scholarly journals Photoprotection by carotenoids of Plantago media photosynthetic apparatus in natural conditions.

2012 ◽  
Vol 59 (1) ◽  
Author(s):  
Tamara Golovko ◽  
Olga Dymova ◽  
Ilya Zakhozhiy ◽  
Igor Dalke ◽  
Galina Tabalenkova
Keyword(s):  
Heat Dissipation ◽  
Photosynthetic Apparatus ◽  
Photochemical Quenching ◽  
Total Pool ◽  
Plantago Media ◽  
Non Photochemical Quenching ◽  
Sun Leaves ◽  
Daily Changes ◽  
Shade Plants

The study of daily changes in photosynthetic rate, of energy used in photochemical and non-photochemical processes, and of carotenoid composition aimed at evaluating the role of xanthophyll cycle (XC) in protection of hoary plantain plants (Plantago media) in nature. The leaves of sun plants differed from shade plants in terms of CO(2) exchange rate and photosynthetic pigments content. The total pool XC pigments and the conversion state increased from morning to midday in sun plants. An increase in zeaxanthin content occurred concomitantly with the violaxanthin decrease. About 80% violaxanthin was involved in conversion. The maximum of zeaxanthin in XC pigments pool was 60%. The conversion state of XC was twice as lower in shade plants than that in sun plants. The photosynthesis of sun leaves was depressed strongly at midday, but changes of maximum quantum yield of PS2 (F(v)/F(m)) were not apparent at that time. The coefficient qN (non-photochemical quenching) in the sun leaves changed strongly, from 0.3 to 0.9 as irradiance increased. The direct relation between heat dissipation and the conversion state of XC in plantain leaves was revealed. Thus, plantain leaves were found to be resistant to excess solar radiation due to activation of qN mechanisms associated with the XC de-epoxidation.

scholarly journals Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 721
Author(s):  
Magdalena Trojak ◽  
Ernest Skowron
Keyword(s):  
Photosynthetic Pigments ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Performance ◽  
Photochemical Quenching ◽  
Light Spectrum ◽  
Negative Effects ◽  
Tomato Plants ◽  
Lower Amplitude ◽  
Non Photochemical Quenching

Photosynthetic pigments of plants capture light as a source of energy for photosynthesis. However, the amount of energy absorbed often exceeds its utilization, thus causing damage to the photosynthetic apparatus. Plants possess several mechanisms to minimize such risks, including non-photochemical quenching (NPQ), which allows them to dissipate excess excitation energy in the form of harmless heat. However, under non-stressful conditions in indoor farming, it would be favorable to restrict the NPQ activity and increase plant photosynthetic performance by optimizing the light spectrum. Towards this goal, we investigated the dynamics of NPQ, photosynthetic properties, and antioxidant activity in the leaves of tomato plants grown under different light qualities: monochromatic red (R), green (G), or blue (B) light (L) at 80 µmol m−2 s−1 and R:G:B = 1:1:1 (referred to as the white light (WL)) at 120 µmol m−2 s−1. The results confirm that monochromatic BL increased the quantum efficiency of PSII and photosynthetic pigments accumulation. The RL and BL treatments enhanced the NPQ amplitude and showed negative effects on antioxidant enzyme activity. In contrast, plants grown solely under GL or WL presented a lower amplitude of NPQ due to the reduced accumulation of NPQ-related proteins, photosystem II (PSII) subunit S (PsbS), PROTON GRADIENT REGULATION-LIKE1 (PGRL1), cytochrome b6f subunit f (cytf) and violaxanthin de-epoxidase (VDE). Additionally, we noticed that plants grown under GL or RL presented an increased rate of lipid peroxidation. Overall, our results indicate the potential role of GL in lowering the NPQ amplitude, while the role of BL in the RGB spectrum is to ensure photosynthetic performance and photoprotective properties.

scholarly journals PsbS Dependence in Lipid and Pigment Composition in Rice Plants

2021 ◽  
Vol 7 (9) ◽  
pp. 59-68
Author(s):  
Pashayeva
Keyword(s):  
Lipid Level ◽  
Ph Sensor ◽  
Photosynthetic Apparatus ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Pigment Composition ◽  
Short Term ◽  
Non Photochemical Quenching ◽  
Psbs Protein

Plants acclimate to fluctuations in light conditions by adjusting their photosynthetic apparatus. When the light intensity exceeds, an unbalanced excitation of the two photosystems occurs. It results in reduced photosynthetic efficiency. Photosystem II (PSII) is the most susceptible and dynamically regulated part of the light reactions in the thylakoid membrane. Non-photochemical quenching of chlorophyll fluorescence (NPQ) is one of the short-term photoprotective mechanisms, which consist of the number of components. The strongest NPQ component — qE is localized in the PSII antenna and induced in plants by lumen acidification, the activation of the pH sensor PsbS, and the conversion of the violaxanthin to zeaxanthin within the xanthophyll cycle. Here, I present data that characterizes the role of the PsbS protein in organization of PSII structural components in isolated PSII-enriched membranes. The preparations were isolated from wild-type (WT) and PsbS-less (PsbS-KO) mutant rice plant. Based on the obtained results, the PSII-enriched membranes from WT and PsbS-KO differ as in the level of lipids, also in carotenoids. I conclude that the PsbS-dependent changes in membrane fluidity in PsbS-KO mutant plants compensated with increased lipid level in mutant plants.

scholarly journals The Role of Acidic Residues in the C Terminal Tail of the LHCSR3 Protein of Chlamydomonas reinhardtii in Non-Photochemical Quenching

2021 ◽  
pp. 6895-6900
Author(s):  
Franco V. A. Camargo ◽  
Federico Perozeni ◽  
Gabriel de la Cruz Valbuena ◽  
Luca Zuliani ◽  
Samim Sardar ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Photochemical Quenching ◽  
Acidic Residues ◽  
Non Photochemical Quenching

Non-photochemical quenching of chlorophyll a fluorescence: early history and characterization of two xanthophyll-cycle mutants of Chlamydomonas reinhardtii

2002 ◽  
Vol 29 (10) ◽  
pp. 1141 ◽  
Author(s):  
Govindjee ◽  
Manfredo J. Seufferheld
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Photochemical Quenching ◽  
Chl A ◽  
Fluorescence Transient ◽  
Chl A Fluorescence ◽  
Non Photochemical Quenching

This paper deals first with the early, although incomplete, history of photoinhibition, of 'non-QA-related chlorophyll (Chl) a fluorescence changes', and the xanthophyll cycle that preceded the discovery of the correlation between non-photochemical quenching of Chl a fluorescence (NPQ) and conversion of violaxanthin to zeaxanthin. It includes the crucial observation that the fluorescence intensity quenching, when plants are exposed to excess light, is indeed due to a change in the quantum yield of fluorescence. The history ends with a novel turn in the direction of research — isolation and characterization of NPQ xanthophyll-cycle mutants of Chlamydomonas reinhardtii Dangeard and Arabidopsis thaliana (L.) Heynh., blocked in conversion of violaxanthin to zeaxanthin, and zeaxanthin to violaxanthin, respectively. In the second part of the paper, we extend the characterization of two of these mutants (npq1, which accumulates violaxanthin, and npq2, which accumulates zeaxanthin) through parallel measurements on growth, and several assays of PSII function: oxygen evolution, Chl a fluorescence transient (the Kautsky effect), the two-electron gate function of PSII, the back reactions around PSII, and measurements of NPQ by pulse-amplitude modulation (PAM 2000) fluorimeter. We show that, in the npq2 mutant, Chl a fluorescence is quenched both in the absence and presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). However, no differences are observed in functioning of the electron-acceptor side of PSII — both the two-electron gate and the back reactions are unchanged. In addition, the role of protons in fluorescence quenching during the 'P-to-S' fluorescence transient was confirmed by the effect of nigericin in decreasing this quenching effect. Also, the absence of zeaxanthin in the npq1 mutant leads to reduced oxygen evolution at high light intensity, suggesting another protective role of this carotenoid. The available data not only support the current model of NPQ that includes roles for both pH and the xanthophylls, but also are consistent with additional protective roles of zeaxanthin. However, this paper emphasizes that we still lack sufficient understanding of the different parts of NPQ, and that the precise mechanisms of photoprotection in the alga Chlamydomonas may not be the same as those in higher plants.

scholarly journals Chilling tolerance in Zizania latifólia

2016 ◽  
Vol 34 (1) ◽  
pp. 39-45
Author(s):  
Zihong Ye ◽  
Haifeng Cui ◽  
Xinxin An ◽  
Xiaoping Yu
Keyword(s):  
Cold Stress ◽  
Heat Dissipation ◽  
Chilling Tolerance ◽  
Photochemical Quenching ◽  
Electric Transport ◽  
Zizania Latifolia ◽  
Critical Pathways ◽  
Photosynthesis Inhibition ◽  
Non Photochemical Quenching ◽  
Latent Activity

ABSTRACT: The tumescent stems of Zizania latifolia are consumed as vegetable in southern and eastern Asia. This study aimed to compare photosynthesis and chilling tolerance parameters between two well-known Zizania latifolia cultivars: Longjiao 2 and Zhejiao 911, which are chilling tolerant and sensitive, respectively. We found that severe cold stress induced photosynthesis inhibition (5°C) resulted from non-stomatal factors. However, net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of the cultivar Longjiao 2 were higher than that of Zhejiao 911 with more gradual variations. Six parameters of chlorophyll fluorescence including latent activity of PSII (Fv/F0), efficiency of primary photochemistry (Fv/Fm), photochemical quenching coefficient (qP), non-photochemical quenching coefficient (qN), quantum yield of electric transport (Yield) and the ratio of electric transport at PSII (ETR) were analyzed in the two cultivars. We found that Longjiao 2 had significantly higher Fv/Fm and qN than Zhejiao 911 while qP values were only slightly different for the two lines at severe cold stress. In our experiments, Yield and ETR changed in a similar way in both Longjiao 2 and Zhejiao 911. In addition, the ability of heat dissipation of Longjiao 2 was statistically higher than that found in Zhejiao 911 when treated at 5°C for one day. These data suggest that cultivar Longjiao 2 induces chilling tolerance by modulating critical pathways including photosynthesis and energy dissipation.

scholarly journals The role of LHCBM1 in non-photochemical quenching in Chlamydomonas reinhardtii

2022 ◽  
Author(s):  
Xin Liu ◽  
Wojciech J Nawrocki ◽  
Roberta Croce
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Ph Sensor ◽  
High Light ◽  
Photochemical Quenching ◽  
Knock Out ◽  
Photosynthetic Organisms ◽  
Pigment Protein Complexes ◽  
Non Photochemical Quenching

Non-photochemical quenching (NPQ) is the process that protects photosynthetic organisms from photodamage by dissipating the energy absorbed in excess as heat. In the model green alga Chlamydomonas reinhardtii, NPQ was abolished in the knock-out mutants of the pigment-protein complexes LHCSR3 and LHCBM1. However, while LHCSR3 was shown to be a pH sensor and switching to a quenched conformation at low pH, the role of LHCBM1 in NPQ has not been elucidated yet. In this work, we combine biochemical and physiological measurements to study short-term high light acclimation of npq5, the mutant lacking LHCBM1. We show that while in low light in the absence of this complex, the antenna size of PSII is smaller than in its presence, this effect is marginal in high light, implying that a reduction of the antenna is not responsible for the low NPQ. We also show that the mutant expresses LHCSR3 at the WT level in high light, indicating that the absence of this complex is also not the reason. Finally, NPQ remains low in the mutant even when the pH is artificially lowered to values that can switch LHCSR3 to the quenched conformation. It is concluded that both LHCSR3 and LHCBM1 need to be present for the induction of NPQ and that LHCBM1 is the interacting partner of LHCSR3. This interaction can either enhance the quenching capacity of LHCSR3 or connect this complex with the PSII supercomplex.

scholarly journals The role of coccoliths in protecting <i>Emiliania huxleyi</i> against stressful light and UV radiation

2016 ◽  
Vol 13 (16) ◽  
pp. 4637-4643 ◽  
Author(s):  
Juntian Xu ◽  
Lennart T. Bach ◽  
Kai G. Schulz ◽  
Wenyan Zhao ◽  
Kunshan Gao ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Uv Radiation ◽  
Growth Rates ◽  
Emiliania Huxleyi ◽  
Photochemical Quenching ◽  
Visible Radiation ◽  
Light Levels ◽  
Relative Electron ◽  
Non Photochemical Quenching

Abstract. Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400–700 nm) by 7.5 %, that of UV-A (315–400 nm) by 14.1 % and that of UV-B (280–315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

Different strategies of acclimation of photosynthesis, electron transport and antioxidative activity in leaves of two cotton species to water deficit

2016 ◽  
Vol 43 (5) ◽  
pp. 448 ◽  
Author(s):  
Xiao-Ping Yi ◽  
Ya-Li Zhang ◽  
He-Sheng Yao ◽  
Hong-Hai Luo ◽  
Ling Gou ◽  
...  
Keyword(s):  
Electron Transport ◽  
Water Deficit ◽  
Heat Dissipation ◽  
Photosynthetic Apparatus ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Antioxidant Systems ◽  
Mehler Reaction ◽  
Cotton Species ◽  
Excess Light

To better understand the adaptation mechanisms of the photosynthetic apparatus of cotton plants to water deficit conditions, the influence of water deficit on photosynthesis, chlorophyll a fluorescence and the activities of antioxidant systems were determined simultaneously in Gossypium hirsutum L. cv. Xinluzao 45 (upland cotton) and Gossypium barbadense L. cv. Xinhai 21 (pima cotton). Water deficit decreased photosynthesis in both cotton species, but did not decrease chlorophyll content or induce any sustained photoinhibition in either cotton species. Water deficit increased ETR/4 − AG, where ETR/4 estimates the linear photosynthetic electron flux and AG is the gross rate of carbon assimilation. The increase in ETR/4 − AG, which represents an increase in photorespiration and alternative electron fluxes, was particularly pronounced in Xinluzao 45. In Xinluzao 45, water deficit increased the activities of antioxidative enzymes, as well as the contents of reactive oxygen species (ROS), which are related to the Mehler reaction. In contrast, moderate water deficit particularly increased non-photochemical quenching (NPQ) in Xinhai 21. Our results suggest that Xinluzao 45 relied on enhanced electron transport such as photorespiration and the Mehler reaction to dissipate excess light energy under mild and moderate water deficit. Xinhai 21 used enhanced photorespiration for light energy utilisation under mild water deficit but, when subjected to moderate water deficit, possessed a high capacity for dissipating excess light energy via heat dissipation.

scholarly journals RETRACTED ARTICLE: Increased biomass productivity in green algae by tuning non-photochemical quenching

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Silvia Berteotti ◽  
Matteo Ballottari ◽  
Roberto Bassi
Keyword(s):  
Heat Dissipation ◽  
Biomass Productivity ◽  
Growth Conditions ◽  
Complex Stress ◽  
Biofuel Production ◽  
Photochemical Quenching ◽  
Protein Accumulation ◽  
Potential Productivity ◽  
Wide Range ◽  
Non Photochemical Quenching

Abstract Photosynthetic microalgae have a high potential for the production of biofuels and highly valued metabolites. However, their current industrial exploitation is limited by a productivity in photobioreactors that is low compared to potential productivity. The high cell density and pigment content of the surface layers of photosynthetic microalgae result in absorption of excess photons and energy dissipation through non-photochemical quenching (NPQ). NPQ prevents photoinhibition, but its activation reduces the efficiency of photosynthetic energy conversion. In Chlamydomonas reinhardtii, NPQ is catalyzed by protein subunits encoded by three lhcsr (light harvesting complex stress related) genes. Here, we show that heat dissipation and biomass productivity depends on LHCSR protein accumulation. Indeed, algal strains lacking two lhcsr genes can grow in a wide range of light growth conditions without suffering from photoinhibition and are more productive than wild-type. Thus, the down-regulation of NPQ appears to be a suitable strategy for improving light use efficiency for biomass and biofuel production in microalgae.

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