Cyclic electron transport in C₃ plants: fact or artefact?

• Published in: Journal of experimental botany 2005-01, Vol.56 (411), p.407-416
• Main Author: Johnson, Giles N
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; C3 plants; Cell physiology; chlorophyll; chloroplasts; Cyclic electron transport; cytochrome b6f; electron transfer; Electron Transport; electron transport chain; fluorescence; Fundamental and applied biological sciences. Psychology; literature reviews; non-photochemical quenching; NPQ pgr5; Photosynthesis - physiology; Photosynthetic Reaction Center Complex Proteins - physiology; photosystem I; photosystem II; Plant Physiological Phenomena; plant physiology; Plant physiology and development; Plants - metabolism; Plasma membrane and permeation; redox potential; Signal Transduction; thylakoids; ΔpH
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/eri106

The phenomenon of cyclic electron transport was first characterized in higher plant chloroplasts 50 years ago, yet there is still a debate about whether or not this is a physiological process. The recent isolation of mutants that appear to lack cyclic electron transport, as well as new data providing functional evidence for its occurrence, support the notion that this pathway plays an important role in plant responses to stress, providing a pH gradient across the thylakoid membrane to trigger non-photochemical quenching of chlorophyll fluorescence. At present, little is known about the regulation of cyclic electron transport, but it is possible that this is activated in response to a low redox potential in the chloroplast stroma.