ISSN:
1435-8107
Keywords:
Key words: Double-water-film-electrode; Chara; Plasmodesma(ta); Electrical properties; Homeostatic control; Intercellular communication.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract A ``double-water-film electrode technique'' has been developed for the long-term characterization of the electrical properties across the interface between the nodal (N) and internodal (A or B) cells and the vacuole along the length of an internode of Chara as a function of time and temperature. The electrode unit consisted of a pair of the water-film electrodes described elsewhere (Chilcott 1988; Chilcott and others 1983; Coster and others 1984; Lucas 1985; and Ogata 1983). The distance between two water-film probes was fixed at 1.0 cm. By scanning the electrode unit, the spatial variations in electrical resistance and capacitance along the longitudinal axis of Chara were observed. Analysis was performed by applying an electrical equivalent circuit for the biomembrane (Philippson 1921). Across the internode (−A or −B)/central nodal cells interface, the specific parallel resistance (Rm) and the parallel capacitance (Cm) at 20°C were 30 ± 5 × 10−3Ωm2 and 1.5 ± 0.5 × 10−1Fm−2 (at 30 Hz), respectively. And the series resistance, corresponding to the vacuole of the internode was 8 × 10−3Ωm2. Study of temperature dependencies of Rm and Cm suggested that a dynamic homeostatic regulation was operating at the interface where numerous plasmodesmata were observed with an electron microscope (Pickett-Heaps 1967; Spanswick and Costerton 1967). Assuming that the individual cylinder of plasmodesma was filled only with cytoplasm, the number of plasmodesma per interface was estimated at 2.6 × 105.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003440000010
Permalink