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

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

    Research output: Contribution to journalArticlepeer-review

    4 Citations (Scopus)

    Abstract

    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)
    Volume74
    Issue number6
    DOIs
    Publication statusPublished - Jun 2009

    Keywords

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

    ASJC Scopus subject areas

    • Biochemistry

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