Open-vacuole method for measuring membrane potential and membrane resistance of Characeae cells

元データ 日本植物生理学会

概要

A simple method called the open-vacuole (o.v.) method was developed to measure the vacuolar potential (E_<vo>) and membrane resistance (R_m) of Characeae cells without inserting a microelectrode into the vacuole. Values of E_<vo> and R_m measured by this method are higher than those measured by the microelectrode method. Using the o.v. method we can measure E_<vo> and R_m exactly in cells with internal media of extremely low ionic concentrations. In respect to E_<vo> and R_m, the tonoplast is less sensitive than the plasmalemma to a change in ionic concentration. The existence of a significant amount of E_<vo> (-40 mV), even when both the internal and external media are isotonic artificial pond water with a high Ca^<2+>-content, may be accounted for by the difference in sensitivity to ionic species between these two membranes. Irrespective of the presence or absence of Ca^<2+> in the vacuole, practically the same values of E_<vo> and R_m were measured with the open-vacuole method, when measurements were carried out within 20 min after the end of perfusion. The discrepancies between the present and previous results (16) may be accounted for by the difference in methods.

著者

NAKAGAWA Shigeo Department of Physics, Rikkyo (St. Paul's) University
Kikuyama Munehiro Department Of Biology Faculty Of Science Niigata University
Kikuyama Munehiro Department Of Biology Faculty Of Science Osaka University
Tazawa Masashi Departlnent Of Biology Faculty Of Science Osaka University
Nakagawa Shigeo Department Of Biology Faculty Of Science Osaka University:(present)sanki Engineering Ltd.
Nakagawa Shigeo Department Of Biology Faculty Of Science Osaka University:(present)sanki Engineering Limited

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