Mechanism of calcium‐dependent salt tolerance in cells of Nitellopsis obtusa: role of intracellular adenine nucleotides

Maki Katsuhara, M. TAZAWA

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14 Citations (Scopus)


Abstract. The tonoplasts of internodal cells of Nitellopsis were removed by perfusing the vacuoles with media containing a Ca2 chelator, EGTA. Treatment of tonoplast‐free cells with 100 mol m3 NaCl induces a large membrane depolarization, a drastic decrease in the membrane resistance and an increase in Na+ influx. These events are identical to those that occur in intact cells subjected to high NaCl. These responses to NaCl are prevented if 10 mol m3 Ca2+ is supplied together with 100 mol m3 NaCl. The protective effect of Ca2+ is evident only when the intracellular ATP concentration exceeds 0.1 mol m3 and does not occur full when the intracellular ATP is removed. AMP at concentrations greater than 0.5 mol m3 or 0.25 mol m3 AMPPNP can replace ATP. It is concluded that ATP does not act as an energy source nor as a substrate for protein phosphorylation. ATP seems to exert its effects as a coeffector with Ca2+ in regulating the Na+ permeability of the plasma membrane.

Original languageEnglish
Pages (from-to)179-184
Number of pages6
JournalPlant, Cell and Environment
Issue number2
Publication statusPublished - 1990
Externally publishedYes



  • ATP
  • calcium
  • charophyte
  • effector
  • Nitellopsis obtusa
  • salt stress
  • salt tolerance

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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