Effect of (C6H5)3PbCl and (C6H5)3SnCl on Delayed Luminescence Intensity, Evolving Oxygen and Electron Transport Rate in Photosystem II of Chlorella vulgaris

During a five-year period, components of the thylakoid membrane in needles of the second generation of undamaged and damaged trees of Norway spruce were studied at three different mountain sites in West Germany. Visible signs of damage at these sites are a yellowing of the light-exposed sides of the needles as well as the loss of needles. The goal of this study was to determine damage-induced alterations in composition and physiological reactions of the thylakoid membranes in spruce needles. In order to meet this purpose, contents of chlorophyll a and b, electron transport rate of photosystem II, contents of the D 1 protein, cytochrome f, as well as P-700 were measured. The chlorophyll content in the needles of the damaged spruce trees was significantly lower than in the needles of the undamaged trees. In addition to this, the typical annual course of chlorophyll content was exclusively observed in the needles of the undamaged spruce trees. If related to dry weight, a drastic reduction of the electron transport rate and of the redox components of the thylakoid membrane was observed due to damage, indicating a degeneration of the photosynthetic membranes. The contents of D1 protein and the photosynthetic electron transport rates were also markedly reduced in the needles of the damaged trees, when related to chlorophyll content of thylakoids, suggesting an early and particular impairment of photosystem II. The comparison of spruce trees showing different signs of damage demonstrates that certain biochemical parameters concerning the photosynthetic membranes (chlorophyll, cytochrome f, ratio photosystem II/I) reflect the extent of damage and are suitable for an early indication of a beginning, but still invisible damage of spruce trees.

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A Diterpene γ-Lactone Derivative from Pterodon polygalaeflorus Benth. as a Photosystem II Inhibitor and Uncoupler of Photosynthesis

Zeitschrift für Naturforschung C ◽

10.1515/znc-2006-3-412 ◽

2006 ◽

Vol 61 (3-4) ◽

pp. 227-233 ◽

Cited By ~ 6

Author(s):

Beatriz King-Díaz ◽

Flávio J. L. dos Santos ◽

Mayura M. M. Rubinger ◽

Dorila Piló -Veloso ◽

Blas Lotina-Hennsen

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Electron Transport Rate ◽

Atp Synthesis ◽

Transport Rate ◽

Hill Reaction ◽

Oxygen Evolving Complex ◽

Photosynthesis Inhibition ◽

Chlorophyll A Fluorescence Transient ◽

Oxygen Evolving

6α,7β-Dihydroxyvouacapan-17β-oic acid (1) was isolated from Pterodon polygalaeflorus Benth. Modification of 1 yielded 6α-hydroxyvouacapan-7β,17β-lactone (2) and then 6-oxovouacapan- 7β,17β-lactone (3). Photosynthesis inhibition by 3 was evaluated in spinach chloroplasts. The uncoupled non-cyclic electron transport rate and ATP synthesis were inhibited by 3, which behaved as a Hill reaction inhibitor. Furthermore, 3 acted as an uncoupler because it enhanced the basal and phosphorylating electron transport rate on thylakoids. This last property of 3 was corroborated when it was observed that it enhances the Mg2+-ATPase activity. In contrast, 3 did not affect photosystem I (PSI) activity. Analysis of the partial photosystem II (PSII) reactions from water to DCPIPox and water to silicomolybdate allowed to locate the inhibition sites at the redox components of PSII. The OJIP test of the chlorophyll a fluorescence transient confirmed that the inhibition sites were 1.) the oxygen-evolving complex (OEC) and 2.) by the formation of silent centers in the non-QA reducing centers.

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Photosynthetic capacity of three phytoplanktonic species measured by a pulse amplitude fluorometric method

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202009000300001 ◽

2009 ◽

Vol 21 (3) ◽

pp. 167-174 ◽

Cited By ~ 1

Author(s):

Cleber Cunha Figueredo ◽

Alessandra Giani ◽

José Pires Lemos Filho

Keyword(s):

Electron Transport ◽

Quantum Yield ◽

Photosystem Ii ◽

Photosynthetic Capacity ◽

Electron Transport Rate ◽

Morphological Characteristics ◽

Volume Ratio ◽

Photochemical Reactions ◽

Transport Rate ◽

Photosynthetic Parameters

During photosynthesis, absorbed energy that is not used in photochemical reactions dissipates as fluorescence. Fluorescence provides important information on the physiological conditions of the studied organisms and its measurement is widely used by plant physiologists and can be valuable in phytoplankton studies. We describe a method adapting a plant fluorometric equipment to measure the photosynthetic capacity of microalgae. Unialgal cultures of three planktonic chlorophytes were exposed to 3(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosystem II, at concentrations of 0.1, 1.0 and 10.0 µmol.L-1. Estimates were made of photosynthetic parameters, including operational and potential photosystem II quantum yield and electron transport rate between photosystems, using algal cells concentrated on glass-fiber filters. The technique allowed reliable measurements of fluorescence, and detection of distinct levels of inhibition. Physiological or morphological characteristics of the selected species might provide an explanation for the observed results: differences on the surface/volume ratio of the cells and colony morphology, for example, were associated with contrasting resistance to the toxicant. To characterize inhibition on phytoplanktonic photosynthesis, we suggest operational quantum yield and electron transport rate as best parameters, once they were more sensitive to the DCMU toxicity.

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Is carbonic anhydrase activity of photosystem II required for its maximum electron transport rate?

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/j.bbabio.2018.01.009 ◽

2018 ◽

Vol 1859 (4) ◽

pp. 292-299 ◽

Cited By ~ 6

Author(s):

Alexandr V. Shitov ◽

Vasily V. Terentyev ◽

Sergey K. Zharmukhamedov ◽

Margarita V. Rodionova ◽

Mehmet Karacan ◽

...

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Carbonic Anhydrase ◽

Electron Transport Rate ◽

Carbonic Anhydrase Activity ◽

Transport Rate ◽

Maximum Electron Transport Rate

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Diffusional conductance to CO2 is the key limitation to photosynthesis in salt-stressed leaves of rice (Oryza sativa)

10.1101/204578 ◽

2017 ◽

Cited By ~ 1

Author(s):

Xiaoxiao Wang ◽

Wencheng Wang ◽

Jianliang Huang ◽

Shaobing Peng ◽

Dongliang Xiong

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Quantum Efficiency ◽

Photosynthetic Rate ◽

Osmotic Potential ◽

Electron Transport Rate ◽

Transport Rate ◽

Total Soluble Protein ◽

Mesophyll Conductance ◽

Leaf Osmotic Potential

Salinity significantly limits leaf photosynthesis but the photosynthetic limiting factors in salt- stressed leaves remain unclear. In the present work, photosynthetic and biochemical traits were investigated in four rice genotypes under two NaCl (0 and 150 mM) concentration to assess the stomatal, mesophyll and biochemical contributions to reduced photosynthetic rate (A) in salt stressed leaves. Our results indicated that salinity led to a decrease in A, leaf osmotic potential, electron transport rate and CO2 concentrations in the chloroplasts (Cc) of rice leaves. Decreased A in salt-stressed leaves was mainly attributable to low Cc, which was determined by stomatal and mesophyll conductance. The increased stomatal limitation was mainly related to the low leaf osmotic potential caused by soil salinity. However, the increased mesophyll limitation in salt stressed leaves was related to both osmotic stress and ion stress. These findings highlight the importance of considering mesophyll conductance when developing salinity-tolerant rice cultivars.AbbreviationsAphotosynthetic rateCc, CO2concentration at carboxylation sitesCEapparent Rubisco activityChltotal chlorophyll contentCiintercellular CO2 concentrationETRelectron transport rateF0initial fluorescence of photosystem II in darknessFmmaximum fluorescence of photosystem IIFvmaximum variable fluorescence of photosystem IIFv/Fmmaximum quantum efficiency of photosystem IIgmmesophyll conductiongsstomatal conductionJmaxmaximum electron transport rateKleaf K contentLMAleaf mass per areaNleaf N contentPleaf P contentOPosmotic potentialProteinleaf total soluble protein contentqNnon-chemical quenching efficiencyRdday respirationRdarkdark respirationRubiscoRubisco contentVcmaxmaximum carboxylation rateαleaf light absorptance efficiencyβthe distribution of electrons between PSI and PSIIΓ*CO2 compensation point in the absence of respirationΦPSIIquantum efficiency of photosystem II.

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Photoinhibition of Electron Transport Activity of Photosystem II in Isolated Thylakoids Studied by Thermoluminescence and Delayed Luminescence

Zeitschrift für Naturforschung C ◽

10.1515/znc-1988-11-1213 ◽

1988 ◽

Vol 43 (11-12) ◽

pp. 871-876 ◽

Cited By ~ 35

Author(s):

Imre Vass ◽

Narendranath Mohanty ◽

Sándor Demeter

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Photosystem I ◽

Half Life ◽

Delayed Luminescence ◽

Transport Activity ◽

Primary Target ◽

Electron Transport Activity ◽

The Stability ◽

Spinach Thylakoids

Abstract The effect of photoinhibition on the primary (QA) and secondary (QB) quinone acceptors of photosystem I I was investigated in isolated spinach thylakoids by the methods of thermoluminescence and delayed luminescence. The amplitudes of the Q (at about 2 °C) and B (at about 30 °C) thermoluminescence bands which are associated with the recombination of the S2QA- and S2QB charge pairs, respectively, exhibited parallel decay courses during photoinhibitory treatment. Similarly, the amplitudes of the flash-induced delayed luminescence components ascribed to the recombination of S20A and S2OB charge pairs and having half life-times of about 3 s and 30 s, respectively, declined in parallel with the amplitudes of the corresponding Q and B thermoluminescence bands. The course of inhibition of thermoluminescence and delayed luminescence intensity was parallel with that of the rate of oxygen evolution. The peak positions of the B and Q thermoluminescence bands as well as the half life-times of the corresponding delayed luminescence components were not affected by photoinhibition. These results indicate that in isolated thylakoids neither the amount nor the stability of the reduced OB acceptor is preferentially decreased by photoinhibition. We conclude that either the primary target of photodamage is located before the O b binding site in the reaction center of photosystem II or QA and OB undergo simultaneous damage.

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Controlling electron transport rate and recombination process of TiO2 dye-sensitized solar cells by design of double-layer films with different arrangement modes

Electrochimica Acta ◽

10.1016/j.electacta.2012.06.087 ◽

2012 ◽

Vol 78 ◽

pp. 384-391 ◽

Cited By ~ 43

Author(s):

A.M. Bakhshayesh ◽

M.R. Mohammadi ◽

D.J. Fray

Keyword(s):

Solar Cells ◽

Electron Transport ◽

Double Layer ◽

Electron Transport Rate ◽

Dye Sensitized Solar Cells ◽

Recombination Process ◽

Transport Rate ◽

Dye Sensitized ◽

Sensitized Solar Cells

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Updating the steady state model of C4 photosynthesis

10.1101/2021.03.13.435281 ◽

2021 ◽

Author(s):

Susanne von Caemmerer

Keyword(s):

Steady State ◽

Electron Transport ◽

Electron Transport Rate ◽

Transport Rate ◽

Initial Slope ◽

Carboxylase Activity ◽

Quantitative Correlation ◽

Steady State Model ◽

State Models

AbstractC4 plants play a key role in world agriculture. For example, C4 crops such as maize and sorghum are major contributors to both first and third world food production and the C4 grasses sugarcane; miscanthus and switchgrass are major plant sources of bioenergy. In the challenge to manipulate and enhance C4 photosynthesis, steady state models of leaf photosynthesis provide and important tool for gas exchange analysis and thought experiments that can explore photosynthetic pathway changes. Here the C4 photosynthetic model by von Caemmerer and Furbank (1999) has been updated with new kinetic parameterisation and temperature dependencies added. The parameterisation was derived from experiments on the C4 monocot, Setaria viridis, which for the first time provides a cohesive parametrisation. Mesophyll conductance and its temperature dependence have also been included, as this is an important step in the quantitative correlation between the initial slope of the CO2 response curve of CO2 assimilation and in vitro PEP carboxylase activity. Furthermore, the equations for chloroplast electron transport have been updated to include cyclic electron transport flow and equations have been added to calculate electron transport rate from measured CO2 assimilation rates.HighlightThe C4 photosynthesis model by von Caemmerer and Furbank (1999) has been updated. It now includes temperature dependencies and equations to calculate electron transport rate from measured CO2 assimilation rates.

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