Integrative use of maize grain embryo extract and bioactive compounds to enhance salinity tolerance in bread wheat (Triticum aestivum L.)

Salinity stress severely reduces wheat growth and productivity by impairing photosynthesis, nutrient uptake, and membrane integrity while inducing oxidative damage. This study assessed the effect of grain soaking (GS) using maize grain embryo extract (MGEE) combined with foliar spraying (FS) of gibberellic acid (GA₃), ascorbate (AsA), or selenium (Se), in improving wheat performance under salinity stress. Field trials were conducted over two consecutive winter seasons (2022–2023 and 2023–2024) on loamy saline soils (ECe: 7.55–7.61 dS m⁻¹) using a split-plot design within a randomized complete block arrangement with three replicates. Among all treatments, MGEE × FS-AsA consistently produced the greatest improvements across physiological, biochemical, anatomical, and yield-related traits. Compared to the untreated control (GS and FS with water), MGEE × FS-AsA increased net photosynthesis and stomatal conductance by 144 and 133%, and enhanced chlorophyll and carotenoid contents by 57 and 37%, respectively. Relative water content and membrane stability improved by 39 and 95%, while oxidative markers—electrolyte leakage, MDA, H₂O₂, and O₂^•⁻—decreased by 61, 71, 74, and 42%, respectively. Antioxidant enzyme activities (catalase, peroxidase and super oxide dismutase) rose by up to 107%, along with substantial increases in non-enzymatic antioxidants (ascorbate, glutathione, and α-tocopherol). Osmolyte accumulation and anatomical traits, including midrib width and mesophyll thickness, increased by 212 and 89%, respectively. Yield attributes such as 1000-grain weight, grain yield per plant, and total yield increased by up to 111, 112, and 104%, respectively. These findings suggest MGEE priming with FS-AsA as a sustainable strategy to enhance wheat tolerance to salinity.