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http://nopr.niscpr.res.in/handle/123456789/15394| Title: | Shortening of life-time of the pair [P680 +Pheo-] contributes to general inhibitory effect of dinoseb on electron transfer in PS-II |
| Authors: | Klimov, Vyacheslav V Allakhverdiev, Suleyman I Zharmukhamedov, Serguei K |
| Issue Date: | Dec-2000 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | It is shown that dinoseb, added to subchloroplast photosystem
(PS-II) preparations from pea at a concentration
higher than 5 μM, 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 : ( I) acceleration of the
dark relaxation of absorbance ( ΔA
) and chlorophyll fluorescence (ΔF
) changes related to photoreduction of
Pheo as a result of the photoreaction [P680
Pheo]  [P680 Pheo] that leads to
elimination of the ΔA and
ΔF
at a concentration of the inhibitor
higher than 50 μM; (2) lowering of the
maximum level of fluorescence (F) due to a decrease of ΔF
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 ΔA related to photooxidation
of P680; (5)
activation of ΔA
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 thaat 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.
|
| Page(s): | 491-497 |
| ISSN: | 0975-0959 (Online); 0301-1208 (Print) |
| Appears in Collections: | IJBB Vol.37(6) [December 2000] |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| IJBB 37(6) 491-497.pdf | 1.59 MB | Adobe PDF | View/Open |
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