Chitosan nanoparticles enhance physiological and biochemical responses of maize under salinity stress

In recent years, it has been discovered that chitosan nanoparticles )CSNPs(, as messengers and elicitors, play a fundamental role in growth and development processes, improving plants’ adaptation to adverse environmental conditions. Salt stress poses a serious threat to plants, significantly reducing their growth and performance by disrupting osmotic balance. Maize is an important cereal crop after rice. The development of this crop is crucial for providing food for livestock, poultry, and humans. The present study investigates the effects of the growth regulator CSNPs on the mineral elements, physiological, and biochemical characteristics of maize plants under salt stress. Salinity stress was applied using NaCl at concentrations of 0, 50, and 100 mM. CSNPs were also used as foliar sprays at concentrations of 50 and 100 mg L − 1 . Salt stress negatively affected maize plants by decreasing mineral elements, reducing water availability, diminishing photosynthetic pigments, and decreasing photosynthetic efficiency. It also disrupted stomatal opening and altered intercellular CO 2 levels. Furthermore, salt stress increased ion leakage and H 2 O 2 production while elevating proline and sugar levels, indicating unfavorable conditions. However, exogenous application of CSNPs mitigated these negative effects and improved plant growth by activating the plants’ antioxidant defense systems. Overall, foliar application of CSNPs enhanced maize tolerance to salt stress by maintaining redox homeostasis and photosynthetic efficiency.