Optimising the linear electron transport rate measured by chlorophyll a fluorescence to empirically match the gross rate of oxygen evolution in white light: towards improved estimation of the cyclic electron flux around photosystem I in leaves

2018 ◽  
Vol 45 (11) ◽  
pp. 1138 ◽  
Author(s):  
Meng-Meng Zhang ◽  
Da-Yong Fan ◽  
Guang-Yu Sun ◽  
Wah Soon Chow
Keyword(s):  
Chlorophyll A ◽  
Oxygen Evolution ◽  
Photosystem I ◽  
Chlorophyll A Fluorescence ◽  
Near Infrared ◽  
Electron Flux ◽  
Linear Electron ◽  
Total Electron ◽  
Gross Rate

The cyclic electron flux (CEF) around photosystem I (PSI) was discovered in isolated chloroplasts more than six decades ago, but its quantification has been hampered by the absence of net formation of a product or net consumption of a substrate. We estimated in vivo CEF in leaves as the difference (ΔFlux) between the total electron flux through PSI (ETR1) measured by a near infrared signal, and the linear electron flux through both photosystems by optimised measurement of chlorophyll a fluorescence (LEFfl). Chlorophyll fluorescence was excited by modulated green light from a light-emitting diode at an optimal average irradiance, and the fluorescence was detected at wavelengths >710 nm. In this way, LEFfl matched the gross rate of oxygen evolution multiplied by 4 (LEFO2) in broad-spectrum white actinic irradiance up to half (spinach, poplar and rice) or one third (cotton) of full sunlight irradiance. This technique of estimating CEF can be applied to leaves attached to a plant.

Metabolic control of photosynthetic electron transport in crassulacean acid metabolism-induced Mesembryanthemum crystallinum

2002 ◽  
Vol 29 (6) ◽  
pp. 697 ◽  
Author(s):  
Mark Aurel Schöttler ◽  
Helmut Kirchhoff ◽  
Engelbert Weis ◽  
Katharina Siebke
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Crassulacean Acid Metabolism ◽  
Acid Metabolism ◽  
Electron Flux ◽  
Photosynthetic Electron Transport ◽  
Mesembryanthemum Crystallinum ◽  
Phase Iii ◽  
Linear Electron

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. We investigated photosynthetic electron transport in leaves of the facultative crassulacean acid metabolism (CAM) plant Mesembryanthemum crystallinum L. After CAM induction, electron transport exhibited variable redox kinetics during the diurnal CAM cycle. In CAM Phase IV, most of PSI (P700) and chlorophyll a fluorescence relaxed with a halftime of 20 ms after a saturating light pulse. This time-constant may reflect the overall linear electron flux from PSII to PSI in saturating light. Comparable relaxation kinetics were also determined for C3 plants. At the end of CAM Phase I and during Phase II, slow components (> 50% of signal amplitude) appeared in both P700 reduction and fluorescence relaxation. They displayed halftimes > 250 ms and > 1 s, suggesting a strong restriction of the linear electron flux from H2O to NADP. The appearance of the slow redox components was accompanied by a decrease in the Fv/Fm ratio of chlorophyll a fluorescence, suggesting a reversible detachment of light-harvesting complex (LHC) II from PSII. The slow redox fractions and the depression of Fv/Fm disappeared again in parallel to malate decarboxylation during CAM Phase III. We discuss a reversible downregulation of linear electron flux during CAM Phases II and III, due to a reversible deprivation of cytochrome-b6f complexes (cyt-bfs) and PSI from the linear system. In parallel, a redistribution of some LHCIIs could also occur. This could be an adaptive response to a reduced metabolic demand for NADPH due to a limited carbon flux through the Calvin cycle, resulting from low Rubisco activation. Furthermore, the cyt-bfs and PSIs deprived of linear electron transport could support cyclic electron flux to cover an increased ATP demand during gluconeogenesis in CAM Phase III.

scholarly journals SENSITIVITY TO ENVIRONMENTAL STRESS OF PRATA,JAPIRA AND VITÓRIA BANANA CULTIVARS PROVEN BY CHLOROPHYLL a FLUORESCENCE

2017 ◽  
Vol 39 (2) ◽  
Author(s):  
PRISCILA NOBRES DOS SANTOS ◽  
DIOLINA MOURA SILVA ◽  
CAMILLA ZANOTTI GALLON ◽  
JOSÉ AIRES VENTURA
Keyword(s):  
Environmental Stress ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Physiological Responses ◽  
Fluorescence Emission ◽  
Conservation Of Energy ◽  
Post Harvest ◽  
Mda Content ◽  
Two Stages

ABSTRACT This study aimed to evaluate the physiological responses to environmental stress during pre- and post-harvest of the following banana cultivars: Prata (AAB), Japira (AAAB) and Vitoria (AAAB). Analyses were carried out on young plants at vegetative stage (daughter-plant) and adult plants at reproductive stage (motherplant). The experimental design was completely randomized. In the in vivo pre-harvest analysis were used seven replications, in a factorial scheme (3x2x2), three cultivars and two stages (vegetative and reproductive) and two collection periods (March and June). For the analysis of post-harvest quality were used five replications in a factorial design (3x2x5), corresponding to three cultivars, two development stages and five periods of post-harvest analysis, carried out every two days from stage 4 of fruit ripening. The chlorophyll a fluorescence emission kinetics showed low photochemical performance of the three cultivars in June, a period characterized by lower temperatures and water deficit. Prata was the cultivar with the lowest tolerance to abiotic physiological behavior changes, which also reflected in fruit quality, because there was a change in physical and physicochemical parameters. Japira and Vitoria cultivars showed similar physiological responses in the pre- and post-harvest periods, according to their phylogenetic proximity. The total performance index, i.e., the conservation of energy absorbed by PSII up to the reduction of the final PSI acceptors (PItotal) and the di-malonic aldehyde (MDA) content were significantly higher in Japira and Vitoria cultivars compared to Prata cultivar in the reproductive phase. There was no significant change in the potential quantum efficiency of PSII (FV / FM = jP0) among the three cultivars. It was concluded that Japira and Vitoria cultivars showed greater plasticity to tolerate or even adapt to abiotic variations keeping higher fruit yield. PItotal is the most sensitive parameter during the banana life cycle and important tool for distinguishing different cultivars yields.

scholarly journals In Vivo Assessment of Cold Tolerance through Chlorophyll-a Fluorescence in Transgenic Zoysiagrass Expressing Mutant Phytochrome A

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0127200 ◽  
Author(s):  
Mayank Anand Gururani ◽  
Jelli Venkatesh ◽  
Markkandan Ganesan ◽  
Reto Jörg Strasser ◽  
Yunjeong Han ◽  
...  
Keyword(s):  
Cold Tolerance ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Phytochrome A ◽  
In Vivo Assessment

Chlorella fusca (Chlorophyta) grown in thin-layer cascades: Estimation of biomass productivity by in-vivo chlorophyll a fluorescence monitoring

2016 ◽  
Vol 17 ◽  
pp. 21-30 ◽  
Author(s):  
Celia G. Jerez ◽  
José R. Malapascua ◽  
Magda Sergejevová ◽  
Jiří Masojídek ◽  
Félix L. Figueroa
Keyword(s):  
Thin Layer ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Biomass Productivity ◽  
Chlorella Fusca

The Effect of Deoxycholate-Treatment to the Photoreactions of the Active Pigments in Photosynthesis

1976 ◽  
Vol 31 (1-2) ◽  
pp. 64-67 ◽  
Author(s):  
Günter Döring
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Electron Flow ◽  
Heavy Fraction ◽  
Sodium Ascorbate ◽  
Linear Electron ◽  
System P ◽  
Heat Treated ◽  
Donor System

Abstract In the heavy fraction of deoxycholate-treated spinach chloroplasts the chlorophyll an activity is high and the chlorophyll aI activity is low when no artificial electron donor is added. The addition of the photosystem I donor system N-methyl-phenazonium sulphate plus sodium ascorbate (PMS + Asc) leads to a complete reactivation of the chlorophyll aI reaction. The addition of the photo­system II donor system p-benzohydroquinone plus sodium ascorbate (HQ + Asc) leads to an inhibition of the chlorophyll aII activity. From these results we conclude: 1. Besides an interruption of the linear electron flow between the two photosystems deoxycholate-treatment leads to a block of the electron flow from water to photosystem II. 2. In deoxycholate-treated chloroplasts the linear electron flow in photosystem II just like in Triswashed, heat-treated or aged chloroplasts, is replaced by a cyclic one.

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