Selenium seed priming enhanced the growth of salt-stressed Brassica rapa L. through improving plant nutrition and the antioxidant system

Abstract

Various abiotic stresses may affect the germination, growth, and yield of direct-seeded vegetable crops. Seed priming with effective antioxidant mediators may alleviate these environmental stresses by maintaining uniformity in seed germination and improving the subsequent health of developing seedlings. Salt-induced stress has become a limiting factor for the successful cultivation of <i>Brassica rapa</i> L., especially in Southeast Asian countries. The present study was performed to elucidate the efficacy of seed priming using selenium (Se) in mitigating salt-induced oxidative stress in turnip crops by reducing the uptake of Na⁺. In this study, we administered three different levels of Se (Se-1, 75 μmol L^-1; Se-2, 100 μmol L^-1; and Se-3, 125 μmol L^-1) alone or in combination with NaCl (200 mM). Conspicuously, salinity and Se-2 modulated the expression levels of the antioxidant genes, including catalase (<i>CAT</i>), peroxidase (<i>POD</i>), superoxide dismutase (<i>SOD</i>), and ascorbate peroxidase (<i>APX</i>). The upregulated expression of stress-responsive genes alleviated salt stress by scavenging the higher reactive oxygen species (ROS) level. The stress ameliorative potential of Se (Se-2 = 100 μmol L^-1) enhanced the final seed germination percentage, photosynthetic content, and seedling biomass production up to 48%, 56%, and 51%, respectively, under stress. The advantageous effects of Se were attributed to the alleviation of salinity stress through the reduction of the levels of malondialdehyde (MDA), proline, and H₂O₂. Generally, treatment with Se-2 (100 μmo L^-1) was more effective in enhancing the growth attributes of <i>B. rapa</i> compared to Se-1 (75 μmo L^-1) and Se-3 (125 μmo L^-1) under salt-stressed and non-stressed conditions. The findings of the current study advocate the application of the Se seed priming technique as an economical and eco-friendly approach for salt stress mitigation in crops grown under saline conditions.