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'Chlorophyll Fluorescence' in keywords Facet   Publication Year 1999  [X]
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1999[X]
1Author    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 
2Author    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 
3Author    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 
4Author    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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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0665.pdf 
 Identifier    ZNC-1999-54c-0665 
 Volume    54 
5Author    Juliane Peters, M. Soledad, Jim Énez, Domingo MoralesRequires cookie*
 Title    Effect of Extreme Temperature on Quantum Yield of Fluorescence and Membrane Leakage of the Canarian Endemic Pine (Pinus canariensis)  
 Abstract    The effect of extreme temperature on the quantum yield of fluorescence and membrane leakage of Pinus canariensis growing in 5 stands at different altitudes and orientation in Tenerife (Canary Islands, Spain) was determined. Needles were collected from the field and transferred to the laboratory where they were kept in a closed chamber with water-saturated air overnight. Then they were exposed for 30 minutes in plastic bags in a water bath at temperature treatments with steps of 2K between 56 °C and -2 4 °C and the effect was deter­ mined immediately and 24 hours after the treatment by chlorophyll fluorescence and electro­ lyte leakage. Needles presented incipient damage at temperatures ranging from -5 to -1 0 °C depending on the altitude and orientation of the stand. The results were more evident when the mea­ surements were done 24 hours after the cold treatment and values were consistent with the electrolyte leakage results. Different resistance to high temperature depending on the alti­ tude and orientation was also found, varying the temperature for incipient damage from 42 to 44 °C detected with the fluorescence parameters but not with the leakage of electrolytes which was not found until 50 °C. The amplitude of thermal limits for photosynthetic effi­ ciency alteration in needles of P. canariensis was relatively narrow and similar to that of evergreen Canarian laurel forest trees. 
  Reference    Z. Naturforsch. 54c, 681—6 (1999); received December 10 1998/February 20 1999 
  Published    1999 
  Keywords    Pinus canariensis, Low Temperature, High Temperature, Altitudinal Gradient, Chlorophyll Fluorescence, Electrolyte Leakage 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0681.pdf 
 Identifier    ZNC-1999-54c-0681 
 Volume    54 
6Author    Domingo Morales3, Juliane Peters3, M. Soledad, Jim Énez3, Michael Tauszb, Astrid Wonischb, Dieter GrillbRequires cookie*
 Title    Gas Exchange of Irrigated and Non-Irrigated Pinus canariensis Seedlings Growing Outdoors in La Laguna, Canary Islands, Spain  
 Abstract    Chlorophyll fluorescence, gas exchange, water potential and relative water content were measured in the needles of five year old seedlings of Pinus canariensis in order to know their response to mild water stress. Two trial plots of ten plants per plot, of similar age and characteristics were irrigated daily until the experiment was undertaken, then one of the plots was left without watering while the other one was irrigated as before. After a week of treatment, the water potential at midday did not change in any of the irrigated or non-irrigated plants maintaining around -0 .4 MPa, and the relative water content changed from 93% in irrigated to 84% in non-irrigated seedlings. The stomatal conductance decreased 60% in non irrigated plants and as a result C 0 2 assimilation decreased by 50% and transpiration was reduced at a higher proportion (70%), indicating a good control against water loss, before any change in water status in the needles could be observed suggesting an isohydric water economy in this plant. 
  Reference    Z. Naturforsch. 54c, 693—6 (1999); received December 14 1998/March 21 1999 
  Published    1999 
  Keywords    Pinus canariensis, Mild Water Stress, Gas Exchange, Water Potential, Chlorophyll Fluorescence, Seedlings 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0693.pdf 
 Identifier    ZNC-1999-54c-0693 
 Volume    54 
7Author    Claus Buschm, HartmutK. LichtenthalerRequires cookie*
 Title    Contribution of Chlorophyll Fluorescence to the Reflectance of Leaves in Stressed Plants as Determined with the VIRAF-Spectrometer  
 Abstract    Reflectance spectra allow the early detection of stressors causing differences in pigment content as well as changes of leaf tissue structure and photosynthetic activity. The reflectance decreased with increasing Chi content in greening bean leaves. In stressed leaves, in turn, the reflectance increased with decreasing Chi content. This also caused a shift of the red reflection rise ("red edge") to shorter wavelengths ("blue shift") associated with a blue shift of the inflection point of the red edge. The contribution of the red and far-red Chi fluores­ cence to the reflectance signal at the red edge of the spectrum and the shift of the wavelength position of the inflection point are demonstrated and discussed. 
  Reference    Z. Naturforsch. 54c, 849 (1999); received May 20 1999 
  Published    1999 
  Keywords    Chlorophyll Fluorescence, Red Edge of Reflectance, Remote Sensing, Spectroscopic Techniques, Stress Detection 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0849.pdf 
 Identifier    ZNC-1999-54c-0849 
 Volume    54