Electromagnetic field (EMF) and its effect on crop plant growth and their quality parameters is increasingly gaining the interest of researchers in agronomic science. However, the exact mechanism of EMF action in plant cells is still unclear. Among the completely unexplored parameters is the relationship between the EMF effects and the seed size. Thus, the EMF effect was analyzed in winter wheat seeds categorized into two size groups, small and big. The study focused on the germination kinetics, early growth parameters, and phytohormone concentrations (indole-3-acetic acid, IAA and abscisic acid, ABA) in seeds, roots, and coleoptiles after exposure to EMFs (50 Hz, 7 mT) and their controls. EMF exposure resulted in faster germination and the more rapid early growth of organs, especially in big seeds in dark conditions. The faster germination and seedling growth of small seeds in control conditions, and of big seeds after EMF exposure, corresponds largely to the decline in IAA and ABA levels. This study confirms that presowing treatment with an EMF is a promising tool for sustainable seed crop improvement, but detailed studies on the EMF mechanism of action, including phytohormones, are necessary to better control future crop yield, especially considering the factor of seed size.

Research interest into the exposure of plants to magnetic fields (MF), including electromagnetic fields (EMF), has increased recently but results often vary depending on factors such as plant species and treatment dose. In this study, we exposed young (one year) and old (four years) field bean (Vicia faba L. (partim)) seeds to EMF (50 Hz, 7 mT) and observed seed germination and seedling growth under different conditions (growth media and light). The results indicated a stimulation by EMF of germination and early root growth of Petri dish-sown old seeds in continuous darkness and inhibition of germination of the pot-sown young seeds under long-day conditions. Root growth of two-week-old seedlings from pot-sown young seeds was stimulated by EMF treatment while their stem growth was inhibited. Some selected biochemical traits were examined, showing specific changes in membrane integrity, amylase activity, H₂O₂ levels, photosynthetic pigments, and content of the main groups of phytohormones, depending on seed age. The results indicate that priming of field bean seeds with EMF (50 Hz, 7 mT) could be a eustress factor that influences germination, early growth, and cellular activities and could positively influence the ability of field bean plants to grow and develop in more stressful conditions at later stages.