Use of a Biostimulant to Mitigate Salt Stress in Maize Plants

Salinity is considered among the abiotic stresses most impacting agriculture for its ability to interfere with crop development and quality. For this reason, practices and innovations that could contain the deleterious effects of such stress are of pivotal importance for maintaining acceptable crop yields. In this context, this work has concerned the study of severe salt stress (100 mM NaCl) on maize seedlings and the effects of a plant biostimulant (Megafol–Meg) in helping plants to cope with this adversity. Biomass production, pigments, the content Na⁺ and K⁺, the accumulation of hydrogen peroxide (H₂O₂) and lipid peroxidation products (MDA), total phenolic compounds (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were investigated in control samples, in samples treated with NaCl alone, and in samples treated with NaCl in combination with the biostimulant. The results showed that the biostimulant significantly mitigated the impact of the salt stress on shoot length and fresh weight, on chlorophyll and carotenoid contents, and reduced the amount of Na⁺ taken up by the species. Regarding the oxidative status, the biostimulated samples revealed lower amounts of H₂O₂ and MDA, while maize seedlings grown with NaCl alone exhibited the highest increases in the TPC, ABTS, and FRAP. The explanation for these effects is provided by highlighting the effectiveness of the biostimulant in avoiding Na⁺ accumulation, which resulted in a lower content of H₂O₂, MDA, TPC, and antioxidant activity.