scholarly journals The quantitative contribution of different Photosystem II compartments to non-photochemical quenching in Arabidopsis

2021 ◽  
Author(s):  
Lauren Nicol ◽  
Vincenzo Mascoli ◽  
Herbert van Amerongen ◽  
Roberta Croce
Keyword(s):  
Photosystem Ii ◽  
Excitation Energy ◽  
Quantitative Description ◽  
Photosynthetic Apparatus ◽  
Intrinsic Rate ◽  
High Light Intensity ◽  
Photochemical Quenching ◽  
Irreversible Damage ◽  
Fluorescence Measurements ◽  
Non Photochemical Quenching

Excess excitation energy in the light-harvesting antenna of Photosystem II (PSII) can cause irreversible damage to the photosynthetic apparatus. In periods of high light intensity, a feedback mechanism known as non-photochemical quenching (NPQ), induces the formation of quenchers which can safely dissipate excess excitation energy as heat. Although quenchers have been identified in more than one compartment of the PSII supercomplex, there is currently no quantitative description of how much NPQ is occurring at each of these locations. Here, we perform time-resolved fluorescence measurements on WT and antenna mutants lacking LHCII (NoL) and all peripheral antenna (Ch1 and Ch1lhcb5). By combining the results with those of steady-state fluorescence experiments we are able to estimate the intrinsic rate of NPQ for each plant and each PSII compartment. It is concluded that 60-70% of quenching occurs in LHCII, 15-20% in the minor antenna and 15-20% in the PSII core.

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.

Dynamic quenching in single photosystem II supercomplexes

2016 ◽  
Vol 18 (37) ◽  
pp. 25852-25860 ◽  
Author(s):  
J. Michael Gruber ◽  
Pengqi Xu ◽  
Jevgenij Chmeliov ◽  
Tjaart P. J. Krüger ◽  
Maxime T. A. Alexandre ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Photochemical Quenching ◽  
Dynamic Quenching ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Non Photochemical Quenching

Time-resolved fluorescence measurements of single PSII supercomplexes to investigate blinking and dynamic quenching in the context of non-photochemical quenching (NPQ).

scholarly journals The carotenoid pathway: what is important for excitation quenching in plant antenna complexes?

2017 ◽  
Vol 19 (34) ◽  
pp. 22957-22968 ◽  
Author(s):  
Kieran F. Fox ◽  
Vytautas Balevičius ◽  
Jevgenij Chmeliov ◽  
Leonas Valkunas ◽  
Alexander V. Ruban ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Excitation Energy ◽  
Light Harvesting ◽  
High Light ◽  
Photochemical Quenching ◽  
Non Photochemical Quenching ◽  
Carotenoid Pathway

Plant light-harvesting is regulated by the Non-Photochemical Quenching (NPQ) mechanism involving the slow trapping of excitation energy by carotenoids in the Photosystem II (PSII) antenna in response to high light.

Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541a-541
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami ◽  
Patrick J. Breen
Keyword(s):  
High Light ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Free Radical Formation ◽  
Highly Correlated ◽  
Non Photochemical Quenching ◽  
Leaf N

Bench-grafted Fuji/M26 apple trees were fertigated with different concentrations of nitrogen by using a modified Hoagland solution for 6 weeks, resulting in a range of leaf N from 1.0 to 4.3 g·m–2. Over this range, leaf absorptance increased curvilinearly from 75% to 92.5%. Under high light conditions (1500 (mol·m–2·s–1), the amount of absorbed light in excess of that required to saturate CO2 assimilation decreased with increasing leaf N. Chlorophyll fluorescence measurements revealed that the maximum photosystem II (PSII) efficiency of dark-adapted leaves was relatively constant over the leaf N range except for a slight drop at the lower end. As leaf N increased, non-photochemical quenching under high light declined and there was a corresponding increase in the efficiency with which the absorbed photons were delivered to open PSII centers. Photochemical quenching coefficient decreased significantly at the lower end of the leaf N range. Actual PSII efficiency increased curvilinearly with increasing leaf N, and was highly correlated with light-saturated CO2 assimilation. The fraction of absorbed light potentially used for free radical formation was estimated to be about 10% regardless of the leaf N status. It was concluded that increased thermal dissipation protected leaves from photo-oxidation as leaf N declined.

scholarly journals An alternative method for correcting fluorescence quenching

Ocean Science ◽  
2015 ◽  
Vol 11 (1) ◽  
pp. 83-91 ◽  
Author(s):  
L. Biermann ◽  
C. Guinet ◽  
M. Bester ◽  
A. Brierley ◽  
L. Boehme
Keyword(s):  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Fluorescence Emission ◽  
Euphotic Zone ◽  
Light Level ◽  
High Light Intensity ◽  
Photochemical Quenching ◽  
Layer Depth ◽  
Southern Elephant Seals ◽  
Non Photochemical Quenching

Abstract. Under high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. We present data from the Southern Ocean, collected over five austral summers by 19 southern elephant seals tagged with fluorometers. Conventionally, fluorescence data collected during the day (quenched) were corrected using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, distinct deep fluorescence maxima were measured in approximately 30% of the night (unquenched) data. To account for the evidence that chlorophyll is not uniformly mixed in the upper layer, we propose correcting from the limit of the euphotic zone, defined as the depth at which photosynthetically available radiation is ~ 1% of the surface value. Mixed layer depth exceeded euphotic depth over 80% of the time. Under these conditions, quenching was corrected from the depth of the remotely derived euphotic zone Zeu, and compared with fluorescence corrected from the depth of the density-derived mixed layer. Deep fluorescence maxima were evident in only 10% of the day data when correcting from mixed layer depth. This was doubled to 21% when correcting from Zeu, more closely matching the unquenched (night) data. Furthermore, correcting from Zeu served to conserve non-uniform chlorophyll features found between the 1% light level and mixed layer depth.

scholarly journals Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 316 ◽  
Author(s):  
Elias Kaiser ◽  
Dirk Walther ◽  
Ute Armbruster
Keyword(s):  
Photosystem Ii ◽  
Chemical Potential ◽  
Genomic Variation ◽  
Operating Efficiency ◽  
Photochemical Quenching ◽  
Low Light ◽  
Trait Variation ◽  
Light Regimes ◽  
Fluctuating Light ◽  
Non Photochemical Quenching

The capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non-photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.

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