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- Demmig-Adams, Barbara, et al.
(författare)
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Modulation of PsbS and flexible vs sustained energy dissipation by light environment in different species
- 2006
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 127, s. 670-80
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Tidskriftsartikel (refereegranskat)abstract
- Contrasting acclimation strategies of photosynthesis and photoprotection were identified for annual mesophytes (spinach, pumpkin, and Arabidopsis) vs the tropical evergreen Monstera deliciosa. The annual species utilized full sunlight for photosynthesis to a much greater extent than the evergreen species. Conversely, the evergreen species exhibited a greater capacity for photoprotective thermal energy dissipation as well as a greater expression of the PsbS protein in full sun than the annual species. In all species, the majority of thermal energy dissipation [assessed as non-photochemical fluorescence quenching (NPQ)] was the flexible, ΔpH-dependent form of NPQ over the entire range of growth light environments. However, in response to a transfer of shade-grown plants to high light, the evergreen species exhibited a high level of sustained thermal dissipation (qI), but the annual species did not. This sustained energy dissipation in the evergreen species was not ΔpH-dependent nor did the low level of PsbS in shade leaves increase upon transfer to high light for several days. Sustained ΔpH-independent NPQ was correlated (a) initially, with sustained D1 protein phosphorylation and xanthophyll cycle arrest and (b) subsequently, with an accumulation over several days of PsbS-related one-helix proteins and newly synthesized zeaxanthin and lutein.
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| 2. |
- Zarter, C Ryan, et al.
(författare)
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Winter acclimation of PsbS and related proteins in the evergreen Arctostaphylos uva-ursi as influenced by altitude and light environment.
- 2006
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Ingår i: Plant, Cell & Environment. - : Wiley. - 0140-7791 .- 1365-3040. ; 29:5, s. 869-78
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Tidskriftsartikel (refereegranskat)abstract
- The evergreen groundcover bearberry (Arctostaphylos uva-ursi[L.] Sprengel) was characterized over two successive years (2002–2004) from both sun-exposed and shaded sites at a montane ponderosa pine and subalpine forest community of 1900- and 2800-m-high altitudes, respectively. During summer, photosynthetic capacities and pre-dawn photosystem II (PSII) efficiency were similarly high in all four populations, and in winter, only the sun-exposed and shaded populations at 2800 m exhibited complete down-regulation of photosynthetic oxygen evolution capacity and consistent sustained down-regulation of PSII efficiency. This photosynthetic down-regulation at high altitude involved a substantial decrease in PSII components [pheophytin, D1 protein, oxygen evolving complex ([OEC)], a strong up-regulation of several anti-early-light-inducible protein (Elip)- and anti-high-light-inducible protein (Hlip)-reactive bands and a warm-sustained retention of zeaxanthin and antheraxanthin (Z + A). PsbS, the protein modulating the rapid engagement and disengagement of Z + A in energy dissipation, exhibited its most pronounced winter increases in the shade at 1900 m, and thus apparently assumes a greater role in providing rapidly reversible zeaxanthin-dependent photoprotection during winter when light becomes excessive in the shaded population, which remains photosynthetically active. It is attractive to hypothesize that PsbS relatives (Elips/Hlips) may be involved in sustained zeaxanthin-dependent photoprotection under the more extreme winter conditions at 2800 m.
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