Effect of high-light acclimation on photosynthetic apparatus of Norway spruce

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Effect of high-light acclimation on photosynthetic apparatus of Norway spruce

Popis výsledku v původním jazyce

The photosynthetic apparatus of Norway spruce displays several specific features differing from typical land plants. Absence of Lhcb3 and Lhcb6 in light-harvesting complexes (LHC) of photosystem II (PSII) was found in the gymnosperm genera Picea and Pinus (family Pinaceae), resulting in different PSII supercomplex structure and macro-organization. Further, the significantly different lipid composition of spruce thylakoid membrane might contribute to higher PSII thermal stability and more pronounced acceleration of light-induced violaxanthin deepoxidation at elevated temperatures in spruce needles, as compared to Arabidiposis or barley. In this work, we have primarily focused our attention on high-light (HL) acclimation of the photosynthetic apparatus of spruce. Circular dichroism spectra of thylakoid membranes isolated from HL-acclimated seedlings revealed strongly diminished psi-type circular dichroism bands, suggesting a reduced degree of the long-range order of PSII-LHCII supercomplexes compared to the control. Also, in vitro 77K fluorescence spectroscopy of chlorophyll a revealed that, in contrast to control membranes, in HL thylakoid membranes the emission ratio of PSI/PSII and the absorption cross-sections of PSII and PSI were very similar under stacking and unstacking conditions, indicating a suppressed lateral segregation of the two photosystems. The induction of non-photochemical quenching of chlorophyll fluorescence (NPQ) was found to be fast in both HL-acclimated and control seedlings, although the magnitude of NPQ was significantly reduced, suggesting sustained energy dissipation in HL-acclimated leaves. These results are discussed by also taking into account the effects of HL acclimation on the composition of photosynthetic pigment-system (a surprisingly pronounced increase of lutein) and of the thylakoid lipids (a considerable reduction of MGDG content but increased relative content of SQDG) - unusual features in typical angiosperms.

Název v anglickém jazyce

Effect of high-light acclimation on photosynthetic apparatus of Norway spruce

Popis výsledku anglicky

The photosynthetic apparatus of Norway spruce displays several specific features differing from typical land plants. Absence of Lhcb3 and Lhcb6 in light-harvesting complexes (LHC) of photosystem II (PSII) was found in the gymnosperm genera Picea and Pinus (family Pinaceae), resulting in different PSII supercomplex structure and macro-organization. Further, the significantly different lipid composition of spruce thylakoid membrane might contribute to higher PSII thermal stability and more pronounced acceleration of light-induced violaxanthin deepoxidation at elevated temperatures in spruce needles, as compared to Arabidiposis or barley. In this work, we have primarily focused our attention on high-light (HL) acclimation of the photosynthetic apparatus of spruce. Circular dichroism spectra of thylakoid membranes isolated from HL-acclimated seedlings revealed strongly diminished psi-type circular dichroism bands, suggesting a reduced degree of the long-range order of PSII-LHCII supercomplexes compared to the control. Also, in vitro 77K fluorescence spectroscopy of chlorophyll a revealed that, in contrast to control membranes, in HL thylakoid membranes the emission ratio of PSI/PSII and the absorption cross-sections of PSII and PSI were very similar under stacking and unstacking conditions, indicating a suppressed lateral segregation of the two photosystems. The induction of non-photochemical quenching of chlorophyll fluorescence (NPQ) was found to be fast in both HL-acclimated and control seedlings, although the magnitude of NPQ was significantly reduced, suggesting sustained energy dissipation in HL-acclimated leaves. These results are discussed by also taking into account the effects of HL acclimation on the composition of photosynthetic pigment-system (a surprisingly pronounced increase of lutein) and of the thylakoid lipids (a considerable reduction of MGDG content but increased relative content of SQDG) - unusual features in typical angiosperms.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10610 - Biophysics

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů