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Titolo:
Photosynthetic electron transport adjustments in overwintering Scots pine (Pinus sylvestris L.)
Autore:
Ivanov, AG; Sane, PV; Zeinalov, Y; Malmberg, G; Gardestrom, P; Huner, NPA; Oquist, G;
Indirizzi:
Umea Univ, Dept Plant Physiol, UPSC, S-90187 Umea, Sweden Umea Univ UmeaSweden S-90187 Plant Physiol, UPSC, S-90187 Umea, Sweden Univ Western Ontario, Dept Plant Sci, London, ON N6A 5B7, Canada Univ Western Ontario London ON Canada N6A 5B7 London, ON N6A 5B7, Canada Bulgarian Acad Sci, Inst Plant Physiol, BU-1113 Sofia, Bulgaria Bulgarian Acad Sci Sofia Bulgaria BU-1113 ysiol, BU-1113 Sofia, Bulgaria
Titolo Testata:
PLANTA
fascicolo: 4, volume: 213, anno: 2001,
pagine: 575 - 585
SICI:
0032-0935(200108)213:4<575:PETAIO>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
COLD-ACCLIMATED SEEDLINGS; HIGH LIGHT LEVELS; PHOTOSYSTEM-I; CHLOROPHYLL FLUORESCENCE; STROMAL COMPONENTS; SEASONAL-CHANGES; FREEZING TEMPERATURES; THYLAKOID MEMBRANES; SPRUCE CHLOROPLASTS; PLASTOQUINONE POOL;
Keywords:
electron transport; P700; photosynthesis; Pinus (winter stress); thermoluminescence; winter stress;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: Oquist, G Umea Univ, Dept Plant Physiol, UPSC, S-90187 Umea, Sweden Umea Univ Umea Sweden S-90187 siol, UPSC, S-90187 Umea, Sweden
Citazione:
A.G. Ivanov et al., "Photosynthetic electron transport adjustments in overwintering Scots pine (Pinus sylvestris L.)", PLANTA, 213(4), 2001, pp. 575-585

Abstract

As shown before [C. Ottander et al. (1995) Planta 197:176-183], there is asevere inhibition of the photosystem (PS) II photochemical efficiency of Scots pine (Pinus sylvestris L.) during the winter. In contrast, the in vivoPSI photochemistry is less inhibited during winter as shown by in vivo measurements of DeltaA(820)/Delta (820) (P700(+)). There was also an enhanced cyclic electron transfer around PSI in winter-stressed needles as indicatedby 4-fold faster reduction kinetics of P700(+). The differential functional stability of PSII and PSI was accompanied by a 3.7-fold higher intersystem electron pool size, and a 5-fold increase in the stromal electron pool available for P700(+) reduction. There was also a strong reduction of the QB band in the thermoluminescence glow curve and markedly slower Q-A re-oxidation in needles of winter pine, indicating an inhibition of electron transfer between QA and QB. The data presented indicate that the plastoquinone pool is largely reduced in winter pine, and that this reduced state is likely to be of metabolic rather than photochemical origin. The retention of PSI photochemistry, and the suggested metabolic reduction of the plastoquinone pool in winter stressed needles of Scots pine are discussed in terms of the need for enhanced photoprotection of the needles during the winter and the role of metabolically supplied energy for the recovery of photosynthesis from winter stress in evergreens.

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Documento generato il 01/12/20 alle ore 16:39:07