Proportionality of 60-Hz electric field bioeffect severity to average induced transmembrane potential magnitude in a root model system.

The postulate that electric field-induced bioeffects in the root model system are related to the induction of 60-Hz transmembrane potentials (Vim) was quantitatively tested. Root segment growth rate data and the calculated mean 60-Hz Vim which would arise in the cortical cells of a segment under specified exposure conditions were subjected to regression analysis. Statistically significant correlations between segmental growth rate and segmental-average Vim were obtained using data analyzed (1) within species at a constant applied field strength, (2) within species and pooled across field exposures, and (3) pooled across both species and exposures. In C. sativus roots, segmental growth is inhibited when segmental-average Vim attain a value of 3.4-3.6 mV. In C. maxima roots, growth inhibition occurs when Vim attain or exceed 2.3-2.7 mV. Segmental growth cessation is predicted to occur when segmental-average Vim exceed 7-9 mV.