Identification of two quenching sites active in the regulation of photosynthetic light-harvesting studied by time-resolved fluorescence

Alfred R. Holzwarth, Yuliya Miloslavina, Manuela Nilkens, Peter Jahns

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The regulation of light-harvesting (called non-photochemical quenching, NPQ) is an essential photoprotective mechanism active in plants. Total NPQ is dependent on PsbS, a pH-sensing protein, and on the action of the xanthophyll carotenoid zeaxanthin (Zx). Using ultrafast fluorescence on intact leaves we demonstrate two independent NPQ quenching sites in vivo which depend differently on the actions of PsbS and Zx. The first site is formed in the functionally detached major light-harvesting complex of PS II and depends strictly on PsbS. The second site is in the minor antennae of photosystem (PS) II and quenching depends on the presence of Zx.

Original languageEnglish
Pages (from-to)262-267
Number of pages6
JournalChemical Physics Letters
Issue number4-6
Publication statusPublished - Dec 1 2009


ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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