DOI: 10.1111/j.1751-1097.1969.tb05696.x. UN NOUVEAU MODELE DES CENTRES PHOTOCHIMIQUES DU SYSTEME II*

UN NOUVEAU MODELE DES CENTRES PHOTOCHIMIQUES DU SYSTEME II*

10.1111/j.1751-1097.1969.tb05696.x

Crossref journal-article

Wiley

Photochemistry and Photobiology (311)

Abstract

Abstract— The amount of oxygen evolved by Chlorella cells or by isolated chloroplasts has been measured after illumination by short saturating flashes. In all conditions, the amount of oxygen evolved by one flash is proportional to the fraction of the photochemical centers susceptible to produce oxygen.If dark adapted algae or chloroplasts are illuminated by a sene of flashes, no oxygen is produced by the first flash. This phenomenon is related to the activation process.If yn is the amount of oxygen evolved by the nth flash of the sequence, it appears that the sene yn shows large oscillations with a period 4. These oscillations are completely damped after 4–6 periods and the amount of oxygen evolved by a flash reaches a stationary value. For any value of n. the quantities yn and yn+2 are linked by a recurrent relation which is the same for Chlorella cells and spinach chloroplasts. No relation can be found between the terms yn and y(n+1).The mathematical properties of the series yn can be understood if one admits that a two memory process is involved in the photochemical reaction.The results have been interpreted in terms of a new model of the System II photochemical centers. The main characteristics of this model are:(1) Each photochemical center includes two electron donors (Z) and one electron acceptor (Q).(2) The formation of one atom of oxygen requires a two quantum process corresponding to the transfer of two electrons from the same electron donor (first memory).(3) The photochemical center acts as a switch which connects alternately each donor to the acceptor (second memory). The switch process occurs after each photoact with an efficiency of about 85 per cent.Other arguments in favor of this model are obtained from studies of the rate of oxygen production at the onset of a weak illumination.

Bibliography

Joliot, P., Barbieri, G., & Chabaud, R. (1969). UN NOUVEAU MODELE DES CENTRES PHOTOCHIMIQUES DU SYSTEME II*. Photochemistry and Photobiology, 10(5), 309â329. Portico.

Authors 3

P. Joliot (first)
G. Barbieri (additional)
R. Chabaud (additional)

References 16 Referenced 570

10.1016/0006-3002(62)90735-7
P.Joliot J. Chim. Phys. (1961).
10.1016/0926-6585(65)90207-4
10.1111/j.1751-1097.1967.tb08759.x
10.1111/j.1751-1097.1968.tb05889.x
10.1016/0005-2728(68)90106-0
{'key': 'e_1_2_1_8_2', 'first-page': '179', 'volume-title': 'Comparative Biochemistry and Biophysics of Photosynthesis', 'author': 'Yamashita T.', 'year': '1968'} / Comparative Biochemistry and Biophysics of Photosynthesis by Yamashita T. (1968)
10.1051/jcp/1966631423
10.1016/0005-2728(68)90190-4
10.1016/0003-9861(55)90100-4
10.1093/jxb/9.3.311
C.Lemasson Communication personnelle.
{'key': 'e_1_2_1_14_2', 'first-page': '4622', 'volume': '258', 'author': 'Joliot P.', 'year': '1964', 'journal-title': 'Compt. Rend.'} / Compt. Rend. by Joliot P. (1964)
10.1016/0003-9861(57)90140-6
J.Lavorel Communication au3ème Congrés International de Photosynthèse. Freudenstadt Germany(1968).
10.1073/pnas.58.1.75

Dates

Type	When
Created	17 years, 7 months ago (Jan. 2, 2008, 4:09 p.m.)
Deposited	1 year, 9 months ago (Nov. 6, 2023, 6:36 p.m.)
Indexed	12 hours, 33 minutes ago (Aug. 23, 2025, 9:51 p.m.)
Issued	55 years, 9 months ago (Nov. 1, 1969)
Published	55 years, 9 months ago (Nov. 1, 1969)
Published Online	17 years, 7 months ago (Jan. 2, 2008)
Published Print	55 years, 9 months ago (Nov. 1, 1969)

Funders 0

None

BibTeX

@article{Joliot_1969, title={UN NOUVEAU MODELE DES CENTRES PHOTOCHIMIQUES DU SYSTEME II*}, volume={10}, ISSN={1751-1097}, url={http://dx.doi.org/10.1111/j.1751-1097.1969.tb05696.x}, DOI={10.1111/j.1751-1097.1969.tb05696.x}, number={5}, journal={Photochemistry and Photobiology}, publisher={Wiley}, author={Joliot, P. and Barbieri, G. and Chabaud, R.}, year={1969}, month=nov, pages={309–329} }

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