Hybrid nanocomposites of cerium oxide nanoparticles in chitosan/alginate to enhance the salinity stress tolerance of Carrizo citrange rootstock

An innovative hybrid nanocomposite based on ceria was synthesized to enhance the salinity stress tolerance of Carrizo citrange rootstock. Our approach involved loading ceria nanoparticles (CeO₂) in chitosan (Chi) and alginate (Alg) biopolymeric nanocomposites, obtaining a water dispersion easily sprayable to plants leaves. The material properties were assessed by chemical and morphological analysis, revealing the success of preparation in terms of nanometric sizes and stability. The quantification of metal oxide content in the Chi/Alg-CeO₂ hybrid nanocomposite suspension was achieved by Inductively Coupled Plasma Mass Spectrometry resulting in 15 mg/L of cerium. The hybrid nanocomposite degradation was also studied by accelerated aging under UV-A radiation, evidencing a depletion of polymeric counterparts. The water dispersion of Chi/Alg-CeO₂ hybrid nanocomposites was tested on one year old potted seedlings to evaluate its efficacy in mitigating the plant tolerance against saline stress. Morphological and biochemical behaviour together to antioxidant activities were monitored for different saline concentrations. Increased proline levels and total polyphenols were recorded with Chi/Alg-CeO₂ treatment. Data revealed that Chi/Alg-CeO₂ increased provided a remarkable solution in alleviating high levels of oxidative processes, allowing higher water absorption to form the root system, thus inducing plant growth in conditions of mid-low photosynthetic capacity.