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

2017 ◽  
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.

scholarly journals Minor Antenna Proteins CP24 and CP26 Affect the Interactions between Photosystem II Subunits and the Electron Transport Rate in Grana Membranes of Arabidopsis

2008 ◽  
Vol 20 (4) ◽  
pp. 1012-1028 ◽  
Author(s):  
Silvia de Bianchi ◽  
Luca Dall'Osto ◽  
Giuseppe Tognon ◽  
Tomas Morosinotto ◽  
Roberto Bassi
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Antenna Proteins

Studies of Components of the Thylakoid Membrane of Undamaged and Damaged Spruce Trees at Different Mountain Sites

1993 ◽  
Vol 48 (11-12) ◽  
pp. 911-922 ◽  
Author(s):  
Aloysius Wild ◽  
Petra Strobel ◽  
Ute Flammersfeld
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll Content ◽  
Thylakoid Membrane ◽  
Electron Transport Rate ◽  
D1 Protein ◽  
Cytochrome F ◽  
West Germany ◽  
Transport Rate ◽  
Photosynthetic Membranes

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.

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

2006 ◽  
Vol 61 (3-4) ◽  
pp. 227-233 ◽  
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.

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

2009 ◽  
Vol 21 (3) ◽  
pp. 167-174 ◽  
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.

scholarly journals Improving the estimation of mesophyll conductance to CO2: on the role of electron transport rate correction and respiration

2013 ◽  
Vol 64 (11) ◽  
pp. 3285-3298 ◽  
Author(s):  
Samuel C.V. Martins ◽  
Jeroni Galmés ◽  
Arántzazu Molins ◽  
Fábio M. DaMatta
Keyword(s):  
Electron Transport ◽  
Electron Transport Rate ◽  
Transport Rate ◽  
Mesophyll Conductance

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

2018 ◽  
Vol 1859 (4) ◽  
pp. 292-299 ◽  
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

scholarly journals Investigating on relationship between effective quantum efficiency and irradiance

2017 ◽  
Author(s):  
Zi-Piao Ye ◽  
Shuang-Xi Zhou ◽  
Xiao-Long Yang ◽  
Hua-Jing Kang ◽  
Piotr Robakowski
Keyword(s):  
Excited State ◽  
Electron Transport ◽  
Quantum Efficiency ◽  
Cross Section ◽  
Electron Transport Rate ◽  
Photosynthetic Pigment ◽  
Transport Rate ◽  
Absorption Cross ◽  
Ps Ii ◽  
The Relationship

AbstractModels describing the relationship between effective quantum efficiency of PS II (ΦPSII) and irradiance (I) are routinely used to determine how irradiance influences effective quantum efficiency and photosynthetic electron transport rate (ETR). However, with no single model one can accurately describe the relationship between ΦPSII and I, and explain the interdependence between ΦPSII and biophysical properties of photosynthetic pigments, especially in plants growing under low level irradiances. Basing on the mechanistic model of photosynthetic electron transport rate we have developed the model of the relationship between ΦPSII and I. The new model reveals that ΦPSII increases with photochemistry (kP) and heat dissipation (kD). Furthermore, the values of key parameters calculated using the new model were compared with the values calculated with two other empirical models. The new model was perfectly fitted to the light-response curves of ΦPSII. The key calculated photosynthetic parameters: maximum ΦPSII, maximum ETR and their corresponding saturation irradiance were close to the measured values. In addition, our model associates ΦPSII with intrinsic features of photosynthetic pigments. We concluded that ΦPSII decreased with increasing I due to the decrease in the effective absorption cross-section of photosynthetic pigments molecules.HighlightA model of the relationship between effective quantum efficiency of PS II (ΦPSII) and irradiance (I) has been developed. Using this new model it was found that ΦPSII decreased with increasing I due to the decrease in the effective absorption cross-section of photosynthetic pigments molecules.AbbreviationsETRElectron transport rateETRmaxMaximum electron transport rateFSteady-state fluorescenceFm′Maximum fluorescence in the lightFvVariable fluorescence yield of the dark-adapted leafgiDegeneration of energy level of photosynthetic pigment molecules in the ground state igkDegeneration of energy level of photosynthetic pigment molecules in the excited state kIIrradianceNPQNon-photochemical quenchingN0Total light-harvesting pigment moleculesPARsatSaturation irradiance corresponding to ETRmaxkPRate of photochemical reactionkDRate of non-radiative heat dissipationPS IIPhotosystem IIaeInitial slope of light-response curve of electron transport rateα′Fraction of light absorbed by PS IIβ′Leaf absorptanceξ1Probability of photochemistryξ2Probability of non-radiative heat dissipationξ3Probability of fluorescenceσikEigen-absorption cross-section of photosynthetic pigment from ground state i to excited state k due to light illuminationEffective optical absorption cross-section of photosynthetic pigment molecule from ground state i to excited state k due to light illuminationφExciton-use efficiency in PS IIτAverage lifetime of the photosynthetic pigment molecules in the lowest excited stateΣPSIIEffective quantum efficiency of PS II

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