title: Membrane potential fluctuations in Chara australis: a characteristic signature of high external sodium.
abstract: We have studied fluctuations in membrane PD in Chara australis at frequencies between 1 and 500 mHz, by classical noise analysis and by inspection of the PD time-course. The former shows (1) a quasi-Lorentzian (1/f (2)) rise of noise power as frequency falls, and (2) a marked increase in noise power when the cell is exposed to high salinity (Chara australis is a salt-sensitive species). The latter shows that, as well as initiating depolarization, exposure to 50 mM Na as either chloride or sulfate usually initiates a continuous but random series of small depolarizations which gives rise to the increase in noise and whose mechanism is discussed.
authors.affiliation: Plant Membrane Biophysics Group, School of Physics, University of NSW, Sydney, NSW, 2052, Australia.
authors.forename: Sabah
authors.initials: S
authors.lastname: Al Khazaaly
authors.forename: N
authors.initials: N
authors.lastname: Alan Walker
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Beilby
authors.forename: Virginia A
authors.initials: VA
authors.lastname: Shepherd
mesh_terms: D044784:Chara / Q000166:cytology* / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008564:Membrane Potentials / Q000187:drug effects*; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D054712:Salinity; D012964:Sodium / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012964:Sodium