Published online by Cambridge University Press: 12 June 2017
Seed lots of Macartney rose (Rosa bracteata Wendl.), yaupon (Ilex vomitoria Ait.) huisache [Acacia farnesiana (L.) Willd.], and honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] were exposed for various periods to radiofrequency (RF) dielectric heating by electromagnetic fields of 10 and 39 megahertz (MHz) at various field intensities in attempts to increase their germination. Both continuous-wave and pulse-modulated exposures were used at 39 MHz. Seed samples were preconditioned at temperatures from 24 to −43 C before exposure. Sixty-Hz a-c and d-c electrical treatments were included in some experiments. Although significant increases in germination were obtained by RF treatment of huisache and honey mesquite seed in some experiments, results with different huisache seed lots were inconsistent. The germination of Macartney rose seed was not increased, and no germination was observed in yaupon, regardless of the treatment employed.