Inhibition of non-photochemical quenching increases functional absorption cross-section of photosystem II as excitation from closed reaction centres is transferred to open centres, facilitating earlier light saturation of photosynthetic electron transport

2021 ◽  
Author(s):  
Charles Barry Osmond ◽  
Wah Soon Chow ◽  
Sharon A. Robinson
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Photosynthetic Electron Transport ◽  
Photochemical Quenching ◽  
Absorption Cross ◽  
Light Saturation ◽  
Reaction Centres ◽  
Non Photochemical Quenching

State of the phycobilisome determines effective absorption cross-section of Photosystem II in Synechocystis sp. PCC 6803

2021 ◽  
Vol 1862 (12) ◽  
pp. 148494
Author(s):  
Elena A. Protasova ◽  
Taras K. Antal ◽  
Dmitry V. Zlenko ◽  
Irina V. Elanskaya ◽  
Evgeny P. Lukashev ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Effective Absorption ◽  
Synechocystis Sp ◽  
Pcc 6803

Kinetic response of photosystem II photochemistry in the cyanobacterium Spirulina platensis to high salinity is characterized by two distinct phases

1999 ◽  
Vol 26 (3) ◽  
pp. 283 ◽  
Author(s):  
Congming Lu ◽  
Giuseppe Torzillo ◽  
Avigad Vonshak
Keyword(s):  
Electron Transport ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Spirulina Platensis ◽  
High Salinity ◽  
Photochemical Quenching ◽  
Second Phase ◽  
Ps Ii ◽  
Reaction Centres ◽  
Two Phases

The kinetic response of photosystem II (PS II) photochemistry in Spirulina platensis(Norstedt M2 ) to high salinity (0.75 M NaCl) was found to consist of two phases. The first phase, which was independent of light, was characterized by a rapid decrease (15–50%) in the maximal efficiency of PS II photochemistry (Fv /Fm), the efficiency of excitation energy capture by open PS II reaction centres (Fv′/Fm′), photochemical quenching (qp) and the quantum yield of PS II electron transport (Φ PS II) in the first 15 min, followed by a recovery up to about 80–92% of their initial levels within the next 2 h. The second phase took place after 4 h, in which further decline in above parameters occurred. Such a decline occurred only when the cells were incubated in the light, reaching levels as low as 45–70% of their initial levels after 12 h. At the same time, non-photochemical quenching (qN) and Q B -non-reducing PS II reaction centres increased significantly in the first 15 min and then recovered to the initial level during the first phase but increased again in the light in the second phase. The changes in the probability of electron transfer beyond QA (ψo) and the yield of electron transport beyond QA (φ Eo), the absorption flux (ABS/RC) and the trapping flux (TRo /RC) per PS II reaction centre also displayed two different phases. The causes responsible for the decreased quantum yield of PS II electron transport during the two phases are discussed.

Differences in photosynthetic activity between coral sections infested and not infested by boring spionid polychaetes

2006 ◽  
Vol 86 (4) ◽  
pp. 727-728 ◽  
Author(s):  
Jeffrey Wielgus ◽  
Oren Levy
Keyword(s):  
Photosystem Ii ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Repetition Rate ◽  
Photosynthetic Activity ◽  
Mean Value ◽  
Absorption Cross ◽  
Physiological Mechanisms ◽  
Coral Colony ◽  
The Mean

A SCUBA-based fast repetition rate fluorometer (FRRF) was used to study differences in the functional absorption cross-section of Photosystem II (σPSII) between areas of a coral colony of Astreoporamyriophthalma that were infested with spionid polychaetes vs areas lacking worms. The mean value of σPSII in infested areas (mean±SD=347.62±30.67 Å2) was significantly higher than in the areas that were not infested (316.32±17.49 Å2; P<0.0001). Several physiological mechanisms are discussed that may contribute to the observed differences.

scholarly journals The chloroplast NADPH thioredoxin reductase C, NTRC, controls non-photochemical quenching of light energy and photosynthetic electron transport inArabidopsis

2016 ◽  
Vol 39 (4) ◽  
pp. 804-822 ◽  
Author(s):  
Belén Naranjo ◽  
Clara Mignée ◽  
Anja Krieger-Liszkay ◽  
Dámaso Hornero-Méndez ◽  
Lourdes Gallardo-Guerrero ◽  
...  
Keyword(s):  
Electron Transport ◽  
Thioredoxin Reductase ◽  
Photosynthetic Electron Transport ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Non Photochemical Quenching

Functionalized gold-nanoparticles enhance Photosystem II driven photocurrent in a hybrid nano-bio-photoelectrochemical cell

2021 ◽  
Author(s):  
Hagit Shoyhet ◽  
Nicholas G. Pavlopoulos ◽  
Lilac Amirav ◽  
Noam Adir
Keyword(s):  
Gold Nanoparticles ◽  
Photosystem Ii ◽  
Solar Energy ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Electrical Current ◽  
Photoelectrochemical Cell ◽  
Photoelectrochemical Cells ◽  
Absorption Cross ◽  
Functionalized Gold Nanoparticles

The use of Photosystem II (PSII) in hybrid bio-photoelectrochemical cells for conversion of solar energy to electrical current is hampered by PSII's narrow absorption cross-section and the generally poor electrical...

scholarly journals Providing an additional electron sink by the introduction of cyanobacterial flavodiirons enhances the growth of Arabidopsis thaliana in varying light

2020 ◽  
Author(s):  
Suresh Tula ◽  
Fahimeh Shahinnia ◽  
Michael Melzer ◽  
Twan Rutten ◽  
Rodrigo Gómez ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Electron Transport ◽  
Photosystem I ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Performance ◽  
Growth Potential ◽  
Photochemical Quenching ◽  
Transport Chain ◽  
Non Photochemical Quenching ◽  
Electron Sink

AbstractThe ability of plants to maintain photosynthesis in a dynamically changing environment is of central importance for their growth. As their photosynthetic machinery typically cannot adapt rapidly to fluctuations in the intensity of radiation, the level of photosynthetic efficiency is not always optimal. Cyanobacteria, algae, non-vascular plants (mosses and liverworts) and gymnosperms all produce flavodiirons (Flvs), a class of proteins not represented in the angiosperms; these proteins act to mitigate the photoinhibition of photosystem I. Here, genes specifying two cyanobacterial Flvs have been expressed in the chloroplasts of Arabidopsis thaliana in an attempt to improve the robustness of Photosystem I (PSI). The expression of Flv1 and Flv3 together shown to enhance the efficiency of the utilization of light and to boost the plant’s capacity to accumulate biomass. Based on an assessment of the chlorophyll fluorescence in the transgenic plants, the implication was that photosynthetic activity (including electron transport flow and non-photochemical quenching during a dark-to-light transition) was initiated earlier in the transgenic than in wild type plants. The improved photosynthetic performance of the transgenics was accompanied by an increased production of ATP, an acceleration of carbohydrate metabolism and a more pronounced partitioning of sucrose into starch. The indications are that Flvs are able to establish an efficient electron sink downstream of PSI, thereby ensuring that the photosynthetic electron transport chain remains in a more oxidized state. The expression of Flvs in a plant acts to both protect photosynthesis and to control the ATP/NADPH ratio; together, their presence is beneficial for the plant’s growth potential.

scholarly journals Photosynthetic light harvesting and thylakoid organization in a CRISPR/Cas9 Arabidopsis thaliana LHCB1 knockout mutant.

2021 ◽  
Author(s):  
Hamed Sattari Vayghan ◽  
Wojciech J Nawrocki ◽  
Christo Schiphorst ◽  
Dimitri Tolleter ◽  
Hu Chen ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Cross Section ◽  
Photosystem I ◽  
Absorption Cross Section ◽  
Light Harvesting ◽  
Higher Plants ◽  
Oxygenic Photosynthesis ◽  
Growth Delay ◽  
Absorption Cross ◽  
Light Harvesting Complexes

Light absorbed by chlorophylls of photosystem II and I drives oxygenic photosynthesis. Light-harvesting complexes increase the absorption cross-section of these photosystems. Furthermore, these complexes play a central role in photoprotection by dissipating the excess of absorbed light energy in an inducible and regulated fashion. In higher plants, the main light-harvesting complex is the trimeric LHCII. In this work, we used CRISPR/Cas9 to knockout the five genes encoding LHCB1, which is the major component of the trimeric LHCII. In absence of LHCB1 the accumulation of the other LHCII isoforms was only slightly increased, thereby resulting in chlorophyll loss leading to a pale green phenotype and growth delay. Photosystem II absorption cross-section was smaller while photosystem I absorption cross-section was unaffected. This altered the chlorophyll repartition between the two photosystems, favoring photosystem I excitation. The equilibrium of the photosynthetic electron transport was partially maintained by a lower photosystem I over photosystem II reaction center ratio and by the dephosphorylation of LHCII and photosystem II. Loss of LHCB1 altered the thylakoid structure, with less membrane layers per grana stack and reduced grana width. Stable LHCB1 knock out lines allow characterizing the role of this protein in light harvesting and acclimation and pave the way for future in vivo mutational analyses of LHCII.

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