In today's era of sustainable agriculture, discovering ecological and cost-effective approaches for enhancing crop performance has become essential. A growing body of research highlights magnetic and electromagnetic treatments as innovative, non-invasive techniques that hold potential for improving seed quality and thereby increasing agricultural productivity [1,2,3]. Known as magneto-priming, this approach employs different types of magnetic fields (MFs) to trigger beneficial physiological responses in plants. These MFs include extremely low-frequency magnetic fields, either static magnetic fields (SMF) or pulsed magnetic fields (PMF), which can be applied for various durations and at diverse frequencies based on plant species and specific growth stages [4]. Such magnetic treatments influence various aspects of plant physiology and biochemistry, leading to enhanced seed germination rates, improved nutrient uptake, and increased resistance to environmental stress [5,6] and ultimately improved plant growth.

Pre-sowing exposure of seeds to static magnetic fields (SMF) has shown remarkable improvements in plant growth metrics such as germination rate, germination speed, seedling length, and dry weight in crops like sunflower, soybean, and maize [7,8,9]. Previous reports on MF in vitro have revealed that MF influences cell membrane properties, modulates functional response of cells, and impacts growth dynamics [10]. Notably, PMF exposure enhances the biosynthesis of protein, enzyme activity, and mineral uptake in soybean seedlings relative to controls [11]. Additionally, PMF exposure has been shown to stimulate root and shoot regeneration in cultured explants [12].

Research also suggests that MF pre-treatments may counteract inhibitory stresses, thereby supporting plant resilience. Treating seeds with magnetic fields enhance seed vigor, growth, and resilience against stressors like saline (during wastewater irrigation) and drought conditions [13,14]. SMF exposure has been beneficial in mitigating negative effects associated with weeding and optimizing plants solar radiation use [15,16]. In addition, MF treatment has been linked to improvements in photosynthetic function, where photosynthetic pigment synthesis, PSII physiological activity, and cell membrane stability are positively influenced [17]. Following exposure to SMF and PMF, enhanced maximal photochemical efficiency and electron transport within PSII have been observed. Notably, SMF has also demonstrated a positive effect on energy absorption and transfer within PSII reaction centers [7].

Despite these advances, the effects of SMF and PMF on PSI remain unclear, as does the relationship between PSII and PSI under these conditions. For a complete understanding of magnetic treatment impacts on the photosynthetic apparatus, it is crucial to concurrently assess PSI and PSII activities. This dual focus could elucidate underlying mechanisms and clarify how magnetic fields interact with the photosynthetic machinery, fostering deeper insights into their potential agricultural applications.

In this study, we employed the Dual-PAM-100 to investigate the influence PMF and SMF on the activities of PSII and PSI, cyclic electron flow (CEF), and the regulatory interactions between PSII and PSI in soybean plants. In light reactions, a balanced activity between PSI and PSII is essential for maximum photochemical efficiency. Three key sensitive sites in the photosynthetic apparatus are: (i) PSII, particularly its oxygen-evolving complex (ii) PSI, and (iii) the carbon assimilation processes. While extensive research has focused on how external factors affect PSII and carbon assimilation, there is limited information on changes in PSI's energy conversion. Given that PSI is generally less sensitive than PSII, it is crucial to analyze both photosystems simultaneously to fully understand the overall electron transport chain. The Dual-PAM-100 enables simultaneous measurement of energy conversion in PSI and PSII, critical for evaluating plant performance, which depends on a harmonious balance between the rates of energy conversion in both photosystems [18,19,20,21]. By using Dual-PAM-100, PSII energy partitioning is evaluated via chlorophyll a fluorescence yield parameters using the saturation pulse (SP) method, while PSI efficiency is assessed by detecting changes in the redox state of the PSI reaction center (P700) through absorbance shifts in the 800–835 nm region due to the P700+ cation-radical [22]. Investigating MT induced alterations in the photosynthetic electron transport chain is essential, as they contribute to ATP/NADPH balance regulation, vital for carbon fixation, downstream metabolic pathways and consequently, biomass and growth.

Our experimental findings reveal, for the first time, shifts in PSI energy conversion efficiency in soybean plants grown from magneto-primed seeds. To the best of our knowledge, no prior studies have documented the effects of both SMF and PMF on the functional performance of both photosystems. We propose a mechanistic and functional hypothesis to explain the results obtained by us as well as previous reports on magneto-priming. Our research offers foundational insights, paving the way for future studies on the molecular mechanisms by which MT influences photosynthetic regulation.