The pH dependence of delayed and prompt fluorescence in uncoupled chloroplasts

Wraight, Colin A.; Kraan, G.P.B.; Gerrits, Nathalie

doi:10.1016/0005-2728(72)90242-3

Cited by 36 publications

(6 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two further observations support the second possible mechanism; the removal of qNi by freezing to 77 K in the dark (Waiters and Horton 1991) and the effects of low pH on electron donation by the oxygen-evolving complex to Tyr z and thence to P680 (Wraight et al 1972, Ono and lnoue 1988, Meyer et al 1989) are both consistent with q N i being due to a limitation being placed on electron transport on the donor side of PS II; this would result in an increased lifetime for oxidised P680, a species believed to be a potent quencher of fluorescence (Butler 1972). Since such species would only be present at closed reaction centres, this would correspond to an increase in k d at closed centres.…”

Section: Characterisation Of Qnmentioning

confidence: 81%

Theoretical assessment of alternative mechanisms for non-photochemical quenching of PS II fluorescence in barley leaves

1993

View full text Add to dashboard Cite

The components of non-photochemical chlorophyll fluorescence quenching (qN) in barley leaves have been quantified by a combination of relaxation kinetics analysis and 77 K fluorescence measurements (Walters RG and Horton P 1991). Analysis of the behaviour of chlorophyll fluorescence parameters and oxygen evolution at low light (when only state transitions - measured as qNt - are present) and at high light (when only photoinhibition - measured as qNi - is increasing) showed that the parameter qNt represents quenching processes located in the antenna and that qNi measures quenching processes located in the reaction centre but which operate significantly only when those centres are closed. The theoretical predictions of a variety of models describing possible mechanisms for high-energy-state quenching, measured as the residual quenching, qNe, were then tested against the experimental data for both fluorescence quenching and quantum yield of oxygen evolution. Only one model was found to agree with these data, one in which antennae exist in two states, efficient in either energy transfer or energy dissipation, and in which those photosynthetic units in a dissipative state are unable to exchange energy with non-dissipative units.

show abstract

Section: Characterisation Of Qnmentioning

confidence: 81%

Theoretical assessment of alternative mechanisms for non-photochemical quenching of PS II fluorescence in barley leaves

1993

View full text Add to dashboard Cite

show abstract

“…The somewhat faster loss of light-limited rates of electron transport, compared to light-saturated rates, and the rapid fluorescence quenching that precede loss of electron transport [reviewed by Powles (1984) and Kyle (1987)], a Chl+-like signal evident in the EPR spectrum after photoinhibition (Ohad et al, 1990), and the loss of the D, followed by D2 proteins (Virgin et al, 1988;Jergerschold et al, 1990;Hundal et al, 1990b) are all consistent with the scheme presented. Possibly, at high light intensities, the internal pH of the lumen becomes sufficiently acidic to decrease the S3 -*• S4 transition of the water-oxidizing complex (Wraight et al, 1972;Bowes & Crofts, 1981) and to slow Yz -*…”

Section: Discussionmentioning

confidence: 99%

Photoinhibition of hydroxylamine-extracted photosystem II membranes: identification of the sites of photodamage

Blubaugh¹,

Atamian²,

Babcock³

et al. 1991

Biochemistry

View full text Add to dashboard Cite

Electron paramagnetic resonance (EPR) analyses (g = 2 region) and optical spectrophotometric analyses of P680+ were made of NH2OH-extracted photosystem II (PSII) membranes after various durations of weak-light photoinhibition, in order to identify the sites of damage responsible for the observed kinetic components of the loss of electron transport [Blubaugh, D.J., & Cheniae, G.M. (1990) Biochemistry 29, 5109-5118]. The EPR spectra, recorded in the presence of K3Fe(CN)6, gave evidence for rapid (t1/2 = 2-3 min) and slow (t1/2 = 3-4) losses of formation of the tyrosyl radicals YZ+ and YD+, respectively, and the rapid appearance (t1/2 = 0.8 min) of a 12-G-wide signal, centered at g = 2.004, which persisted at 4 degrees C in subsequent darkness in rather constant abundance (approximately 1/2 spin per PSII). This latter EPR signal is correlated with quenching of the variable chlorophyll a fluorescence yield and is tentatively attributed to a carotenoid (Car) cation. Exogenous reductants (NH2OH greater than or equal to NH2NH2 greater than DPC much greater than Mn2+) were observed to reduce the quencher, but did not reverse other photoinhibition effects. An additional 10-G-wide signal, tentatively attributed to a chlorophyll (Chl) cation, is observed during illumination of photoinhibited membranes and rapidly decays following illumination. The amplitude of formation of the oxidized primary electron donor, P680+, was unaffected throughout 120 min of photoinhibition, indicating no impairment of charge separation from P680, via pheophytin (Pheo), to the first stable electron acceptor, QA. However, a 4-microsecond decay of P680+, reflecting YZ----P680+, was rapidly (t1/2 = 0.8 min) replaced by an 80-140 microsecond decay, presumably reflecting QA-/P680+ back-reaction. Photoinhibition caused no discernible decoupling of the antenna chlorophyll from the reaction center complex. We conclude that the order of susceptibility of PSII components to photodamage when O2 evolution is impaired is Chl/Car greater than YZ greater than YD much greater than P680, Pheo, QA.

show abstract

“…Intracellular pH is critical to cellular energy turnover, metabolism, and catabolism (Pasternak et al, ; Rengel, ; Smith & Raven, ), which regulate enzyme activity and many physiological activities in cells, such as ATP synthesis, DNA replication, RNA and protein synthesis, cell growth, and endocytosis (Kurkdjian & Guern, ; Molinagutierrez, Stippl, Delgado, Gänzle, & Vogel, ). Under excess light conditions, plants induce the high‐light protection mechanism (energy‐dependent quenching) by reducing the pH of thylakoid membranes to prevent the leaves from being injured (Niyogi, Li, Rosenberg, & Jung, ; Wraight, Kraan, & Gerrits, ). Furthermore, cellular pH also acts as a second messenger that signals apical growth, plant hormone response and other physiological activities (Scott & Allen, ).…”

Section: Introductionmentioning

confidence: 99%

“…Under excess light conditions, plants induce the high-light protection mechanism (energy-dependent quenching) by reducing the pH of thylakoid membranes to prevent the leaves from being injured (Niyogi, Li, Rosenberg, & Jung, 2004;Wraight, Kraan, & Gerrits, 1972). Furthermore, cellular pH also acts as a second messenger that signals apical growth, plant hormone response and other physiological activities (Scott & Allen, 1999).…”

Section: Introductionmentioning

confidence: 99%

Foliar pH, an emerging plant functional trait: Biogeography and variability across northern China

Liu

Yan

Chen

et al. 2018

Global Ecol Biogeogr

View full text Add to dashboard Cite

Aims Plant pH is a functional trait deserving more attention than the current few studies at local scales, given its roles in nutrient cycling and physiological processes. How plant pH varies and is regulated at large scales remain unclear. Here we explore the biogeography of foliar pH and the potential drivers. Location East–west transect of northern China with increasing aridity westward. Time period 2016–2017. Major taxa Spermatophytes. Methods We analysed foliar pH of plants from 22 sites across northern China, and investigated its spatial pattern and relationships with climate, soil, and plant functional type (PFT). Results Foliar pH was generally acidic (5.33 ± .04) in northern China, showing distinct geographical variability: foliar pH decreased significantly westward at an average rate of 0.25 units per 10° longitude. Climate, soil and PFT explained 11, 17 and 59% of the variance in foliar pH, respectively. Foliar pH decreased (about 0.16) with mean annual precipitation (per 100 mm), soil stress coefficient (per 10%) and aridity index (per 0.14), but increased with mean annual temperature (per 2 °C). Across PFTs, herbs exhibited higher foliar pH than woody plants (6.0 vs. 4.9); gymnosperms relative to angiosperms had lower foliar pH (3.7 vs. 5.6); and monocotyledons showed higher foliar pH compared with dicotyledons (6.0 vs. 5.5). Main conclusions This study provides the first comprehensive analysis of the evident pattern of foliar pH over a large spatial scale. Foliar pH is higher in warm‐arid northwestern relative to cold‐humid northeastern China and in later‐ than earlier‐evolved plants. Similar to leaf mineral elements, foliar‐pH biogeography is shaped by the joint effects of climate, soil and PFT; PFT and moisture are the most influential factors. Our findings provide a new impetus for understanding functional biogeography, and lay the groundwork for research on the linkage of foliar pH to ecological functions and macroevolutionary implications.

show abstract

The pH dependence of delayed and prompt fluorescence in uncoupled chloroplasts

Cited by 36 publications

References 18 publications

Theoretical assessment of alternative mechanisms for non-photochemical quenching of PS II fluorescence in barley leaves

Theoretical assessment of alternative mechanisms for non-photochemical quenching of PS II fluorescence in barley leaves

Photoinhibition of hydroxylamine-extracted photosystem II membranes: identification of the sites of photodamage

Foliar pH, an emerging plant functional trait: Biogeography and variability across northern China

Contact Info

Product

Resources

About