Shortening of life-time of the pair [P680+Pheo-] contributes to general inhibitory effect of dinoseb on electron transfer in PS-II.
Indian J Biochem Biophys
;
2000 Dec; 37(6): 491-7
Article
Dans Anglais
| IMSEAR
| ID: sea-26588
ABSTRACT
It is shown that dinoseb, added to subchloroplast photosystem-II (PS-II) preparations from pea at a concentration higher than 5 microM, along with blocking the electron transfer on the acceptor side of PS-II, induces the following effects revealing its capability to have redox interaction with the components of PS-II reaction center (RC)-pheophytin (Pheo) and chlorophyll P680 (1) acceleration of the dark relaxation of absorbance (delta A) and chlorophyll fluorescence (delta F) changes related to photoreduction of Pheo as a result of the photoreaction [P680Pheo] [symbol see text] [P680Pheo-] that leads to elimination of the delta A and delta F at a concentration of the inhibitor higher than 50 microM; (2) lowering of the maximum level of fluorescence (F) due to a decrease of delta F under the condition when the electron acceptor, QA, is reduced; (3) loss of the described effects of dinoseb and appearance of its capability to donate electron to RC of PS-II in the presence of dithionite which reduces dinoseb in the dark; (4) inhibition of delta A related to photooxidation of P680; (5) activation of delta A related to photooxidation P700 in photosystem-I (PS-I) preparations (a similar effect is observed upon the addition of 0.2 mM methylviologen). It is suggested that redox interaction with the pair [P680+Pheo-] leading to the shortening of its life-time contributes to the general effect of inhibition of electron transfer in PS-II by dinoseb.
Texte intégral:
Disponible
Indice:
IMSEAR (Asie du Sud-Est)
Sujet Principal:
Pisum sativum
/
2,4-Dinitro-phénol
/
Complexe protéique du centre réactionnel de la photosynthèse
/
Complexes collecteurs de lumière
/
Complexe protéique du photosystème I
/
Complexe protéique du photosystème II
/
Transport d'électrons
/
Herbicides
langue:
Anglais
Texte intégral:
Indian J Biochem Biophys
Année:
2000
Type:
Article
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