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.
- cell capacitance
- maize coleoptile protoplasts
- capacitance measurements
Thiel, G., Sutter, J. U., & Homann, U. (2000). Ca2+-sensitive and Ca2+-insensitive exocytosis in maize coleoptile protoplasts. Pflugers Archiv - European Journal of Physiology, 439(3 Suppl), R152-3. https://doi.org/10.1007/s004240000127