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'Photosystem II' in keywords Facet   Publication Year 1999  [X]
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1999[X]
1Author    Zoltán Takács, Zsolt Csintalan, Zoltán TubaRequires cookie*
 Title    Responses of the Lichen Cladonia convoluta to High C 0 2 Level and Heavy Metal Treatment  
 Abstract    Despite of the downward acclimation of photosynthesis in C. convoluta, increased net photosynthesis and carbon balance can be anticipated in response to elevated atmospheric C 0 2 level. C 0 2 exchange measurement seems to be m ore indicative when detecting heavy metal stress than fluorescence parameters. Among these, the relative fluorescence decrease ratio (R F d 690) shows damage first, suggesting that the primary attack site for heavy metal ions is C 0 2 fixation and reaction centres are harmed last. Long-term elevated C 0 2 amelio­ rates partly this damage by improving C-balance to a greater extent in the heavy-metal stressed lichens. 
  Reference    Z. Naturforsch. 54c, 797—8 (1999); received November 15 1998/M arch 5 1999 
  Published    1999 
  Keywords    Cadmium, Lead, Fluorescence, Respiration, Photosystem II 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0797.pdf 
 Identifier    ZNC-1999-54c-0797 
 Volume    54 
2Author    Jaber Rahoutei3, MatildeB. Arón3, IsabelG. Arcía-Luqueb, Magdolna Droppac, András Neményic, G. Ábor, H. OrváthcRequires cookie*
 Title    Effect of Tobamovirus Infection on Thermoluminescence Characteristics of Chloroplasts from Infected Plants  
 Abstract    Changes of thermoluminescence characteristics as well as the 0 2-evolving capacity was analysed in chloroplasts isolated from Nicotiana benthamiana infected with pepper and pa­ prika mild mottle viruses and their chimeric hybrids. The electron transport activity in thyla­ koids of virus-infected plants was inhibited and could be restored by adding DPC or Ca2+ which indicated that the virus infection altered the oxygen-evolving complex. In thermolumi­ nescence characteristics of plants infected with either viruses, the first well defined response was a shift in the peak position of the B band from 20 °C to 35 °C corresponding to S3(S2)Q b-and S2Q b~ charge recombinations, respectively, which showed an inhibition in the formation of higher S states in the water splitting system. Simultaneously, a new band ap­ peared around 70 °C due to chemiluminescence of lipid peroxidation. Further progress of the viral infection dramatically decreased the intensity of bands originated from charge re­ combinations with a concomitant increase of the band at 70 °C indicating the general oxida­ tive breakdown of injured thylakoids. 
  Reference    Z. Naturforsch. 54c, 634 (1999); received November 15 1998/January 15 1999 
  Published    1999 
  Keywords    Biotic Stress, Photosynthetic Electron Transport, Photosystem II, Thermoluminescence, Virus Infection 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0634.pdf 
 Identifier    ZNC-1999-54c-0634 
 Volume    54 
3Author    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 
4Author    Merope Tsimilli-Michaelab, Martin Pêcheux3, RetoJ. Strasser3Requires cookie*
 Title    Light and Heat Stress Adaptation of the Symbionts of Temperate and Coral Reef Foraminifers Probed in Hospite by the Chlorophyll a Fluorescence Kinetics  
 Abstract    Since the early 80's massive bleaching affects the reef ecosystem. It involves, besides corals, several other species among which large foraminifers, and it corresponds to the loss of their photosynthetic symbionts or the symbionts' pigments. The cause is unclear, though temper­ ature elevation and strong irradiation have been considered to be primary factors. In this work we investigated in two genera of coral reef foraminifers (Amphistegina lobifera and Amphisorus heimprichii) and in the temperate foraminifer Sorites variabilis the response of photosystem II (P SII) of their symbionts in hospite upon light stress (white light of 550 |aE n r 2 s_1 and red light of 3200 |iE m~2 s" 1) and heat stress (up to 32 °C), by means of the Chla fluorescence transients O -J-I-P they exhibit upon illumination. The transients were analysed according to the JIP-test which leads to the calculation of several structural and functional parameters providing a quantification of PSII behaviour. We observed that the various parameters undergo modifications that differ concerning both their extent and their degree of elasticity, thus indicating that different adaptive strategies are employed in response to stress. The most pronounced of these regulatory changes is a wide decrease of the quantum yield of electron transport. However, the extent of the changes, different for the three studied species, was in general smaller when the cultures were kept under low light (70 ^iE m -2 s-1) than in darkness. By the applied stressors, PSII was not damaged and, except for some cells in which an expulsion of symbionts was initiated, no bleaching was observed. This can be well correlated with the observed adaptability of PSII. As a working hypothesis, it is proposed that the decrease of the capacity for electron transport activity might be among the factors trigger­ ing bleaching in the field. 
  Reference    Z. Naturforsch. 54c, 671 (1999); received November 10 1998 
  Published    1999 
  Keywords    Coral-Reef Bleaching, Electron Transport Activity, JIP-test, Photosystem II, Thermoprotection 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0671.pdf 
 Identifier    ZNC-1999-54c-0671 
 Volume    54