The difficulty of estimating the electron transport rate at photosystem I

Furutani, Riu; Ohnishi, Miho; Mori, Yuki; Wada, Shin‐Ichiro; Miyake, Chikahiro

doi:10.1007/s10265-021-01357-6

Cited by 16 publications

(11 citation statements)

References 54 publications

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“…Recently, the SP method was shown not to be fully reliable measure for a possible acceptor-side limitation of PSI as the steady-state concentration of P700 + may be influenced by electrons contributed from the PSII via the PQ pool 46 , 47 . Therefore, to determine steady-state P700 + , we exposed S and ES thylakoid membranes to six intermittent cycles of far-red (FR) light 48 in the presence of Antimycin A (Fig.…”

Section: Resultsmentioning

confidence: 99%

Flavodiiron-mediated O2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring

et al. 2023

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Green organisms evolve oxygen (O2) via photosynthesis and consume it by respiration. Generally, net O2 consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O2 consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O2 consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O2 photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.

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Section: Resultsmentioning

confidence: 99%

Flavodiiron-mediated O2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring

et al. 2023

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“…Although the double exponential model can be used to fit the ETR – I curve of algae, it needs to be coupled with modified exponential model to derive ETR max and I sat , and the obtained ETR max and I sat values are significantly higher than the measured values ( Maxwell and Johnson, 2000 ; Brading et al., 2011 ; Buckley and Diaz-Espejo, 2015 ). On the other hand, the YRS method not only effectively fits the ETR response curves of plants and algae to light but also shows no significant difference between the fitted ETR max and I sat values and the observation values ( Liang et al., 2018 ; Yang et al., 2018 ; Furutani et al., 2022 ). In this study, the results obtained using the YRS model for fitting also exhibit no significant difference from the observation values, further demonstrating the applicability and reliability of this model.…”

Section: Discussionmentioning

confidence: 99%

Investigation on absorption cross-section of photosynthetic pigment molecules based on a mechanistic model of the photosynthetic electron flow-light response in C3, C4 species and cyanobacteria grown under various conditions

Ye,

Stirbet,

et al. 2023

Front. Plant Sci.

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Investigation on intrinsic properties of photosynthetic pigment molecules participating in solar energy absorption and excitation, especially their eigen-absorption cross-section (σik) and effective absorption cross-section (σ′ik), is important to understand photosynthesis. Here, we present the development and application of a new method to determine these parameters, based on a mechanistic model of the photosynthetic electron flow-light response. The analysis with our method of a series of previously collected chlorophyll a fluorescence data shows that the absorption cross-section of photosynthetic pigment molecules has different values of approximately 10−21 m2, for several photosynthetic organisms grown under various conditions: (1) the conifer Abies alba Mill., grown under high light or low light; (2) Taxus baccata L., grown under fertilization or non-fertilization conditions; (3) Glycine max L. (Merr.), grown under a CO2 concentration of 400 or 600 μmol CO2 mol−1 in a leaf chamber under shaded conditions; (4) Zea mays L., at temperatures of 30°C or 35°C in a leaf chamber; (5) Osmanthus fragrans Loureiro, with shaded-leaf or sun-leaf; and (6) the cyanobacterium Microcystis aeruginosa FACHB905, grown under two different nitrogen supplies. Our results show that σik has the same order of magnitude (approximately 10−21 m2), and σ′ik for these species decreases with increasing light intensity, demonstrating the operation of a key regulatory mechanism to reduce solar absorption and avoid high light damage. Moreover, compared with other approaches, both σik and σ′ik can be more easily estimated by our method, even under various growth conditions (e.g., different light environment; different CO2, NO2, O2, and O3 concentrations; air temperatures; or water stress), regardless of the type of the sample (e.g., dilute or concentrated cell suspensions or leaves). Our results also show that CO2 concentration and temperature have little effect on σik values for G. max and Z. mays. Consequently, our approach provides a powerful tool to investigate light energy absorption of photosynthetic pigment molecules and gives us new information on how plants and cyanobacteria modify their light-harvesting properties under different stress conditions.

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“…The Y(I) was determined by Y(I) = Pm’/Pm. Pm and Pm’ are the maximal absorbance changes induced by applying the saturating light under dark and actinic light, respectively 70 .…”

Section: Methodsmentioning

confidence: 99%

Weak acids produced during anaerobic respiration suppress both photosynthesis and aerobic respiration

Nawrocki

Cardol

et al. 2023

Nat Commun

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While photosynthesis transforms sunlight energy into sugar, aerobic and anaerobic respiration (fermentation) catabolizes sugars to fuel cellular activities. These processes take place within one cell across several compartments, however it remains largely unexplored how they interact with one another. Here we report that the weak acids produced during fermentation down-regulate both photosynthesis and aerobic respiration. This effect is mechanistically explained with an “ion trapping” model, in which the lipid bilayer selectively traps protons that effectively acidify subcellular compartments with smaller buffer capacities – such as the thylakoid lumen. Physiologically, we propose that under certain conditions, e.g., dim light at dawn, tuning down the photosynthetic light reaction could mitigate the pressure on its electron transport chains, while suppression of respiration could accelerate the net oxygen evolution, thus speeding up the recovery from hypoxia. Since we show that this effect is conserved across photosynthetic phyla, these results indicate that fermentation metabolites exert widespread feedback control over photosynthesis and aerobic respiration. This likely allows algae to better cope with changing environmental conditions.

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The difficulty of estimating the electron transport rate at photosystem I

Cited by 16 publications

References 54 publications

Flavodiiron-mediated O2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring

Flavodiiron-mediated O2 photoreduction at photosystem I acceptor-side provides photoprotection to conifer thylakoids in early spring

Investigation on absorption cross-section of photosynthetic pigment molecules based on a mechanistic model of the photosynthetic electron flow-light response in C3, C4 species and cyanobacteria grown under various conditions

Weak acids produced during anaerobic respiration suppress both photosynthesis and aerobic respiration

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