Spectroscopy of non-photochemical and photochemical quenching of chlorophyll fluorescence in leaves; evidence for a role of the light harvesting complex of Photosystem II in the regulation of energy dissipation

1994 ◽  
Vol 40 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Alexander V. Ruban ◽  
Peter Horton
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
Photochemical Quenching ◽  
Light Harvesting Complex

scholarly journals Changes in Photo-Protective Energy Dissipation of Photosystem II in Response to Beneficial Bacteria Consortium in Durum Wheat under Drought and Salinity Stresses

2020 ◽  
Vol 10 (15) ◽  
pp. 5031 ◽  
Author(s):  
Mohammad Yaghoubi Khanghahi ◽  
Sabrina Strafella ◽  
Carmine Crecchio
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Durum Wheat ◽  
Photochemical Quenching ◽  
Plant Growth Promoting Bacteria ◽  
Psii Photochemistry ◽  
Non Photochemical Quenching

The present research aimed at evaluating the harmless dissipation of excess excitation energy by durum wheat (Triticum durum Desf.) leaves in response to the application of a bacterial consortium consisting of four plant growth-promoting bacteria (PGPB). Three pot experiments were carried out under non-stress, drought (at 40% field capacity), and salinity (150 mM NaCl) conditions. The results showed that drought and salinity affected photo-protective energy dissipation of photosystem II (PSII) increasing the rate of non-photochemical chlorophyll fluorescence quenching (NPQ (non-photochemical quenching) and qCN (complete non-photochemical quenching)), as well as decreasing the total quenching of chlorophyll fluorescence (qTQ), total quenching of variable chlorophyll fluorescence (qTV) and the ratio of the quantum yield of actual PSII photochemistry, in light-adapted state to the quantum yield of the constitutive non-regulatory NPQ (PQ rate). Our results also indicated that the PGPB inoculants can mitigate the adverse impacts of stresses on leaves, especially the saline one, in comparison with the non-fertilized (control) treatment, by increasing the fraction of light absorbed by the PSII antenna, PQ ratio, qTQ, and qTV. In the light of findings, our beneficial bacterial strains showed the potential in reducing reliance on traditional chemical fertilizers, in particular in saline soil, by improving the grain yield and regulating the amount of excitation energy.

scholarly journals Photoprotective qH in Arabidopsis occurs in the light-harvesting complex II trimer

2021 ◽  
Author(s):  
Pierrick Bru ◽  
Collin J. Steen ◽  
Soomin Park ◽  
Cynthia L. Amstutz ◽  
Emily J. Sylak-Glassman ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Light Harvesting ◽  
Single Photon ◽  
Photochemical Quenching ◽  
Average Lifetime ◽  
Wild Type ◽  
Photosynthetic Membrane ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Excess light can induce photodamage to the photosynthetic machinery, therefore plants have evolved photoprotective mechanisms such as non-photochemical quenching (NPQ). Different NPQ components have been identified and classified based on their relaxation kinetics and molecular players. The NPQ component qE is induced and relaxed rapidly (seconds to minutes), whereas the NPQ component qH is induced and relaxed slowly (hours or longer). Molecular players regulating qH have recently been uncovered, but the photophysical mechanism of qH and its location in the photosynthetic membrane have not been determined. Using time-correlated single-photon counting analysis of the Arabidopsis thaliana suppressor of quenching 1 mutant (soq1), which displays higher qH than the wild type, we observed shorter average lifetime of chlorophyll fluorescence in leaves and thylakoids relative to wild type. Comparison of isolated photosynthetic complexes from plants in which qH was turned ON or OFF revealed a chlorophyll fluorescence decrease specifically in the trimeric light-harvesting complex II (LHCII) fraction when qH was ON. LHCII trimers are composed of Lhcb1, 2 and 3 proteins, so CRISPR-Cas9 edited and T-DNA insertion lhcb1, lhcb2 and lhcb3 mutants were crossed with soq1. In soq1 lhcb1, soq1 lhcb2, and soq1 lhcb3, qH was not abolished, indicating that no single major Lhcb isoform is necessary for qH. Using transient absorption spectroscopy of isolated thylakoids, no spectral signatures for chlorophyll-carotenoid excitation energy quenching or charge transfer quenching were observed, suggesting that qH may occur through chlorophyll-chlorophyll excitonic interaction.

scholarly journals Singlet Energy Dissipation in the Photosystem II Light-Harvesting Complex Does Not Involve Energy Transfer to Carotenoids

ChemPhysChem ◽  
2010 ◽  
Vol 11 (6) ◽  
pp. 1289-1296 ◽  
Author(s):  
Marc G. Müller ◽  
Petar Lambrev ◽  
Michael Reus ◽  
Emilie Wientjes ◽  
Roberta Croce ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Dissipation ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
Light Harvesting Complex

Regulation of Non-Photochemical Quenching of Chlorophyll Fluorescence in Plants

1995 ◽  
Vol 22 (2) ◽  
pp. 221 ◽  
Author(s):  
AV Ruban ◽  
P Horton
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Excited States ◽  
Light Harvesting ◽  
Structure And Function ◽  
Photochemical Quenching ◽  
Dynamic Nature ◽  
Dissipation Of Energy ◽  
And Function ◽  
Non Photochemical Quenching

Non-photochemical quenching of chlorophyll fluorescence indicates the de-excitation of light-generated excited states in the chlorophyll associated with photosystem II (PSII). The principle process contributing to this quenching is dependent on the formation of the thylakoid proton gradient and is an important mechanism for protecting PSII from photodamage. Evidence points to the importance of the light-harvesting chlorophyll proteins as the site of dissipation of energy, and suggests that the structure and function of these proteins are regulated by protonation and the ratio of zeaxanthin to violaxanthin. The minor light-harvesting proteins may have a particularly important role as the primary sites of proton binding and because of their enrichment in xanthophyll cycle carotenoids. The dynamic nature of the light-harvesting system is an important part of the process by which plants are able to adapt to different light environments.

Sign in / Sign up

Export Citation Format

Share Document