Characterization of chlorophyll fluorescence quenching in chloroplasts by fluorescence spectroscopy at 77 K I. ΔpH-dependent quenching

Krause, G. Heinrich; Briantais, Jean-Marie; Vernotte, C.

doi:10.1016/0005-2728(83)90116-0

Cited by 117 publications

(66 citation statements)

References 24 publications

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“…Without the Mg 2+ and chelation treatment there is a strong attenuation in the lifetime centre of the 2.0 ns (F 685 ) PS II distribution mode that results in a strongly inhibited F v /F m and inhibited xanthophyll-cycledependent energy dissipation (Gilmore et al 1996). The well-documented Mg 2+ -sensitive PS II quenching by PS I primarily a¡ects F m and not F o (Krause et al 1983). To explain the in vivo results of this study, in light of the clo f 2 phenotype, we hypothesize that PS II units that structurally interface with PS I units in the outer, poorly formed granal stacks in the leaves may exhibit strong quenching by energy transfer to PS I that shortens the F m £uorescence lifetimes.…”

Section: Discussionmentioning

confidence: 99%

Global spectral–kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley

Gilmore

Itoh

Govindjee

2000

Phil. Trans. R. Soc. Lond. B

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This study presents a novel measurement, and simulation, of the time-resolved room temperature chlorophyll a £uorescence emission spectra from leaves of the barley wild-type and chlorophyll-b-de¢cient chlorina (clo) f 2 and f104 mutants. The primary data were collected with a streak-camera-based picosecond-pulsed £uorometer that simultaneously records the spectral distribution and time dependence of the £uorescence decay. A new global spectral-kinetic analysis programme method, termed the double convolution integral (DCI) method, was developed to convolve the exciting laser pulse shape with a multimodal-distributed decay pro¢le function that is again convolved with the spectral emission band amplitude functions. We report several key results obtained by the simultaneous spectral-kinetic acquisition and DCI methods. First, under conditions of dark-level £uorescence, when photosystem II (PS II) photochemistry is at a maximum at room temperature, both the clo f 2 and clo f104 mutants exhibit very similar PS II spectral-decay contours as the wild-type (wt), with the main band centred around 685 nm. Second, dark-level £uorescence is strongly in£uenced beyond 700 nm by broad emission bands from PS I, and its associated antennae proteins, which exhibit much more rapid decay kinetics and strong integrated amplitudes. In particular a 705^720 nm band is present in all three samples, with a 710 nm band predominating in the clo f 2 leaves. When the PS II photochemistry becomes inhibited, maximizing the £uorescence yield, both the clo f104 mutant and the wt exhibit lifetime increases for their major distribution modes from the minimal 250^500 ps range to the maximal 1500^2500 ps range for both the 685 nm and 740 nm bands. The clo f 2 mutant, however, exhibits several unique spectral-kinetic properties, attributed to its unique PS I antennae and thylakoid structure, indicating changes in both PS II £uorescence reabsorption and PS II to PS I energy transfer pathways compared to the wt and clo f104. Photoprotective energy dissipation mediated by the xanthophyll cycle pigments and the PsbS protein was uninhibited in the clo f 104 mutant but, as commonly reported in the literature, signi¢cantly inhibited in the clo f 2; the inhibited energy dissipation is partly attributed to its thylakoid structure and PS II to PS I energy transfer properties. It is concluded that it is imperative with steady-state £uorometers, especially for in vivo studies of PS II e¤ciency or photoprotective energy dissipation, to quantify the in£uence of the PS I spectral emission.

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Section: Discussionmentioning

confidence: 99%

Global spectral–kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley

Gilmore

Itoh

Govindjee

2000

Phil. Trans. R. Soc. Lond. B

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“…One kind of nonradiative energy dissipation has been related to thylakoid membrane energization ('high energy quenching') and relaxes rapidly (8). The study presented here is concerned with a type of quenching with longer induction and relaxation times, which persists in the dark (4).…”

Section: Discussionmentioning

confidence: 99%

“…In this way, sample and fiber optics were maintained at a constant distance, allowing direct comparison in the absolute level of fluorescence emission from different samples. All fluorescence measurements were preceded by a 5-min period of complete darkness to allow for relaxation of any fluorescence quenching associated with thylakoid membrane energization (8). 02 Exchange.…”

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confidence: 99%

Photoinhibition and Zeaxanthin Formation in Intact Leaves

Demmig¹,

Winter²,

Krüger³

et al. 1987

Plant Physiol.

711

195

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Comparative studies of chlorophyll a fluorescence, measured with a pulse amplitude modulated fluorometer, and of the pigment composition of leaves, suggest a specific role of zeaxanthin, a carotenoid formed in the xanthophyll cycle, in protecting the photosynthetic apparatus aginst the adverse effects of excessive light. This conclusion is based on the following fmdings: (a) (7), photoinhibitory damage to PSII reaction centers, i.e. a decrease in the rate constant for PSII photochemistry, leads to a rise in initial fluorescence at open PSII traps, F0,3 whereas an increase in the rate constant ofnonradiative energy dissipation leads to a decrease in both initial fluorescence, FO, and maximum fluorescence at closed PSII traps, FM. Such an increase in thermal de-excitation could function as an overflow valve to allow for nondestructive dissipation of excess excitation energy and may therefore be viewed as a potentially protective process rather than as an indication of damage, e.g. to proteins (10) of the thylakoid membrane. Increased nonradiative energy dissipation, as indicated by Chl 77 K fluorescence characteristics, was shown to occur under conditions of excess excitation in low light (in 2% 02 and the absence of C02) with no evidence for simultaneous photoinhibitory damage to the PSII reaction centers, as well as at high light levels where there was evidence for simultaneous damage (4). This paper presents a striking parallel between the occurrence of conditions, at both high and low light levels, under which increased nonradiative energy dissipation is observed, and the accumulation of the carotenoid zeaxanthin in leaves exposed to such conditions. Zeaxanthin is known to be formed by deepoxidation of violaxanthin in the so-called violaxanthin or xanthophyll cycle which is present in thylakoid membranes and which is fine-tuned to respond to the balance of electron transport reactions and CO2 uptake (6, 23). The function of this cycle has been unknown thus far. We propose that the formation of zeaxanthin under photoinhibitory conditions is indicative of a specific function of this particular carotenoid compound in the prevention of photoinhibitory damage.

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“…Dissipation of excitation energy via pathways other than PSII photochemistry leads to fluorescence quenching. One component of fluorescence quenching which relaxes within 30 s upon darkening (16,17) has been termed high energy state quenching (14,15). A second component of fluorescence quenching shows slower relaxation kinetics (typically between 30 to 60 min) upon darkening (8,9).…”

mentioning

confidence: 99%

Zeaxanthin and the Heat Dissipation of Excess Light Energy in Nerium oleander Exposed to a Combination of High Light and Water Stress

Demmig¹,

Winter²,

Krüger³

et al. 1988

Plant Physiol.

255

129

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Upon termination of watering of plants of Nerium oleander exposed to high light, photochemical efficiency became reduced as leaf water content decreased. Evidence is presented that this type of photoinhibition reflects to a substantial degree radiationless dissipation of excitation energy, probably mediated by the carotenoid zeaxanthin. During the imposition of water stress, the zeaxanthin content of leaves increased at the expense of violaxanthin and a-carotene as a water deficit developed over a period of several days. The increase in zeaxanthin content was linearly related to an increase in the rate of radiationless energy dissipation in the antenna chlorophyll as calculated from the characteristics of chlorophyll a fluorescence measured with a pulse amplitude modulated fluorometer at room temperature. The increase in the rate of radiationless dissipation was also linearly related to a decrease in PSII photochemical efficiency as indicated by the ratio of variable to maximum fluorescence. Leaves of well-watered shade plants of N. oleander exposed to strong light showed a similar increase in zeaxanthin content as sun leaves of the same species subjected to drought in strong light. Shade leaves possessed the same capacity as sun leaves to form zeaxanthin at the expense of both violaxanthin and jcarotene. The resistance of this species to the destructive effects of excess light appears to be related to interconversions between 13-carotene and the three carotenoids of the xanthophyll cycle.Prolonged exposure of leaves to light levels where the excitation energy exceeds the capacity for orderly dissipation by the photosynthetic system can lead to photoinhibition. Photoinhibition is characterized by a sustained decrease in the efficiency of photon utilization by PSII photochemistry and is observed (a) when shade leaves are abruptly exposed to bright light which greatly exceeds the PFD2 experienced by the leaves during their development and (b) when sun leaves acclimated to natural sunlight are exposed to additional environmental stresses water deficit or unfavorably high or low temperatures (for a review see Ref. 22). Under these conditions, a given light level which previously was nonexcessive becomes excessive, because the utilization of energy through photosynthesis is decreased by the additional stress treatment. The mechanism by which the photon yield of photosynthesis is lowered in these two cases is probably not the same (3,8). Shade leaves exposed to bright light show evidence of damage to PSII reaction centers, whereas sun leaves exposed to a combination of high light levels and water stress (Nerium oleander) or salinity stress (various species of mangroves) do not. Rather, in these sun leaves, the decrease in photochemical efficiency of PSII can to a large extent be accounted for by a strong increase in thermal deactivation of excitation energy in the antenna Chl (3, 8). Excitation energy is thereby diverted away from the photosynthetic reaction centers and is no longer available for photochemis...

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Characterization of chlorophyll fluorescence quenching in chloroplasts by fluorescence spectroscopy at 77 K I. ΔpH-dependent quenching

Cited by 117 publications

References 24 publications

Global spectral–kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley

Global spectral–kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley

Photoinhibition and Zeaxanthin Formation in Intact Leaves

Zeaxanthin and the Heat Dissipation of Excess Light Energy in Nerium oleander Exposed to a Combination of High Light and Water Stress

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