Biometrical parameters, pigment content and functional characteristics of photosynthetic apparatus of Bistortavivipara within the territory of West Spitsbergen

2016 ◽  
Vol 6 (1) ◽  
pp. 1-12
Author(s):  
Eugenia Fedorovna Markovskaya ◽  
Natalya Yurievna Shmakova ◽  
Elena Valentinovna Novichonok
Keyword(s):  
Fluorescence Quenching ◽  
Photosynthetic Pigment ◽  
Photosynthetic Apparatus ◽  
Fluorescence Yield ◽  
Pigment Content ◽  
Photochemical Quenching ◽  
Protective Mechanism ◽  
Plant Structure ◽  
Ps Ii ◽  
West Spitsbergen

In the present paper, the results of the research of biometric and functional parameters of photosynthetic apparatus of Bistorta vivipara from West Spitsbergen are presented and discussed. A high intraspecific variability of biometric parameters (linear dimensions and biomass) was found. The differences found in biomass suggest that biological productivity is associated with the functional activity of the plant individuals. A direct dependence of the biomass on the photosynthetic pigment content per unit dry mass of leaf has been revealed. A high variability of non-photochemical fluorescence quenching (NPQ), basic fluorescence yield (F0), maximal fluorescence yield (FM) and variable fluorescence yield (FV) have been shown contrastingly to relatively constant values of the maximum photochemical quantum yield of PS II (FV/FM) and the coefficient of photochemical fluorescence quenching (qP). Close-to-theoretical-maximum FV/FM values indicated the absence of stress conditions and the presence of regulation systems in chloroplastic photosynthetic apparatus (PA) level functioning during varying microclimate parameters of the daily climate. The relatively constant qP indicated the same photosynthetic activity of the B. vivipara leaves, unaffected by the varying weather conditions. The NPQ data suggest that the non-photochemical quenching acts as a protective mechanism, sustaining the PA in an optimally active state and reducing probability of negative changes to PSII. The revealed high PA adaptability at the level of the plant structure and light-dependent reactions of photosynthesis makes it possible for B. vivipara to develop at a high functional level at various values of environmental factors, which provides for the successful growth of the species in the high Arctic region. The high PA flexibility suggests that B. vivipara is capable of active adaptation in the context of the forecast climate change.

Eco-physiological peculiarities of Stellaria humifusa in West Spitsbergen

2019 ◽  
Vol 9 (2) ◽  
pp. 152-159
Author(s):  
Eugenia Fedorovna Markovskaya ◽  
Elena Valentinovna Novichonok ◽  
Natalya Yurievna Shmakova
Keyword(s):  
Quantum Yield ◽  
Rapid Development ◽  
Photosynthetic Apparatus ◽  
Thick Layer ◽  
Sharp Decrease ◽  
Stress Factors ◽  
Carotenoid Content ◽  
Photochemical Quenching ◽  
Ps Ii ◽  
West Spitsbergen

In the present paper, the results of the research of biometric parameters and functional peculiarities of photosynthetic apparatus of Stellaria humifusa in West Spitsbergen are discussed. The study showed that the largest proportion of the mat is composed of a brown layer of dead leaves covering the assimilative organs (about 70%). Green leaves and shoots accounted for about 20%, whereas generative organs – for about 10% of the mat mass. The values of the maximum photochemical quantum yield of PS II (FV/FM) in all the studied plants were lower than the optimal values (0.83), which suggests that the plants are exposed to stress factors. The low values of chlorophyll and carotenoid content and relatively high values of the light-harvesting complex (70-80%), the sharp decrease in the quantum yield of PS II (FPSII) entailed by a marginal increase in PPFD indicative of a sufficiently high of photochemical activity within the range of low and medium values of light. It also suggests that Stellaria humifusa is well-adapted to the shaded conditions created in the mat. Besides, a considerable decrease the maximum fluorescence yield of a light-adapted leaf (FM´) at increasing PPFD was observed, which suggests that Stellaria humifusa has a well-developed mechanism of energy dissipation via the non-photochemical (NPQ) pathway. The rapid development of NPQ gives reason to assume that, under high light conditions, non-photochemical quenching is likely to serve as the main mechanism for preventing the photodamage of the photosynthetic apparatus. Thus, it was shown that the photosynthetic apparatus of Stellaria humifusa works efficiently under the conditions created in the mat, and the thick layer of dead leaves covering the assimilative organs, on the one hand, protects them from excessive light, and on the other hand, absorbs thermal energy, which raises temperature of the local habitat.

scholarly journals Leaf Gas Exchange and Chlorophyll a Fluorescence Imaging of Rice Leaves Infected with Monographella albescens

2015 ◽  
Vol 105 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Sandro Dan Tatagiba ◽  
Fábio Murilo DaMatta ◽  
Fabrício Ávila Rodrigues
Keyword(s):  
Gas Exchange ◽  
Fluorescence Imaging ◽  
Leaf Gas Exchange ◽  
Photosynthetic Pigment ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
Photochemical Quenching ◽  
Chl A ◽  
Chl A Fluorescence ◽  
Rice Leaves

This study was intended to analyze the photosynthetic performance of rice leaf blades infected with Monographella albescens by combining chlorophyll (Chl) a fluorescence images with gas exchange and photosynthetic pigment pools. The net CO2 assimilation rate, stomatal conductance, transpiration rate, total Chl and carotenoid pools, and Chl a/b ratio all decreased but the internal CO2 concentration increased in the inoculated plants compared with their noninoculated counterparts. The first detectable changes in the images of Chl a fluorescence from the leaves of inoculated plants were already evident at 24 h after inoculation (hai) and increased dramatically as the leaf scald lesions expanded. However, these changes were negligible for the photosystem II photochemical efficiency (Fv/Fm) at 24 hai, in contrast to other Chl fluorescence traits such as the photochemical quenching coefficient, yield of photochemistry, and yield for dissipation by downregulation; which, therefore, were much more sensitive than the Fv/Fm ratio in assessing the early stages of fungal infection. It was also demonstrated that M. albescens was able to impair the photosynthetic process in both symptomatic and asymptomatic leaf areas. Overall, it was proven that Chl a fluorescence imaging is an excellent tool to describe the loss of functionality of the photosynthetic apparatus occurring in rice leaves upon infection by M. albescens.

scholarly journals Energy-Saving LED Light Affects the Efficiency of the Photosynthetic Apparatus and Carbohydrate Content in Gerbera jamesonii Bolus ex Hook. f. Axillary Shoots Multiplied In Vitro

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1035
Author(s):  
Monika Cioć ◽  
Krzysztof Tokarz ◽  
Michał Dziurka ◽  
Bożena Pawłowska
Keyword(s):  
Energy Saving ◽  
Sugar Content ◽  
Photosynthetic Apparatus ◽  
Photochemical Quenching ◽  
Gerbera Jamesonii ◽  
Axillary Shoots ◽  
Glucose Content ◽  
Ps Ii ◽  
Led Light

An energy-saving light emitting diode (LED) system allows for adjustment of light quality, which affects plant development and metabolic processes in in vitro cultures. The study investigated the content of endogenous carbohydrates and the condition of the photosynthetic apparatus of Gerbera jamesonii Bolus ex Hook. f. Our aim was to analyze the effects of different LED light qualities—100% red light (R LED), 100% blue (B LED), a mixture of red and blue (7:3) (RB LED), and a fluorescent lamp as a control (Fl)—during the multiplication of axillary shoots. After 40 days, the culture measurements were performed using a non-invasive pulse amplitude modulation (PAM) fluorimeter. Sugar content was assessed with high performance liquid chromatography (HPLC). Two forms of free monosaccharides (glucose and fructose), two sugar alcohol derivatives (inositol and glycerol), and seven forms of free oligosaccharides were identified. Of those, glucose content was the highest. LEDs did not disturb the sugar metabolism in multiplied shoots. Their monosaccharides were three times more abundant than oligosaccharides; the same results were found in plants grown under control light. R light depleted the performance of the photosynthetic apparatus and caused its permanent damage. The RB LED spectrum ensured the most efficient non-photochemical quenching of the photosystem II (PS II) excitation state and high shoot quality.

Characterisation of Three Components of Non-photochemical Fluorescence Quenching and Their Response to Photoinhibition

1988 ◽  
Vol 15 (2) ◽  
pp. 163 ◽  
Author(s):  
B Demmig ◽  
K Winter
Keyword(s):  
Fluorescence Quenching ◽  
Heat Dissipation ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
Nerium Oleander ◽  
Photochemical Quenching ◽  
Ps Ii ◽  
Fluorescence Characteristics ◽  
Non Photochemical Quenching ◽  
Three Components

Three components of non-photochemical fluorescence quenching were distinguished according to their response to irradiance and to their relaxation kinetics upon darkening. Two components of quenching were restricted to excessive irradiance and were interpreted to reflect radiationless dissipation. One relaxed rapidly upon darkening, and increased sharply when irradiance became excessive, i.e. as soon as net CO2 assimilation rate was no longer linearly related to irradiance, and attained a maximum value with only small further increases in irradiance. The second component relaxed slowly, increased mark- edly when the rapidly relaxing component had reached its maximum, and continued to increase linearly with increasing irradiance. The third component was already present at low irradiances, relaxed very slowly, and may be related to an altered distribution of excitation energy between PS II and PS I. Following exposure to weak illumination under conditions preventing photosynthetic electron transport (20 mbar O2, zero CO2), the reduction state of Q was initially high and decreased as non- photochemical fluorescence quenching indicative of radiationless dissipation developed. Subsequent to photoinhibitory treatments in high light and 20 mbar O2, zero CO2, an increased reduction state of Q as well as increased non-photochemical quenching of the two types indicative of increased heat dissipation was observed. In sunflower a lasting increase in the reduction state of Q was observed and fluorescence characteristics reflected photoinhibitory damage. In Nerium oleander, increased radiationless dissipation of the slowly relaxing type was the predominant response and the reduction state of Q was increased only transiently.

scholarly journals PHOTOPROTECTIIVE STRATEGIES OF UNICELULAR RED ALGA RHODELLA VIOLACEA DURING ACCLIMATION TO STRONG LIGHT

2020 ◽  
Vol 3 (11(80)) ◽  
pp. 31-38
Author(s):  
K. Neverov
Keyword(s):  
Fluorescence Quenching ◽  
Red Algae ◽  
Molecular Mechanisms ◽  
Light Exposure ◽  
Photosynthetic Apparatus ◽  
Water Soluble ◽  
Photochemical Quenching ◽  
Strong Light ◽  
Rhodella Violacea ◽  
Chl Fluorescence

Red algae contain in their photosynthetic machinery water-soluble antenna complexes - phycobilisomes (PBSs) attached to thylakoid membranes to transfer excitation energy to photosystems. Strong light absorbed by the PBSs triggers a fast formation of transthylakoid ΔpH that follows the non-photochemical quenching of chlorophyll (Chl) fluorescence. The ΔpH build-up seems to be essential for photoprotecting the photosynthetic apparatus in the absence of xanthophyll cycle common to higher plants. However, the photoprotective mechanisms of red algae are not studied in details yet.  We present here our research of the Chl fluorescence quenching in unicellular red algae Rhodella violacea and its correlation with the ΔpH gradient being formed. The relation of this phenomenon to photoprotection of photosystem 2 (PS 2) in the normal and high light-acclimated Rhodella cells is also examined.  Under the photoinhibitory conditions (white light of 2000-3000 μE/m2s), the ΔpH-dependent Chl fluorescence quenching was found to delay the kinetics of PS 2 photoinhibition. The uncouplers like nigericin and NH4Cl are known to break down ΔpH gradient, lead to the dissipation of Chl fluorescence quenching followed by enhancing the PS 2 photoinhibition rate. The same effect showed far-red (FR) light consuming transthylakoid ΔpH. ATPase inhibitor, DCCD, having no impact on ΔpH didn’t influence PS 2 photoinhibition as well this implies the photoprotection to be fulfilled by the proton gradient rather than by ATP synthesis.  Long-term acclimation of Rhodella cells to higher irradiances (500-1000 μE/m2s) results in a partial loss of the periphery phycoerythrin-containing subunits by PBSs. The light-acclimated cultures display a higher resistance to the photoinhibitory light than the non-acclimated ones. This could be explained by diminishing the energy transfer from the reduced PBSs to PS 2 as well as light screening by the secondary carotenoids synthesized during light exposure.  Data on low-temperature (77K) fluorescence allow to evaluate the molecular mechanisms of light-induced Chl fluorescence suppression in Rhodella cells and its recovery in darkness. 

High Light Acclimated Developing Primary Leaves of Wheat Seedlings Generate Signal for Stress Adaptation through Super Oxide Dismutase

2018 ◽  
Vol 4 (02) ◽  
pp. 68-73
Author(s):  
Sandip Kumar Behera ◽  
Geetgovind Sinam ◽  
Lalitendu Nayak ◽  
Padmanav Joshi ◽  
Basanti Biswal
Keyword(s):  
Osmotic Stress ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Protective Mechanism ◽  
Oxygen Species ◽  
Sod Activity ◽  
Wheat Seedlings ◽  
Ps Ii ◽  
Super Oxide Dismutase

Wheat seedlings grown in petri dishes were acclimated to high light during their development and subsequently were subjected to osmotic stress by application of polyethylene glycol (PEG). The photochemical efficiency of photosystem II (PS II) of the acclimated seedlings was found to be higher than that of non-acclimated ones under osmotic stress during senescence. The damage of the photosynthetic apparatus seems to be mediated by reactive oxygen species. The higher level of lutein (Lut) and superoxide dismutase (SOD) activity in acclimated seedlings suggest their involvement in the protective mechanism. The senescing leaves, although in a deteriorating phase, exhibit tolerance to osmotic stress due to the adaptation potential acquired earlier during high light (HL) acclimation.

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 Phytotoxicity of Silver Nanoparticles on Tobacco Plants: Evaluation of Coating Effects on Photosynthetic Performance and Chloroplast Ultrastructure

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 744
Author(s):  
Petra Peharec Štefanić ◽  
Karla Košpić ◽  
Daniel Mark Lyons ◽  
Lara Jurković ◽  
Biljana Balen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Inhibitory Effects ◽  
Tobacco Plants ◽  
Agriculture And Food ◽  
The Impact

Silver nanoparticles (AgNPs) are the most exploited nanomaterial in agriculture and food production, and their release into the environment raises concern about their impact on plants. Since AgNPs are prone to biotransformation, various surface coatings are used to enhance their stability, which may modulate AgNP-imposed toxic effects. In this study, the impact of AgNPs stabilized with different coatings (citrate, polyvinylpyrrolidone (PVP), and cetyltrimethylammonium bromide (CTAB)) and AgNO3 on photosynthesis of tobacco plants as well as AgNP stability in exposure medium have been investigated. Obtained results revealed that AgNP-citrate induced the least effects on chlorophyll a fluorescence parameters and pigment content, which could be ascribed to their fast agglomeration in the exposure medium and consequently weak uptake. The impact of AgNP-PVP and AgNP-CTAB was more severe, inducing a deterioration of photosynthetic activity along with reduced pigment content and alterations in chloroplast ultrastructure, which could be correlated to their higher stability, elevated Ag accumulation, and surface charge. In conclusion, intrinsic properties of AgNP coatings affect their stability and bioavailability in the biological medium, thereby indirectly contributing changes in the photosynthetic apparatus. Moreover, AgNP treatments exhibited more severe inhibitory effects compared to AgNO3, which indicates that the impact on photosynthesis is dependent on the form of Ag.

scholarly journals Environmental effects on photosynthetic capacity of bean genotypes

2004 ◽  
Vol 39 (7) ◽  
pp. 615-623 ◽  
Author(s):  
Rafael Vasconcelos Ribeiro ◽  
Mauro Guida dos Santos ◽  
Gustavo Maia Souza ◽  
Eduardo Caruso Machado ◽  
Ricardo Ferraz de Oliveira ◽  
...  
Keyword(s):  
High Temperature ◽  
Natural Condition ◽  
Temperature Effects ◽  
Environmental Changes ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Co2 Assimilation ◽  
Fluorescence Yield ◽  
Environmental Condition ◽  
Response Curves

Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and controlled conditions for Guarumbé and 'Ouro Negro', the lower photosynthetic capacity of these genotypes under natural condition seems to be caused by high temperature effects on biochemical reactions, as suggested by increased alternative electron sinks. The highest g s values of 'Carioca' were observed at controlled condition, providing evidences that reduction of photosynthetic capacity at natural condition was due to low g s in addition to the high temperature effects on the photosynthetic apparatus. 'Carioca' exhibited the highest photosynthetic rates under optimum environmental condition, and was more affected by daily changes of air temperature and leaf-to-air vapor pressure difference.

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