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The extremely low frequency electrical properties of plant stems
Author(s) -
Hart Francis X.
Publication year - 1985
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250060305
Subject(s) - dielectric , capacitance , materials science , dielectric spectroscopy , conductance , conductivity , dielectric loss , low frequency , frequency response , frequency domain , electrode , analytical chemistry (journal) , chemistry , optoelectronics , electrical engineering , mathematics , condensed matter physics , physics , electrochemistry , mathematical analysis , engineering , chromatography , astronomy
The electrical properties (variation of capacitance and conductance with frequency) of a plant stem can be conveniently measured in vivo by time domain dielectric spectroscopy. In this technique a voltage step is applied to a stem. The resulting polarization current is sampled by a microprocessor and Fourier‐transformed to yield these properties. Spectra were obtained for seven electrode separations along a Poinsettia stem. The inverse capacitance and conductance were plotted vs separation for 50 frequencies from .35 to 350 Hz. Least‐square fits yielded the effective dielectric constant and conductivity of the stem over this frequency range. In this way electrode effects were eliminated. A similar procedure was carried out for Coleus. A log‐log plot of dielectric constant vs frequency shows a two‐stage linear decrease for both plants. The conductivity is primarily DC. The dielectric loss decreases smoothly with frequency for Coleus. These results are compared to those for bone and the inorganic material hollandite. The dielectric properties seem best described by a cooperative, manybody approach.