Document Detail

Rapid light-response curves of chlorophyll fluorescence in microalgae: relationship to steady-state light curves and non-photochemical quenching in benthic diatom-dominated assemblages.
MedLine Citation:
PMID:  17111236     Owner:  NLM     Status:  MEDLINE    
Rapid light-response curves (RLC) of variable chlorophyll fluorescence were measured on estuarine benthic microalgae with the purpose of characterising its response to changes in ambient light, and of investigating the relationship to steady-state light-response curves (LC). The response of RLCs to changes in ambient light (E, defined as the irradiance level to which a sample is acclimated to prior to the start of the RLC) was characterised by constructing light-response curves for the RLC parameters alpha (RLC), the initial slope, ETR(m,RLC), the maximum relative electron transport rate, and E (k,RLC), the light-saturation parameter. Measurements were carried out on diatom-dominated suspensions of benthic microalgae and RLC and LC parameters were compared for a wide range of ambient light conditions, time of day, season and sample taxonomic composition. The photoresponse of RLC parameters was typically bi-phasic, consisting of an initial increase of all parameters under low ambient light (E < 21-181 micromol m(-2) s(-1)), and of a phase during which alpha (RLC) decreased significantly with E, and the increase of ETR(m,RLC) and E (k,RLC) was attenuated. The relationship between RLC and LC parameters was dependent on ambient irradiance, with significant correlations being found between alpha (RLC) and alpha, and between ETR(m,RLC) and ETR(m), for samples acclimated to low and to high ambient irradiances, respectively. The decline of alpha (RLC) under high light (Deltaalpha (RLC)) was strongly correlated (P < 0.001 in all cases) with the level of non-photochemical quenching (NPQ) measured before each RLC. These results indicate the possibility of using RLCs to characterise the steady-state photoacclimation status of a sample, by estimating the LC parameter E (k), and to trace short-term changes in NPQ levels without dark incubation.
João Serôdio; Sónia Vieira; Sónia Cruz; Helena Coelho
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-11-17
Journal Detail:
Title:  Photosynthesis research     Volume:  90     ISSN:  0166-8595     ISO Abbreviation:  Photosyn. Res.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2007-01-12     Completed Date:  2007-04-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954728     Medline TA:  Photosynth Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  29-43     Citation Subset:  IM    
Departamento de Biologia & CESAM, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
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MeSH Terms
Algae / physiology*,  radiation effects
Chlorophyll / metabolism*
Diatoms / physiology,  radiation effects
Spectrometry, Fluorescence
Reg. No./Substance:

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