Comparative Effectiveness of Iodine Nanoparticles and Potassium Iodide on Nitrogen Assimilation, Biomass, and Yield in Lettuce Patiño-Cruz, Juan J. Ochoa-Chaparro, Erick H. Navarro León, Eloy Chávez-Mendoza, Celia Muñoz-Márquez, Ezequiel Guevara-Aguilar, Alexandro Pérez-Álvarez, Sandra Sánchez-Chávez, Esteban Lactuca sativa L. foliar fertilization iodine nanoparticles We would like to thank the Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI—Mexico) for the support provided by the scholarship granted to Juan José Patiño Cruz through the “Becas Nacionales SECIHTI” program with CVU No. 1317558 Efficient nitrogen assimilation in crops remains a key challenge for sustainable agriculture. This study investigated the physiological effects of foliar application of iodine on Lactuca sativa L. cv. Butterhead, comparing two different chemical forms—nanoparticulate iodine (INPs) and potassium iodide (KI)—selected to contrast a conventional ionic source with a nanoformulations of growing interest in plant nutrition. Plants were treated under passive hydroponic conditions with INPs and KI at concentrations of 40, 80, and 160 µM. The results showed that INPs at 40 µM significantly increased total biomass and soluble amino acid accumulation compared to the control, with no signs of phytotoxicity. In contrast, KI treatments significantly increased nitrate reductase activity, suggesting a role in the activation of the nitrogen pathway. However, neither form consistently outperformed the other across all evaluated variables. Yield and total chlorophyll content remained statistically unchanged between treatments, indicating a complex and form-dependent response. These findings highlight the differential physiological effects of iodine formulations on nitrogen-related metabolism and provide preliminary evidence for their potential integration into precision fertilization strategies focused on biochemical efficiency and metabolic modulation. 2025-09-23T11:19:40Z 2025-09-23T11:19:40Z 2025-09-16 journal article Patiño-Cruz, J.J.; OchoaChaparro, E.H.; Navarro-León, E.; Chávez-Mendoza, C.; MuñozMárquez, E.; Guevara-Aguilar, A.; Pérez-Álvarez, S.; Sánchez, E. Comparative Effectiveness of Iodine Nanoparticles and Potassium Iodide on Nitrogen Assimilation, Biomass, and Yield in Lettuce. Nitrogen 2025, 6, 85. https://doi.org/10.3390/nitrogen6030085 https://hdl.handle.net/10481/106561 10.3390/nitrogen6030085 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI