Magnetic Field Effects on the Growth and Physiology of Wheat (Triticum aestivum) by Modulation of Photosynthetic Activity and Gene Expression

Magnetic field (MF) treatment is a promising approach in boosting plant growth and yield. Although it is an eco-friendly and safe practice, research on the optimal MF strength, magnetic sensing, and MF-induced molecular response mechanisms in plants is limited. In this study, we investigated the effects of different MF strengths (20, 40, 120, and 250 milliTesla-mT) on key physiological indices (seed germination, tissue growth, physiological indicators, cell membrane integrity, photosynthetic activity, and pigmentation) in wheat. Confocal and scanning electron microscopies were used to observe cellular and morphological changes. Relative expression levels of key genes associated with metal homeostasis, antioxidant defense, and hormone metabolism (YSLA, NRAMP, FER1, CAT, HSP70, GPX, and PSIK) were quantified by RT-PCR. The results showed that MF treatment remarkably enhanced germination (18.75%), root (41%) and shoot (110%) growth. While lower MF strength acted as a biostimulant, higher intensities caused damage. A significant increase in the electron transport rate (ETR), photosynthetic yield (Y(II)), and pigmentation at 20–40 mT indicates effective conversion of light into chemical energy. Conversely, higher MF strengths (≥ 120 mT) induced cell membrane injury and caused root deformation. Significant upregulation of genes related to metal homeostasis (YSLA, NRAMP) and antioxidant activity (CAT), and downregulation of genes related to hormone regulation-associated gene (PSIK) were demonstrated. These findings suggest that MF, particularly at high intensities, is perceived as a potent abiotic stressor by wheat seedlings. This perception activates metal transporters while suppressing growth-related signaling. On the other side, low-power MF (20–40 mT) can be effectively applied to promote plant growth.