Microwave exposure added characteristics to the wounding-induced variation potential of Aloe arborescens leaves

Abstract

The influence of radiofrequency electromagnetic radiation on the wounding-induced electric potentials (EPs) in Aloe arborescens plants was investigated. Burn wounding-induced electrical potentials of mature A. arborescens plants were observed under the exposure of 2.45 ​GHz, 3.5 ​GHz and 5.5 ​GHz microwaves at incident power density 1.5 ​± ​0.2 ​W ​m⁻². Aloe leaves were subjected to flame wounding at the leaf tips and propagation EPs were recorded by inserting a glass Ag/AgCl microelectrode into the leaf pulp. The propagation of electrical potential and a standard deviation of the fluctuations in electrical potential (SDEF) were investigated. The flame wounding generated propagating characteristic electric potential, and the exposure of microwaves added extra characteristics to the signals by reversing the electrical potential temporally for a shorter duration. The characteristics appeared in the repolarization phase of the signal under 2.45 ​GHz and 3.5 ​GHz exposure; for the 5.5 ​GHz exposure, 3 out of 6 characteristics appeared during the depolarization phase. Averaged polarization rates of the characteristics were increased with the increased microwave frequency. Added characteristics to the electric potential may have resulted from a secondary signal triggered due to microwave exposure, which should be further studied. The repolarization and depolarization rates of the wound signals were not different between control and microwave exposures. SDEFs were also not affected by microwave exposure.