Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow
نویسنده
چکیده
The reactivation of the Hill reaction in C 0 2-depleted broken chloroplasts by various concen trations of bicarbonate was measured in the absence and in the presence o f photosystem II herbicides. It appears that these herbicides decrease the apparent affinity o f the thylakoid membrane for bicarbonate. Different characteristics o f bicarbonate binding were observed in chloroplasts o f triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the QB-protein and their interference with photosynthetic electron transport.
منابع مشابه
Reevaluation of the role of bicarbonate and formate in the regulation of photosynthetic electron flow in broken chloroplasts.
The stimulation of the Hill reaction in CO(2)-depleted broken chloroplasts (Pisum sativum L. cv Rondo) by the total amount of dissolved CO(2) and HCO(3) (-) (bicarbonate(*)) was measured at several formate concentrations. Formate appears to be a competitive inhibitor of the bicarbonate(*) stimulation of electron flow. From these experiments we have obtained a reactivation constant (K(r)) of 78 ...
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