Different sensitivities of photosystem II in green algae and cyanobacteria to phenylurea and phenol-type herbicides: effect on electron donor side

Ekaterina K. Yotsova, Martin A. Stefanov, Anelia G. Dobrikova, Emilia L. Apostolova
  • Zeitschrift für Naturforschung C, January 2017, De Gruyter
  • DOI: 10.1515/znc-2016-0089

Different sensitivity of photosystem II to herbicides

What is it about?

The effects of short-term treatment with phenylurea (DCMU, isoproturon) and phenol-type (ioxynil) herbicides on the green alga Chlorella kessleri and the cyanobacterium Synechocystis salina with different organization of photosystem II (PSII) were investigated using Pulse Amplitude Modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution measured by polarographic oxygen electrodes (Clark-type and Joliot-type).

Why is it important?

This study suggests that the herbicides affect not only the acceptor side, but also the donor side of PSII by modifications of the Mn cluster of the oxygen-evolving complex. We propose that one of the reasons for the different PSII inhibition caused by herbicides is their influence in a different extent on the kinetic parameters of the oxygen-evolving reactions (the initial S0-S1 state distribution, the amount of blocked centers SB, the turnover time of Si states, misses and double hits).


Emilia Apostolova
Institute of Biophysics and Biomedical Engineering

The relationship between the herbicide-induced inhibition and the changes in the kinetic parameters is discussed.

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The following have contributed to this page: Emilia Apostolova