Green Synthesis of Hyperbranched Spermine-Coated Fe₃O₄ Nanoparticles and Their Effect on Corn Seedlings under Copper Oxide Stress

The coating of Fe3O4-NPs with SMand HS isa new strategy to increase the efficiency of nanofertilizers and improvethe quality and resistance of plants against environmental stresses.In this study, aqueous extracts of spinach and guar were used forthe green synthesis of Fe3O4-NPs and CuO-NPs,respectively. The surface of the Fe3O4-NPs wasthen coated with SM and HS. UV-vis, thermogravimetric analysis,Fourier transform infrared spectroscopy, X-ray diffraction, scanningelectron microscopy, transmission electron microscopy, and dynamiclight scattering analyses all confirmed the formation of nanoparticles.The first experiment was carried out as a factorial in a completelyrandomized design. The effect of nanoparticles and determination ofthe optimal concentration of Fe3O4-NPs, SM,HS, Fe3O4-SM, and Fe3O4-HS with concentrations (control, 25, 50, 75, and 100 mg/L) and twomethods of application (seed priming and addition to planting medium)were determined. The results showed that seed priming with 75 mg/LFe3O4-NPs and single-stranded and multibranchedpolyamines improves germination and increases the dry matter contentand seedling length. Then, a pot test was performed for the effectsof Fe3O4-NPs and single-branched and poly branchedpolyamines under CuO stress conditions. The factors were six polymers(control, Fe3O4, SM, Fe3O4-SM, HS, and Fe3O4-HS) and CuO-NPs (control,60, and 120 & mu;L). Under stress conditions, the application ofFe(3)O(4)-HS caused an increase of 34.11, 41, 39.37,and 68.25% in the activity of CAT, POX, PPO, and proline, respectively,and a decrease of 46 and 33.33% in MDA and hydrogen H2O2 compared to the control treatment. Also, the use of NPs understress conditions caused more absorption of N and Fe by the plant.Consequently, the plant's resistance to CuO stress conditionsincreased. Biodegradability, rapidity performance,features and benefitsof structures, and optimal environmental conditions during hyperbranchedspermine production and decomposition created a sustainable biopolymer.(1) Evaluation of the optimal concentration of iron oxide nanoparticles(Fe3O4-NPs) and single-branched and multibranchedpolyamines on improving germination and increasing the dry mattercontent and length of corn seedlings. (2) Determining the best methodof using Fe3O4-NPs and single-branched and multibranchedpolyamines (seed priming and addition to planting medium) to improvethe characteristics of germination and growth of corn seedlings. (3)Reduction of copper oxide stress in corn through the application ofFe(3)O(4)-NPs and single-branched and multibranchedpolyamines and their effect on plant antioxidant activity.