Light Regulation of the Photosystem II and Photosystem I Reaction Centres of Plant Thylakoid Membranes

1990 ◽  
pp. 1895-1898 ◽  
Author(s):  
W. S. Chow ◽  
Jan M. Anderson
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Light Regulation ◽  
Thylakoid Membranes ◽  
Reaction Centres

Variable stoichiometries of photosystem II to photosystem I reaction centres

1988 ◽  
Vol 17 (3) ◽  
pp. 277-281 ◽  
Author(s):  
W. S. Chow ◽  
Jan M. Anderson ◽  
A. B. Hope
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Reaction Centres

Modulation of the Cytochrome b6/f Complex and Photosystem I Under Growth-Limiting Light in Amaranthus hypochondriacus, an NAD-ME C4 Plant

1996 ◽  
Vol 23 (3) ◽  
pp. 305 ◽  
Author(s):  
MV Sailaja ◽  
VSR Das
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Thylakoid Membranes ◽  
Bundle Sheath ◽  
C4 Plant ◽  
Cytochrome B6 ◽  
Amaranthus Hypochondriacus ◽  
Energy Consuming ◽  
Electron Transport Rates

Highly characteristic responses of thylakoid membranes were observed in function and composition when fully developed plants of Amaranthus hypochondriacus L. grown under light sufficient (2000 μmol m-2 s-1) conditions were transferred to light limited conditions (650 μmol m-2 s-1 and 200 μmol m-2 s-1). The whole-chain, photosystem I and photosystem II electron transport rates were depressed in both bundle sheath and mesophyll thylakoids with remarkable differences between them in variation of rates under limiting light. The reduction in PSI electron transport in the mesophyll could be attributed to reduced PSI centres, while in the bundle sheath, a modulation of cytochrome b6/f complex regulated the rates of PSI electron transport. The requirement for an unaltered number of PSI centres under limiting light in the bundle sheath is ascribed to operation of an energy-consuming C4 pump.

Freeze-fracture analysis of thylakoid membranes and photosystem I and II enriched fractions from Phormidium laminosum

1986 ◽  
Vol 80 (1) ◽  
pp. 57-73
Author(s):  
R.E. Glick ◽  
R.E. Triemer ◽  
B.A. Zilinskas
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Freeze Fracture ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Fracture Face ◽  
Phormidium Laminosum ◽  
Hydrophobic Component ◽  
Photosystem I And Ii ◽  
Protoplasmic Fracture Face

Thylakoid membranes of the thermophilic cyanobacterium Phormidium laminosum have been fractionated into photosystem II and photosystem I particles. These fractions have been characterized by their partial electron transport activities, and biochemical and spectral properties. Exoplasmic fracture face and protoplasmic fracture face particles in the unfractionated thylakoid membranes were shown to correspond in size to particles in freeze-fractured photosystem II and photosystem I fractions, respectively. Differences between the histograms of the thylakoid membrane protoplasmic fracture face particles and the isolated photosystem I particles suggest that in addition to photosystem I complexes some of the particles on the thylakoid protoplasmic fracture face may be related to cytochrome b/f complexes, the hydrophobic component of the coupling factor, or respiratory complexes.

scholarly journals Evidence for thylakoid membrane fusion during zygote formation in Chlamydomonas reinhardtii.

1991 ◽  
Vol 114 (5) ◽  
pp. 905-915 ◽  
Author(s):  
B Baldan ◽  
J Girard-Bascou ◽  
F A Wollman ◽  
J Olive
Keyword(s):  
Photosystem Ii ◽  
Chlamydomonas Reinhardtii ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
De Novo ◽  
Electron Flow ◽  
Thylakoid Membranes ◽  
Structural Basis ◽  
Zygote Formation ◽  
Thin Sections

To understand whether fusions of thylakoid membranes from the parental chloroplasts occurred during zygote formation in Chlamydomonas reinhardtii, we performed an ultrastructural analysis of the zygotes produced by crossing mutants lacking photosystem I or II protein complexes, in the absence of de novo chloroplast protein synthesis. Thylakoid membranes from each parent could be distinguished on thin sections due to their organization in "supergrana" in mutants lacking photosystem I centers, by freeze-fracturing due to the absence of most of the exoplasmic-face (EF) particles in mutants lacking photosystem II centers, by immunocytochemistry using antibodies directed against photosystem II subunits. We demonstrate that a fusion of the thylakoid membranes occurred during zygote formation approximately 15 h after mating. These fusions allowed a lateral redistribution of the thylakoid membrane proteins. These observations provide the structural basis for the restoration of photosynthetic electron flow in the mature zygote that we observed in fluorescence induction experiments.

scholarly journals Differential Changes in the Steady State Levels of Thylakoid Membrane Proteins during Senescence in Cucumis sativus Cotyledons

2001 ◽  
Vol 56 (7-8) ◽  
pp. 585-592 ◽  
Author(s):  
Jogadhenu S. S. Prakash ◽  
Masroor A. Baig ◽  
Prasanna Mohanty
Keyword(s):  
Steady State ◽  
Membrane Proteins ◽  
Photosystem Ii ◽  
Cucumis Sativus ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
Thylakoid Membranes ◽  
Reaction Centre ◽  
Thylakoid Membrane Proteins ◽  
Steady State Levels

Chloroplast structure and function is known to alter during foliar senescence. Besides, the alterations in the structural organisation of thylakoid membranes changes in the steady state levels of thylakoid membrane proteins occur due to leaf ageing. We monitored temporal changes in some of the specific proteins of thylakoid membrane protein complexes by western blotting in the Cucumis sativus cotyledons as a function of the cotyledon age. We observed that the levels of D1 and D2 proteins of photosystem II started declining at the early stages of senescence of Cucumis cotyledons and continued to decline with the progress of cotyledon age. Similarly the level of Cyt f of Cyt b6/f complex declined rapidly with progress of senescence in these cotyledons. The reaction centre proteins of photosystem I were relatively found to be more stable than that of photosystem II reaction centre proteins reflecting possibly the disorganisation of photosystem II prior to photosystem I. The 33 kDa extrinsic protein (MSP) of oxygen evolving complex, the LHCII apoprotein and the β-subunit of ATPsynthase showed the declined levels with the progress of cotyledon age. However, the extents of loss of these proteins were not as high as the reaction centre proteins of photosystem II and the Cyt f. These results provide that during senescence, proteins of thylakoid membranes degrade in a specific temporal sequence and thereby affect the temporal photo­chemical functions in Cucumis sativus cotyledons

Relationship between quenching of variable fluorescence and thermal dissipation in isolated thylakoid membranes: similar terminology and mathematical treatments may be used

1995 ◽  
Vol 73 (5-6) ◽  
pp. 247-252 ◽  
Author(s):  
Dejan Z. Markovic ◽  
Robert Carpentier
Keyword(s):  
Energy Storage ◽  
Photosystem Ii ◽  
Light Intensity ◽  
Photosystem I ◽  
Thermal Emission ◽  
Thylakoid Membranes ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Variable Component ◽  
Fluorescence Measurements

Simultaneous measurements of chlorophyll fluorescence and thermal emission using photoacoustic spectroscopy have been done in isolated thylakoid membranes to study the relationship between the photochemical quenching of fluorescence (qPF) and energy storage measured in photoacoustic experiments. It is shown that energy storage can be interpreted as the photochemical quenching of a variable component of thermal dissipation termed qPH. The parameters qPF and qPH were similarly sensitive to light intensity as demonstrated by their half-saturation light intensity. However, the nonvariable part of thermal dissipation (Ho) represented a greater proportion of the maximal thermal dissipation yield in comparison with the corresponding non-variable component of fluorescence (Fo) as a result of the thermal energy losses occurring during electron transport. A residual qPH found when qPF was removed indicated the participation of cyclic photosystem I or photosystem II in the measured qPH. The participation of cyclic photosystem I was also suggested by a low constant K, representing the quasi equilibria between (re)oxidized and reduced photosystem II quinone acceptors as determined from the logarithmic plots of the hyperbolic relationship obtained between qPH and light intensity. It is finally concluded that the terminology and mathematical treatments used for fluorescence measurements can also be applied to thermal dissipation.Key words: photosynthesis, thylakoid membranes, thermal dissipation, fluorescence quenching, plastoquinone.

Sign in / Sign up

Export Citation Format

Share Document