An optimised method for correcting quenched fluorescence yield

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.

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Acclimation of Tobacco Leaves to High Light Intensity Drives the Plastoquinone Oxidation System—Relationship Among the Fraction of Open PSII Centers, Non-Photochemical Quenching of Chl Fluorescence and the Maximum Quantum Yield of PSII in the Dark

Plant and Cell Physiology ◽

10.1093/pcp/pcp032 ◽

2009 ◽

Vol 50 (4) ◽

pp. 730-743 ◽

Cited By ~ 35

Author(s):

Chikahiro Miyake ◽

Katsumi Amako ◽

Naomasa Shiraishi ◽

Toshio Sugimoto

Keyword(s):

Quantum Yield ◽

Light Intensity ◽

High Light Intensity ◽

High Light ◽

Photochemical Quenching ◽

Maximum Quantum Yield ◽

Non Photochemical Quenching ◽

Quantum Yield Of Psii ◽

Oxidation System ◽

Chl Fluorescence

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Roles of OsSOQ1 in photoprotection and fatty acid metabolism of rice

10.21203/rs.3.rs-273323/v1 ◽

2021 ◽

Author(s):

Zhen-Hui Kang ◽

Yang Gou ◽

Qi-Rui Deng ◽

Zi-yu Hu ◽

Guan-Rong Li

Keyword(s):

Fatty Acid ◽

Light Intensity ◽

Fatty Acid Metabolism ◽

Acid Metabolism ◽

Function Analysis ◽

Photochemical Efficiency ◽

High Light Intensity ◽

High Light ◽

Redox Activity ◽

Photochemical Quenching

Abstract Presented here is the function analysis of a homolog of Arabidopsis SOQ1, OsSOQ1 in rice. Homozygous mutants (ossoq1) were obtained by CRISPR/Cas9 to knockout OsSOQ1. The mutants showed significant lower plant height, tiller number, panicle length, effective panicle, and grain number per panicle compared to the wild-type (WT). Western blot analysis showed that OsSOQ1 is a thylakoid membrane protein, with the thioredoxin-like (Trx-like) domain facing the lumen. Loss of OsSOQ1 did not significantly affect the protein level of photosystem II (PSII) subunits, but down-regulated the content of a non-photochemical quenching (NPQ) player PsbS, resulting in a low NPQ under high light intensity in the mutant. UPLC-MS/MS experiments showed that OsSOQ1 is involved in the fatty acid biosynthesis pathway of rice. The Trx-like domain possessed redox activity in vitro as shown by insulin assay; and in the yeast two-hybrid experiment, it was found that the Trx-like domain interacted with the chloroplast lipocalin OsLCNP, which usually binds lipid molecules. These findings revealed that the role of OsSOQ1 is to maintain the photochemical efficiency of PSII under high light intensity and regulate fatty acid metabolism in rice.

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Characteristics of Photosynthesis in Different Wheat Cultivars under High Light Intensity and High Temperature Stresses

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2008.02196 ◽

2009 ◽

Vol 34 (12) ◽

pp. 2196-2201 ◽

Cited By ~ 3

Author(s):

Xue-Li QI ◽

Lin HU ◽

Hai-Bin DONG ◽

Lei ZHANG ◽

Gen-Song WANG ◽

...

Keyword(s):

High Temperature ◽

Light Intensity ◽

High Light Intensity ◽

High Light ◽

Wheat Cultivars ◽

Temperature Stresses

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Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽

10.21273/hortsci.33.3.541a ◽

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.

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Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

Energy Procedia ◽

10.1016/j.egypro.2017.09.307 ◽

2017 ◽

Vol 124 ◽

pp. 331-337 ◽

Cited By ~ 1

Author(s):

Amir Abdallah ◽

Ounsi El Daif ◽

Brahim Aïssa ◽

Maulid Kivambe ◽

Nouar Tabet ◽

...

Keyword(s):

Solar Cell ◽

High Temperature ◽

Light Intensity ◽

High Light Intensity ◽

High Light ◽

Heterojunction Solar Cell ◽

Cell Configuration ◽

Silicon Heterojunction Solar Cell

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Gradual Response of Cyanobacterial Thylakoids to Acute High-Light Stress—Importance of Carotenoid Accumulation

Cells ◽

10.3390/cells10081916 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1916

Author(s):

Myriam Canonico ◽

Grzegorz Konert ◽

Aurélie Crepin ◽

Barbora Šedivá ◽

Radek Kaňa

Keyword(s):

Single Cell ◽

Thylakoid Membrane ◽

Intermediate Phase ◽

Light Stress ◽

Fast Response ◽

High Light ◽

Photochemical Quenching ◽

Second Phase ◽

Ros Scavenging ◽

Non Photochemical Quenching

Light plays an essential role in photosynthesis; however, its excess can cause damage to cellular components. Photosynthetic organisms thus developed a set of photoprotective mechanisms (e.g., non-photochemical quenching, photoinhibition) that can be studied by a classic biochemical and biophysical methods in cell suspension. Here, we combined these bulk methods with single-cell identification of microdomains in thylakoid membrane during high-light (HL) stress. We used Synechocystis sp. PCC 6803 cells with YFP tagged photosystem I. The single-cell data pointed to a three-phase response of cells to acute HL stress. We defined: (1) fast response phase (0–30 min), (2) intermediate phase (30–120 min), and (3) slow acclimation phase (120–360 min). During the first phase, cyanobacterial cells activated photoprotective mechanisms such as photoinhibition and non-photochemical quenching. Later on (during the second phase), we temporarily observed functional decoupling of phycobilisomes and sustained monomerization of photosystem II dimer. Simultaneously, cells also initiated accumulation of carotenoids, especially ɣ–carotene, the main precursor of all carotenoids. In the last phase, in addition to ɣ-carotene, we also observed accumulation of myxoxanthophyll and more even spatial distribution of photosystems and phycobilisomes between microdomains. We suggest that the overall carotenoid increase during HL stress could be involved either in the direct photoprotection (e.g., in ROS scavenging) and/or could play an additional role in maintaining optimal distribution of photosystems in thylakoid membrane to attain efficient photoprotection.

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