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

Zhang, Mengmeng; Fan, Dayong; Guang-yu, Sun; Chow, Wah Soon

doi:10.1071/fp18039

Cited by 13 publications

(4 citation statements)

References 22 publications

(23 reference statements)

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“…We cannot eliminate the possibility that the lack of a change in CEF is due to a decrease of linear electron transport under FL, since ETR(II) also decreased (Figure 3b). In addition, it is difficult to estimate CEF by calculating ETR changes when plants are grown under a light intensity about 300 μmol photons m −2 s −1 because the ratio of CEF to LEF is very low (Zhang, Fan, Sun, & Chow, 2018). However, we found a rapidly disappearing PIR within 1 day of FL treatment, indicating a decrease of NDH‐CEF under FL conditions (Essemine et al, 2016; Figure 2g, Figure S8g).…”

Section: Discussionmentioning

confidence: 99%

Leaf photosynthetic and anatomical insights into mechanisms of acclimation in rice in response to long‐term fluctuating light

Wei

Duan

Sun

et al. 2020

Plant Cell & Environment

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Long‐term fluctuating light (FL) conditions are very common in natural environments. The physiological and biochemical mechanisms for acclimation to FL differ between species. However, most of the current conclusions regarding acclimation to FL were made based on studies in algae or Arabidopsis thaliana. It is still unclear how rice (Oryza sativa L.) integrate multiple physiological changes to acclimate to long‐term FL. In this study, we found that rice growth was repressed under long‐term FL. By systematically measuring phenotypes and physiological parameters, we revealed that: (a) under short‐term FL, photosystem I (PSI) was inhibited, while after 1–7 days of long‐term FL, both PSI and PSII were inhibited. Higher acceptor‐side limitation in electron transport and higher overall nonphotochemical quenching (NPQ) explained the lower efficiencies of PSI and PSII, respectively. (b) An increase in pH differences across the thylakoid membrane and a decrease in thylakoid proton conductivity revealed a reduction of ATP synthase activity. (c) Using electron microscopy, we showed a decrease in membrane stacking and stomatal opening after 7 days of FL treatment. Taken together, our results show that electron flow, ATP synthase activity and NPQ regulation are the major processes determining the growth performance of rice under long‐term FL conditions.

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Section: Discussionmentioning

confidence: 99%

Leaf photosynthetic and anatomical insights into mechanisms of acclimation in rice in response to long‐term fluctuating light

Wei

Duan

Sun

et al. 2020

Plant Cell & Environment

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“…Under low actinic irradiance (< 500 µmol photons m −2 s −1 ), Kou et al (2013a) showed that ETR2 can be equated to ; further, at low actinic irradiance, the matching of ETR2 with is independent of the spectral distribution of the excitation light (Zhang et al 2018). in the present study is the gross oxygen evolution rate during illumination recorded by MIMS multiplied by four (since four electrons are released for each oxygen molecule evolved).…”

Section: Methodsmentioning

confidence: 99%

Cyclic electron flow and light partitioning between the two photosystems in leaves of plants with different functional types

et al. 2019

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Cyclic electron flow (CEF) around photosystem I (PSI) is essential for generating additional ATP and enhancing efficient photosynthesis. Accurate estimation of CEF requires knowledge of the fractions of absorbed light by PSI (f I ) and PSII (f II ), which are only known for a few model species such as spinach. No measures of f I are available for C 4 grasses under different irradiances. We developed a new method to estimate (1) f II in vivo by concurrently measuring linear electron flux through both photosystems LEF O 2 in leaf using membrane inlet mass spectrometry (MIMS) and total electron flux through PSII (ETR2) using chlorophyll fluorescence by a Dual-PAM at low light and (2) CEF as ETR1-LEF O 2 . For a C 3 grass, f I was 0.5 and 0.4 under control (high light) and shade conditions, respectively. C 4 species belonging to NADP-ME and NAD-ME subtypes had f I of 0.6 and PCK subtype had 0.5 under control. All shade-grown C 4 species had f I of 0.6 except for NADP-ME grass which had 0.7. It was also observed that f I ranged between 0.3 and 0.5 for gymnosperm, liverwort and fern species. CEF increased with irradiance and was induced at lower irradiances in C 4 grasses and fern relative to other species. CEF was greater in shade-grown plants relative to control plants except for C 4 NADP-ME species. Our study reveals a range of CEF and f I values in different plant functional groups. This variation must be taken into account for improved photosynthetic calculations and modelling.

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“…Data of Zhang et al . (2018) and Ver Sagun et al . (2019) suggested that cyclic electron transport around PSI increased with increasing I abs .…”

Section: Introductionmentioning

confidence: 95%

The Kok effect revisited

et al. 2020

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Summary The Kok effect refers to the abrupt decrease around the light compensation point in the slope of net photosynthetic rate vs irradiance. Arguably, this switch arises from light inhibition of respiration, allowing the Kok method to estimate day respiration (Rd). Recent analysis suggests that increasing proportions of photorespiration (quantified as Γ*/Cc, the ratio of CO2 compensation point Γ* to chloroplast CO2 concentration, Cc) with irradiance explain much of the Kok effect. Also, the Kok method has been modified to account for the decrease in PSII photochemical efficiency (Φ2) with irradiance. Using a model that illustrates how varying Rd, Γ*/Cc, Φ2 and proportions of alternative electron transport could engender the Kok effect, we quantified the contribution of these parameters to the Kok effect measured in sunflower across various O2 and CO2 concentrations and various temperatures. Overall, the decreasing Φ2 with irradiance explained c. 12%, and the varying Γ*/Cc explained c. 25%, of the Kok effect. Maximum real light inhibition of Rd was much lower than the inhibition derived from the Kok method, but still increased with photorespiration. Photorespiration had a dual contribution to the Kok effect, one via the varying Γ*/Cc and the other via its participation in light inhibition of Rd.

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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

Cited by 13 publications

References 22 publications

Leaf photosynthetic and anatomical insights into mechanisms of acclimation in rice in response to long‐term fluctuating light

Leaf photosynthetic and anatomical insights into mechanisms of acclimation in rice in response to long‐term fluctuating light

Cyclic electron flow and light partitioning between the two photosystems in leaves of plants with different functional types

The Kok effect revisited

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