scholarly journals Derivation of an electron-transport rate equation, energy-conservation equations and a luminescence-flux equation of algal and plant photosynthesis

1978 ◽  
Vol 174 (2) ◽  
pp. 569-577 ◽  
Author(s):  
Y S Li
Keyword(s):  
Electron Transport ◽  
Energy Conservation ◽  
Water Splitting ◽  
Rate Equation ◽  
Ad Hoc ◽  
Electron Transport Rate ◽  
Photosynthetic Electron Transport ◽  
Primary Electron ◽  
Transport Rate ◽  
Conservation Equations

On the assumption that the photosynthetic electron-transport rate is sometimes limited on the water-splitting side of Q (the oxidized primary electron acceptor), and that Q reduction, as well as primary charge recombination, is not kinetically a monomolecular process, a rate equation, a luminescence-flux equation and several versions of energy-conservation equations are derived. The energy-conservation equations explain most, if not all, observed relationships between rate and fluorescence. In particular, by assuming that the limiting site on the water-splitting side of Q is uncoupler-sensitive, these equations explain the uncoupler-induced simultaneous stimulations of rate and fluorescence as well as inhibition of luminescence without additional assumption ad hoc for each individual phenomenon. A newly introduced parameter central to the derivation of these equations is the specific affinity between two electron carriers.

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.

Micronutrient homeostasis and chloroplast iron protein expression is largely maintained in a chloroplast copper transporter mutant

2020 ◽  
Vol 47 (12) ◽  
pp. 1041 ◽  
Author(s):  
Gretchen E. Kroh ◽  
Marinus Pilon
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Electron Transport Rate ◽  
Photosynthetic Electron Transport ◽  
Metal Homeostasis ◽  
Transport Rate ◽  
Fe Deficiency ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Cu Homeostasis

PAAI is a P-Type ATPase that functions to import copper (Cu) into the chloroplast. Arabidopsis thaliana (L.) Heynh. paa1 mutants have lowered plastocyanin levels, resulting in a decreased photosynthetic electron transport rate. In nature, iron (Fe) and Cu homeostasis are often linked and it can be envisioned that paa1 acclimates its photosynthetic machinery by adjusting expression of its chloroplast Fe-proteome, but outside of Cu homeostasis paa1 has not been studied. Here, we characterise paa1 ultrastructure and accumulation of electron transport chain proteins in a paa1 allelic series. Furthermore, using hydroponic growth conditions, we characterised metal homeostasis in paa1 with an emphasis on the effects of Fe deficiency. Surprisingly, the paa1 mutation does not affect chloroplast ultrastructure or the accumulation of other photosynthetic electron transport chain proteins, despite the strong decrease in electron transport rate. The regulation of Fe-related photosynthetic electron transport proteins in response to Fe status was maintained in paa1, suggesting that regulation of the chloroplast Fe proteins ignores operational signals from photosynthetic output. The characterisation of paa1 has revealed new insight into the regulation of expression of the photosynthetic electron transport chain proteins and chloroplast metal homeostasis and can help to develop new strategies for the detection of shoot Fe deficiency.

Measurement of Primary Productivity of Phytoplankton Based on Photosynthetic Electron Transport Rate

2018 ◽  
Vol 38 (11) ◽  
pp. 1126001
Author(s):  
陈双 Chen Shuang ◽  
殷高方 Yin Gaofang ◽  
赵南京 Zhao Nanjing ◽  
覃志松 Qin Zhisong ◽  
张小玲 Zhang Xiaoling ◽  
...  
Keyword(s):  
Electron Transport ◽  
Primary Productivity ◽  
Electron Transport Rate ◽  
Photosynthetic Electron Transport ◽  
Transport Rate

The OsPS1-F gene regulates growth and development in rice by modulating photosynthetic electron transport rate

2017 ◽  
Vol 37 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Rengasamy Ramamoorthy ◽  
Bhushan Vishal ◽  
Srinivasan Ramachandran ◽  
Prakash P. Kumar
Keyword(s):  
Electron Transport ◽  
Growth And Development ◽  
Electron Transport Rate ◽  
Photosynthetic Electron Transport ◽  
Transport Rate ◽  
F Gene

Photosynthetic electron transport rate (ETR) in the littoral herb Launaea sarmentosa known as mole crab in Thailand

2021 ◽  
Author(s):  
Raymond J. Ritchie ◽  
Suhailar Sma-Air ◽  
Napapit Limsathapornkul ◽  
Nedrangsee Pranama ◽  
Meakha Nakkeaw ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Transport Rate ◽  
Photosynthetic Electron Transport ◽  
Transport Rate
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