title: Differential accumulation of photosynthetic proteins regulates diurnal photochemical adjustments of PSII in common fig (Ficus carica L.) leaves.
abstract: Molecular processes involved in photosystem II adaptation of woody species to diurnal changes in light and temperature conditions are still not well understood. Regarding this, here we investigated differences between young and mature leaves of common fig (Ficus carica L.) in photosynthetic performance as well as accumulation of the main photosynthetic proteins: light harvesting complex II, D1 protein and Rubisco large subunit. Investigated leaf types revealed different adjustment mechanisms to keep effective photosynthesis. Rather stable diurnal accumulation of light harvesting complex II in mature leaves enabled efficient excitation energy utilization (negative L-band) what triggered faster D1 protein degradation at high light. However, after photoinhibition, greater accumulation of D1 during the night enabled them faster recovery. So, the most photosynthetic parameters, as the maximum quantum yield for primary photochemistry, electron transport and overall photosynthetic efficiency in mature leaves successfully restored to their initial values at 1a.m. Reduced connectivity of light harvesting complexes II to its reaction centers (positive L-band) in young leaves increased dissipation of excess light causing less pressure to D1 and its slower degradation. Decreased electron transport in young leaves, due to reduced transfer beyond primary acceptor QA-most probably additionally induced degradation of Rubisco large subunit what consequently led to the stronger decrease of overall photosynthetic efficiency in young leaves at noon.
authors.affiliation: Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, HR-31000 Osijek, Croatia. Electronic address: smlinaric@biologija.unios.hr.
authors.forename: Selma
authors.initials: S
authors.lastname: Mlinarić
authors.affiliation: Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, HR-31000 Osijek, Croatia. Electronic address: jasenka.antunovic@biologija.unios.hr.
authors.forename: Jasenka
authors.initials: J
authors.lastname: Antunović Dunić
authors.affiliation: Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, HR-10000 Zagreb, Croatia. Electronic address: mskendrovic@agr.hr.
authors.forename: Martina
authors.initials: M
authors.lastname: Skendrović Babojelić
authors.affiliation: Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, HR-31000 Osijek, Croatia. Electronic address: vcesarus@yahoo.com.
authors.forename: Vera
authors.initials: V
authors.lastname: Cesar
authors.affiliation: Faculty of Humanities and Social Sciences, Josip Juraj Strossmayer University of Osijek, L. Jägera 9, HR-31000 Osijek, Croatia. Electronic address: hlepedus@yahoo.com.
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Lepeduš
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D002940:Circadian Rhythm; D030681:Ficus / Q000502:physiology*; D005453:Fluorescence; D007700:Kinetics; D017785:Photons; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: L-band; OJIP; Performance index; Photoinhibition; Photosystem II