Photophysics of Photosynthetic Pigment-Protein Complexes

Ostroumov, Evgeny E.; Khan, Yaser R.; Scholes, Gregory D.

doi:10.1007/978-94-017-9032-1_4

Cited by 12 publications

(4 citation statements)

References 189 publications

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“…NPQ significantly reduces the quantum yield of variable fluorescence (by even 60%, see Ostroumov et al, 2014) and affects the efficiency of energy transfer from the antenna to the reaction centers (see review on the energy-transfer dynamics in photosynthesis Mirkovic et al, 2016). In higher plants, NPQ occurs mainly in the light-harvesting antenna (Gilmore et al, 1995; Horton et al, 1996; Belgio et al, 2012).…”

Section: Regulatory Role Of Protons and Ions In Triggering Non-photocmentioning

confidence: 99%

Role of Ions in the Regulation of Light-Harvesting

Kaňa

Govindjee

2016

Front. Plant Sci.

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Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer (EDL). Further, there is a heterogeneous organization of soluble ions (K+, Mg2+, Cl−) attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids), provides an electrical field. The EDL is affected by the valence of the ions and interferes with the regulation of “state transitions,” protein interactions, and excitation energy “spillover” from Photosystem II to Photosystem I. These effects are reflected in changes in the intensity of chlorophyll a fluorescence, which is also a measure of photoprotective non-photochemical quenching (NPQ) of the excited state of chlorophyll a. A triggering of NPQ proceeds via lumen acidification that is coupled to the export of positive counter-ions (Mg2+, K+) to the stroma or/and negative ions (e.g., Cl−) into the lumen. The effect of protons and anions in the lumen and of the cations (Mg2+, K+) in the stroma are, thus, functionally tightly interconnected. In this review, we discuss the consequences of the model of EDL, proposed by Barber (1980b) Biochim Biophys Acta 594:253–308) in light of light-harvesting regulation. Further, we explain differences between electrostatic screening and neutralization, and we emphasize the opposite effect of monovalent (K+) and divalent (Mg2+) ions on light-harvesting and on “screening” of the negative charges on the thylakoid membrane; this effect needs to be incorporated in all future models of photosynthetic regulation by ion channels and transporters.

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Section: Regulatory Role Of Protons and Ions In Triggering Non-photocmentioning

confidence: 99%

Role of Ions in the Regulation of Light-Harvesting

Kaňa

Govindjee

2016

Front. Plant Sci.

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“…The energy is transferred through a network of the antenna complexes to reach the reaction center on short timescales (typically hundreds of picoseconds) for stable charge separation that drives a cascade of biochemical events, ultimately reducing CO 2 to carbohydrate. Under high light intensities, the charge separation and subsequent electron transport chain are saturated, and so the chlorophyll singlet excited states undergo other photophysical pathways, including intersystem crossing to generate triplet states (1). The chlorophyll triplet states can sensitize the formation of singlet oxygen, which damages the photosynthetic machinery.…”

Section: Introductionmentioning

confidence: 99%

Membrane-dependent heterogeneity of LHCII characterized using single-molecule spectroscopy

Manna

Davies

Hoffmann

et al. 2021

Biophysical Journal

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“…Chlorophyll molecules emit light as chlorophyll fluorescence when transitioning from an excited state to a non-excited state [25,26]. Chlorophyll fluorescence is commonly used as an indicator for calculating the photosynthetic energy conversion in higher plants, algae, and bacteria [27].…”

Section: Mesotrione Destroyed Chloroplast Structure and Affected The ...mentioning

confidence: 99%

Mechanisms Underlying the Differential Sensitivity to Mesotrione in Sweet Corn

Lv,

Li,

Wang

et al. 2024

Agronomy

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Mesotrione is a widely used post-emergence herbicide for maize. The toxicity of mesotrione to maize (especially sweet corn) has been widely reported, and some sweet corn varieties are highly sensitive to mesotrione, which affects subsequent plant growth periods. However, the molecular mechanisms responsible for the differences in susceptibility to mesotrione are not known. By comparing changes in the transcriptome of mesotrione-tolerant line 301 and mesotrione-sensitive line 276 after mesotrione treatment, we found that the genes coding light-harvesting chlorophyll protein complex were induced in 301, and the genes coding loosening cell walls were overrepresented in 276. The net photosynthetic rate, maximum photochemical efficiency of leaf PSII, photochemical quenching of chlorophyll fluorescence, and the electron transport rate were significantly higher in 301 than in 276 after mesotrione treatment, and these effects became more severe as time passed. In addition, oxidative balance was also affected by mesotrione. Compared with 301, SOD, POD, and CAT activities were significantly reduced with longer exposure time in 276. The results suggested that sweet corn can mitigate herbicide mesotrione toxicity by improving photosynthesis, ROS scavenging, and cell wall synthesis.

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Photophysics of Photosynthetic Pigment-Protein Complexes

Cited by 12 publications

References 189 publications

Role of Ions in the Regulation of Light-Harvesting

Role of Ions in the Regulation of Light-Harvesting

Membrane-dependent heterogeneity of LHCII characterized using single-molecule spectroscopy

Mechanisms Underlying the Differential Sensitivity to Mesotrione in Sweet Corn

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