Analysis of the Electrical Fluctuations in Red Beet (Beta Vulgaris L.) Vacuoles
Like animal cells, plant cells possess ionic pumps, such as ATPases, and ionic channels. The plant ATPases have been mainly studied by use of biochemical methods. Membrane fractions enriched with plasmalemma or with tonoplast have been prepared, and vesicles reconstituted from them. ATPases activities have been described, both on the plasmalemma and on the tonoplast. These activities are increased by MgATP. In the higher plants, the plasmalemma pump is strongly inhibited by vanadate, while the proton pump of the tonoplast is inhibited by NO3−(Leigh, 1983; Marre and Ballarin-Denti, 1985). Besides the specific ionic effects, the ATPase activities are sensitive to the ionic strength of the bathing medium, which affects the surface electrostatic interactions in the membrane (Thibaud et al., 1984; Gibrat et al., 1985). In contrast with the active transports, the biochemical study of the passive ionic transports of the plant cells has practically not begun.
KeywordsATPase Activity Noise Spectrum Bathing Medium Guard Cell Protoplast Specific Ionic Effect
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