scholarly journals Effectiveness of Light-Quality and Dark-White Growth Light Shifts in Short-Term Light Acclimation of Photosynthesis in Arabidopsis

2022 ◽  
Vol 12 ◽  
Author(s):  
Elisabeth Hommel ◽  
Monique Liebers ◽  
Sascha Offermann ◽  
Thomas Pfannschmidt
Keyword(s):  
Light Quality ◽  
Photosynthetic Performance ◽  
Light Acclimation ◽  
Photosynthetic Acclimation ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Dark Light ◽  
Light Shifts ◽  
Set Up ◽  
Photosynthetic Antenna

Photosynthesis needs to run efficiently under permanently changing illumination. To achieve this, highly dynamic acclimation processes optimize photosynthetic performance under a variety of rapidly changing light conditions. Such acclimation responses are acting by a complex interplay of reversible molecular changes in the photosynthetic antenna or photosystem assemblies which dissipate excess energy and balance uneven excitation between the two photosystems. This includes a number of non-photochemical quenching processes including state transitions and photosystem II remodeling. In the laboratory such processes are typically studied by selective illumination set-ups. Two set-ups known to be effective in a highly similar manner are (i) light quality shifts (inducing a preferential excitation of one photosystem over the other) or (ii) dark-light shifts (inducing a general off-on switch of the light harvesting machinery). Both set-ups result in similar effects on the plastoquinone redox state, but their equivalence in induction of photosynthetic acclimation responses remained still open. Here, we present a comparative study in which dark-light and light-quality shifts were applied to samples of the same growth batches of plants. Both illumination set-ups caused comparable effects on the phosphorylation of LHCII complexes and, hence, on the performance of state transitions, but generated different effects on the degree of state transitions and the formation of PSII super-complexes. The two light set-ups, thus, are not fully equivalent in their physiological effectiveness potentially leading to different conclusions in mechanistic models of photosynthetic acclimation. Studies on the regulation of photosynthetic light acclimation, therefore, requires to regard the respective illumination test set-up as a critical parameter that needs to be considered in the discussion of mechanistic and regulatory aspects in this subject.

scholarly journals Photomorphogenesis in the Picocyanobacterium Cyanobium gracile Includes Increased Phycobilisome Abundance Under Blue Light, Phycobilisome Decoupling Under Near Far-Red Light, and Wavelength-Specific Photoprotective Strategies

2021 ◽  
Vol 12 ◽  
Author(s):  
Gábor Bernát ◽  
Tomáš Zavřel ◽  
Eva Kotabová ◽  
László Kovács ◽  
Gábor Steinbach ◽  
...  
Keyword(s):  
Electron Transport ◽  
Growth Rates ◽  
Incident Light ◽  
Red Light ◽  
Photosynthetic Performance ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Strong Light ◽  
Antenna Size ◽  
Moderate Growth

Photomorphogenesis is a process by which photosynthetic organisms perceive external light parameters, including light quality (color), and adjust cellular metabolism, growth rates and other parameters, in order to survive in a changing light environment. In this study we comprehensively explored the light color acclimation of Cyanobium gracile, a common cyanobacterium in turbid freshwater shallow lakes, using nine different monochromatic growth lights covering the whole visible spectrum from 435 to 687 nm. According to incident light wavelength, C. gracile cells performed great plasticity in terms of pigment composition, antenna size, and photosystem stoichiometry, to optimize their photosynthetic performance and to redox poise their intersystem electron transport chain. In spite of such compensatory strategies, C. gracile, like other cyanobacteria, uses blue and near far-red light less efficiently than orange or red light, which involves moderate growth rates, reduced cell volumes and lower electron transport rates. Unfavorable light conditions, where neither chlorophyll nor phycobilisomes absorb light sufficiently, are compensated by an enhanced antenna size. Increasing the wavelength of the growth light is accompanied by increasing photosystem II to photosystem I ratios, which involve better light utilization in the red spectral region. This is surprisingly accompanied by a partial excitonic antenna decoupling, which was the highest in the cells grown under 687 nm light. So far, a similar phenomenon is known to be induced only by strong light; here we demonstrate that under certain physiological conditions such decoupling is also possible to be induced by weak light. This suggests that suboptimal photosynthetic performance of the near far-red light grown C. gracile cells is due to a solid redox- and/or signal-imbalance, which leads to the activation of this short-term light acclimation process. Using a variety of photo-biophysical methods, we also demonstrate that under blue wavelengths, excessive light is quenched through orange carotenoid protein mediated non-photochemical quenching, whereas under orange/red wavelengths state transitions are involved in photoprotection.

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.

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 Recovery of Vitis vinifera L. cv. ‘Kékfrankos’ from ‘bois noir’ disease

2019 ◽  
Vol 156 (3) ◽  
pp. 987-991
Author(s):  
Anikó Mátai ◽  
Péter Teszlák ◽  
Gábor Jakab
Keyword(s):  
Gas Exchange ◽  
Vitis Vinifera ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Vitis Vinifera L ◽  
Bois Noir ◽  
Flavescence Dorée ◽  
Exchange Performance ◽  
Concentration Changes ◽  
Non Photochemical Quenching

AbstractInvestigation of diseases caused by phytoplasmas, a group of cell-wall-less gram-positive bacteria has received significant attention in plant pathology. Grapevine is a host of two, genetically distinct phytoplasmas: Line Flavescence dorée (FD) phytoplasma associated to ‘flavescence dorée’ and ‘Candidatus Phytoplasma solani’ responsible for ‘bois noir’ (BN) disease. In the current study, we focused on BN diseased grapevines (Vitis vinifera L. cv. ‘Kékfrankos’), measured their photosynthetic performance and leaf hydrogen peroxide (H2O2) concentration. The latter is generally considered as a key molecule in the process of ‘recovery’ which is a spontaneous and unpredictable long-term remission of disease symptoms. This phenomenon also occurred during the time of our experiment. Infection resulted in reduced gas exchange performance and maximum quantum efficiency of PSII with an increased regulated non-photochemical quenching of PSII and H2O2 concentration. Changes in gas exchange seem to be a systemic response, while reduced photochemistry is a local response to ‘Ca. P. solani’ infection. H2O2 accumulation in BN phytoplasma infected plants, unlike in FD disease, was found to be a typical response to the appearance of a biotic stressor.

scholarly journals Nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance in the diatom <i>Phaeodactylum tricornutum</i>

2015 ◽  
Vol 12 (8) ◽  
pp. 2383-2393 ◽  
Author(s):  
W. Li ◽  
K. Gao ◽  
J. Beardall
Keyword(s):  
Ocean Acidification ◽  
Uv Radiation ◽  
Phaeodactylum Tricornutum ◽  
Nitrogen Limitation ◽  
Multiple Stressors ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Low Co2 ◽  
Uv Irradiance ◽  
Non Photochemical Quenching

Abstract. It has been proposed that ocean acidification (OA) will interact with other environmental factors to influence the overall impact of global change on biological systems. Accordingly we investigated the influence of nitrogen limitation and OA on the physiology of diatoms by growing the diatom Phaeodactylum tricornutum Bohlin under elevated (1000 μatm; high CO2 – HC) or ambient (390 μatm; low CO2 – LC) levels of CO2 with replete (110 μmol L−1; high nitrate – HN) or reduced (10 μmol L−1; low nitrate – LN) levels of NO3- and subjecting the cells to solar radiation with or without UV irradiance to determine their susceptibility to UV radiation (UVR, 280–400 nm). Our results indicate that OA and UVB induced significantly higher inhibition of both the photosynthetic rate and quantum yield under LN than under HN conditions. UVA or/and UVB increased the cells' non-photochemical quenching (NPQ) regardless of the CO2 levels. Under LN and OA conditions, activity of superoxide dismutase and catalase activities were enhanced, along with the highest sensitivity to UVB and the lowest ratio of repair to damage of PSII. HC-grown cells showed a faster recovery rate of yield under HN but not under LN conditions. We conclude therefore that nutrient limitation makes cells more prone to the deleterious effects of UV radiation and that HC conditions (ocean acidification) exacerbate this effect. The finding that nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance of the diatom P. tricornutum implies that ocean primary production and the marine biological C pump will be affected by OA under multiple stressors.

scholarly journals Non-photochemical Quenching Plays a Key Role in Light Acclimation of Rice Plants Differing in Leaf Color

2017 ◽  
Vol 7 ◽  
Author(s):  
Xia Zhao ◽  
Tingting Chen ◽  
Baohua Feng ◽  
Caixia Zhang ◽  
Shaobing Peng ◽  
...  
Keyword(s):  
Light Acclimation ◽  
Photochemical Quenching ◽  
Leaf Color ◽  
Rice Plants ◽  
Non Photochemical Quenching

The perception of light—dark transitions

1983 ◽  
Vol 303 (1116) ◽  
pp. 523-536 ◽  
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Laboratory Experiments ◽  
Light Quality ◽  
Accurate Method ◽  
Dark Light ◽  
Timing Mechanism ◽  
Rapid Formation ◽  
Special Case ◽  
Dark Transition

Transitions between light and darkness are particularly important where these serve as Zeitgebers to synchronize circadian rhythms. A special case is photoperiodism, which depends on the accurate detection of light—dark transitions and on the coupling of this information to a timing mechanism that appears to be based on the circadian clock. Results from laboratory experiments are considered in relation to the natural changes experienced at dawn and dusk, and evidence is presented that the light—dark transitions that couple to the timing mechanism in short-day plants are perceived through changes in irradiance rather than through changes in light quality. It has been generally accepted that the light—dark transition is sensed by a decrease of P fr levels in darkness, whereas dark—light is sensed by the rapid formation of P fr in the light. However, P fr in light-grown plants appears to be rather stable and so changes in P fr level after transfer to darkness may not be a sufficiently accurate method of detecting the light—dark transition in photoperiodism. The paper reviews some of the evidence from photoperiodic experiments and concludes that the plant may discriminate between light and darkness through the continuous or intermittent formation o f ‘new’ P fr .

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