Chlorophyll a fluorescence induction: a personal perspective of the thermal phase, the J–I–P rise

Stirbet, Alexandrina; Govindjee, .

doi:10.1007/s11120-012-9754-5

Cited by 265 publications

(171 citation statements)

References 341 publications

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“…The decrease of IP-amplitude is typical for drought stress [67]; however, in some species it occurs only at severe drought stress [68] and it disappears after rehydration [69]. Although the full interpretation of J-I-P kinetics is rather complicated [70,71], the IP amplitude was suggested to be a measure of relative abundance of PSI with respect to PSII [72,73], and its decrease was previously ascribed to decrease of PSI content in leaves [67,74]. In our experiment (Fig.…”

Section: Effects Of Drought Stress Analyzed By Simultaneously Recordementioning

confidence: 43%

Photosynthetic proton and electron transport in wheat leaves under prolonged moderate drought stress

Živčák

Kalaji

Shao

et al. 2014

Journal of Photochemistry and Photobiology B: Biology

144

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a b s t r a c tIn conditions of long-lasting moderate drought stress, we have studied the photoprotective responses in leaves of wheat (Triticum aestivum L., cv. Katya) related to the photosynthetic electron and proton transport. The dark-interval relaxation kinetics of electrochromic bandshift (ECS) indicated a decrease of electric and an increase of osmotic component of the proton motive force in drought stressed leaves, but neither the total proton motive force (pmf) nor the thylakoid proton conductance (gH + ) were affected.We observed the enhanced protection against overreduction of PSI acceptor side in leaves of drought stressed plants. This was obviously achieved by the rapid buildup of transthylakoid pH gradient at relatively low light intensities, directly associated to the steep increase of NPQ and the down-regulation of linear electron transport. It was further accompanied by the steep increase of redox poise at PSII acceptor side and PSI donor side. The early responses related to thylakoid lumen acidification in drought-stressed leaves could be associated with the activity of an enhanced fraction of PSI not involved in linear electron flow, which may have led to enhanced cyclic electron pathway even in relatively low light intensities, as well as to the drought-induced decrease of IP-amplitude in fast chlorophyll fluorescence kinetics.

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Section: Effects Of Drought Stress Analyzed By Simultaneously Recordementioning

confidence: 43%

Photosynthetic proton and electron transport in wheat leaves under prolonged moderate drought stress

Živčák

Kalaji

Shao

et al. 2014

Journal of Photochemistry and Photobiology B: Biology

144

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“…On the stromal side, the Q A binding pocket is formed by D2 and, analogously, the Q B pocket by D1. A bicarbonate ion (HCO 3 Ϫ ) is bound to a nonheme iron (II) located between Q A and Q B (36). The rate of electron transfer between plastoquinones depends on the coordinative properties of the nonheme iron (II) and the corresponding HCO 3 Ϫ (49).…”

Section: Discussionmentioning

confidence: 99%

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803

Zhang

Zhu

et al. 2017

Appl Environ Microbiol

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Nitrite, a common form of inorganic nitrogen (N), can be used as a nitrogen source through N assimilation. However, high levels of nitrite depress photosynthesis in various organisms. In this study, we investigated which components of the photosynthetic electron transfer chain are targeted by nitrite stress in Synechocystis sp. strain PCC 6803 cells. Measurements of whole-chain and photosystem II (PSII)-mediated electron transport activities revealed that high levels of nitrite primarily impair electron flow in PSII. Changes in PSII activity in response to nitrite stress occurred in two distinct phases. During the first phase, which occurred in the first 3 h of nitrite treatment, electron transfer from the primary quinone acceptor (Q A ) to the secondary quinone acceptor (Q B ) was retarded, as indicated by chlorophyll (Chl) a fluorescence induction, S-state distribution, and Q A Ϫ reoxidation tests. In the second phase, which occurred after 6 h of nitrite exposure, the reaction center was inactivated and the donor side of photosystem II was inhibited, as revealed by changes in Chl fluorescence parameters and thermoluminescence and by immunoblot analysis. Our data suggest that nitrite stress is highly damaging to PSII and disrupts PSII activity by a stepwise mechanism in which the acceptor side is the initial target. IMPORTANCE In our previous studies, an alga-based technology was proposed to fix the large amounts of nitrite that are released from NO X -rich flue gases and proved to be a promising industrial strategy for flue gas NO X bioremediation (W. Chen et al., Environ Sci Technol 50:1620 -1627, https://doi.org/10.1021/ acs.est.5b04696; X. Zhang et al., Environ Sci Technol 48:10497-10504, 2014, https:// doi.org/10.1021/es5013824). However, the toxic effects of high concentrations of nitrite on algal cells remain obscure. The analysis of growth rates, photochemistry, and protein profiles in our study provides important evidence that the inhibition by nitrite occurs in two phases: in the first phase, electron transfer between Q A Ϫ and Q B is retarded, whereas in the second, the donor side of PSII is affected. This is an excellent example of investigating the "early" inhibitory effects (i.e., within the first 6 h) on the PSII electron transfer chain in vivo. This paper provides novel insights into the mechanisms of nitrite inhibition of photosynthesis in an oxygenic phototrophic cyanobacterium.

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“…Under these conditions, an upregulation of OJ phase was detected. This higher OJ phase rise is closely related to the increased photo-reduction of Q A in the active PSII centers (Stirbet andJee, 2011, 2012), mainly because of a blockage of electron flow. (Fig.…”

Section: Resultsmentioning

confidence: 97%

High salicylic acid concentration alters the electron flow associated with photosystem II in barley

Habibi

Vaziri

2017

AAS

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In this study, the effects of exogenously applied salicylic acid (0.5 and 5 mM SA) on the rates of photosystem II (PSII) activity was analysed in 4-week-old barley (Hordeum vulgare'Bahman') seedlings using chlorophyll (Chl) a fluorescence transient (OJIP) measurements. No evident changes in Chl and carotenoid contents as well as chlorophyll fluorescence transient curves were observed in either of the studied concentrations after 24 h of SA application. After 5 d, low SA concentration (0.5 mM) increased PSII activity, Chl b and carotenoid contents in barley seedlings. In contrary, 5 days after 5 mM SA treatment, the maximal quantum efficiency of PSII (F v /F m ) and the Performance Index (PI ABS ), as an indicator of PSII structure and functioning, were significantly decreased. This lower F v /F m and PI ABS coupled with lower levels of Chl b and carotenoids, and lower values of photosynthetic electron transport chain components including the electron transport flux (φE o ) and the inferred oxygen evolving complex activity (F v /F o ). By monitoring the chlorophyll a fluorescence rise kinetics, from the initial "O" level to the "P" (the peak) level, a dramatic increase in "OJ" phase was detected, which coincides with an increased photoreduction of Q A as a result of blockage of electron flow. This study provided the evidence that the high concentration of SA induced damage to different sites of the PSII. . Pri spremljanju povečanja fluorescence klorofila a od začetne "O" na največjo vrednost "P" je bilo opazno njeno dramatično povečanje v fazi "OJ", kar je soupadalo s povečano fotoredukcijo Q A kot posledica blokade fotosintezenega elektronskega pretoka. Raziskava dokazuje, da večja koncentracija salicilne kisline povzroči poškodbe na večih mestih PSII.

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Chlorophyll a fluorescence induction: a personal perspective of the thermal phase, the J–I–P rise

Cited by 265 publications

References 341 publications

Photosynthetic proton and electron transport in wheat leaves under prolonged moderate drought stress

Photosynthetic proton and electron transport in wheat leaves under prolonged moderate drought stress

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803

High salicylic acid concentration alters the electron flow associated with photosystem II in barley

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