Background: Salinity stress, an escalating concern in the realm of agriculture, significantly hampers crop productivity worldwide. In recent years, nano-fertilizers have been identified as an innovative and promising avenue for improving nutrient use efficiency and mitigating salt stress in plants.

Aims: This study delves into the comparative efficacy of nano-fertilizers (Zn and Si) and their conventional sources in bolstering maize's resilience against salt stress.

Methods: The hydroponic experiment was conducted to test maize plants under salt stress along with Zn and Si nanoparticles (NPs) application. The analysis extends to their impacts on ionic homeostasis, specifically focusing on potassium and sodium concentrations, K/Na ratio, stomatal conductance, chlorophyll content, and the osmotic potential (OP) within the shoots and roots of maize.

Results: Nanoparticles relatively helped plants better under stress, compared to their respective bulk mode of applications. Nano-Zn treatment considerably boosts the K+ concentration and enhanced K/Na ratio, as a key physiological trait in salt-resistant species, while nano-Si demonstrates a prominent role in modulating OP and limiting Na+ accumulation along with higher Zn and Si accumulation in plants. The salt tolerance index confirmed the contribution of these ionic and osmotic adjustments in helping maize plant against salt stress.

Conclusions: Our findings confirm that the application of nutrients as nano-fertilizers, particularly nano-Zn, enhanced K/Na ratio and improved nutrient availability and uptake of the plant. Si nanoparticles are also attributed to better osmotic adjustment and facilitating water movement, thus highlighting the potential of nano-fertilizers in improving overall agricultural productivity and related environmental issues.