Imatinib–Zinc Complex Seed Pre-Treatment Improves Early Responses of Maize (Zea mays L.) to Gamma Irradiation

Ionizing radiation induces oxidative damage and disrupts plant growth and photosynthetic function. This study evaluated whether seed pre-treatment with a synthesized imatinib–zinc complex (ZnIM), with the proposed composition Zn(C₂₉H₃₁N₇O)₂, could mitigate the effects of gamma irradiation in maize (Zea mays L.). Maize seeds were pre-treated with 0.001%, 0.01%, or 0.1% (w/v) ZnIM and subsequently exposed to 150 Gy gamma irradiation. Germination, seedling growth, malondialdehyde (MDA) content, photosynthetic pigments, maximum quantum efficiency of photosystem II (Fv/Fm), and selected mature-plant traits were assessed. Irradiation reduced germination, germination energy, root length, and shoot length by 9.3%, 9.7%, 9.8%, and 12.7%, respectively. Chlorophyll a, total chlorophyll, and Fv/Fm decreased by 32.0%, 30.4%, and 6.2%, while first-week MDA content increased 2.06-fold. Plant height and 1000-grain weight declined by 11.1% and 5.4%, respectively. ZnIM partially mitigated these effects, with responses varying among concentrations. The 0.01% treatment most consistently restored germination, germination energy, and root length and improved chlorophyll a, total chlorophyll, and Fv/Fm. The 0.1% treatment produced the most sustained MDA reduction. Improvements in mature-plant traits were numerical but not statistically significant. Overall, ZnIM provided partial radioprotection, particularly during germination and early seedling development.