Effect of pH on the Slow Phase Components of Delayed Luminescence in Chloroplasts

Éva Hideg, Sandor Demeter
1987 Zeitschrift für Naturforschung C - A Journal of Biosciences  
The pH dependence of two, flash-induced slowly decaying delayed luminescence components - resulting from charge recombination of QA- and QB- with the S2 and S3 states (S2QA- + S3QA- and S2QB- + S3QB- recombinations) - in untreated and herbicide treated chloroplasts was investigated within a pH range of 5.5 to 8.5. The component associated with QA- showed the same pH-dependence in untreated and in DCMU-treated chloroplasts: its half-decay time increased with increasing pH reflecting an appr. +5
more » ... ecting an appr. +5 meV/pH change in the free energy of activation. Contrary to this the component associated with Ob exhibited an opposite behaviour: its half-decay time decreased with increasing pH and the free energy of activation changed with about -5 meV/pH. It is concluded that both acceptor and donor side effects are involved in the pH-dependence of slow phase delayed luminescence components.
doi:10.1515/znc-1987-9-1021 fatcat:sapomgbby5d6xbu5d5lv6hodyu