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1Author    WieslawI. Gruszecki, ZbigniewK. RupaRequires cookie*
 Title    Changes of Excitation Spectra of in vivo Chlorophyll Fluorescence during Induction of Photosynthesis  
 Abstract    Excitation spectra of chlorophyll fluorescence from intact rye leaves were registered at dif­ ferent steps of the induction of photosynthesis after dark adaptation. Analysis of these spectra indicates that at least two processes related to spectroscopic features are responsible for a flu­ orescence quenching. The first one, active during the first 100 s of illumination, was interpret­ ed to consists in an overall decrease of the fluorescence quantum yield of antenna pigments and chlorophylls, in particular close to the reaction centers. The second type of a fluorescence decrease (between 100 s and 300 s o f illumination) was found to be in large extent related to decrease of the rate of an excitation energy transfer between accessory xanthophyll pigments and chlorophylls emitting fluorescence. This latter molecular mechanism is discussed as being related to violaxanthin availability to de-epoxidation in the xanthophyll cycle. 
  Reference    Z. Naturforsch. 48c, 46—51 (1993); received September 21/December 31 1992 
  Published    1993 
  Keywords    Chlorophyll Fluorescence, Photosynthesis, Violaxanthin, Xanthophyll Cycle 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0046.pdf 
 Identifier    ZNC-1993-48c-0046 
 Volume    48 
2Author    M. Ciscato3 ', J. Vangronsveldb, R. Valcke3Requires cookie*
 Title    Effects of Heavy Metals on the Fast Chlorophyll Fluorescence Induction Kinetics of Photosystem II: a Comparative Study  
 Abstract    The effects of toxic concentrations of Cu, Zn and Cd on the fast induction kinetics of fluorescence from photosystem(PS)II were investigated in a comparative way. The fast fluo­ rescence transient from primary leaves of m etal-treated bean plants was studied. During several days after metal application, the time course of the changes induced by the different metals was monitored. The results evidenced not only a different time course of the changes in fluorescence related parameters for the three metals, but also different effects on the fluorescence induction kinetics, which could possibly be linked to different mechanisms of action of the metals. 
  Reference    Z. Naturforsch. 54c, 735 (1999); received November 8 1998/M arch 10 1999 
  Published    1999 
  Keywords    Cadmium, Chlorophyll Fluorescence, Copper, Heavy Metals, Zinc 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0735.pdf 
 Identifier    ZNC-1999-54c-0735 
 Volume    54 
3Author    Bernd Schmidt, HansJ. RurainskiRequires cookie*
 Title    Light-Dependent Interactions of Phenazine Methosulfate with 3-(3,4-Dichlorophenyl)-l,l-dimethylurea-Poisoned Chloroplasts  
 Abstract    The chlorophyll fluorescence of isolated chloroplasts in the presence of phenazine methosulfate (PMS) and 3-(3,4-dichlorophenyl)-l,l-dimethylurea (DCMU) can be quenched in a light-dependent reaction. This phenomenan has been studied and the following observations were made: 1. Quenching occurs under non-phosphorylating conditions and is stimulated by Mg2+ ions. 2. Under the same conditions, a light-dependent, Mg2+ stimulated transient decrease of absorp­ tion at 388 nm is observed which shows the spectral characteristics of PMS. 3. PMS is reversibly bound to chloroplasts. Under the experimental conditions used, binding amounts to as much as 0.5 mol PMS/mol chlorophyll. 4. Some uncouplers of photophosphorylation such as carbonylcyanide-m-chlorophenylhydrazon (CCCP) and atebrin analog abolish quenching, transient absorption change and binding of PMS. Others, such as methylamine, ammonia, gramicidin and nigericin do not. It is suggested that fluorescence quenching, transient absorption change and binding of PMS are causally related. The concept, postulated by others, that a high-energy state of the chloroplast membrane is involved in the fluorescence lowering 
  Reference    (Z. Naturforsch. 31c, 722 [1976]; received August 10 1976) 
  Published    1976 
  Keywords    Chlorophyll Fluorescence, Chloroplasts, Fluorescence Quenching, Energized Membrane 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0722.pdf 
 Identifier    ZNC-1976-31c-0722 
 Volume    31 
4Author    Klaus Pfister, H. Artm, K. Lichtenthaler, G. Ünther Burger, Hans Musso, M.Anuel ZahnRequires cookie*
 Title    The Inhibition of Photosynthetic Light Reactions by Halogenated Naphthoquinones  
 Abstract    Halogenated naphthoquinones act as inhibitors o f photosynthetic electron flow. I50 concentra­ tion for inhibition of methylviologen reduction were found to range between 2 x 10-5 m to 2 x 10-6 M. Comparing their effects on several partial reactions o f electron flow, the inhibition site o f the naphthoquinones was found to be at the reducing site o f PS II. Studies o f fluorescence transients in presence o f halogenated naphthoquinones give further evidence for a site action similar to that o f diuron and different to that of DBMIB. All naphthoquinones act as quenchers o f chlorophyll fluorescence with pure chlorophyll a, and with much higher efficiency in green algae and chloroplasts. It is concluded, that the halogenated naphthoquinones act similar to PS II-inhibitors like diuron, but do not share a common binding site at the PS II-complex. Implications of a possible involvement of phylloquinone K 1 in photosynthetic electron transport are discussed. The synthesis o f 2-chloro-as well as 2-bromo-3-isopropyl-1,4-naphthoquinone is described. 
  Reference    Z. Naturforsch. 36c, 645—655 (1981); received April 271981 
  Published    1981 
  Keywords    Chlorophyll Fluorescence, Electron Transport, Inhibitors, Naphthoquinones, Photosynthesis, Quenchers 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0645.pdf 
 Identifier    ZNC-1981-36c-0645 
 Volume    36 
5Author    D. Anny, J. Blubaugh, G. OvindjeeRequires cookie*
 Title    Comparison of Bicarbonate Effects on the Variable Chlorophyll a Fluorescence of C 0 2-Depleted and Non-C02-Depleted Thylakoids in the Presence of Diuron  
 Abstract    Evidence is presented from chlorophyll a fluorescence transient data for two sites o f bicar­ bonate (H C O j*) action in photosystem II. Both the absence o f H C O j (H C O j-depleted thyla­ koids) and a high concentration o f H C O j (60 m M H C O j added to non-depleted thylakoids) accelerate the variable chlorophyll a fluorescence rise in the presence o f 10 |i m diuron (D C M U). In non-HCOj-depleted thylakoids the effect is independent o f the order in which H C O j and DCM U are added, whereas in H CO J-depleted thylakoids, the effect is seen only when H C O j is added before DCM U. We propose that the effect seen in H C O j-depleted thylakoids is indirectly due to the binding o f H C O j functionally near the site o f D C M U binding, which is also where H CO j exerts its major effect on electron transport between the primary quinone QA and the plasto-quinone pool. We suggest that the smaller effect seen in non-HCOj-depleted thylakoids is due to the binding of HCOj at a second, lower affinity site. Binding at this site appears to require light, in con­ trast to the higher affinity site, which is inhibited by light. Bathocuproine, an inhibitor o f the H20 -to-silicomolybdate partial reaction, is synergistic with H C O j in its effect on the variable chlorophyll a fluorescence o f non-H C O j-depleted thylakoids, and may bind heterotropically with H CO j. Thus, this second site o f H C O j binding appears to be functionally near the batho­ cuproine binding site. 
  Reference    Z. Naturforsch. 39c, 378 (1984); received N ovem ber 14 1983 
  Published    1984 
  Keywords    Bicarbonate Effect, Chlorophyll Fluorescence, Photosystem II, Diuron, Bathocuproine 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0378.pdf 
 Identifier    ZNC-1984-39c-0378 
 Volume    39 
6Author    Ulrich Schreiber, Christof Klughammer, Christian NeubauerRequires cookie*
 Title    Measuring P700 Absorbance Changes around 830 nm with a New Type of Pulse Modulation System  
 Abstract    A new measuring system for monitoring absorbance changes around 830 nm is described, which was developed by modification of a commercially available pulse modulation fluorometer. All modifications concern the emitter-detector unit of the fluorometer, such that only this unit needs to be exchanged when changing from fluorescence to absorbance measurements and vice versa. The new system is shown to be well-suited for measuring redox changes of P700, the reaction center of photosystem I, in intact leaves and isolated chloroplasts. The observed kinetic changes at 830 nm in response to single turnover or multiple turnover saturating flashes are practically identical to those previously measured around 700 nm. The signal/noise ratio is sufficiently high to give well-resolved kinetics without signal averaging. When P700 is oxidized by far-red back-ground light, valuable information on the state of the intersystem electron transport chain is given by the re-reduction kinetics induced by single or multiple turnover saturating flashes. Such meas-urements are facilitated by the use of poly-furcated fiberoptics. With intact leaves, almost identi-cal responses are found when measuring through the leaf (transmission mode) or from the leaf surface (remission mode). Modulated chlorophyll fluorescence can be measured in parallel; appli-cation of saturation pulses for fluorescence quenching analysis produces transient P700 oxidation without oversaturating the measuring system. The information on the P700 redox state comple-ments that obtained from fluorescence measurements, yielding a new practical tool in plant physiological research. 
  Reference    Z. Naturforsch. 43c, 686—698 (1988); received May 9 1988 
  Published    1988 
  Keywords    P700, Chlorophyll Fluorescence, Pulse Modulation, Photosynthesis 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0686.pdf 
 Identifier    ZNC-1988-43c-0686 
 Volume    43 
7Author    K. H. GrumbachRequires cookie*
 Title    Herbicides which Inhibit Electron Transport or Produce Chlorosis and Their Effect on Chloroplast Development in Radish Seedlings I. Chlorophyll a Fluorescence Transients and Photosystem II Activity  
 Abstract    Diuron and bentazon are very strong inhibitors o f the photosynthetic electron transport in isolated radish chloroplasts. The chlorosis producing herbicide SAN 6706 also inhibited the photosystem II dependent oxygen evolution. Aminotriazole had no effect. The inhibitor concentration for 50% inhibition o f photosystem II activity was 10-7 m for diuron and 10-4 m for bentazon and SAN 6706 respectively. Diuron and bentazon quenched the chlorophyll a fluorescence transients in isolated radish chloroplasts drastically, while aminotriazole was not effective. It was o f particular interest that the bleaching herbicide SAN 6706 inhibited photosystem II dependent oxygen evolution in a similar concentration as bentazon but had no effect on the chlorophyll a-fluorescence transients suggesting that SAN 6706 is not binding to the same site o f the electron transport chain as diuron and bentazon. Apart from their direct influence on electron transport in isolated photosynthetically active chloroplasts the photosystem II and bleaching herbicides assayed also strongly affected photosynthesis in radish seedlings that were grown in the presence o f the herbicides for a long time. As already obtained using isolated chloroplasts, photosystem II dependent oxygen evolution like the chlorophyll a fluorescence transients were strongly inhibited by the photosystem II herbicides diuron and bentazon. A reduction but no inhibition o f photosystem II activity was observed in plants that were grown in the presence o f aminotriazole. The pyridazinone SAN 6706 was behaving contradictory. In partly green plants photosystem II activity was still maintained and even higher than in untreated plants while in albinistic plants no photosynthetic activity was detected. 
  Reference    Z. Naturforsch. 37c, 268—275 (1982); received December 3 1981 
  Published    1982 
  Keywords    Bleaching Herbicides, Photosynthesis, Photosystem II Herbicides, Photosystem II Activity, Chlorophyll Fluorescence 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0268.pdf 
 Identifier    ZNC-1982-37c-0268 
 Volume    37 
8Author    J.M D Ucruet, P. G. Aillard, J. V. IenotRequires cookie*
 Title    Use of Chlorophyll Fluorescence Induction Kinetics to Study Translocation and Detoxication of DCMU-Type Herbicides in Plant Leaves  
 Abstract    Transient levels o f the fluorescence induction rise were used to quantify partial photosynthesis inhibition by DC M U -type herbicides in w hole leaves. Assays in different crop or weed species showed a good accuracy in measurements (generally, variation was lower than 5%). This technique was applied to the problem o f varietal selectivity o f wheat towards chlortoluron. 
  Reference    Z. Naturforsch. 39c, 354 (1984); received N ovem ber 15 1983 
  Published    1984 
  Keywords    Chlorophyll Fluorescence, Photosystem II, H erbicides Translocation, D etoxication 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0354.pdf 
 Identifier    ZNC-1984-39c-0354 
 Volume    39 
9Author    Z. NaturforschRequires cookie*
 Title    Redox-State Dependent Changes of Inhibitor-Binding to the Photosystem II Acceptor Complex  
 Abstract    Binding o f radioactively labelled D C M U , ioxynil and terbutryn to spinach chloroplasts is determined following preillum ination by single-turnover, saturating light flashes. W ith all o f the three herbicides binary oscillations o f binding are observed. D ark-adapted sam ples, or those pre­ illuminated by an even number o f flashes, bind more inhibitor than sam ples preillum inated by an odd number o f flashes. Binding oscillations depend on inhibitor incubation tim e and on the seasonal adaptation o f the plants. The binding kinetics follow ing a single flash display three phases, the last two o f which can be correlated with reoxidation kinetics o f the secondary p h oto­ system II acceptor Qb, as determined by fluorescence measurem ents. Analysis o f the binding at DCM U concentrations up to 10"7 M free D C M U yields identical binding constants for dark-and flash preilluminated samples, but much less binding sites follow ing one flash. It is concluded that up to 10~7 M free DCM U, centers with bound Q b do not contribute significantly to total binding. Displacement o f Q b from the binding site is half-saturated at about 10-6 M D C M U , as m onitored via fluorescence induction. The data are considered strong support for the Velthuys 'inhibitor-Q i competition model'. 
  Reference    Z. Naturforsch. 39c, 397 (1984); received D ecem ber 1 1983 
  Published    1984 
  Keywords    Inhibitor Binding, Photosystem II, Binary O scillation, Chlorophyll Fluorescence 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0397.pdf 
 Identifier    ZNC-1984-39c-0397 
 Volume    39 
10Author    Salil Bose, R. M. Annar, M. Annan, C. J. ArntzenRequires cookie*
 Title    Increased Synthesis of Photosystem II in Triticum vulgare when Grown in the Presence of BAS 13-338  
 Abstract    Addition o f BAS 13-338 (4-chloro-5-dim ethylam ino-2-phenyl-3(2H)-pyridazinone) to a sus­ pension o f chloroplast thylakoids caused an increase in the / level o f chlorophyll fluorescence induction without affecting the F0 level and with a slight decrease in the Fmax level in a manner similar to the addition o f D C M U to a thylakoid suspension. A ddition o f BAS 13-338 also inhibited the rate o f Hill reaction H20 -» dichlorophenol indophenol with 50% inhibition occurring at about 10 hm BAS 13-338. The inhibition was not reversed by diphenyl carbazide used as an artificial electron donor to photosystem II. These results suggest that the site o f in h ib i­ tion by BAS 13-338 is between Q (next to the primary electron acceptor) and plastoquinone. When the plants were grown in the presence o f sublethal dose o f BAS 13-338, the follow ing changes were noted in the thylakoids o f the treated plants as com pared to the thylakoids isolated from the control plants: The F0 and the norm alized variable fluorescence (4F/F0) levels increased, chlorophyll a/b ratio decreased, chlorophyll/P 700 ratio increased. Furthermore, the rate o f photosystem II electron transport both under saturated intensity and the lim iting intensity of illumination increased, and the ratio o f plastoquinone to Q decreased. These observations have been interpreted as due to an increase in the ratio o f photosystem II to photosystem I in plants grown in the presence o f BAS 13-338. 
  Reference    Z. Naturforsch. 39c, 510 (1984); received D ecem ber 1 1983 
  Published    1984 
  Keywords    Photosynthesis, Electron Transport, Chlorophyll Fluorescence, Photosystem II, BAS 13-338 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0510.pdf 
 Identifier    ZNC-1984-39c-0510 
 Volume    39 
11Author    Wolfgang Schmidt, Ulrich Schreiber, Wolfgang UrbachRequires cookie*
 Title      
 Abstract    The effects of short-time fumigation (0-60 min) of intact spinach leaves with S0 2 (2 ppm) on the photosynthetic apparatus were investigated. A rather high S0 2 concentration was applied to monitor immediate effects on the fluorescence behaviour with the influence of repair processes or secondary types of damage being minimized. Three different types of in vivo chlorophyll fluores-cence measurements were used: Rapid induction kinetics (Kautsky effect), slow induction kinetics with repetitive application of saturation pulses (saturation pulse method), and decay kinetics following a single turnover saturating flash. The slow induction kinetics with repetitive application of saturation pulses reacts in the most sensitive way indicating a primary damage at the level of the enzymatic reactions of the Calvin cycle. It is suggested that stromal acidification upon S0 2 uptake interferes with light activation of Calvin cycle enzymes. With longer fumigation times also damage at the level of photosystem II becomes apparent: A decrease in variable fluorescence yield reflects a lowering of photosystem II quantum yield, and the slowing down of fluorescence relaxation kinetics reveals an effect on the secondary electron transport from Q A to Q B . The detrimental effects of S0 2 depend to a great extent on the application of light during fumigation. Besides a light requirement for S0 2 uptake by stomata opening also the possibility of photoinhibitory damage is discussed. The susceptibility of leaves to photoinhibition may increase with a lowering of Calvin cycle activity by S0 2 . 
  Reference    Z. Naturforsch. 43c, 269—274 (1988); received December 7 1987 
  Published    1988 
  Keywords    Chlorophyll Fluorescence, S0 2, Spinach, Intact Leaves, Calvin Cycle 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0269.pdf 
 Identifier    ZNC-1988-43c-0269 
 Volume    43 
12Author    W. Bilger, U. Heber, U. SchreiberRequires cookie*
 Title    Kinetic Relationship between Energy-Dependent Fluorescence Quenching, Light Scattering, Chlorophyll Luminescence and Proton Pumping in Intact Leaves  
 Abstract    A measuring system was designed for simultaneous recording of modulated chlorophyll fluorescence and light scattering changes. The kinetic relationship was investigated between light-induced changes in non-photochemical fluorescence quenching, as determined by the saturation pulse method, and in light scattering, as measured via the apparent absorbance change at 543 nm. Very similar, but not identical kinetics were observed, reflecting a close non-linear relationship between these two indicators of thylakoid membrane energization. Fluorescence was found more sensitive at low levels of energization, while scattering continued indicating further increases in energization when quenching already was saturated. A general relationship between quenching and scattering is demonstrated which holds irrespective of whether energization is varied during induction or via changes in light intensity or C02 concentration. In the light-off responses, only part of fluorescence quenching was found to relax with the same kinetics as scattering. It is suggested that at high levels of energization slowly reversible membrane changes may be induced which have the potential of non-photochemical quenching at a low level of energization, and which are not accompanied by scattering changes. Neither quenching nor scattering changes displayed kinetics sufficiently fast to be taken as a direct expression of internal thylakoid acidifica-tion in intact leaves. This conclusion is drawn from comparative measurements of proton-uptake, as reflected by C02-solubilization upon light-induced stroma alkalization, and of chlorophyll luminescence. Both, the initial C02-gulp and the pH-dependent luminescence rise were found to clearly precede the development of energy-dependent quenching. 
  Reference    Z. Naturforsch. 43c, 877—887 (1988); received July 18 1988 
  Published    1988 
  Keywords    Chlorophyll Fluorescence, Light Scattering, Chlorophyll Luminescence, Thylakoid Membrane, Proton Pumping 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0877.pdf 
 Identifier    ZNC-1988-43c-0877 
 Volume    43 
13Author    J. SymRequires cookie*
 Title    The Role of D 1* in Light-Induced D 1 Protein Turnover in Leaves  
 Abstract    ea, H arald R . B olh à r-N ord en kam pfb, and C hrista C ritch ley3 Light-induced degradation o f the D 1 protein of photosystem II (PS II) was determined by radioactive pulse-chase labelling experiments in intact leaves o f Schefflera polybotrya. PS II photochemical efficiency was monitored by measuring chlorophyll fluorescence. A significant and consistent decline in the F J F m ratio was taken to indicate photoinhibition. The formation and degradation o f a modified form o f the D 1 protein, D 1*, was different under photoinhibi-tory or non-photoinhibitory light conditions. At photoinhibitory irradiance greater amounts o f D 1 * were formed relative to D 1, and the degradation of D 1* was slower when compared with non-photoinhibitory irradiance. The formation and degradation o f D 1* were therefore shown to be at least partly light intensity dependent. Higher light intensities appeared to slow D 1* degradation, which suggests a modification in PS II turnover properties. 
  Reference    Z. Naturforsch. 48c, 246 (1993); received December 12 1992 
  Published    1993 
  Keywords    Photosynthesis, Photosystem II, Photoinhibition, D 1 Degradation, Chlorophyll Fluorescence 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0246.pdf 
 Identifier    ZNC-1993-48c-0246 
 Volume    48 
14Author    StefanD. Renkard3, JürgenM. Aguhnb, D. Ietm Ar Knoppik3Requires cookie*
 Title    Simultaneous Gas-Exchange and Fluorescence Measurements with Ozone-Fumigated Spruce  
 Abstract    A method was developed for carrying out gas-exchange and chlorophyll-fluorescence measurements simultaneously during fumigation of spruce twigs with peroxidic photooxi­ dants. It is thus now possible to investigate how a pollutant affects distinct sectors of the photosynthetic apparatus of the plant: whereas fluorescence reveals any changes in the pri­ mary light reaction, C 0 2 gas-exchange measurements supply information about the bio­ chemical reactions of the Calvin cycle. Results of short-time fumigation with 750 ppb ozone are presented here. Gas-exchange and fluorescence data are affected strongly in early sum­ mer, but not in autumn. The assimilation rate decreases significantly: primarily as a result of Rubisco activity and possibly because of direct inhibition of the electron-transport chain as well. Closure of the stomata leads to further reduction in the assimilation rate. Though no damage becomes visible on the needles, the perturbance of the photosynthetic apparatus caused by ozone fumigation is not reversible within 24 h. 
  Reference    Z. Naturforsch. 49c, 819—833 (1994); received June 21 1994 
  Published    1994 
  Keywords    Spruce, Photosynthetic Apparatus, Gas Exchange, Chlorophyll Fluorescence, Ozone Fumigation 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0819.pdf 
 Identifier    ZNC-1994-49c-0819 
 Volume    49 
15Author    Carina Barth, G.Heinrich KrauseRequires cookie*
 Title    Inhibition of Photosystems I and II in Chilling-Sensitive and Chilling-Tolerant Plants under Light and Low-Temperature Stress  
 Abstract    The responses of photosystems (PS) I and II to light stress at 4 °C and 20 °C were studied in leaf discs from three chilling-sensitive plant species, Cucumis sativus, Cucurbita maxima and Nicotiana tabacum, and in the chilling-tolerant Spinacia oleracea. The chilling-sensitive plants were grown at 24 °C under 8 0 -1 2 0 j.imol photons m-2 s-1 (Cucumis and Cucurbita) or 30 [imol photons m -2 s_1 (Nicotiana). Spinacia was cultivated outdoors during winter and early spring. The P700 absorbance change around 820 nm served as a relative measure of PSI activity. The potential efficiency of PSII was determined in dark-adapted leaf discs by means of the ratio of variable to maximum chlorophyll (Chi) a fluorescence emission (F v/ F m). In Cucurbita, Nicotiana and Spinacia, PSI was not or only slightly inhibited by 2 h illumination with 200 [imol m-2 s-1 at 4 °C or with 2000 ^imol m-2 s-1 at 20 °C. In leaves of Cucurbita and Nicotiana, exposure to 2000 j.imol photons m -2 s_1 at 4 °C resulted in a decline in PSI activity and potential PSII efficiency approximately to the same extent (about 50% within 2 h). In contrast, in Cucumis, both moderate and high light at low temperature caused a PSI inhibition that proceeded considerably faster than the decline in PSII efficiency. Such preferential photoinhibition of PSI was not observed in the other three species tested. In Spinacia, a lower susceptibility of PSI and PSII to photoinhibition at 4 °C was associated with a faster de-epoxidation kinetics of violaxanthin, as compared to the three chilling-sensi-tive species. In addition, leaves of Spinacia were characterized by a significantly larger pool of xanthophyll-cycle pigments and a higher content of ß-carotene based on Chi a+b. When leaves of Cucurbita were preincubated with methylviologen, which catalyzes formation of superoxide anion radicals at the acceptor side of PSI, the decline in potential PSII efficiency under 2000 jimol photons m -2 s_1 at 20 °C and 4 °C was strongly enhanced, whereas the P700 signal was less affected. Our data demonstrate that in the species tested, PSI may be inhibited in vivo besides PSII under light stress, but preferential photoinhibition of PSI is not a general phenomenon in chilling-sensitive plants. At low temperatures, a reduced function of the xanthophyll cycle and of the antioxidative scavenging system might account for enhanced PSI and PSII inhibition in vivo. 
  Reference    Z. Naturforsch. 54c, 645 (1999); received November 8 1998/January 30 1999 
  Published    1999 
  Keywords    Active Oxygen Species, Chlorophyll Fluorescence, P700 Absorbance Change, Photoinhibition, Xanthophyll Cycle 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0645.pdf 
 Identifier    ZNC-1999-54c-0645 
 Volume    54 
16Author    András Neményi3, JohnH. Georgakopoulosb, Judit Kissimon3, András Badacsonyic, G. Ábor, Horváth3Requires cookie*
 Title    Trachycarpus fortunei H. Wendl. under Winter and Summer Conditions  
 Abstract    A study was conducted to analyze the contribution of high irradiance and resulting photo­ inhibition to the decline in net photosynthesis in the leaves of palm Trachycarpus fortunei during summer and winter as well as at normal growth and low temperatures in field and laboratory conditions, respectively. Fluorescence induction measurements indicated that there was a 10% decrease in the F v/Fm ratio in field conditions at midday during both summer and winter, due to the relatively low intensity of incident light resulting from the partial leaf segment folding. Fluorescence parameters completely recovered by the evening hours. In summer the midday decay was due to the decrease of F m which probably represents a rapidly reversible component of photoinhibition by the protective down-regulation of PSII mediated by the xanthophyll cycle. In winter, however, the initial Fv/Fm ratio was 40% less than as measured in summer and its midday decline was associated with the decrease of Fv indicating the partial inactivation of PS II. TTie net C 0 2 assimilation rate followed the pattern of the Fv/Fm ratio but it could not recover due to the stomatal closure after midday. Comparing the fluorescence and gas exchange measurements we have concluded that the photoinhibition of T. fortunei represented by the F v/Fm ratio changes is a regulatory adjustment of PS II effi­ ciency to limiting carbon utilization and to limiting carbon availability imposed by stomatal closure. Leaves photoinhibited under laboratory conditions at growth temperature showed a substantial decrease of 50% in the F v/Fm ratio due to the perpendicular exposure, but no apparent changes in D[ protein content could be detected. Phytotron grown plants exposed to cold stress (6 °C) and low irradiance (250 [.imol m~2 s_1) under laboratory conditions showed a time related but much slower continuous decrease in F v/Fm ratio. After high irradi­ ance the recovery kinetics in the dark at normal growth temperature (28 °C) strongly de­ pended on the extent of the photoinhibition, while after low irradiance complete recovery occurred in 12 hours irrespective of the initial Fv/Fm value, independently from the time of cold treatment, indicating that at low light and cold treatments only reversible inactive PS IIs were formed. 
  Reference    Z. Naturforsch. 54c, 658 (1999); received December 18 1998/February 11 1999 
  Published    1999 
  Keywords    Arecaceae, Chlorophyll Fluorescence, Cold Stress, Light Stress, Photosynthetic Gas Exchange 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0658.pdf 
 Identifier    ZNC-1999-54c-0658 
 Volume    54 
17Author    Sándor Dulai3, István Molnár3, Evelin Pélia, Endre LehoczkiabRequires cookie*
 Title    Short-Term Responses of Photosystem II to Heat Stress in Cold-Acclimated Atrazine-Resistant and Susceptible Biotypes of Erigeron canadensis (L.)  
 Abstract    When leaves of atrazine-resistant (A R) and atrazine-sensitive (S) Erigeron canadensis (L.) plants grown at 5 °C were exposed to an elevated temperature (35 °C) for 30 min, the critical (T c) and peak temperatures (Tp) of the F0 vs. T curves were considerably higher for the leaves of the S biotype, but not for those of the A R biotype. The temperature dependences of F J F m and AFIFm' were not greatly different for the heat-treated cold-acclimated A R biotype, in contrast with the situation for the S plants. This short-term heat treatment resulted in a more significant shift in the optimal thermal interval of C 0 2 fixation for the S than for the A R biotypes. 
  Reference    Z. Naturforsch. 54c, 665 (1999); received November 2 1998/February 19 1999 
  Published    1999 
  Keywords    Erigeron canadensis, Heat Stress, Chlorophyll Fluorescence, Photosystem II, Photosynthesis 
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 Identifier    ZNC-1999-54c-0665 
 Volume    54 
18Author    Ulrich Schreiber, K. Onrad, Colbow\., WilliamV. IdaverRequires cookie*
 Title    Tem perature — Jump Chlorophyll F luorescence Induction in Plants  
 Abstract    In contrast to slower heating rates, a temperature jump reveals complex rise phases in the heat induced chlorophyll fluorescence emission increase in intact plants. Three rise phases have been detected which indicate the stepwise loss of different quenching mechanism of system II fluorescence. Two of the phases appear to reflect heat deactivation of the system II reaction centers, while the other may be as­ sociated with the induction of hydrogenase activity. Varia­ tions in T max of the jump, for the increase in different plant varieties, suggest a correlation with membrane lipid phase transitions affecting thylakoid membrane structure and the fluorescence increase. Chlorophyll fluorescence has been a valuable in ­ dicator for the state and functioning of the photo-synthetic apparatus (for a review, cf. ref. 1). 
  Reference    (Z. Naturforsch. 30c, 689—690 [1975]; received May 12 1975) 
  Published    1975 
  Keywords    Chlorophyll Fluorescence, Temperature Jump, Heat Deacti­ vation, Watersplitting, Enzyme System, Lipid Phase Transition 
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 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0689_n.pdf 
 Identifier    ZNC-1975-30c-0689_n 
 Volume    30 
19Author    H. K. Lichtenthaler, G. Kuhn, U. Prenzel, C. Buschmann, D. MeierRequires cookie*
 Title    Adaptation of Chloroplast-Ultrastructure and of Chlorophyll- Protein Levels to High-Light and Low-Light Growth Conditions  
 Abstract    Adaptation In saturating light radish seedlings grown in high-light growth conditions (90 W • n r 2) possess a much higher photosynthetic capacity on a chlorophyll and leaf area basis than the low-light grown plants (10 W • m-2). The higher C 0 2-fixation rate o f HL-plants is due to the presence of HL-chloroplasts which possess a different ultrastructure and also different levels o f the individual chlorophyll-carotenoid-proteins than the LL-chloroplasts of LL-seedlings. 1. Ultrastructure: The high-light adapted chloroplasts are characterized by fewer photo­ synthetic membranes per chloroplast section, by low grana stacks (only few thylakoids per granum), a lower stacking degree o f thylakoids, a higher proportion o f non-appressed mem­ branes (stroma thylakoids + end grana membranes) and a high starch content. The LL-chloro­ plasts possess no starch, their grana stacks are higher (up to 17 thylakoids per granum) and also significantly broader than that o f HL-chloroplasts. 2. Chlorophyll-proteins: The photosynthetic apparatus o f HL-chloroplasts contains a larger proportion of chlorophyll a-proteins of photosystem I (CPIa + CPI) and of photosystem II (CPa, the presumable reaction center o f PS II) than the LL-chloroplasts which possess a higher propor­ tion of light-harvesting chlorophyll a/fc-proteins (LHCP,, LHCP2, LHCP3, LHCPy). The higher levels of LHCPs in LL-plants are associated with a higher ground fluorescence fo and maximum fluorescence fp of the in vivo chlorophyll. 3. Chlorophyll and carotenoid ratios: The chloroplasts o f HL-plants possess a higher proportion of chlorophyll a and /2-carotene (higher values for the ratios chlorophyll a /b and lower values for a/c and x /c) which reflect the increased level o f the chlorophyll a//?-carotene-proteins CPIa, CPI and CPa. The higher level o f light-harvesting chlorophyll a/6-xanthophyll-proteins (LHCPs) in LL-plants is also indicated by an increased content o f xanthophylls and chlorophyll b as seen from lower a /b and higher x /c and a /c ratios. 4. The results indicate that plants possess the capacity for an ontogenetic adaptation o f their photosynthetic apparatus to the incident light intensity. The HL-chloroplasts o f HL-plants which contain less antenna chlorophyll, are adapted for a more efficient photosynthetic quantum conversion at light saturation than the LL-chloroplasts with high grana stacks. The correlation between higher levels o f light-harvesting chlorophyll ö/6-proteins (LHCPs) and a higher stacking degree of thylakoids, and the involvement o f LHCPs in stacking is discussed. Abbreviations: a/b, ratio chlorophyll a/b', a /c, weight ratio chlorophyll a to /^-carotene, CPI and CPIa, the two P700 containing chlorophyll a /?-carotene-proteins o f photosys­ tem I; CPa, chlorophyll a /?-carotene-protein o f photosys­ tem II, c/x, ratio /?-carotene/xanthophylls; fo, ground fluo­ rescence of the in vivo chlorophyll fluorescence; fp, maxi­ mum level of the in vivo chlorophyll fluorescence; FP, free pigments; HL, high-light growth condition; LHCPs, sum of the 4 light-harvesting-chlorophyll a/6-proteins L H C P,, LHCP2, LHCP3 and LHCPy; LL, low light growth condi­ tion; PAGE, polyacrylamide-gel electrophoresis; PS I and PS II photosynthetic photosystem I and II; SDS, sodium dodecylsulphate; Tris, tris (hydroxymethyl)-aminomethan; v/v, volume per volume; w/v, weight per volume; x/c, weight ratio xanthophylls to /7-carotene. * The work described here, was presented on the European Symposium Light Mediated Plant Development in April 1981 in Bischofsmais, Bavaria. 
  Reference    Z. Naturforsch. 37c, 464 (1982); received March 2 1982 
  Published    1982 
  Keywords    of Chloroplasts, Chlorophyll Fluorescence, Chlorophyll a-Proteins, Chloroplast Ultrastructure, High-Light Chloroplasts 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0464.pdf 
 Identifier    ZNC-1982-37c-0464 
 Volume    37 
20Author    W. Bilger, U. SchreiberRequires cookie*
 Title    Modulation of Millisecond Chlorophyll Luminescence by Non-Photochemical Fluorescence Quenching  
 Abstract    By combining a high frequency modulation system for measurement of fluorescence with a phosphoroscope type apparatus for measurement of luminescence, recordings of fluorescence and luminescence induction kinetics under identical conditions were obtained. Both measuring sys­ tems tolerated the application of saturating pulses of white light for rapid, transient elimination of photochemical quenching at photosystem II reaction centers, thus allowing determination of the non-photochemical quenching component. The saturation pulse induction curves of luminescence are well correlated with the corresponding curves of fluorescence, suggesting that luminescence yield is lowered by the same type of non-photochemical quenching (mostly "energy dependent quenching") as fluorescence. Hence, in order to evaluate luminescence signals in terms of the rate of charge recombination at photosystem II reaction centers, knowledge of fluorescence quenching is required. 
  Reference    Z. Naturforsch. 44c, 966 (1989); received June 28 1989 
  Published    1989 
  Keywords    Chlorophyll Luminescence, Chlorophyll Fluorescence, Energy Dependent Quenching, Photo­ system II, Photosynthesis Induction 
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 Identifier    ZNC-1989-44c-0966 
 Volume    44 
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