scholarly journals Photosynthesis sensitivity to NH4+-N change with nitrogen fertilizer type

2014 ◽  
Vol 60 (No. 6) ◽  
pp. 274-279 ◽  
Author(s):  
A. Nasraoui-Hajaji ◽  
H. Gouia
Keyword(s):  
Net Photosynthesis ◽  
Dry Weight ◽  
N Fertilization ◽  
Photochemical Quenching ◽  
Negative Effects ◽  
Ps Ii ◽  
Chl A ◽  
Inhibitory Site ◽  
Tomato Growth ◽  
Non Photochemical Quenching

N-fertilization type affected differently tomato growth. In the field experiment, hydroponic cultures were conducted using NO<sub>3</sub>-N (5 mmol); mixture of KNO<sub>3</sub>-N (3 mmol) and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>-N (2 mmol); NH<sub>4</sub><sup>+</sup>-N (5 mmol) or urea&nbsp;(5 mmol) as nitrogen source. Compared to nitrate, ammonium and urea had negative effects on morphology and dry matter production. Effects of the different nitrogen forms were investigated by measuring several photosynthesis parameters and chl a fluorescence. Two different significant types of reaction were found. When nitrogen was added as ammonium or urea, dry weight, chlorophyll tenor, transpiration rate, stomatal conductance and photosynthetic activity were inhibited. Supply of ammonium or urea, reduced the ratio (F<sub>v</sub>/F<sub>m</sub>), photochemical quenching and enhanced the non photochemical quenching. These data suggest that the adverse decrease in tomato growth under ammonium or urea supply may be related principally to inhibition of net photosynthesis activity. The high non photochemical quenching shown in tomato fed with ammonium or urea indicated that PS II was the inhibitory site of NH<sub>4</sub><sup>+</sup>-N which was directly uptaken by roots, or librated via urea hydrolysis cycle.

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.

Salt stress resilience potential of a fungal inoculant isolated from tea cultivation area in maize

Biologia ◽  
2017 ◽  
Vol 72 (6) ◽  
Author(s):  
Nuran Durmus ◽  
Abdullah Muhammed Yesilyurt ◽  
Necla Pehlivan ◽  
Sengul Alpay Karaoglu
Keyword(s):  
Salt Stress ◽  
Water Status ◽  
Cost Effective ◽  
Nacl Stress ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Stress Resilience ◽  
Ps Ii ◽  
Tea Plants ◽  
Non Photochemical Quenching

AbstractAgriculture needs to be sustained by organic processes in current era as population explosion energy and the number of individuals undernourished are raising public concerns. Global warming poses additional threat by lifting the damage of salt stress especially in agro-economically vital crops like maize whose cultivation dates back to Mayans. To that end, cost-effective and organic fungal agents may be great candidates in stress resilience. We isolated the fungal strain from the soil of tea plants and characterized that via 5.8 S rDNA gene with internal transcribed spacer ITS-1 and ITS-2 regions, then named the target strain as TA. Reduced maximum quantum efficiency of PS II (Fv/Fm), the effective quantum yield of PS2 (ΦPS2), electron transport rate (ETR), photochemical quenching (qP) and increased non-photochemical quenching (NPQ) were detected in maize plants stressed with dose dependent salt. Enhanced Fv/Fm, ΦPS2, ETR, qP and decreased NPQ was observed in TA primed plus NaCl treated plants. TA biopriming significantly increased the lengths, fresh and dry weights of root/shoots and decreased the lipid peroxidation. Maize seedlings bioprimed with TA had less MDA and higher soluble protein, proline, total chlorophyll, carotenoid and RWC under NaCl. Furthermore, SOD, GPX and GR activities were much more increased in root and leaves of TA primed seedlings, however CAT activity did not significantly change. This is the first report to our knowledge that TA reverses the damage of NaCl stress on maize growth through improving water status, antioxidant machinery and especially photosynthetic capacity.

An Arabidopsis thaliana mutant, altered in the γ-subunit of ATP synthase, has a different pattern of intensity-dependent changes in non-photochemical quenching and kinetics of the P-to-S fluorescence decay

2002 ◽  
Vol 29 (4) ◽  
pp. 425 ◽  
Author(s):  
Govindjee ◽  
Paul Spilotro
Keyword(s):  
Arabidopsis Thaliana ◽  
Xanthophyll Cycle ◽  
Fluorescence Decay ◽  
Coupling Factor ◽  
Photochemical Quenching ◽  
Wild Type ◽  
Marked Rise ◽  
Chl A ◽  
Chl A Fluorescence ◽  
Non Photochemical Quenching

A major photoprotective mechanism that plants employ against excess light involves interplay between the xanthophyll cycle and the accumulation of protons. Using mutants in the xanthophyll cycle, the roles of violaxanthin, antheraxanthin and zeaxanthin have already been well established. In this paper, we present data on intact leaves of a mutant [coupling factor quick recovery mutant (cfq); atpC1:E244K] of Arabidopsis thaliana that we expected, based on 515-nm absorbance changes (Gabrys et al. 1994, Plant Physiology 104, 769–776), to have differences in light-induced ΔpH. The significance of this paper is: (i) it is the first study of the photoprotective energy dissipation involving a mutant of the pH gradient; it establishes that protons play an important role in the pattern of non-photochemical quenching (NPQ) of chlorophyll (Chl) a fluorescence; and (ii) differences between the cfq and the wild type (wt) are observed only under subsaturating light intensities, and are strongest in the initial few minutes of the induction period. Our results on light-intensity dependent Chl* a fluorescence transients (the Kautsky effect), and on NPQ of Chl a fluorescence, at 50–250 μmol photons m–2 s–1 demonstrate: (i) the ‘P-to-S’ (or ‘T’) decay, known to be related to [H+] (Briantais et al. 1979, Biochimica et Biophysica Acta 548, 128–138), is slowed in the mutant; and (ii) the pattern of NPQ kinetics is different in the initial 100 s — in the wt leaves, there is a marked rise and decline, and in the cfq mutant, there is a slowed rise. These differences are absent at 750 μmol photons m–2 s–1. Pre-illumination and nigericin (an uncoupler that dissipates the proton gradient) treatment of the cfq mutant, which has lower ΔpH relative to wild type, confirm the conclusion that protons play an important role in the quenching of Chl a fluorescence.

scholarly journals Leaf gas exchange and chlorophyll index in guava fertirrigated with bovine biofertilizer and nitrogen

2020 ◽  
Vol 9 (9) ◽  
pp. e588997606
Author(s):  
Elisson Alves Santana ◽  
Francisco Eduardo dos Santos Gomes ◽  
Jackson Teixeira Lobo ◽  
Alberto de Andrade Soares Filho ◽  
Ítalo Herbert Lucena Cavalcante ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Psidium Guajava ◽  
N Fertilization ◽  
Chl A ◽  
Internal Co2 ◽  
Chlorophyll Index ◽  
Photosynthetic Responses

The objective of this work was to evaluate the influence of fertirrigation with nitrogen and liquid bovine biofertilizer on gas exchange and leaf chlorophyll index of 'paluma' guava (Psidium guajava L.). The experimental design was randomized blocks with treatments distributed in a factorial arrangement (2 × 4) referring to mineral fertilizing with N (50% and 100% of N recommended) and biofertilizer concentrations (0, 2.5, 5.0 and 7.5% of the fertirrigated volume). Variables evaluated were chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll indexes (Chltotal), internal CO2 concentration (Ci), stomatal conductance (gs), transpiration (E), net photosynthesis (A), instant carboxylation efficiency (iCE) and water use efficiency (WUE). The biofertilizer significantly affected Chl a, Chl b, Chltotal, A, gs and E, with quadratic polynomial adjustment of the results. However, there was no effect of N fertilization and interaction between the factors. Maximum index of Chltotal was 32.31 obtained with the estimated dose of 3.8% of the biofertilizer; while A, gs and E presented maximum responses of 19.09 µmol of CO2 m-2 s-1, 0.28 mol of H2O m-2 s-1 and 4.93 mmol of H2O m-2 s-1, with estimated doses of 3.6%, 3.6%, and 3.7%, respectively. Generally, liquid bovine biofertilizer applied via fertirrigation affects positively the photosynthetic responses in 'paluma' guava, however, with decreasing effects for doses above 3.8%.

scholarly journals Allosteric regulation of the light-harvesting system of photosystem II

2000 ◽  
Vol 355 (1402) ◽  
pp. 1361-1370 ◽  
Author(s):  
Peter Horton ◽  
Alexander V. Ruban ◽  
Mark Wentworth
Keyword(s):  
Photosystem Ii ◽  
Xanthophyll Cycle ◽  
Light Harvesting ◽  
Allosteric Regulation ◽  
Photochemical Quenching ◽  
Protein Subunit ◽  
Ps Ii ◽  
Non Photochemical Quenching

Non–photochemical quenching of chlorophyll fluorescence (NPQ) is symptomatic of the regulation of energy dissipation by the light–harvesting antenna of photosystem II (PS II). The kinetics of NPQ in both leaves and isolated chloroplasts are determined by the transthylakoid ΔpH and the de–epoxidation state of the xanthophyll cycle. In order to understand the mechanism and regulation of NPQ we have adopted the approaches commonly used in the study of enzyme–catalysed reactions. Steady–state measurements suggest allosteric regulation of NPQ, involving control by the xanthophyll cycle carotenoids of a protonationdependent conformational change that transforms the PS II antenna from an unquenched to a quenched state. The features of this model were confirmed using isolated light–harvesting proteins. Analysis of the rate of induction of quenching both in vitro and in vivo indicated a bimolecular second–order reaction; it is suggested that quenching arises from the reaction between two fluorescent domains, possibly within a single protein subunit. A universal model for this transition is presented based on simple thermodynamic principles governing reaction kinetics.

Effects of short-term low temperature stress on chlorophyll fluorescence transients in Antarctic lichen species

2016 ◽  
Vol 6 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Michaela Marečková ◽  
Miloš Barták
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Temperature Effects ◽  
Photochemical Quenching ◽  
Short Term ◽  
Ps Ii ◽  
Species Specific ◽  
Non Photochemical Quenching ◽  
Fluorescence Transients ◽  
Chlorophyll Fluorescence Transients

Chlorophyll fluorescence is an effective tool for investigating characteristics of any photosynthesizing organisms and its responses due to different stressors. Here, we have studied a short-term temperature response on two Antarctic green algal lichen species: Umbilicaria antarctica, and Physconia muscigena. We measured slow chlorophyll fluorescence transients in the species during slow a cooling of thallus temperature from 20°C to 5°C with a 10 min. acclimation at each temperature in dark. The measurements were supplemented with saturation pulses for the analysis of chlorophyll fluorescence parameters: maximum yield of PS II photochemistry (FV/FM), effective quantum yield of PS II photochemistry (FPSII) and non-photochemical quenching (NPQ). In response to decreasing thallus temperature, we observed species-specific changes in chlorophyll fluorescence levels P, S, M, T reached during chlorophyll fluorescence transient as well as in the shape of the chlorophyll fluorescence transients. With a decrease in temperature, the time at which M and T chlorophyll fluorescence levels were reached, increased. These changes were attributed to redox state of plastoquinon pool, changes in Calvin-Benson cycle activity, non-photochemical quenching components, state transition in particular. In this study, we present some chlorophyll fluorescence ratios (P/M, M/T, P/T) and chlorophyll fluorescence increase rates (FR1, i.e. O to P, and FR2 - i.e. S to M) as the parameters reflecting direct temperature effects on chloroplastic apparatus of lichen alga sensitively. We proposed that species-specific changes in the slow phase of chlorophyll fluorescence transients could be potentially used as indicators of low temperature effects in photosynthetic apparatus of lichen algal photobionts. Interspecific differences in response to low temperature might be evaluated using the approach as well.

scholarly journals Alteration of photosystem II properties with non-photochemical excitation quenching

2000 ◽  
Vol 355 (1402) ◽  
pp. 1405-1418 ◽  
Author(s):  
A. Laisk ◽  
V. Oja
Keyword(s):  
Photosystem Ii ◽  
Turnover Rate ◽  
Photochemical Quenching ◽  
Ps Ii ◽  
Single Turnover ◽  
Acceptor Side ◽  
Donor And Acceptor ◽  
Inhibitory Type ◽  
Non Photochemical Quenching ◽  
Oxygen Yield

Oxygen yield from single turnover flashes and multiple turnover pulses was measured in sunflower leaves differently pre–illuminated to induce either ‘energy–dependent type’ non–photochemical excitation quenching ( q E ) or reversible, inhibitory type non–photochemical quenching ( q I ). A zirconium O 2 analyser, combined with a flexible gas system, was used for these measurements. Oxygen yield from saturating single turnover flashes was the equivalent of 1.3–2.0 μmol e − m −2 in leaves pre–adapted to low light. It did not decrease when q E quenching was induced by a 1 min exposure to saturating light, but it decreased when pre–illumination was extended to 30–60 min. Oxygen evolution from saturating multiple turnover pulses behaved similarly: it did not decrease with the rapidly induced q E but decreased considerably when exposure to saturating light was extended or O 2 concentration was decreased to 0.4%. Parallel recording of chlorophyll fluorescence and O 2 evolution during multiple turnover pulses, interpreted with the help of a mathematical model of photosystem II (PS II) electron transport, revealed PS II donor and acceptor side resistances. These experiments showed that PS II properties depend on the type of non–photochemical quenching present. The rapidly induced and rapidly reversible q E type (photoprotective) quenching does not induce changes in the number of active PS II or in the PS II maximum turnover rate, thus confirming the antenna mechanism of q E. The more slowly induced but still reversible q I type quenching (photoinactivation) induced a decrease in the number of active PS II and in the maximum PS II turnover rate. Modelling showed that, mainly, the acceptor side resistance of PS II increased in parallel with the reversible q I. Oxygen yield from single turnover flashes and multiple turnover pulses was measured in sunflower leaves differently pre–illuminated to induce either ‘energy–dependent type’ non–photochemical excitation quenching ( q E ) or reversible, inhibitory type non–photochemical quenching ( q I ). A zirconium O 2 analyser, combined with a flexible gas system, was used for these measurements. Oxygen yield from saturating single turnover flashes was the equivalent of 1.3–2.0 μmol e − m −2 in leaves pre–adapted to low light. It did not decrease when q E quenching was induced by a 1 min exposure to saturating light, but it decreased when pre–illumination was extended to 30–60 min. Oxygen evolution from saturating multiple turnover pulses behaved similarly: it did not decrease with the rapidly induced q E but decreased considerably when exposure to saturating light was extended or O 2 concentration was decreased to 0.4%. Parallel recording of chlorophyll fluorescence and O 2 evolution during multiple turnover pulses, interpreted with the help of a mathematical model of photosystem II (PS II) electron transport, revealed PS II donor and acceptor side resistances. These experiments showed that PS II properties depend on the type of non–photochemical quenching present. The rapidly induced and rapidly reversible q E type (photoprotective) quenching does not induce changes in the number of active PS II or in the PS II maximum turnover rate, thus confirming the antenna mechanism of q E. The more slowly induced but still reversible q I type quenching (photoinactivation) induced a decrease in the number of active PS II and in the maximum PS II turnover rate. Modelling showed that, mainly, the acceptor side resistance of PS II increased in parallel with the reversible q I.

scholarly journals Supermolecular structure of photosystem II and location of the PsbS protein

2000 ◽  
Vol 355 (1402) ◽  
pp. 1337-1344 ◽  
Author(s):  
Jon Nield ◽  
Christiane Funk ◽  
James Barber
Keyword(s):  
Three Dimensional ◽  
Supermolecular Structure ◽  
Dimensional Structure ◽  
Photochemical Quenching ◽  
Particle Analysis ◽  
Lhc Ii ◽  
Ps Ii ◽  
Improved Model ◽  
Non Photochemical Quenching ◽  
Psbs Protein

This paper addresses the question of whether the PsbS protein of photosystem two (PS II) is located within the LHC II–PS II supercomplex for which a three–dimensional structure has been obtained by cryoelectron microscopy and single particle analysis. The PsbS protein has recently been implicated as the site for non–photochemical quenching. Based both on immunoblotting analyses and structural considerations of an improved model of the spinach LHC II–PS II supercomplex, we conclude that the PsbS protein is not located within the supercomplex. Analyses of other fractions resulting from the solubilization of PS II–enriched membranes derived from spinach suggest that the PsbS protein is located in the LHC II–rich regions that interconnect the supercomplex within the membrane.

Physiological changes and UV protection in the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia along an altitudinal gradient of UV-B radiation

2006 ◽  
Vol 33 (11) ◽  
pp. 1025 ◽  
Author(s):  
María Arróniz-Crespo ◽  
Encarnación Núñez-Olivera ◽  
Javier Martínez-Abaigar ◽  
Hans Becker ◽  
Jochen Scher ◽  
...  
Keyword(s):  
Altitudinal Gradient ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Secondary Compounds ◽  
Photochemical Quenching ◽  
Physiological Variables ◽  
Linear Relationships ◽  
Spatial Changes ◽  
Uv Absorbing Compounds ◽  
Non Photochemical Quenching

Here we report the effects of a natural altitudinal gradient of UV-B radiation, from 1140 to 1816 m altitude, on the physiology of the aquatic liverwort Jungermannia exsertifolia Steph. subsp. cordifolia (Dumort.) Váña collected in mountain streams. Photosynthetic pigments, net photosynthesis and dark respiration rates, chlorophyll fluorescence, protein concentration, sclerophylly, and UV-absorbing compounds [both global UV absorbance of methanol-extractable UV-absorbing compounds (MEUVAC) and concentrations of five individual compounds] were measured. Two new caffeic acid derivatives were discovered: 5″-(7″,8″-dihydroxycoumaroyl)-2-caffeoylmalic acid and 5″-(7″,8″-dihydroxy-7-O-β-glucosyl-coumaroyl)-2-caffeoylmalic acid, whereas three additional compounds were already known in other species: p-coumaroylmalic acid, phaselic acid (both compounds in their cis- and trans- forms) and feruloylmalic acid. Most physiological variables changed considerably along the altitudinal gradient, but only six showed significant linear relationships with altitude: MEUVAC levels, the concentrations of the two new secondary compounds, the maximal apparent electron transport rate through PSII (ETRmax) and the maximal non-photochemical quenching (NPQmax) increased with altitude, whereas photoinhibition percentage decreased. A principal components analysis (PCA) was conducted to rank the values of the physiological and ecological variables obtained along the altitudinal transect, showing that those variables correlated with altitude were responsible for the ordination of the sampling points. The liverwort was not adversely affected by the changing conditions along the altitudinal gradient and, in particular, by the increasing UV-B irradiance, probably because the characteristics shown by high-altitude populations may confer tolerance to high UV-B levels. The response to UV-B of the two new compounds suggests that they could be used as indicators of the spatial changes in UV-B radiation.

scholarly journals Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. II. Analysis of non-photochemical quenching mechanisms activated by low to medium light doses

2014 ◽  
Vol 4 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Petra Očenášová ◽  
Miloš Barták ◽  
Josef Hájek
Keyword(s):  
High Light ◽  
Photochemical Quenching ◽  
Ps Ii ◽  
Chlorophyll Fluorescence Parameters ◽  
Main Emphasis ◽  
James Ross Island ◽  
Quenching Mechanisms ◽  
Non Photochemical Quenching ◽  
Short Time ◽  
Energy Dependent

The paper focus sensitivity of an Antarctic lichen Usnea antarctica to photoinhibition studied under controlled laboratory conditions. Main emphasis was given to the analysis of quenching mechanisms, i.e. deexcitation pathways of absorbed light energy exploited in non-photochemical processes. Thalli of U. antarctica were collected at the James Ross Island, Antarctica (57°52´57´´ W, 63°48´02´´ S) and transferred in dry state to the Czech Republic. After rewetting in a laboratory, they were exposed to medium light intensities (300, 600 and 1000 mmol m-2 s-1 of photosynthetically active radiation) for 6 h. Before and during photoinhibitory treatments, chlorophyll fluorescence parameters, photoinhibitory (qI), state 1-2 transition (qT), and energy-dependent quenching (qE) in particular were measured to evaluate dose- and time-dependent changes in these parameters. The results showed that among the components forming non-photochemical quenching (qN), qI contributes to the largest extent to qN, while qE and qT contribute less. This finding differs from our earlier studies made in a short term-, and high light-treated U. antarctica that found qE together with qI is the most important part of non-photochemical quenching. Possible explanation is that photoinhibition in PS II in U. ant-arctica, when induced by low to medium light, activates qE to only limited extend and for a relatively short time (tens of minutes). With prolonged high light treatment lasting several hours, qE tends to be reduced to the values close to zero and qI then forms a major part of qN.

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