Foliar application of bio-nano-selenium enhances selenium biofortification and nutritional quality in ‘Nai’ plum (Prunus salicina L.)

This study investigated whether foliar application of bio-nano-selenium enhances the nutritional quality of ‘Nai’ plum without compromising sensory attributes. A field experiment with seven treatments (three replicates each, 21 trees in a completely randomized design) was conducted using two dosages (600 mL or 900 mL of 50 mg L⁻¹ solution) applied at different fruit developmental stages. Key sensory parameters—including soluble sugars (SS), titratable acids (TA), total soluble solids (TSS), and fruit shape index (FSI)—showed no statistically significant differences across treatments. Bio-nano-selenium significantly increased tannin and vitamin C (Vc) content, indicating selective stimulation of secondary metabolism, and elevated cationic mineral levels (K, Ca, Mg). All treated fruits achieved organic selenium proportions exceeding 70%. The T1-2 treatment (600 mL applied at the rapid enlargement and coloring stages) yielded optimal selenium enrichment (0.044 mg kg⁻¹ total Se, 0.04 mg kg⁻¹ organic Se). Multiple treatments met the group standard for selenium-rich agricultural products (T/CATEA 003–2022). These results demonstrate that foliar bio-nano-selenium application represents an effective strategy under our experimental conditions for simultaneous selenium biofortification and nutritional enhancement in plum production. • Bio-nano-selenium enriches ‘Nai’ plum fruits with over 70% organic selenium. • Fruit sensory qualities remained stable under bio-nano-selenium treatments. • Bio-nano-selenium selectively boosts tannin and vitamin C content. • Key mineral nutrients (K, Ca, Mg) were enhanced by bio-nano-selenium.