Rates and roles of cyclic and alternative electron flow in potato leaves

DC FieldValueLanguage
dc.contributor.authorLaisk, Agu
dc.contributor.authorEichelmann, Hillar
dc.contributor.authorOja, Vello
dc.contributor.authorTalts, Eero
dc.contributor.authorScheibe, Renate
dc.date.accessioned2021-12-23T16:06:18Z-
dc.date.available2021-12-23T16:06:18Z-
dc.date.issued2007
dc.identifier.issn00320781
dc.identifier.urihttps://osnascholar.ub.uni-osnabrueck.de/handle/unios/7352-
dc.description.abstractMeasurements of 810 nm transmittance changes in leaves, simultaneously with Ch1 fluorescence, CO2 uptake and O-2 evolution, were carried out on potato (Solanum tuberosum L.) leaves with altered expression of plastidic NADP-dependent malate dehydrogenase. Electron transport rates were calculated: J(C) from the CO2 uptake rate considering ribulose-1,5-bisphosphate (RuBP) carboxylation and oxygenation, J(O) from the O-2 evolution rate, JF from Ch1 fluorescence parameters and JI from the post-illumination re-reduction speed of PSI donors. In the absence of external O-2, J(O) equaled (1.005 0.003) J(C), independent of the transgenic treatment, light intensity and CO2 concentration. This showed that nitrite and oxaloacetate reduction rates were very slow. The Mehler-type O2 reduction was evaluated from the rate of electron accumulation at PSI after the O-2 concentration was decreased from 210 to 20 mmol mol(1), and resulted in 1 of the linear flow. J(F) and J(I) did not differ from J(C) while photosynthesis was light-limited, but considerably exceeded JC at saturating light. Then, typically, J(F)=1.2 J(C) and J(I)=1.3 J(C), and J(F)-J(C) and J(I)-J(C) depended little on CO2 and O-2 concentrations. The results showed that the alternative and cyclic electron flow necessary to compensate variations in the ATP/NADPH ratio were only a few percent of the linear flow. The data do not support the requirement of 14H(+)/3ATP by the chloroplast ATP synthase. We suggest that the fast PSI cyclic electron flow J(I)-J(C), as well as the fast J(F)-J(C) are energy-dissipating cycles around PSI and PSII at light saturation.
dc.language.isoen
dc.publisherOXFORD UNIV PRESS
dc.relation.ispartofPLANT AND CELL PHYSIOLOGY
dc.subjectalternative
dc.subjectCell Biology
dc.subjectCHL FLUORESCENCE
dc.subjectCHLOROPHYLL FLUORESCENCE
dc.subjectcyclic
dc.subjectCYTOCHROME B(6)F
dc.subjectelectron transport
dc.subjectINTACT CHLOROPLASTS
dc.subjectleaf
dc.subjectLEAF PHOTOSYNTHESIS
dc.subjectMESOPHYLL CONDUCTANCE
dc.subjectNADP-MALATE DEHYDROGENASE
dc.subjectPHOTOSYSTEM-I
dc.subjectPlant Sciences
dc.subjectPROTON TRANSPORT
dc.subjectSUNFLOWER LEAVES
dc.titleRates and roles of cyclic and alternative electron flow in potato leaves
dc.typejournal article
dc.identifier.doi10.1093/pcp/pcm129
dc.identifier.isiISI:000251037200007
dc.description.volume48
dc.description.issue11
dc.description.startpage1575
dc.description.endpage1588
dc.contributor.orcid0000-0002-8093-6444
dc.identifier.eissn14719053
dc.publisher.placeGREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
dcterms.isPartOf.abbreviationPlant Cell Physiol.
dcterms.oaStatusBronze
crisitem.author.deptFB 05 - Biologie/Chemie-
crisitem.author.deptidfb05-
crisitem.author.orcid0000-0002-6140-6181-
crisitem.author.parentorgUniversität Osnabrück-
crisitem.author.netidScRe288-
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