title: Lutein epoxide cycle, light harvesting and photoprotection in species of the tropical tree genus Inga.
abstract: Dynamics and possible function of the lutein epoxide (Lx) cycle, that is, the reversible conversion of Lx to lutein (L) in the light-harvesting antennae, were investigated in leaves of tropical tree species. Photosynthetic pigments were quantified in nine Inga species and species from three other genera. In Inga, Lx levels were high in shade leaves (mostly above 20 mmol mol(-1) chlorophyll) and low in sun leaves. In Virola surinamensis, both sun and shade leaves exhibited very high Lx contents (about 60 mmol mol(-1) chlorophyll). In Inga marginata grown under high irradiance, Lx slowly accumulated within several days upon transfer to deep shade. When shade leaves of I. marginata were briefly exposed to the sunlight, both violaxanthin and Lx were quickly de-epoxidized. Subsequently, overnight recovery occurred only for violaxanthin, not for Lx. In such leaves, containing reduced levels of Lx and increased levels of L, chlorophyll fluorescence induction showed significantly slower reduction of the photosystem II electron acceptor, Q(A), and faster formation as well as a higher level of non-photochemical quenching. The results indicate that slow Lx accumulation in Inga leaves may improve light harvesting under limiting light, while quick de-epoxidation of Lx to L in response to excess light may enhance photoprotection.
authors.affiliation: Phytosphere Institute (ICG-3), Research Centre Jülich, 52425 Jülich, Germany. s.matsubara@fz-juelich.de
authors.forename: Shizue
authors.initials: S
authors.lastname: Matsubara
authors.forename: G Heinrich
authors.initials: GH
authors.lastname: Krause
authors.forename: Martin
authors.initials: M
authors.lastname: Seltmann
authors.forename: Aurelio
authors.initials: A
authors.lastname: Virgo
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kursar
authors.forename: Peter
authors.initials: P
authors.lastname: Jahns
authors.forename: Klaus
authors.initials: K
authors.lastname: Winter
mesh_terms: D000064:Acclimatization / Q000502:physiology; D002338:Carotenoids / Q000378:metabolism; D003624:Darkness; D004852:Epoxy Compounds / Q000378:metabolism; D007887:Fabaceae / Q000378:metabolism*; D014975:Lutein / Q000031:analogs & derivatives* / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D013045:Species Specificity; D013472:Sunlight; D013997:Time Factors; D014197:Trees
chemical_list: D004852:Epoxy Compounds; D045332:Photosystem II Protein Complex; D002338:Carotenoids; D014975:Lutein