Photosynthesis Research

, Volume 24, Issue 3, pp 237–243

Studies on the mechanism of photosystem II photoinhibition II. The involvement of toxic oxygen species

  • Michael Richter
  • Wolfgang Rühle
  • Aloysius Wild
Regular Paper

DOI: 10.1007/BF00032311

Cite this article as:
Richter, M., Rühle, W. & Wild, A. Photosynth Res (1990) 24: 237. doi:10.1007/BF00032311


In a previous paper it was shown that photoinhibition of reaction centre II of spinach thylakoids was predominantly caused by the degradation of D1-protein. An initial inactivation step at the QB-site was distinguished from its breakdown. The present paper deals with the question as to whether this loss of QB-function is caused by oxygen radical attack. For this purpose the photoinhibition of thylakoids was induced at 20°C in the presence of either superoxide dismutase and catalase or the antioxidants glutathione and ascorbic acid. This resulted in comparable though not total protection of D1-protein, photochemistry and fluorescence from photoinhibition. The combined action of both the enzymatic and the non-enzymatic radical scavenging systems brought about an even more pronounced protective effect against photoinhibition than did either of the two systems singularly at saturating concentrations. The results signify a major contribution of activated oxygen species to the degradation process of D1-protein and the related phenomena of photoinhibition. Thylakoids treated with hydroxyl radicals generated through a Fenton reaction showed a loss of atrazine binding sites, electron transport capacity and variable fluorescence in a similar manner, though not to the same extent, as usually observed following photoinhibitory treatment.

Key words

activated oxygen species D1-protein photoinhibition spinach thylakoids 







reduced glutathione




primary quinone acceptor of PS II


secondary quinone acceptor of PS II


superoxide dismutase

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Michael Richter
    • 1
  • Wolfgang Rühle
    • 1
  • Aloysius Wild
    • 1
  1. 1.Institute of General Botany of the Johannes Gutenberg UniversityMainzFRG

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