The relationship between sensitivity to 60-Hz electric fields and induced transmembrane potentials in plants root cells
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Growth rates and cell diameters were determined from 12 species of plant roots exposed to a 60-Hertz (Hz) electric field of 360 Volts per meter (V/m) in an aqueous inorganic nutrient medium [conductivity: 0.07–0.09 Siemens per meter (S/m)]. The degree of growth depression ranged from zero to nearly 100 percent of control. Cell diameters ranged from 13.5 to 31.8 µm as an averaged value for procambial, cortical, and meristem cells. Sensitivity to the electric field as determined by root growth rate reduction increased with increasing cell size. Sensitivity also increased with increase in 60 Hz induced transmembrane potentials; the transmembrane potential threshold for growth reduction was about 6.0 mV and the potential for near-complete cessation of growth was about 10–11 mV.
Two different hypothetical mechanisms of action by which applied electric fields induce biological effects at the cellular level were tested. The two mechanisms pertain to different possible modes of action of applied electric fields: one mechanism postulates the involvement of the transmembrane field, the other mechanism postulates the tangential electric field as the important factor for inducing biological effects. The data support the transmembrane and not the tangential field mechanism. It is concluded that the effects observed are consistent with a membrane related mechanism and that there is a narrow range (a few mV) between threshold and debilitating induced membrane potentials.
KeywordsApplied Electric Field Inorganic Nutrient Meristem Cell Cell Diameter Growth Rate Reduction
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- 1.Cox C, Davis H, Miller MW, Robertson D (1980) Statistical analysis of root growth rate determination. Environ Exp Bot 20:389–396Google Scholar
- 2.Fröhlich H (1968) Long-range coherence and energy storage in biological systems. Int J Quantum Chem II:641–649Google Scholar
- 3.Inoue M, Miller MW, Cox C, Carstensen EL (in press) Growth rate and mitotic index inVicia faba roots exposed to 60-Hz electric fields. BioelectromagneticsGoogle Scholar
- 4.Inoue M, Miller MW, Cox C, Brayman AA (1985) Absence of an electrolytic contaminant effect from a 60-Hz electric field exposure sufficient to reduce root growth rate ofPisum sativum L. Environ Exp Bot 25:89–97Google Scholar
- 7.Miller MW, Carstensen EL, Kaufman GE, Robertson D (1979) 60-Hz electric field parameters associated with the perturbation of a eukaryotic system. In: Phillips RD, Gillis MF, Kaune WT, Nahlum DD (eds) Biological effects of extremely low frequency electromagnetic fields. (Proc. 18th Ann. Hanford Life Science Symp., October 1978, Richland, Wash). DOE Symposium Series 50. Technical Information Center, Oak Ridge, Tennessee, pp 109–116Google Scholar
- 8.Miller MW, Carstensen EL, Robertson D, Child SZ (1980) 60 Hz electric field parameters associated with the perturbation of a eukaryotic cell system. Radiat Environ Biophys 18:280–300Google Scholar
- 9.Miller MW, Economou P, Cox C, Robertson D (1982) Micronucleic formation inPisum sativum L. root meristem cells exposed to an electric field orγ-rays. Environ Exp Bot 22:271–275Google Scholar
- 14.Voth PD, Hamner N (1943) Effects of nutrient solution concentration on the growth ofMarchantia polymorpha. Bot Gaz 104:591–601Google Scholar