Thermostability and Photostability of Photosystem II of the Resurrection Plant Haberlea rhodopensis Studied by Chlorophyll Fluorescence

2006 ◽  
Vol 61 (3-4) ◽  
pp. 234-240 ◽  
Author(s):  
Katya Georgieva ◽  
Liliana Maslenkova
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Quantum Yield ◽  
Photochemical Efficiency ◽  
Resurrection Plant ◽  
Haberlea Rhodopensis ◽  
Photochemical Efficiency Of Psii ◽  
Light Intensities ◽  
Psii Photochemistry ◽  
Quantum Yield Of Psii

The stability of PSII in leaves of the resurrection plant Haberlea rhodopensis to high temperature and high light intensities was studied by means of chlorophyll fluorescence measurements. The photochemical efficiency of PSII in well-hydrated Haberlea leaves was not significantly influenced by temperatures up to 40 °C. F0 reached a maximum at 50 °C, which is connected with blocking of electron transport in reaction center II. The intrinsic efficiency of PSII photochemistry, monitored as Fv/Fm was less vulnerable to heat stress than the quantum yield of PSII electron transport under illumination (ΦPSII). The reduction of ΦPSII values was mainly due to a decrease in the proportion of open PSII centers (qP). Haberlea rhodopensis was very sensitive to photoinhibition. The light intensity of 120 μmol m−2 s−1 sharply decreased the quantum yield of PSII photochemistry and it was almost fully inhibited at 350 μmol m−2 s−1. As could be expected decreased photochemical efficiency of PSII was accompanied by increased proportion of thermal energy dissipation, which is considered as a protective effect regulating the light energy distribution in PSII. When differentiating between the three components of qN it was evident that the energy-dependent quenching, qE, was prevailing over photoinhibitory quenching, qI, and the quenching related to state 1-state 2 transitions, qT, at all light intensities at 25 °C. However, the qE values declined with increasing temperature and light intensities. The qI was higher than qE at 40 °C and it was the major part of qN at 45 °C, indicating a progressing photoinhibition of the photosynthetic apparatus.

scholarly journals Seasonal Variation in Diurnal Photosynthesis and Chlorophyll Fluorescence of Four Genotypes of Cassava (Manihot esculenta Crantz) under Irrigation Conditions in a Tropical Savanna Climate

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 206 ◽  
Author(s):  
Supranee Santanoo ◽  
Kochaphan Vongcharoen ◽  
Poramate Banterng ◽  
Nimitr Vorasoot ◽  
Sanun Jogloy ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Rainy Season ◽  
Genotypic Variation ◽  
Effective Quantum Yield ◽  
Tropical Savanna ◽  
Psii Photochemistry ◽  
Diurnal Photosynthesis ◽  
Hot Season ◽  
Quantum Yield Of Psii

Photosynthesis performance during early vegetative growth is an important physiological trait determining yield of cassava, but limited information is currently available for the tropical savanna climate of Asia. Diurnal photosynthesis and chlorophyll fluorescence of the three-month-old plants of four commercial cassava genotypes (Rayong 9, RY9; Rayong 11, RY11; Kasetsart 50, KU50 and CMR38-125-77) grown under irrigation, were investigated in three seasons i.e., rainy, cool and hot. The mean daily net photosynthetic rate (Pn) across genotypes in the rainy season (11.75 µmolCO2/m2/s) was significantly lower than that in the cool season (14.60 µmolCO2/m2/s). Daily mean Pn in the hot season was 14.32 µmolCO2/m2/s. In the rainy season, maximum photochemical quantum yield of PSII (Fv/Fm) and effective quantum yield of PSII photochemistry (ΦPSII) were significantly higher than the other seasons, while electron transfer rate (ETR) and non-photochemical quenching (NPQ) were significantly lower. Genotypic variation was observed during the hot season in which RY11 had the highest and CMR38-125-77 the lowest mean daily Pn. The prominent mechanism to avoid damages from stress during afternoon in the hot season was to reduce leaf temperature by enhancing transpiration for RY11; to close stomata early for RY9, and to increase NPQ for CMR38-125-77.

scholarly journals THE INFLUENCE OF BIO-ALGEEN S90 ON THE GROWTHOF MULTIFLORA ROSE SEEDLINGS (Rosa multiflora Thunb.)

2019 ◽  
Vol 18 (3) ◽  
pp. 35-43
Author(s):  
Mariusz Szmagara ◽  
Krystyna Pudelska ◽  
Wojciech Durlak ◽  
Barbara Marcinek ◽  
Kamila Rojek
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photochemical Efficiency ◽  
Morphological Characteristics ◽  
Rosa Multiflora ◽  
Plant Growth And Development ◽  
Agent Based ◽  
Photochemical Efficiency Of Psii ◽  
Stimulate Plant Growth ◽  
Maximum Photochemical Efficiency ◽  
Natural Agent

Striving to intensify horticultural production, new and more effective bio-preparations are being sought to stimulate plant growth and development. Bio-algeen S90 is a natural agent based on sea algae, the high bi- ological activity of which results from the high content of natural growth regulators. The aim of the study was to verify the influence of Bio-algeen S90 on the growth, morphological characteristics and chlorophyll fluorescence of Rosa multiflora seedlings. The bio-preparation was applied one, two and three times at con- centrations: 0.1, 0.2, 0.4 and 0.6 mg.dm−3. Following parameters were measured to evaluate the response of plants to the bio-preparation: F0 – initial fluorescence, Fm – maximal fluorescence in the dark-adapted state, Fv/Fm – maximum photochemical efficiency of PSII. All concentrations of the bio-preparation and frequency of its application stimulated the number of shoots in a bush, the length of shoots and the diameter of the root crown of plants intended for budding. The most beneficial was the two-fold bio-preparation application at a concentration of 0.4 mg.dm–3. Bio-algeen also positively influenced the chlorophyll fluorescence parame- ters. The highest mean F0 and Fm values were recorded with the two-fold preparation treatment. There was no significant effect of the bio-preparation on the Fv/Fm index, which was within the range of 0.75–0.66.

scholarly journals Chlorophyll fluorescence response of wheat to exogenous application of growth regulators under terminal drought stress

2015 ◽  
Vol 70 (1) ◽  
pp. 13
Author(s):  
Hamid Mohammadi ◽  
Mohsen Janmohammadi ◽  
Naser Sabaghnia
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Electron Transport ◽  
Quantum Yield ◽  
Photochemical Quenching ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Exogenous Application ◽  
Terminal Drought ◽  
Terminal Drought Stress

<p>Drought stress negatively affects plant photosynthesis and disturbs the electron transport activity. Evaluation of the chlorophyll fluorescence parameters might reflect influence of the environmental stress on plants and can be applied as an indicator of the primary photochemistry of photosynthesis. In current study the effect of foliar application of benzylaminopurine (BAP, a synthetic cytokinin) and abscisic acid (ABA) on chlorophyll fluorescence parameters of relatively drought tolerant (Pishtaz) and susceptible (Karaj3) bread wheat genotypes under well watered and terminal water deficit condition have been evaluated. Terminal drought was induced by withholding water at anthesis stage (Zadoks scale 65). Results showed that coefficient of non-photochemical quenching of variable fluorescence (qN), quantum yield of PS II photochemistry (ΦPSII) and photochemical quenching (qP) were affected by hormone spray treatments. So that evaluation of parameters at 7 day after foliar treatments revealed that ABA significantly increased electron transport rate (ETR) and qN while considerably decreased ΦPSII, gs and maximum quantum yield of photosystem II (Fv/Fm). However exogenous application of cytokinin could increase gs, Fv/Fm and ΦPSII and the highest value of these parameters was recorded in <em>cytokinin </em>treated plants of Pishtaze cv. under well watered condition. Nevertheless, evaluation of the parameters in different periods after spraying showed that with approaching the maturity stage some traits like as gs, Fv/Fm and ETR significantly decreased in both genotypes. Evaluation of gs and Chlorophyll fluorescence parameters of genotypes between different irrigation levels showed that although cv. Pishtaz showed higher performance of PSII under well watered condition, it failed to maintain its superiority under stress condition. This finding suggests that some more responsive parameter like gs, Fv/Fm and ΦPSII can be considered as reliable indicator for understanding the biochemical and physiological effects of exogenous application of phytohormones under terminal drought stress.</p>

scholarly journals Allelopathic effect of the Baltic picocyanobacterium Synechococcus sp. on selected diatoms

2017 ◽  
Author(s):  
Zofia Konarzewska ◽  
Sylwia Śliwińska-Wilczewska ◽  
Adam Latała
Keyword(s):  
Quantum Yield ◽  
Algal Blooms ◽  
Allelopathic Effect ◽  
Effective Quantum Yield ◽  
Fluorescence Parameters ◽  
Psii Photochemistry ◽  
Synechococcus Sp ◽  
The Baltic ◽  
Allelopathic Interactions ◽  
Quantum Yield Of Psii

It is commonly believed that the structure of phytoplankton and the formation of cyanobacterial and algal blooms may be explained by allelopathic interactions. The main aim of this study was to investigate the allelopathic effect of picocyanobacterium Synechococcus sp. on the following growth and fluorescence parameters: the maximum quantum yield of PSII photochemistry (Fv/Fm), and the effective quantum yield of PSII photochemistry (ΦPSII) of selected diatoms – Nitzschia fonticola, Fistulifera saprophila, Navicula perminuta and Amphora coffeaeformis. In this study, it was demonstrated that picocyanobacterium caused allelopathic effects against Baltic diatoms. The results showed that the addition of cell-free filtrate from Synechococcus sp. increased the number of cells of N. fonticola and F. saprophila. Moreover, it was found that picocyanobacterium was stimulated fluorescence parameters of N. fonticola, F. saprophila, and N. perminuta. On the other hand, it was noted that filtrate obtained from picocyanobacterium caused the inhibition of Fv/Fm parameter of A. coffeaeformis. The results of this experiment may provide further information about allelopathic interactions between Baltic picocyanobacteria and diatoms that are crucial to the understanding of algal blooms in aquatic ecosystems.

scholarly journals Irradiance and nutrient-dependent effects on photosynthetic electron transport in Arctic phytoplankton: A comparison of two chlorophyll fluorescence-based approaches to derive primary photochemistry

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0256410
Author(s):  
Yayla Sezginer ◽  
David J. Suggett ◽  
Robert W. Izett ◽  
Philippe D. Tortell
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Electron Transport Rate ◽  
Photochemical Efficiency ◽  
Photosynthetic Electron Transport ◽  
Marine Phytoplankton ◽  
Transport Rate ◽  
Variable Fluorescence ◽  
Primary Photochemistry ◽  
Electron Transport Rates

We employed Fast Repetition Rate fluorometry for high-resolution mapping of marine phytoplankton photophysiology and primary photochemistry in the Lancaster Sound and Barrow Strait regions of the Canadian Arctic Archipelago in the summer of 2019. Continuous ship-board analysis of chlorophyll a variable fluorescence demonstrated relatively low photochemical efficiency over most of the cruise-track, with the exception of localized regions within Barrow Strait, where there was increased vertical mixing and proximity to land-based nutrient sources. Along the full transect, we observed strong non-photochemical quenching of chlorophyll fluorescence, with relaxation times longer than the 5-minute period used for dark acclimation. Such long-term quenching effects complicate continuous underway acquisition of fluorescence amplitude-based estimates of photosynthetic electron transport rates, which rely on dark acclimation of samples. As an alternative, we employed a new algorithm to derive electron transport rates based on analysis of fluorescence relaxation kinetics, which does not require dark acclimation. Direct comparison of kinetics- and amplitude-based electron transport rate measurements demonstrated that kinetic-based estimates were, on average, 2-fold higher than amplitude-based values. The magnitude of decoupling between the two electron transport rate estimates increased in association with photophysiological diagnostics of nutrient stress. Discrepancies between electron transport rate estimates likely resulted from the use of different photophysiological parameters to derive the kinetics- and amplitude-based algorithms, and choice of numerical model used to fit variable fluorescence curves and analyze fluorescence kinetics under actinic light. Our results highlight environmental and methodological influences on fluorescence-based photochemistry estimates, and prompt discussion of best-practices for future underway fluorescence-based efforts to monitor phytoplankton photosynthesis.

scholarly journals Changes in Photo-Protective Energy Dissipation of Photosystem II in Response to Beneficial Bacteria Consortium in Durum Wheat under Drought and Salinity Stresses

2020 ◽  
Vol 10 (15) ◽  
pp. 5031 ◽  
Author(s):  
Mohammad Yaghoubi Khanghahi ◽  
Sabrina Strafella ◽  
Carmine Crecchio
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Durum Wheat ◽  
Photochemical Quenching ◽  
Plant Growth Promoting Bacteria ◽  
Psii Photochemistry ◽  
Non Photochemical Quenching

The present research aimed at evaluating the harmless dissipation of excess excitation energy by durum wheat (Triticum durum Desf.) leaves in response to the application of a bacterial consortium consisting of four plant growth-promoting bacteria (PGPB). Three pot experiments were carried out under non-stress, drought (at 40% field capacity), and salinity (150 mM NaCl) conditions. The results showed that drought and salinity affected photo-protective energy dissipation of photosystem II (PSII) increasing the rate of non-photochemical chlorophyll fluorescence quenching (NPQ (non-photochemical quenching) and qCN (complete non-photochemical quenching)), as well as decreasing the total quenching of chlorophyll fluorescence (qTQ), total quenching of variable chlorophyll fluorescence (qTV) and the ratio of the quantum yield of actual PSII photochemistry, in light-adapted state to the quantum yield of the constitutive non-regulatory NPQ (PQ rate). Our results also indicated that the PGPB inoculants can mitigate the adverse impacts of stresses on leaves, especially the saline one, in comparison with the non-fertilized (control) treatment, by increasing the fraction of light absorbed by the PSII antenna, PQ ratio, qTQ, and qTV. In the light of findings, our beneficial bacterial strains showed the potential in reducing reliance on traditional chemical fertilizers, in particular in saline soil, by improving the grain yield and regulating the amount of excitation energy.

scholarly journals Differences in photosynthetic capacity, chlorophyll fluorescence, and antioxidant system between invasive Alnus formosana and its native congener in response to different irradiance levels

Botany ◽  
2016 ◽  
Vol 94 (12) ◽  
pp. 1087-1101 ◽  
Author(s):  
Shi-liang Liu ◽  
Rong-jie Yang ◽  
Bo Ren ◽  
Mao-hua Wang ◽  
Ming-dong Ma
Keyword(s):  
Invasive Species ◽  
Chlorophyll Fluorescence ◽  
Antioxidant System ◽  
Photosynthetic Rate ◽  
Native Species ◽  
Antioxidant Activities ◽  
Photochemical Efficiency ◽  
High Irradiance ◽  
Invasion Success ◽  
Photochemical Efficiency Of Psii

We compared the invasive Alnus formosana (Burk.) Makino with its native congener (Alnus cremastogyne Burk.) at three irradiances in terms of photosynthesis, chlorophyll fluorescence, and antioxidant system. The increased light-saturated photosynthetic rate (Amax) and light saturation point (LSP) contributed directly to the increased performance of the invasive. The invasive species had also higher plasticity in carotenoid and total chlorophyll than the native species at 100% irradiance, potentially contributing to invasion success in high-irradiance locations via photoprotection. Moreover, the diurnal photoinhibition of photosynthesis, as judged by the maximum photochemical efficiency of PSII (Fv/Fm) of dark-adapted leaves, was more severe in the native species than in the invasive species. With increasing irradiance, the invasive exhibited increased antioxidant activities and higher antioxidant levels to support the adverse conditions of both low- and high-irradiance acclimation. In contrast, the intercellular CO2 concentration (Ci) and stomatal limitation (Ls) decreased with increases in the net photosynthetic rate (An), stomatal conductance (Gs), and transpiration rate (Tr). We speculated that Ls was the main factor inhibiting the An for both studied species. These results first indicated that the invasive may occupy new habitats successfully through tolerating shading at low irradiance and out-compete native species through higher Amax and antioxidant levels when irradiance is increased.

scholarly journals Salt stress change chlorophyll fluorescence in mango

2012 ◽  
Vol 34 (4) ◽  
pp. 1245-1255 ◽  
Author(s):  
Cicero Cartaxo de Lucena ◽  
Dalmo Lopes de Siqueira ◽  
Hermínia Emilia Prieto Martinez ◽  
Paulo Roberto Cecon
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Early Detection ◽  
Leaf Area ◽  
Photochemical Efficiency ◽  
Leaf Abscission ◽  
Hoagland Solution ◽  
Mango Tree

This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs)/(Fm')], D = (1- Fv'/Fm') and ETR = (ΦPSII×PPF×0,84×0,5) were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm) were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.

Quantitative Mapping of Leaf Photosynthesis Using Chlorophyll Fluorescence Imaging

1995 ◽  
Vol 22 (2) ◽  
pp. 277 ◽  
Author(s):  
B Genty ◽  
S Meyer
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Quantum Yield ◽  
Co2 Assimilation ◽  
Linear Electron ◽  
Leaf Photosynthesis ◽  
Heterogeneous Distribution ◽  
Fluorescence Measurements ◽  
Wide Range ◽  
Photochemical Yield

A method has been developed for routine, non-invasive monitoring of the topography of leaf photochemistry. The method uses video images of leaf chlorophyll fluorescence, taken during steady-state photosynthesis and during a transitory saturation of photochemistry, to construct, pixel by pixel, an image of the photochemical yield of photosystem II (PSII). The photochemical yield of PSII was estimated according to Genty et al. (1989) (Biochimica et Biophysica Acta 990, 87-92). The effectiveness of the method was shown by mapping the heterogeneous distribution of photosynthetic activity after treatment with either a herbicide (DCMU), abscisic acid, or during the course of the induction of photosynthesis. Leaf CO2 assimilation was simultaneously monitored under non- photorespiratory conditions to estimate the average quantum yield of linear electron transport. A unique proportional relationship was found between the mean photochemical yield of PSII calculated from images of the photochemical yield of PSII, and the average quantum yield of linear electron transport in three plant species exposed to a wide range of treatments or conditions. This new ability to quantitatively visualise leaf photochemistry provides a powerful tool to probe the spatial distribution of leaf photosynthesis. Possible errors in estimating the photochemical yield of PSII from mean fluorescence measurements are discussed.

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