High salt stress in coupled and uncoupled thylakoid membranes: A comparative study

P. Mehta, A. Jajoo, S. Mathur, S. I. Allakhverdiev, S. Bharti

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4 Citations (Scopus)


The effect of high salt concentration on photosystem II (PS II) electron transport rates and chlorophyll a fluorescence induction kinetics was investigated in coupled and uncoupled spinach thylakoid membranes. With increase in salt concentration, the rates of electron transport mediated by PS II and the F v/F m ratio were affected more in uncoupled thylakoids as compared to coupled thylakoid membranes. The uncoupled thylakoid membranes seemed to behave like coupled thylakoid membranes at high NaCl concentration (̃1 M). On increasing the salt concentration, the uncoupler was found to be less effective and Na+ probably worked as a coupling enhancer or uncoupling suppressor. We suggest that positive charge of Na + mimics the function of positive charge of H+ in the thylakoid lumen in causing coupled state. The function of NaCl (monovalent cation) could be carried out by even lower concentration of Ca2+ (divalent cation) or Al3+ (trivalent cation). We conclude that this function of NaCl as coupling enhancer is not specific, and in general a positive charge is required for causing coupling in uncoupled thylakoid membranes.

Original languageEnglish
Pages (from-to)620-624
Number of pages5
JournalBiochemistry (Moscow)
Issue number6
Publication statusPublished - Jun 1 2009



  • Electron transport
  • High salt stress
  • PS II and PS I
  • Thylakoid membranes
  • Uncoupler

ASJC Scopus subject areas

  • Biochemistry

Cite this

Mehta, P., Jajoo, A., Mathur, S., Allakhverdiev, S. I., & Bharti, S. (2009). High salt stress in coupled and uncoupled thylakoid membranes: A comparative study. Biochemistry (Moscow), 74(6), 620-624. https://doi.org/10.1134/S0006297909060054