Effects of salinity and turgor on calcium influx in Chara

R. J. REID*, M. TESTER, F. A. SMITH

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Measurements were made of the influx of 45Ca into internodal cells of Chara corallina in solutions containing high concentrations of NaCl. Increasing salinity in the range 4–100mol m−3 NaCl resulted in a doubling of Ca2+ influx at the plasmalemma. A time‐course of Ca2+ influx in 50 mol m−3 NaCl, 0.5mol m−3 CaCl2 showed that while influx at the plasmalemma increased only 1.5‐fold, influx to the vacuole increased by up to 15‐fold. This was interpreted as being due to inhibition of active Ca2+ efflux from the cell. The stimulation of Ca2+ influx by increasing salinity appeared to be principally a response to reduced turgor since similar stimulations were obtained when turgor was reduced by NaCl, Na2SO4 or mannitol. When cells were plasmolysed Ca2+ influx increased by 10–20‐fold. The increased permeability was relatively specific for Ca2+ and was inhibitable by La3+. Survival of cells in high salt conditions was increased by 30 mmol m−3 La3+, which inhibited Ca2+ influx. Paradoxically, survival can also be extended by increasing external Ca2+ which leads to a higher influx. Therefore, it seems unlikely that the ameliorative effect of Ca2+ on the sensitivity of plants to high NaCl is mediated by Ca2+ entry across the plasmalemma. It seems more likely that the principal role of Ca2+ under these conditions is exerted externally through the control of membrane voltage and permeability.

Original languageEnglish (US)
Pages (from-to)547-554
Number of pages8
JournalPlant, Cell & Environment
Volume16
Issue number5
DOIs
StatePublished - Jan 1 1993
Externally publishedYes

Keywords

  • Ca influx
  • Chara corallina
  • Na‐Ca interaction
  • membrane permeability
  • salinity
  • turgor

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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