Effects of high and very low magnetic fields on the growth of hairy roots of daucus carota and atropa belladonna

Hairy roots of Daucus carota and Atropa belladonna, which were induced by inoculation with Agrobacterium rhizogenes that harbored the Ri plasmid, were cultured on Murashige and Skoog's solid medium in magnetic fields of 5 kgauss or 50 μgauss. The growth rate of roots exposed to 5 kgauss was 25% greater than that of the control (0.01 kgauss). In the case of A. belladonna, the growth rate of the roots cultured in a field of 50 μgauss was 40 to 56% greater than that of the control (0.5 gauss). In D. carota, after more than 40 h of incubation, growth rates in both sets of conditions (50 μgauss and control) were the same.