Enhancing maize seed resistance to chilling stress through seed germination and surface morphological changes using high voltage electrostatic field

The effect of high-voltage electrostatic field (HVEF) on maize seeds' resistance to chilling injury remains unclear. This study investigates the chemical and spatial changes induced by HVEF at macroscopic and microscopic levels via the combination of physiological assessments and scanning electron microscopy (SEM). Maize samples were categorized into low and normal-temperature groups. At an HVEF strength of 1.6 kV/cm, all indices in the low-temperature group significantly improved relative to the control (P < 0.01), with germination potential, rate, index, and vigor index increasing by 11.7%, 11.2%, 10.5%, and 31.7%, respectively. Root length, shoot length, and dry weight of maize seedlings rose by 20.3%, 19.2%, and 16.6%. Further analysis revealed a 62.7% increase in soluble sugar content in HVEF-treated seeds and the lowest leaching solution conductivity of 1.6 kV/cm. These results demonstrate that HVEF treatment enhances soluble sugar accumulation during seed germination, regulating osmotic balance within the cells. Furthermore, SEM assessed maize microtissue morphology after chilling injury and HVEF treatment. Optimal HVEF treatment resulted in cell wall expansion, enhanced fiber elasticity, reduced interstitial spaces, and swollen cells, indicating improved hydrophilicity and protease activity. This study offers valuable insights into the mechanisms by which HVEF improves seed performance under low-temperature stress.