In contemporary floriculture, particularly within the cut flower industry, there is a burgeoning interest in innovative methodologies aimed at enhancing the aesthetic appeal and prolonging the postharvest longevity of floral specimens. Within this context, the application of nanotechnology, specifically the utilization of silicon and selenium nanoparticles, has emerged as a promising approach for augmenting the qualitative attributes and extending the vase life of cut roses. This study evaluated the impact of silicon dioxide (SiO2-NPs) and selenium nanoparticles (Se-NPs) in preservative solutions on the physio-chemical properties of ‘Black Magic’ roses. Preservative solutions were formulated with varying concentrations of SiO2-NPs (25 and 50 mg L−1) and Se-NPs (10 and 20 mg L−1), supplemented with a continuous treatment of 3% sucrose. Roses treated with 20 mg L−1 Se-NPs exhibited the lowest relative water loss, highest solution uptake, maximum photochemical performance of PSII (Fv/Fm), and elevated antioxidative enzyme activities. The upward trajectory of hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in petals was mitigated by different levels of SiO2 and Se-NPs, with the lowest H2O2 and MDA observed in preservatives containing 50 mg L−1 SiO2- and 20 mg L−1 SeNPs at the 15th day, surpassing controls and other treatments. Extended vase life and a substantial enhancement in antioxidative capacity were noted under Se and Si nanoparticles in preservatives. The levels of total phenols, flavonoids, and anthocyanin increased during the vase period, particularly in the 50 and 20 mg L−1 Se-NPs and SiO2-NPs. Petal carbohydrate exhibited a declining trend throughout the longevity, with reductions of 8% and 66% observed in 20 mg L−1 Se-NPs and controls, respectively. The longest vase life was achieved with Se-NPs (20 mg L−1), followed by SiO2-NPs (50 mg L−1) up to 16.6 and 15th days, respectively. These findings highlight the significant potential of SiO2- and Se-NP
