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  • 1
    Electronic Resource
    Electronic Resource
    Characterization of chlorophyll fluorescence quenching in chloroplasts by fluorescence spectroscopy at 77 K I. ΔpH-dependent quenching
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 723 (1983), S. 169-175 
    Details
    ISSN: 0005-2728
    Keywords: (Spinach chloroplast) ; Chlorophyll fluorescence ; Fluorescence quenching ; Proton gradient
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2728(83)90116-0
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of chlorophyll fluorescence quenching in chloroplasts by fluorescence spectroscopy at 77 K II. ATP-dependent quenching
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 723 (1983), S. 176-181 
    Details
    ISSN: 0005-2728
    Keywords: (Spinach chloroplast) ; Chlorophyll fluorescence ; Fluorescence quenching
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2728(83)90117-2
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  • 3
    Electronic Resource
    Electronic Resource
    Chlorophyll fluorescence as a probe for the determination of the photo-induced proton gradient in isolated chloroplasts
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 591 (1980), S. 198-202 
    Details
    ISSN: 0005-2728
    Keywords: (Chloroplast) ; 9-Aminoacridine ; Chlorophyll ; Fluorescence quenching ; Gramicidin D ; Protein gradient
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2728(80)90233-9
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  • 4
    Electronic Resource
    Electronic Resource
    Photoinduced quenching of chlorophyll fluorescence in intact chloroplasts and algae. Resolution into two components
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 679 (1982), S. 116-124 
    Details
    ISSN: 0005-2728
    Keywords: (Chlorella, Spinach chloroplast) ; Chlorophyll ; Excitation energy transfer ; Fluorescence quenching ; Proton gradient
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2728(82)90262-6
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  • 5
    Electronic Resource
    Electronic Resource
    A quantitative study of the slow decline of chlorophyll a fluorescence in isolated chloroplasts
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Bioenergetics 548 (1979), S. 128-138 
    Details
    ISSN: 0005-2728
    Keywords: (Chloroplast) ; Cation effect ; Chlorophyll ; Fluorescence quenching ; Proton uptake
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2728(79)90193-2
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  • 6
    Electronic Resource
    Electronic Resource
    Simulation of in situ freezing damage of the photosynthetic apparatus by freezing in vitro of thylakoids suspended in complex media (1986)
    Springer
    Planta 168 (1986), S. 67-76 
    Details
    ISSN: 1432-2048
    Keywords: Amino acid (cryoprotective media) ; Chlorophyll fluorescence ; Freezing damage ; Photosynthesis (electron transport, photophos-phorylation) ; Spinacia (freezing damage) ; Thyllakoid, isolated
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chloroplast thylakoid membranes were isolated from leaves of unhardened and cold-acclimated spinach (Spinacia oleracea L.). For freezethaw treatment, the membranes were suspended in complex media composed to simulate the solute concentrations in the chloroplast stroma in the unhardened and hardened states of the leaves. In particular, high concentrations of amino acids were applied for simulating the hardened state. After frost treatment, photosynthetic activities and chlorophyll fluorescence parameters of the thylakoids were tested to determine the degree of freezing damage. The results revealed a pattern of freezing injury similar to that observed upon frost treatment of thylakoids in situ. A major manifestation of damage was the inhibition of photosynthetic electron transport. Uncoupling of photophosphorylation, which is the dominating effect of freezing of thylakoids suspended in binary solutions (e.g., containing one sugar and one inorganic salt), was also visible but less pronounced in the complex media. Thylakoids obtained from cold-acclimated leaves did not exhibit an increased frost tolerance in vitro, as compared with thylakoids from unhardened plants. The results, furthermore, indicated a strong protective effect of free amino acids at the concentrations and composition found in chloroplasts of hardened leaves. The presence of inorganic salts in the complex media slightly stabilized rather than damaged the membranes during freezing. It is concluded that inactivation of thylakoids in situ may be understood as the destabilizing action of the combined solutes surrounding the thylakoids, occurring when solute concentration is raised due to freezing of water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407011
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  • 7
    Electronic Resource
    Electronic Resource
    Inhibition of photosynthetic reactions by light (1985)
    Springer
    Planta 163 (1985), S. 218-226 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Chloroplast, isolated ; Photoinhibition ; Photosynthesis (electron transport) ; Spinacia (photoinhibition)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Illumination of isolated intact chloroplasts of Spinacia oleracea L. for 10 min with 850 W m-2 red light in the absence of substrate levels of bicarbonate caused severe inhibition of subsequently measured photosynthetic activities. The capacity of CO2-dependent O2 evolution and of non-cyclic electron transport were impaired to similar degrees. This photoinactivation was prevented by addition of bicarbonate which allowed normal carbon metabolism to proceed during preillumination. Photoinhibition of electron transport was observed likewise upon illumination of intact or broken chloroplasts when efficient electron acceptors were absent. Addition of uncouplers did not influence the extent of inhibition. Studies of partial electron-transport reactions indicated that the activity of both photosystems was affected by light. In addition, the water-oxidation system or its connection to photosystem II seemed to be impaired. Preillumination did not cause uncoupling of photophosphorylation. Chlorophyll-fluorescence data obtained at room temperature and at 77 K are consistent with the view that photosystem-II reaction centers were altered. Addition of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) or 1,4-diazabicyclo(2,2,2)octane to isolated thylakoids prior to preillumination substantially diminished photoinhibition. This result shows that reactive oxygen species were involved in the damage. It is concluded that bright light, which normally does not damage the photosynthetic apparatus, may exert the described destructive effects under conditions that restrict metabolic turnover of photosynthetic energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393510
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  • 8
    Electronic Resource
    Electronic Resource
    Photoinhibition at chilling temperature (1989)
    Springer
    Planta 177 (1989), S. 409-416 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Cold acclimation ; Photoinhibition ; Photosynthesis (inhibition) ; Quantum yield ; Spinacia (cold acclimation)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of moderate light at chilling temperature on the photosynthesis of unhardened (acclimated to +18° C) and hardened (cold-acclimated) spinach (Spinacea oleracea L.) leaves were studied by means of fluorescence-induction measurements at 20° C and 77K and by determination of quantum yield of O2 evolution. Exposure to 550 μmol photons·m-2·s-1 at +4° C induced a strong photoinhibition in the unhardened leaves within a few hours. Photoinhibition manifested by a decline in quantum yield was characterized by an increase in initial fluorescence (F o) and a decrease in variable fluorescence (F v) and in the ratio of variable to maximum fluorescence (F V/F M), both at 77K and 20° C. The decline in quantum yield was more closely related to the decrease in the F V/F M ratio measured at 20° C, as compared with F V/F M at 77K. Quenching of the variable fluorescence of photosystem II was accompanied by a decline in photosystem-I fluorescence at 77K, indicating increased thermal de-excitation of pigments as the main consequence of the light treatment. All these changes detected in fluorescence parameters as well as in the quantum yield of O2 evolution were fully reversible within 1–3 h at a higher temperature in low light. The fast recovery led us to the view that this photoinhibition represents a regulatory mechanism protecting the photosynthetic apparatus from the adverse effects of excess light by increasing thermal energy dissipation. Long-term cold acclimation probably enforces other protective mechanisms, as the hardened leaves were insensitive to the same light treatment that induced strong inhibition of photosynthesis in unhardened leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403600
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  • 9
    Electronic Resource
    Electronic Resource
    Two mechanisms of recovery from photoinhibition in vivo: Reactivation of photosystem II related and unrelated to D1-protein turnover (1994)
    Springer
    Planta 194 (1994), S. 15-21 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; D1 protein ; Photoinhibition (photosynthesis) ; Photosystem II (recovery) ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recovery (at 20° C) of spinach (Spinacia oleracea L.) leaf sections from photoinhibition of photosynthesis was monitored by means of the fluorescence parameter FV/FM of intact leaf tissue and of PSII-driven electron-transport activity of isolated thylakoids. Different degrees of photoinactivation of PSII were obtained by preillumination in ambient air (at 4 or 20° C), CO2-free air or at low and high O2 levels (2 or 41 %) in N2. The kinetics of recovery exhibited two distinct phases. The first phase usually was completed within about 20-60 min and was most pronounced after preillumination in low O2. The slow phase proceeded for several hours leading to almost complete reactivation of PSII. Preincubation of the leaves with streptomycin (SM), which inhibits chloroplast-encoded protein synthesis, inhibited the slow recovery phase only, indicating the dependence of this phase on resynthesis of the reaction-centre protein, D1. The fast recovery phase remained largely unaffected by SM. Both phases were strongly but not totally dependent on irradiation of the leaf with low light. When SM was absent, net degradation of the D1 protein could neither be detected upon photoinhibitory irradiation nor during following incubation of the leaf sections in low light or darkness. In the presence of SM, net D1 degradation was seen and tended to increase with O2 concentration during photoinhibition treatment. Based on these data, we suggest that photoinactivation of PSII in vivo occurs in at least two steps. From the first step, reactivation appears possible in low light without D1 turnover (fast recovery phase). Action of oxygen then may lead to a second step, in which the D1 protein is affected and reactivation requires its removal and replacement (slow phase).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201029
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  • 10
    Electronic Resource
    Electronic Resource
    High susceptibility to photoinhibition of young leaves of tropical forest trees (1995)
    Springer
    Planta 197 (1995), S. 583-591 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; Photoinhibition (photosynthesis) ; Photosynthetic gas exchange ; Photo-system II ; Tropical forest species ; Xanthophyll cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photoinhibition of photosynthesis was studied in young (but almost fully expanded) and mature canopy sun leaves of several tropical forest tree species, both under controlled conditions (exposure of detached leaves to about 1.8 mmol photons·m-2·s-1) and in the field. The degree of photoinhibition was determined by means of the ratio of variable to maximum chlorophyll (Chl) fluorescence emission (FV/FM) and also by gas-exchange measurements. For investigations in situ, young and mature leaves with similar exposure to sunlight were compared. The results show a consistently higher degree of photoinhibition in the young leaves. In low light, fast recovery was observed in both types of leaves in situ, as well as in the laboratory. The fluorescence parameter 1 — FS/F′M (where FS = stationary fluorescence and f′M = maximum fluorescence during illumination) was followed in situ during the course of the day in order to test its suitability as a measure of the photosynthetic yield of photosystem II (PSII). Electron-transport rates were calculated from these fluorescence signals and compared with rates of net CO2 assimilation. Measurements of diurnal changes in PSII ‘yield’ confirmed the increased susceptibility of young leaves to photoinhibition. Calculated electron transport qualitatively reflected net CO2 uptake in situ during the course of the day. Photosynthetic pigments were analyzed in darkened and illuminated leaves. Young and mature leaves showed the same Chl a/b ratio, but young leaves contained about 50% less Chl a + b per unit leaf area. The capacity of photosynthetic O2 evolution per unit leaf area was decreased to a similar extent in young leaves. On a Chl basis, young leaves contained more α-carotene, more xanthophyll cycle pigments and, under strong illumination, more zeaxanthin than mature leaves. The high degree of reversible photoinhibition observed in these young sun leaves probably represents a dynamic regulatory process protecting the photosynthetic apparatus from severe damage by excess light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191564
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