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Winter acclimation of PsbS and related proteins in the evergreen Arctostaphylos uva‐ursi as influenced by altitude and light environment
Author(s) -
ZARTER C. RYAN,
ADAMS WILLIAM W.,
EBBERT VOLKER,
ADAMSKA IWONA,
JANSSON STEFAN,
DEMMIGADAMS BARBARA
Publication year - 2006
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2005.01466.x
Subject(s) - photoprotection , antheraxanthin , zeaxanthin , photoinhibition , botany , population , xanthophyll , photosystem ii , biology , evergreen , photosynthesis , photosynthetic capacity , carotenoid , lutein , demography , sociology
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.