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Annual variation in photoacclimation and photoprotection of the photobiont in the foliose lichen Xanthoria parietina

Paper ID Volume ID Publish Year Pages File Format Full-Text
31227 44570 2006 12 PDF Available
Title
Annual variation in photoacclimation and photoprotection of the photobiont in the foliose lichen Xanthoria parietina
Abstract

Seasonal variation in maximal photochemical quantum yield (FV/FM) of photosystem II (PS II), light adapted quantum yield (ΦII) of PS II, non-photochemical quenching (NPQ), contents of chlorophylls, and xanthophyll cycle pigments (VAZ) was studied in Xanthoria parietina repeatedly sampled in one location in S Norway during one year. The seasonal course in the susceptibility to photoinhibition was evaluated as high light-induced changes (1800 μmol photons m−2 s−1 for 24 h) in FV/FM, ΦII, and NPQ, measured as the ability to recover after 2 and 20 h at low light in control thalli with a natural cortical parietin screen, and in thalli from which parietin had been removed prior to high light exposures. FV/FM, ΦII, chlorophyll content, and the conversion state of VAZ (DEPS) reached minimum in spring. At the same time, yearly maxima of VAZ content and NPQ were recorded. Thereafter, FV/FM, ΦII, and chlorophyll content increased gradually, reaching maximum values in late autumn. DEPS peaked already in summer. Similarly, VAZ and NPQ decreased from early summer until winter. All data show that the X. parietina photobiont acclimates to seasonal changes in solar radiation, consistent with the lichen’s preference for well-lit habitats. However, a comparison with a study of seasonal acclimation in the X. parietina mycobiont shows that in order to understand the seasonal photobiont acclimation, one has to consider the seasonal variation in internal screening caused by the fungal regulation of the PAR-absorbing parietin. A joint effort of both bionts seems to be required to avoid serious photoinhibition.

Keywords
Chlorophyll fluorescence; Non-photochemical quenching; Parietin; Photoinhibition; Seasonal dynamics; Zeaxanthin
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Annual variation in photoacclimation and photoprotection of the photobiont in the foliose lichen Xanthoria parietina
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 83, Issue 2, 1 May 2006, Pages 151–162
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us