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Nonphotochemical Chlorophyll Fluorescence Quenching: Mechanism and Effectiveness in Protecting Plants from Photodamage

2016; Oxford University Press; Volume: 170; Issue: 4 Linguagem: Inglês

10.1104/pp.15.01935

1532-2548

Alexander V. Ruban,

Light effects on plants

We review the mechanism underlying nonphotochemical chlorophyll fluorescence quenching (NPQ) and its role in protecting plants against photoinhibition. This review includes an introduction to this phenomenon, a brief history of major milestones in our understanding of NPQ, definitions, and a discussion of quantitative measurements of NPQ. We discuss the current knowledge and unknown aspects in the NPQ scenario, including the following: ƊpH, the proton gradient (trigger); light-harvesting complex II (LHCII), PSII light harvesting antenna (site); and changes in the antenna induced by ƊpH (change), which lead to the creation of the quencher. We conclude that the minimum requirements for NPQ in vivo are ƊpH, LHCII complexes, and the PsbS protein. We highlight the most important unknown in the NPQ scenario, the mechanism by which PsbS acts upon the LHCII antenna. Finally, we describe a novel, emerging technology for assessing the photoprotective “power” of NPQ and the important findings obtained through this technology.