scholarly journals Demonstration of a relationship between state transitions and photosynthetic efficiency in a higher plant

2019 ◽  
Vol 476 (21) ◽  
pp. 3295-3312 ◽  
Author(s):  
Craig R. Taylor ◽  
Wim van Ieperen ◽  
Jeremy Harbinson
Keyword(s):  
Photosynthetic Efficiency ◽  
State Transition ◽  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
State Transitions ◽  
Short Term ◽  
Higher Plant ◽  
Series Configuration ◽  
Use Efficiency ◽  
Sun And Shade

A consequence of the series configuration of PSI and PSII is that imbalanced excitation of the photosystems leads to a reduction in linear electron transport and a drop in photosynthetic efficiency. Achieving balanced excitation is complicated by the distinct nature of the photosystems, which differ in composition, absorption spectra, and intrinsic efficiency, and by a spectrally variable natural environment. The existence of long- and short-term mechanisms that tune the photosynthetic apparatus and redistribute excitation energy between the photosystems highlights the importance of maintaining balanced excitation. In the short term, state transitions help restore balance through adjustments which, though not fully characterised, are observable using fluorescence techniques. Upon initiation of a state transition in algae and cyanobacteria, increases in photosynthetic efficiency are observable. However, while higher plants show fluorescence signatures associated with state transitions, no correlation between a state transition and photosynthetic efficiency has been demonstrated. In the present study, state 1 and state 2 were alternately induced in tomato leaves by illuminating leaves produced under artificial sun and shade spectra with a sequence of irradiances extreme in terms of PSI or PSII overexcitation. Light-use efficiency increased in both leaf types during transition from one state to the other with remarkably similar kinetics to that of F′m/Fm, F′o/Fo, and, during the PSII-overexciting irradiance, ΦPSII and qP. We have provided compelling evidence for the first time of a correlation between photosynthetic efficiency and state transitions in a higher plant. The importance of this relationship in natural ecophysiological contexts remains to be elucidated.

scholarly journals Short-term acclimation of the photosynthetic electron transfer chain to changing light: a mathematical model

2014 ◽  
Vol 369 (1640) ◽  
pp. 20130223 ◽  
Author(s):  
Oliver Ebenhöh ◽  
Geoffrey Fucile ◽  
Giovanni Finazzi ◽  
Jean-David Rochaix ◽  
Michel Goldschmidt-Clermont
Keyword(s):  
Mathematical Model ◽  
Molecular Mechanisms ◽  
Photosynthetic Apparatus ◽  
Light Acclimation ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Short Term ◽  
Dynamic Regulation ◽  
Relative Contribution ◽  
Photosynthetic Eukaryotes

Photosynthetic eukaryotes house two photosystems with distinct light absorption spectra. Natural fluctuations in light quality and quantity can lead to unbalanced or excess excitation, compromising photosynthetic efficiency and causing photodamage. Consequently, these organisms have acquired several distinct adaptive mechanisms, collectively referred to as non-photochemical quenching (NPQ) of chlorophyll fluorescence, which modulates the organization and function of the photosynthetic apparatus. The ability to monitor NPQ processes fluorometrically has led to substantial progress in elucidating the underlying molecular mechanisms. However, the relative contribution of distinct NPQ mechanisms to variable light conditions in different photosynthetic eukaryotes remains unclear. Here, we present a mathematical model of the dynamic regulation of eukaryotic photosynthesis using ordinary differential equations. We demonstrate that, for Chlamydomonas , our model recapitulates the basic fluorescence features of short-term light acclimation known as state transitions and discuss how the model can be iteratively refined by comparison with physiological experiments to further our understanding of light acclimation in different species.

The Occurrence of β-Carotene-5,6-epoxide in the Photosynthetic Apparatus of Higher Plants

1989 ◽  
Vol 44 (11-12) ◽  
pp. 959-965 ◽  
Author(s):  
Andrew Young ◽  
Paul Barry ◽  
George Britton
Keyword(s):  
Higher Plants ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Reaction Centre ◽  
Higher Plant ◽  
Ps Ii ◽  
Photooxidative Damage ◽  
Pigment Protein Complexes ◽  
The Individual ◽  
Β Carotene

Abstract The occurrence of β-carotene-5,6-epoxide in higher plant photosynthetic tissue is described. The compound is found in isolated chloroplasts, thylakoids and other subchloroplast particles but can only be detected in intact leaves or cotyledons of higher plants when these are exposed to very high light intensities or to inhibitors such as monuron or paraquat. The distribution of the epoxide within the individual pigment-protein complexes is given. It is particularly associated with the PS I reaction centres (C P I and CP la) and less so with the PS II reaction centre (CPa). Circular dichroism shows that the β-carotene-5,6-epoxide isolated from photosynthetic tissue is optically inactive. It is therefore not produced enzymically but is a product of photooxidative events in the photosynthetic apparatus. Its presence in photosynthetic tissue is a reliable indicator of photooxidative damage to the thylakoid membrane involving oxidation of β-carotene.

scholarly journals Healthy Photosynthetic Mechanism Suggests ISR Elicited by Bacillus spp. in Capsicum chinense Plants Infected with PepGMV

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 455
Author(s):  
Blancka Yesenia Samaniego-Gámez ◽  
René Garruña ◽  
José M. Tun-Suárez ◽  
Oscar A. Moreno-Valenzuela ◽  
Arturo Reyes-Ramírez ◽  
...  
Keyword(s):  
Photosynthetic Efficiency ◽  
Photosynthetic Apparatus ◽  
Co2 Assimilation ◽  
Capsicum Chinense ◽  
Yield And Quality ◽  
Bacillus Spp ◽  
Use Efficiency ◽  
Photochemical Quantum Yield ◽  
Quantum Yield Of Psii

The aim of this study was to evaluate the effect of inoculation with Bacillus spp. isolates on the photosynthetic apparatus of Capsicum chinense plants infected with PepGMV. In vitro and greenhouse experiments were performed to evaluate whether the inoculation improved plants’ performance through the increase in photosynthetic efficiency to control PepGMV. The results showed that despite PepGMV infection, the plants inoculated with some isolates of Bacillus spp. had a healthy photosynthetic mechanism, as the photochemical parameters and gas exchange increased. The maximum photochemical quantum yield of PSII (Fv/Fm) of plants with PepGMV and inoculated with Bacillus isolates (M9, K46, and K47) increased (7.85, 7.09, and 7.77%, respectively) with respect to uninoculated controls. In inoculated plants, the CO2 assimilation rate increased and the transpiration rate decreased, therefore indicating an increased water use efficiency. This effect was reflected by the less severe symptoms caused by PepGMV in the plants obtained from seeds inoculated with different Bacillus spp. Plants inoculated with K47 isolates showed an increase in fruit yield and quality. This study suggests that it is possible to protect, at the greenhouse level, C. chinense plants from PepGMV through selected rhizobacteria inoculation.

scholarly journals Cadmium against Higher Plant Photosynthesis -a Variety of Effects and Where Do They Possibly Come From?

1999 ◽  
Vol 54 (9-10) ◽  
pp. 723-729 ◽  
Author(s):  
Zbigniew Krupa
Keyword(s):  
Carbon Metabolism ◽  
Metabolic Pathways ◽  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
Structure And Function ◽  
Metabolic Processes ◽  
Higher Plant ◽  
Plant Photosynthesis ◽  
And Function

The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosynthetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism

Complex electron microscopic study of structural and functional arrangement of chloroplast membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 418-419
Author(s):  
S. V. Tageeva ◽  
V. I. Popov ◽  
B. L. Allakhverdov
Keyword(s):  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Particle Morphology ◽  
Chloroplast Envelope ◽  
Higher Plant ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Ultrathin Sections

Supramolecular arrangement of photosynthetic membranes of cyanobacteria and higher plant chloroplasts has been studied by means of electron microscopy, ultrathin sections, freeze-substitution and freeze-fracture technique. Principal similarity between the structural arrangement of the photosynthetic apparatus of higher plants and cyanobacteria has been established. It consists in a continuity of the photosynthetic membranes and their relation to the inner membrane of chloroplast envelope or to plasmalemma in the cyanobacteria; in the ability of thylakoids stacking; in an asymmetrical distribution of principal number and sizes on complemetary faces of membrane fractures revealed by the freeze-fracture (Fig. 1a, b, c, d; Fig. 2a).A comparative analysis of particle morphology was carried out by means of angular and circular shading of fracture faces with Pt, “direct” and “inverse” replicas being obtained.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

scholarly journals Gross Ammonification and Nitrification Rates in Soil Amended with Natural and NH4-Enriched Chabazite Zeolite and Nitrification Inhibitor DMPP

2021 ◽  
Vol 11 (6) ◽  
pp. 2605
Author(s):  
Giacomo Ferretti ◽  
Giulio Galamini ◽  
Evi Deltedesco ◽  
Markus Gorfer ◽  
Jennifer Fritz ◽  
...  
Keyword(s):  
Nitrification Inhibitor ◽  
Natural State ◽  
Silty Clay ◽  
Short Term ◽  
N Losses ◽  
15N Pool Dilution ◽  
Use Efficiency ◽  
Silty Clay Soil ◽  
N Use ◽  
15N Pool Dilution Technique

Using zeolite-rich tuffs for improving soil properties and crop N-use efficiency is becoming popular. However, the mechanistic understanding of their influence on soil N-processes is still poor. This paper aims to shed new light on how natural and NH4+-enriched chabazite zeolites alter short-term N-ammonification and nitrification rates with and without the use of nitrification inhibitor (DMPP). We employed the 15N pool dilution technique to determine short-term gross rates of ammonification and nitrification in a silty-clay soil amended with two typologies of chabazite-rich tuff: (1) at natural state and (2) enriched with NH4+-N from an animal slurry. Archaeal and bacterial amoA, nirS and nosZ genes, N2O-N and CO2-C emissions were also evaluated. The results showed modest short-term effects of chabazite at natural state only on nitrate production rates, which was slightly delayed compared to the unamended soil. On the other hand, the addition of NH4+-enriched chabazite stimulated NH4+-N production, N2O-N emissions, but reduced NO3−-N production and abundance of nirS-nosZ genes. DMPP efficiency in reducing nitrification rates was dependent on N addition but not affected by the two typologies of zeolites tested. The outcomes of this study indicated the good compatibility of both natural and NH4+-enriched chabazite zeolite with DMPP. In particular, the application of NH4+-enriched zeolites with DMPP is recommended to mitigate short-term N losses.

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