Dichromate effect on energy dissipation of photosystem II and photosystem I in Chlamydomonas reinhardtii

François Perreault, Nadia Ait Ali, Cyril Saison, Radovan Popovic, Philippe Juneau

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


In this study, we investigated the energy dissipation processes via photosystem II and photosystem I activity in green alga Chlamydomonas reinhardtii exposed to dichromate inhibitory effect. Quantum yield of photosystem II and also photosystem I were highly decreased by dichromate effect. Such inhibition by dichromate induced strong quenching effect on rapid OJIP fluorescence transients, indicating deterioration of photosystem II electron transport via plastoquinone pool toward photosystem I. The decrease of energy dissipation dependant on electron transport of photosystem II and photosystem I by dichromate effect was associated with strong increase of non-photochemical energy dissipation processes. By showing strong effect of dichromate on acceptor side of photosystem I, we indicated that dichromate inhibitory effect was not associated only with PSII electron transport. Here, we found that energy dissipation via photosystem I was limited by its electron acceptor side. By the analysis of P700 oxido-reduction state with methylviolagen as an exogenous PSI electron transport mediator, we showed that PSI electron transport discrepancy induced by dichromate effect was also caused by inhibitory effect located beyond photosystem I. Therefore, these results demonstrated that dichromate has different sites of inhibition which are associated with photosystem II, photosystem I and electron transport sink beyond photosystems. Crown

Original languageEnglish (US)
Pages (from-to)24-29
Number of pages6
JournalJournal of Photochemistry and Photobiology B: Biology
Issue number1
StatePublished - Jul 17 2009
Externally publishedYes


  • Chlamydomonas reinhardtii
  • Dichromate toxicity
  • Energy dissipation processes
  • Photosynthesis
  • Photosystem I
  • Photosystem II

ASJC Scopus subject areas

  • Radiation
  • Radiological and Ultrasound Technology
  • Biophysics
  • Radiology Nuclear Medicine and imaging


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