Effects of a Magnetic Field on the Growth of Primary Roots of Zea mays

Caryopses with primary roots of Zea mays L. (cv. Golden CrossBantam 70) were incubated on agar-solidified distilled water(0.4% agar) in a magnetic field of 5 k gauss or 0.01 k gauss(control), the direction of root growth corresponding to thedirection of magnetic field from the north- to the south-seekingpole. The rate of growth of the roots exposed to 5 k gauss wasincreased by about 25% over that of the controls (0.01 k gauss).When caryopses with primary roots were incubated on agar-solidifieddistilled water that had previously been exposed to a magneticfield of 5 k gauss or 0.01 k gauss, no differences in ratesof root growth were observed. The growth rate of the primaryroot increased with increased magnetic flux density (from 0.01k to 5 k gauss). The orientation of the root in terms of thedirection of the magnetic field (from the north- to the south-seekingpole) affected the rate of growth of the root. When the directionof root growth was in line with the direction of the magneticfield of 5 k gauss or in the direction opposite to that of thefield, growth rates increased by 27% and 22%, respectively,of the growth rate of the controls (magnetic field of 0.01 kgauss). When the direction of growth was perpendicular to thedirection the field, the growth rate increased by 15% of thatof the control (0.01 k gauss). It appears that a magnetic stimulusmay induce an increase in the rate of root growth in some plantmaterials. (Received March 23, 1988; Accepted August 9, 1988)