Photosynthesis Research

, Volume 41, Issue 2, pp 357–370

Non-photochemical fluorescence quenching and the diadinoxanthin cycle in a marine diatom

  • Miguel Olaizola
  • Julie La Roche
  • Zbigniew Kolber
  • Paul G. Falkowski
Regular paper

DOI: 10.1007/BF00019413

Cite this article as:
Olaizola, M., La Roche, J., Kolber, Z. et al. Photosynth Res (1994) 41: 357. doi:10.1007/BF00019413

Abstract

The diadinoxanthin cycle (DD-cycle) in chromophyte algae involves the interconversion of two carotenoids, diadinoxanthin (DD) and diatoxanthin (DT). We investigated the kinetics of light-induced DD-cycling in the marine diatom Phaeodactylum tricornutum and its role in dissipating excess excitation energy in PS II. Within 15 min following an increase in irradiance, DT increased and was accompanied by a stoichiometric decrease in DD. This reaction was completely blocked by dithiothreitol (DTT). A second, time-dependent, increase in DT was detected ∼ 20 min after the light shift without a concomitant decrease in DD. DT accumulation from both processes was correlated with increases in non-photochemical quenching of chlorophyll fluorescence. Stern-Volmer analyses suggests that changes in non-photochemical quenching resulted from changes in thermal dissipation in the PS II antenna and in the reaction center. The increase in non-photochemical quenching was correlated with a small decrease in the effective absorption cross section of PS II. Model calculations suggest however that the changes in cross section are not sufficiently large to significantly reduce multiple excitation of the reaction center within the turnover time of steady-state photosynthetic electron transport at light saturation. In DTT poisoned cells, the change in non-photochemical quenching appears to result from energy dissipation in the reaction center and was associated with decreased photochemical efficiency. D1 protein degradation was slightly higher in samples poisoned with DTT than in control samples. These results suggest that while DD-cycling may dynamically alter the photosynthesis-irradiance response curve, it offers limited protection against photodamage of PS II reaction centers at irradiance levels sufficient to saturate steady-state photosynthesis.

Key words

diadinoxanthin diatoxanthin fluorescence-quenching photoprotection phytoplankton protein turn-over xanthophyll-cycle 

Abbreviations

CAP

chloramphenicol

D1

PS II reaction center protein

DD

diadinoxanthin

DD

cycle-diadinoxanthin cycle

DT

diatoxanthin

DTT

dithiothreitol

FCP

fucoxanthin chlorophyll a-c protein

Fm

maximum fluorescence yield in the dark-adapted state

Fo

minimum fluorescence yield in the dark-adapted state

F′m and F′o

maximum and minimum fluorescence yields respectively in some light adapted state

Fv

maximum variable fluorescence yield in the dark-adapted state

Ik

Irradiance at the intercept of the initial slope of the photosynthesis-irradiance curve and the maximum photosynthetic rate

kD

first order rate constant for nonradiative de-excitation of excitions in the PS II antenna

kd

first order rate constant for non-radiative de-excitation of excitons in the PS II reaction center

kF

first order rate constant for fluorescence

kT

first order rate constant for exciton transfer to the reaction center

kt

first order rate constant for exciton transfer from the reaction center to the antenna

Rubisco

ribulose bisphosphate carboxylase

SVm

Stern-Volmer quenching coefficient of the maximum fluorescence yield

SVo

Stern-Volmer quenching coefficient of the miniximum fluorescence yield

σPS II

apparent absorption cross-section of PS II

τarr

average interval between exciton arrival to the PS II reaction center (ms)

τrem

average interval between electron turnover during photosynthesis in the PS II reaction center (ms)

Ψd

the probability that an exciton is non-radiatively dissipated in the reaction center

ΨT

the probability that an exciton in the antenna is transferred to the reaction center

Ψt

the probability that an exciton is transferred back from the reaction center to the antenna

Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • Miguel Olaizola
    • 1
  • Julie La Roche
    • 2
  • Zbigniew Kolber
    • 2
  • Paul G. Falkowski
    • 2
  1. 1.Marine Sciences Research CenterState University of New York at Stony BrookStony BrookUSA
  2. 2.Oceanographic and Atmospheric Sciences DivisionBrookhaven National LaboratoryUptonUSA
  3. 3.Joint Research CenterInstitute for Remote Sensing Applications, TP 272IspraItaly

Personalised recommendations