Several studies have been done at Wagner Research in this area. The largest study involved analyzing the distributions of many thousands of plant internodal spacings (spacings between leaves, stems, and branches, for example) around an electric power substation. We measured both the electric and magnetic fields for different samplings of spacings. For certain fields we found, for example, that the spacing average became much longer than for the corresponding averages taken from plants far away from the substation.

We also looked at W-wave modes (frequencies) generated by various sources of electromagnetic field. We found, using the proper detectors, that large amplitude modes were produced by 60 Hertz and several radio frequency sources. The mode frequencies were much different than the electromagnetic frequencies producing them but their frequencies were frequencies that we found to be connected with waves in plants.

Thus it appears that the affects of electromagnetic fields on growing plants are much more subtle than thought heretofore. The data all confirm the wave nature of plants. Plants don't seem to be harmed by electromagnetic waves, if the fields aren't too large, but their growth structure is often changed. See Waves in Dark Matter pp. 129-143 for much more information.