Synergistic Effects of Selenium and Silicon Nanoparticles on Peach Quality Enhancement and Se Biofortification Through Foliar Application

Selenium (Se) biofortification represents a critical strategy for addressing micronutrient deficiency while enhancing fruit nutritional quality. This study investigated foliar applications of Se and Si nanoparticles (NPs) for peach Se biofortification and quality enhancement. Se NPs (95.2 nm) were synthesized and characterized using SEM, EDS, and FTIR analyses. Six treatments were applied: control (Ck), SeNPs-5, SeNPs-10, SiNPs-10, Se5Si10, and Se10Si10. SeNPs-10 achieved maximum Se biofortification (0.47 mg kg−1), representing 5.4-fold increases over controls, with 85% organic Se accumulation. Combined treatments demonstrated synergistic effects on multiple quality parameters. Se5Si10 led to the highest antioxidant enzyme activities (peroxidase: 2254 U g−1, catalase: 61.7 U g−1) and phenolic compound enhancement (chlorogenic acid: 267 mg kg−1, total phenolics: 12.8 mg GAE g−1). Flavonoid biosynthesis was optimized with Se10Si10 achieving maximum rutin accumulation (53.9 mg kg−1) and ascorbic acid content (60.7 mg/100 g). Physical quality improvements included enhanced firmness (100.9 N cm−2) and sugar accumulation (14.1% soluble solids). Combined treatments reduced oxidative stress markers (MDA: 22.11 μmol g−1) while enhancing protein metabolism. These findings demonstrate that Se-Si nanoparticle combinations showed optimal biofortification with synergistic quality enhancement, establishing effective strategies for nutritionally enriched peach production.