Synthesis and characterization of submicron iodinated polymer particles with biostimulant effect on the germination and vigor of corn seedlings

Current agriculture faces challenges caused by climate change, which induce states of stress in plants, reducing crop productivity. Micro- or nanomaterials are biostimulants that mitigate these adverse effects, having greater efficiency compared to conventional materials. Iodine, at low concentrations, improves plant growth and production. This study aimed to: 1) synthesize and characterize polymeric particles functionalized with submicron iodine (PI), 2) evaluate the impact of pretreatment of corn seeds with these particles on the germination rate and growth of the seedlings, and 3) quantify the iodine in the PI and in the seedlings. The synthesis of the PI was carried out by a chemical reaction from iohexol with a crosslinker and the addition of a polyethylene glycol coating. The average hydrodynamic diameter of the PIs determined by dynamic light scattering was 217 nm, and the iodine content in the synthesized PIs was 1.67 %. For the germination test, four PI concentrations (5, 10, 20, and 50 mg∙L<sup>-1</sup>) and a control (distilled water) were used; 50 seeds were imbibed in 10 mL of each solution and placed in a growth chamber at a temperature of 28 °C for 24 h. The results indicate that PIs do not negatively interfere with the seed germination process and the treatment with a concentration of 50 mg∙L<sup>-1</sup> PI significantly favored some growth variables. The latter indicates that the synthesized PIs presented a biostimulant effect and may be a viable alternative as a biofortifier.