikolai

  Julius-von-sachs-institut Fur Biowissenschaften Universitat Wurzburg:(present)timiriasev Instiute Of

• Neimanis Spidola

  Julius-von-sachs-institut Fur Biowissenschaften Universitat Wurzburg

関連論文

• Electron Flow to the Intersystem Chain from Stromal Components and Cyclic Electron Flow in Maize Chloroplasts, as Detedted in Intact Leaves by Monitoring Redox Change of P700 and Chlorophyll Fluorescence
• Pool Size of Electrons That Can Be Donated to P700^+, As Determined in Intact Leaves : Donation to P700^+ from Stromal Components Via the Intersystem Chain : ENVIRONMENTAL AND STRESS RESPONSES : MEMBRANES AND BIOENERGETICS
• Methyl Viologen-Dependent Cyclic Electron Transport in Spinach Chloroplasts in the Absence of Oxygen
• Monodehydroascorbate Radical Detected by Electron Paramagnetic Resonance Spectrometry Is a Sensitive Probe of Oxidative Stress in Intact Leaves
• DETECTION OF PHOTOOXIDATIVE STRESS BY MONODEHYDROASCORBATE IN LEAVES
• Actin Microfilaments are Required for the Expression of Nonhost Resistance in Higher Plants
• Photoproduction and Detoxification of Hydroxyl radicals in Chloroplasts and Leaves and Relation to Photoinactivation of Photosystems I and II
• Calcium ion promotes successful penetration of powdery mildew fungi into barley cells
• Maximum H^+/hv_ Stoichiometry of Proton Transport during Cyclic Electron Flow in Intact Chloroplasts Is at Least Two, but Probably Higher than Two : MEMBRANES AND BIOENERGETICS
• Coupling Ratios H^+/e=3 versus H^+/e=2 in Chloroplasts and Quantum Requirements of Net Oxygen Exchange during the Reduction of Nitrite, Ferricyanide or Methylviologen : MEMBRANES AND BIOENERGETICS
• Photooxidative Damage in Young Leaves of Declining Grapevine: Does It Result from a New and Possibly Viroid-Related Disease?
• Fast Cytoplasmic pH Regulation in Acid-Stressed Leaves : ENVIRONMENTAL AND STRESS RESPONSES : MEMBRANES AND BIOENERGETICS
• Apoplastic Ascorbate Does not Prevent the Oxidation of Fluorescent Amphiphilic Dyes by Ambient and Elevated Concentrations of Ozone in Leaves
• Bioenergetics of Carbon Assimilation in Intact Chloroplasts : Coupling of Proton to Electron Transport at the Ratio H^+/e=3 Is Incompatible with H^+/ATP=3 in ATP Synthesis : MEMBRANES AND BIOENERGETICS

もっと見る 閉じる

スポンサーリンク