Quantification of cyclic electron flow around Photosystem I in spinach leaves during photosynthetic induction
Date
2007
Authors
Fan, Da Yong
Nie, Qin
Hope, Alexander B
Hillier, Warwick
Chow, Wah S (Fred)
Pogson, Barry
Journal Title
Journal ISSN
Volume Title
Publisher
Kluwer Academic Publishers
Abstract
The variation of the rate of cyclic electron transport around Photosystem I (PS I) during photosynthetic induction was investigated by illuminating dark-adapted spinach leaf discs with red + far-red actinic light for a varied duration, followed by abruptly turning off the light. The post-illumination re-reduction kinetics of P700+, the oxidized form of the photoactive chlorophyll of the reaction centre of PS I (normalized to the total P700 content), was well described by the sum of three negative exponential terms. The analysis gave a light-induced total electron flux from which the linear electron flux through PS II and PS I could be subtracted, yielding a cyclic electron flux. Our results show that the cyclic electron flux was small in the very early phase of photosynthetic induction, rose to a maximum at about 30 s of illumination, and declined subsequently to <10% of the total electron flux in the steady state. Further, this cyclic electron flow, largely responsible for the fast and intermediate exponential decays, was sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethyl urea, suggesting an important role of redox poising of the cyclic components for optimal function. Significantly, our results demonstrate that analysis of the post-illumination re-reduction kinetics of P700+ allows the quantification of the cyclic electron flux in intact leaves by a relatively straightforward method.
Description
Keywords
Keywords: chlorophyll; article; electron transport; metabolism; photosynthesis; photosystem I; physiology; plant leaf; spinach; Chlorophyll; Electron Transport; Photosynthesis; Photosystem I Protein Complex; Plant Leaves; Spinacia oleracea; Spinacia oleracea Cyclic electron transport; P700; Photosynthetic induction; Photosystem I
Citation
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Source
Photosynthesis Research
Type
Journal article
Book Title
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DOI
10.1007/s11120-006-9127-z
Restricted until
2037-12-31