Plant and Cell Physiology, 1995, Vol. 36, No. 8 1589-1598
© 1995
Photoactivation of the Electron Flow from NADPH to Plastoquinone in Spinach Chloroplasts
1 The Research Institute for Food Science, Kyoto University Uji, Kyoto, 611 Japan
2 Julius-von-Sachs Institut für Biowissenschaften der Universität Würzburg, Lehrstuhl für Botanik I Mittlerer Dallenbergweg 64, Würzburg, 97082, Germany
Intact chloroplasts from spinach showed a transient increase in Chl fluorescence after saturating illumination with actinic light and its yield depended on the duration of illumination and the intensity of the actinic light (AL). The increase was partially suppressed when antimycin A was added immediately after termination of the AL. The inhibited fluorescence increase, therefore, reflected the electron flow from the reductant(s) that had accumulated during the actinic illumination to the plastoquinone (PQ) pool via ferredoxin and the antimycin A-sensitive Cyt b-559 [Miyake et al. (1995) Plant Cell Physiol. 36: 743]. Addition of dihydroxyacetone phosphate (DHAP) to chloroplasts caused the enhancement of the increase in fluorescence after AL, which was inhibited by antimycin A. Decay of the transiently raised fluorescence was retarded by 2-heptyl-4-hydroxyquinoline N-oxide and stigmatellin, suggesting that re-oxidation of the reduced PQ pool is coupled with the operation of Q-cycle. Although the activity of the stromal enzyme system that supplies NADPH on addition of DHAP was constant irrespective of light or darkness, the capacity of the intact chloroplasts to show a DHAP-dependent fluorescence increase had a limited lifetime after AL was turned off. This result suggests that the antimycin A-sensitive Cyt b-559 or ferredoxin-NADP reductase is activated by light and deactivated in the dark. In ruptured chloroplasts, the addition of NADPH increased the dark fluorescence yield only in the presence of Fd, which also was inhibited by antimycin A. Thus the photoregulatory mechanism of Cyt b-559 (Fd) in intact chloroplasts appeared to be lost when chloroplasts were ruptured.
(Received June 21, 1995; Accepted September 25, 1995)
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. M. Reynolds, B. U. Bruns, W. K. Fitt, and G. W. Schmidt Enhanced photoprotection pathways in symbiotic dinoflagellates of shallow-water corals and other cnidarians PNAS, September 9, 2008; 105(36): 13674 - 13678. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Okegawa, Y. Kagawa, Y. Kobayashi, and T. Shikanai Characterization of Factors Affecting the Activity of Photosystem I Cyclic Electron Transport in Chloroplasts Plant Cell Physiol., May 1, 2008; 49(5): 825 - 834. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. G. Ivanov, L. Hendrickson, M. Krol, E. Selstam, G. Oquist, V. Hurry, and N. P. A. Huner Digalactosyl-Diacylglycerol Deficiency Impairs the Capacity for Photosynthetic Intersystem Electron Transport and State Transitions in Arabidopsis thaliana Due to Photosystem I Acceptor-Side Limitations Plant Cell Physiol., August 1, 2006; 47(8): 1146 - 1157. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. G. Ivanov, M. Krol, D. Sveshnikov, E. Selstam, S. Sandstrom, M. Koochek, Y.-I. Park, S. Vasil'ev, D. Bruce, G. Oquist, et al. Iron Deficiency in Cyanobacteria Causes Monomerization of Photosystem I Trimers and Reduces the Capacity for State Transitions and the Effective Absorption Cross Section of Photosystem I in Vivo Plant Physiology, August 1, 2006; 141(4): 1436 - 1445. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Miyake, S. Horiguchi, A. Makino, Y. Shinzaki, H. Yamamoto, and K.-i. Tomizawa Effects of Light Intensity on Cyclic Electron Flow Around PSI and its Relationship to Non-photochemical Quenching of Chl Fluorescence in Tobacco Leaves Plant Cell Physiol., November 1, 2005; 46(11): 1819 - 1830. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Miyake, M. Miyata, Y. Shinzaki, and K.-i. Tomizawa CO2 Response of Cyclic Electron Flow around PSI (CEF-PSI) in Tobacco Leaves--Relative Electron fluxes through PSI and PSII Determine the Magnitude of Non-photochemical Quenching (NPQ) of Chl Fluorescence Plant Cell Physiol., April 1, 2005; 46(4): 629 - 637. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Miyake, Y. Shinzaki, M. Miyata, and K.-i. Tomizawa Enhancement of Cyclic Electron Flow Around PSI at High Light and its Contribution to the Induction of Non-Photochemical Quenching of Chl Fluorescence in Intact Leaves of Tobacco Plants Plant Cell Physiol., October 15, 2004; 45(10): 1426 - 1433. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Deng, J. Ye, and H. Mi Effects of Low CO2 on NAD(P)H Dehydrogenase, a Mediator of Cyclic Electron Transport Around Photosystem I in the Cyanobacterium Synechocystis PCC6803 Plant Cell Physiol., May 15, 2003; 44(5): 534 - 540. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. José Quiles and J. Cuello Association of Ferredoxin-NADP Oxidoreductase with the Chloroplastic Pyridine Nucleotide Dehydrogenase Complex in Barley Leaves Plant Physiology, May 1, 1998; 117(1): 235 - 244. [Abstract] [Full Text]
|
|