Physiological Role of Cyclic Electron Flow in Higher Plants

Abstract

As an important alternative electron flow, cyclic electron flow (CEF) is essential for photosynthesis in many higher plants. The CEF-dependent generation of proton gradient across thylakoid membranes not only activates ATP synthesis but also protects photosystem from photoinhibition through activating non-photochemical quenching and stabilizing oxygen-evolving complexes. Furthermore, CEF can alleviate the over-reduction of acceptor side of photosystem I (PS I) and generation of superoxide anion, and thus protect PS I from photoinhibition. This review briefly summarizes the pathways of CEF, roles of CEF, response of CEF to environmental stress,and proposes perspectives.