ISSN:
1573-5079
Keywords:
chlorophyll fluorescence quenching
;
diatoxanthin
;
light adaptation
;
photoprotection
;
UV-B effects
;
xanthophyll cycle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In this study we show that the diadinoxanthin cycle in the diatom Phaeodactylum tricornutum is stimulated by mild UV-B radiation. High steady state concentrations of diatoxanthin established during a period of strong actinic illumination with white light (300 μmol photons m-2 s-1 PAR) are further increased if weak UV-B (3 μmol photons m-2 s-1) is additionally applied. Short term increases in the diatoxanthin concentration caused by UV-B strongly correlate with a stoichiometric decrease in diadinoxanthin. The UV-B dependent increase in diatoxanthin is correlated with a concommitant enhancement of non-photochemical quenching of chlorophyll fluorescence and a decrease in the quantum efficiency of oxygen evolution. This indicates that UV-B induced diatoxanthin functions in thermal energy dissipation. Possible scenarios for a stimulation of the diadinoxanthin cycle by UV-B are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006169901482
Permalink
