Abstract:
:Recently, a number of techniques, some of them relatively new and many often used in combination, have given a clearer picture of the dynamic role of electron transport in Photosystem I of photosynthesis and of coupled cyclic photophosphorylation. For example, the photoacoustic technique has detected cyclic electron transport in vivo in all the major algal groups and in leaves of higher plants. Spectroscopic measurements of the Photosystem I reaction center and of the changes in light scattering associated with thylakoid membrane energization also indicate that cyclic photophosphorylation occurs in living plants and cyanobacteria, particularly under stressful conditions.In cyanobacteria, the path of cyclic electron transport has recently been proposed to include an NAD(P)H dehydrogenase, a complex that may also participate in respiratory electron transport. Photosynthesis and respiration may share common electron carriers in eukaryotes also. Chlororespiration, the uptake of O2 in the dark by chloroplasts, is inhibited by excitation of Photosystem I, which diverts electrons away from the chlororespiratory chain into the photosynthetic electron transport chain. Chlororespiration in N-starved Chlamydomonas increases ten fold over that of the control, perhaps because carbohydrates and NAD(P)H are oxidized and ATP produced by this process.The regulation of energy distribution to the photosystems and of cyclic and non-cyclic phosphorylation via state 1 to state 2 transitions may involve the cytochrome b 6-f complex. An increased demand for ATP lowers the transthylakoid pH gradient, activates the b 6-f complex, stimulates phosphorylation of the light-harvesting chlorophyll-protein complex of Photosystem II and decreases energy input to Photosystem II upon induction of state 2. The resulting increase in the absorption by Photosystem I favors cyclic electron flow and ATP production over linear electron flow to NADP and 'poises' the system by slowing down the flow of electrons originating in Photosystem II.Cyclic electron transport may function to prevent photoinhibition to the photosynthetic apparatus as well as to provide ATP. Thus, under high light intensities where CO2 can limit photosynthesis, especially when stomates are closed as a result of water stress, the proton gradient established by coupled cyclic electron transport can prevent over-reduction of the electron transport system by increasing thermal de-excitation in Photosystem II (Weis and Berry 1987). Increased cyclic photophosphorylation may also serve to drive ion uptake in nutrient-deprived cells or ion export in salt-stressed cells.There is evidence in some plants for a specialization of Photosystem I. For example, in the red alga Porphyra about one third of the total Photosystem I units are engaged in linear electron transfer from Photosystem II and the remaining two thirds of the Photosystem I units are specialized for cyclic electron flow. Other organisms show evidence of similar specialization.Improved understanding of the biological role of cyclic photophosphorylation will depend on experiments made on living cells and measurements of cyclic photophosphorylation in vivo.
journal_name
Photosynth Resjournal_title
Photosynthesis researchauthors
Fork DC,Herbert SKdoi
10.1007/BF00033035subject
Has Abstractpub_date
1993-06-01 00:00:00pages
149-68issue
3eissn
0166-8595issn
1573-5079journal_volume
36pub_type
杂志文章abstract::We present the wavelength dependence of homogeneous holewidths of persistent spectral holes burnt in O2-evolving Photosystem II core complexes isolated from spinach, in the temperature range 2.5-8 K. The data supports the assignment that those chlorophylls which undergo persistent spectral hole-burning are specific CP...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-004-7927-6
更新日期:2005-06-01 00:00:00
abstract::The effect of leaf water potential (Ψ) on net CO2 assimilation rate (A), stomatal conductance (g), transpiration (E) and water-use efficiency (WUE) was measured for three cultivars of cacao (Theobroma cacao L.) seedlings during three recurrent drought cycles. Net assimilation varied greatly at high water potentials, b...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/BF00037179
更新日期:1989-09-01 00:00:00
abstract::Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to ...
journal_title:Photosynthesis research
pub_type: 杂志文章,评审
doi:10.1007/s11120-009-9521-4
更新日期:2010-06-01 00:00:00
abstract::The localization of isoprenoid lipids in chloroplasts, the accumulation of particular isoprenoids under high irradiance conditions, and channelling of photosynthetically fixed carbon into plastidic thylakoid isoprenoids, volatile isoprenoids, and cytosolic sterols are reviewed. During leaf and chloroplast development ...
journal_title:Photosynthesis research
pub_type: 杂志文章,评审
doi:10.1007/s11120-007-9204-y
更新日期:2007-05-01 00:00:00
abstract::Productivity of most macroalgae is not currently considered limited by dissolved inorganic carbon (DIC), as the majority of species have CO2-concentrating mechanisms (CCM) allowing the active uptake of DIC. The alternative, diffusive uptake of CO2 (non-CCM), is considered rare (0-9% of all macroalgal cover in a given ...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-015-0114-0
更新日期:2015-05-01 00:00:00
abstract::Heliobacteria contain Type I reaction centers (RCs) and a homodimeric core, but unlike green sulfur bacteria, they do not contain an extended antenna system. Given their simplicity, the heliobacterial RC (HbRC) should be ideal for the study of a prototypical homodimeric RC. However, there exist enormous gaps in our kn...
journal_title:Photosynthesis research
pub_type: 杂志文章,评审
doi:10.1007/s11120-007-9162-4
更新日期:2007-04-01 00:00:00
abstract::A chlorosome is an antenna complex located on the cytoplasmic side of the inner membrane in green photosynthetic bacteria that contains tens of thousands of self-assembled bacteriochlorophylls (BChls). Green bacteria are known to incorporate various esterifying alcohols at the C-17 propionate position of BChls in the ...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-014-0017-5
更新日期:2014-10-01 00:00:00
abstract::The Mg-dechelating activity of extracts of Chenopodium album (goosefoot) was investigated using an artificial substrate, chlorophyllin a. The activity was measured spectrophotometrically by the formation of a reaction product, pheophorbin a (Mg-free chlorin), after release of the central Mg. The Mg-releasing protein w...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/A:1020915812770
更新日期:2002-01-01 00:00:00
abstract::By recording leaf transmittance at 820 nm and quantifying the photon flux density of far red light (FRL) absorbed by long-wavelength chlorophylls of Photosystem I (PS I), the oxidation kinetics of electron carriers on the PS I donor side was mathematically analyzed in sunflower (Helianthus annuus L.), tobacco (Nicotia...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/A:1026070612022
更新日期:2003-01-01 00:00:00
abstract::Cyanobacteria, algae, and plants produce dioxygen from water. Driven and clocked by light quanta, the catalytic Mn(4)Ca Tyrosine centre accumulates four oxidizing equivalents before it abstracts four electrons from water and liberates dioxygen and protons. Intermediates of this reaction cascade are short-lived (<100 m...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-008-9321-2
更新日期:2008-10-01 00:00:00
abstract::This work addresses the question of occurrence and function of photosystem II (PSII) in bundle sheath (BS) cells of leaves possessing NADP-malic enzyme-type C4 photosynthesis (Zea mays). Although no requirement for PSII activity in the BS has been established, several component proteins of PSII have been detected in B...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-014-0009-5
更新日期:2014-10-01 00:00:00
abstract::Relationships between induced high leaf intercellular CO₂ concentrations, leaf K⁺ and NO₃⁻ ion movement and early fruit formation under macronutrient limitation are not well understood. We examined the effects and interactions of reduced K/N input treatments on leaf intercellular CO₂, photosynthesis rate, carboxylatio...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-013-9832-3
更新日期:2013-07-01 00:00:00
abstract::Four Indica and five Japonica varieties of rice (Oryza sativa L.) were examined to elucidate their differences in photosynthetic activity and dark respiratory rate as influenced by leaf nitrogen levels and temperatures. The photosynthetic rates of single leaf showed correlations with total nitrogen and soluble protein...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/BF00032321
更新日期:1987-01-01 00:00:00
abstract::Two lessons I have learned during my research career are the importance of following up unexpected observations and realizing that the most obvious interpretation of such observations can be rational but wrong. When you carry out an experiment there is usually an expectation that the result will fall within a range of...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/B:PRES.0000030439.62331.d0
更新日期:2004-01-01 00:00:00
abstract::We evaluate low-temperature (low-T) emission spectra of photosystem II core complexes (PSII-cc) previously reported in the literature, which are compared with emission spectra of PSII-cc obtained in this work from spinach and for dissolved PSII crystals from Thermosynechococcus (T.) elongatus. This new spectral datase...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-015-0128-7
更新日期:2015-06-01 00:00:00
abstract::Pigment-protein-complexes of two chlorophyll b deficient mutants of Arabidopsis and from the wild type were separated electrophoretically. Light-harvesting proteins were absent in the chlorophyll b free mutant ch(1) and their amount was reduced in the mutant ch(2) which has a reduced content of chlorophyll b. The rati...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/BF00041827
更新日期:1983-01-01 00:00:00
abstract::Biohybrid light-harvesting architectures can be constructed that employ native-like bacterial photosynthetic antenna peptides as a scaffold to which synthetic chromophores are attached to augment overall spectral coverage. Synthetic bacteriochlorins are attractive to enhance capture of solar radiation in the photon-ri...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-014-0021-9
更新日期:2014-11-01 00:00:00
abstract::Phosphatidylglycerol (PG), containing the unique fatty acid Delta3, trans-16:1-hexadecenoic acid, is a minor but ubiquitous lipid component of thylakoid membranes of chloroplasts and cyanobacteria. We investigated its role in electron transfers and structural organization of Photosystem II (PSII) by treating Arabidops...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-006-9126-0
更新日期:2007-07-01 00:00:00
abstract::The photophysical and photochemical reactions, after light absorption by a photosynthetic pigment-protein complex, are among the fastest events in biology, taking place on timescales ranging from tens of femtoseconds to a few nanoseconds. The advent of ultrafast laser systems that produce pulses with femtosecond durat...
journal_title:Photosynthesis research
pub_type: 杂志文章,评审
doi:10.1007/s11120-009-9454-y
更新日期:2009-08-01 00:00:00
abstract::Pulse modulated fluorescence has increasingly been used as an ecological tool to examine changes in the vertical distribution of microphytobenthic cells within the upper layers of estuarine sediments (most often using the minimum fluorescence yield F(o)) as well as to indicate the health of the community (using the ma...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/B:PRES.0000028397.86495.b5
更新日期:2004-01-01 00:00:00
abstract::The oxidation kinetics under far-red light (FRL) of photosystem I (PSI) high potential donors P700, plastocyanin (PC), and cytochrome f (Cyt f) were investigated in sunflower leaves with the help of a new high-sensitivity photometer at 810 nm. The slopes of the 810 nm signal were measured immediately before and after ...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-007-9224-7
更新日期:2007-10-01 00:00:00
abstract::The chloroplast photo-oxidation and the expression of the Cab gene Lhcb1, encoding the Lhcb1 light-harvesting chlorophyll a/b-protein of PS II, have been studied in leaf cells of maize treated with the two bleaching herbicides norflurazon and amitrole and of the two carotenoid-free mutants vp9 and vp2 grown under high...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/A:1006477215572
更新日期:2000-01-01 00:00:00
abstract::Chlorosomes of green photosynthetic bacterium Chlorobium tepidum contain aggregates of bacteriochlorophyll c (BChl c) with carotenoids and isoprenoid quinones. BChl aggregates with very similar optical properties can be prepared also in vitro either in non-polar solvents or in aqueous buffers with addition of lipids a...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-007-9259-9
更新日期:2008-02-01 00:00:00
abstract::The main objective of the present review is to provide a compilation of published data of the effects of several climatic conditions on Rubisco, particularly its activity, state of activation, and concentration, and its influence on leaf gas exchange and photosynthesis. The environmental conditions analyzed include dr...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-013-9861-y
更新日期:2013-11-01 00:00:00
abstract::Using 77 K chlorophyll a (Chl a) fluorescence spectra in vivo, the development was studied of Photosystems II (PS II) and I (PS I) during greening of barley under intermittent light followed by continuous light at low (LI, 50 mumol m(-2) s(-1)) and high (HI, 1000 mumol m(-2) s(-1)) irradiances. The greening at HI inte...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/A:1020943107318
更新日期:2002-01-01 00:00:00
abstract::This contribution gives a brief survey of the short history since the discovery of the aerobic phototrophic bacteria to focus on a general evolutionary scenario. Most of the citations are of reviews that have covered the earlier literature and to which the reader is directed at appropriate places in the following text...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1023/A:1020493518379
更新日期:2002-01-01 00:00:00
abstract::Electron transfer pathways in photosynthesis involve interactions between membrane-bound complexes such as reaction centres with an extrinsic partner. In this study, the biological specificity of electron transfer between the reaction centre-light-harvesting 1-PufX complex and its extrinsic electron donor, cytochrome ...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/s11120-013-9812-7
更新日期:2014-05-01 00:00:00
abstract::Intra- and inter-specific variation in CO2 assimilation rate (A) in Triticum spp. is well documented for reproductive growth stages. Research was conducted to characterize early vegetative photosynthetic variation in a diverse set of cultivated hexaploid wheat (T. aestivum L.) germplasm and in wild tetraploid (T. dico...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/BF00034120
更新日期:1989-05-01 00:00:00
abstract::Thylakoids are complex sub-organellar membrane systems whose role in photosynthesis makes them critical to life. Thylakoids require the coordinated expression of both nuclear- and plastid-encoded proteins to allow rapid response to changing environmental conditions. Transport of cytoplasmically synthesized proteins to...
journal_title:Photosynthesis research
pub_type: 杂志文章,评审
doi:10.1007/s11120-018-0567-z
更新日期:2018-12-01 00:00:00
abstract::The binding characteristics and the inhibitory power of atrazine and DCMU towards uncoupled electron flow activity were studied in acyl lipid-depleted thylakoid membranes from atrazine-susceptible and-resistant biotypes of Solanum nigrum L. For this purpose, phospholipase A2 from Vipera russelli and the lipase from Rh...
journal_title:Photosynthesis research
pub_type: 杂志文章
doi:10.1007/BF00049537
更新日期:1992-01-01 00:00:00