Document Detail

Dynamics of short-term acclimation to UV radiation in marine diatoms.
MedLine Citation:
PMID:  17766142     Owner:  NLM     Status:  MEDLINE    
In order to investigate the dynamics of the acclimation of marine diatoms to ultraviolet radiation (UVR), Amphora coffeaeformis, Odontella aurita and Skeletonema costatum were exposed for 5 h per day to a combination of UVA and UVB (UVBR/UVAR ratio 4.5%) with a total UVR daily dose of 110 kJ m(-2), which is equivalent to that observed in the natural environment. This treatment was applied in the middle of the photoperiod and was repeated on five successive days. During the UVR treatment, chlorophyll fluorescence parameters were monitored, damage and repair constants were calculated from effective quantum yield values (phi(PSII)), and rapid light curves (electron transport rate versus irradiance curves using short light steps of different intensity) were plotted to determine the maximum relative electron transport rate (rETR(max)) and maximum light use efficiency (alpha). In all species the growth rate was lower than control from day 1-3, but increased thereafter, except for S. costatum. The cellular chlorophyll a content increased significantly with repeated daily exposure to UVR for A. coffeaeformis only. In all species, the fluorescence parameters (F(m), the maximum fluorescence level measured in the dark, phi(PSII), rETR(max) and alpha) decreased during UVR exposure, in contrast to F(0) (the minimum fluorescence level measured in the dark). The response to UVR stress was species-specific. S. costatum was very sensitive, and failed to survive for more than three days, whereas A. coffeaeformis and O. aurita were able to acclimate to UVR stress. These two species used different strategies. In A. coffeaeformis, the repair constant was lower than the damage constant, but phi(PSII) values returned to baseline values at the beginning of each experimental day, indicating that an effective active recovery process occurred after stress. In O. aurita, the repair processes took place during the stress, and could account for the UVR tolerance of this species.
Manuela Fouqueray; Jean-Luc Mouget; Annick Morant-Manceau; Gérard Tremblin
Publication Detail:
Type:  Journal Article     Date:  2007-08-02
Journal Detail:
Title:  Journal of photochemistry and photobiology. B, Biology     Volume:  89     ISSN:  1011-1344     ISO Abbreviation:  J. Photochem. Photobiol. B, Biol.     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-11-05     Completed Date:  2008-01-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8804966     Medline TA:  J Photochem Photobiol B     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  1-8     Citation Subset:  IM    
Laboratoire de Physiologie et Biochimie Végétales, EA 2663, Faculté des Sciences et Techniques, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans cedex 9, France.
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MeSH Terms
Acclimatization / radiation effects*
Chlorophyll / metabolism
Diatoms / growth & development,  metabolism,  physiology*,  radiation effects*
Electron Transport / radiation effects
Marine Biology
Oceans and Seas
Photosynthesis / radiation effects
Seawater / microbiology
Species Specificity
Time Factors
Ultraviolet Rays* / adverse effects
Reg. No./Substance:
1406-65-1/Chlorophyll; 479-61-8/chlorophyll a

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