Pre-sowing magnetic treatments of seeds improve photosynthetic performance of two photosystems in soybean plants

Abstract

To investigate the impact of pre-sowing magnetic treatment on soybean plants under natural conditions, a study was carried out focusing on the photosynthetic machinery. Soybean seeds were subjected to magneto-priming through exposure to pulsed magnetic field (PMF, 200 mT for 1 h) and static magnetic field (SMF, 200 mT for 1 h). The dual pulse-amplitude modulator (PAM) technique was employed to assess the simultaneous performance of photosystem II (PSII) and photosystem I (PSI) in magneto-primed soybean seeds. It was observed that after magnetic treatment (MT), the effective quantum yield of photosystem II [Y(II)] exhibited an increase, accompanied by a reduction in non-photochemical quenching (NPQ). Furthermore, the quantum yield of photosystem I [Y(I)] showed enhancement, reaching its maximum in the 200 mT PMF treatment. Non-photochemical quenching was lower in MT-treated seed plants as compared to control, indicating a reduction in energy dissipation and an enhancement in energy transfer from PSII to PSI. The magneto-primed seeds demonstrated an increased electron transport mechanism as evidenced by enhanced ETR(I) and ETR(II). Additionally, lower values of Y(NA) and Y(ND) suggested improved activity of both PSI and PSII in regulating energy transport in cyclic electron flow (CEF) and linear electron flow (LEF). The results suggest that PMF treatment is more beneficial than SMF for enhancing photosynthetic efficiency via regulation of PS II and PSI quantum yield.