Ca2+-sensitive and Ca2+-insensitive exocytosis in maize coleoptile protoplasts

G Thiel, J U Sutter, U Homann

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Ca2+ and osmotic driven extension of the surface area of maize coleoptile protoplasts was investigated using capacitance measurements and photolysis of the caged compound DM-nitrophen. Protoplasts responded to an elevation of cytoplasmic Ca2+ (Ca(i)) with a rapid burst in capacitance reaching a maximal increase of 1.3+/-1.1% over the resting cell capacitance. Subsequent lowering of the osmotic potential in the external medium by 210 mosmol caused a further increase in Cm by 26+/-6%. These data indicate two independent pathways for insertion of membrane into the plasma membrane. One is driven by Ca(i) and recruits membrane from a small pool. The osmotic evoked rise in surface area draws membrane from a much larger reservoir and may be driven by membrane tension.
Original languageEnglish
Pages (from-to)R152-3
JournalPflugers Archiv - European Journal of Physiology
Volume439
Issue number3 Suppl
DOIs
Publication statusPublished - 2000

Keywords

  • cell capacitance
  • maize coleoptile protoplasts
  • capacitance measurements
  • membrane

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