In this study, the growth, antioxidant potential and membrane stability parameters in root and shoot of two wheat (Triticum aestivum L.) cultivars (Unnat PBW 343 and HD 296) treated with 1.5 ppm and 10 ppm zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles under high temperature (32 °C) were studied in twelve day old seedlings. Shoot, root length and biomass activities of superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased more than catalase, with application of ZnO and TiO₂ nanoparticles especially at 32 °C. Apparently, phenols and flavonols showed dramatic increase in parallel with higher free radical scavenging activities as measured by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant potential indicating stress tolerance by scavenging free radicals. Both ZnO and TiO₂ nanoparticles had promoting effect at lower concentration (1.5 ppm) compared with higher concentration. Interestingly, TiO₂ nanoparticles though improved seedling performance slightly better than ZnO nanoparticles; however, antioxidant defense response was greater with ZnO nanoparticles. Nonetheless, compared to the HD 2961 cultivar, the Unnat PBW 343 cultivar had lower malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents along with higher upregulation of antioxidant defense system under heat stress conditions treated with nanoparticles owing to the better expression of antioxidants. Nanoparticles uptake was authenticized using scanning electron microscope–energy-dispersive X-ray spectroscopy. Results demonstrated different shapes and size of nanoparticles such as bunch of irregular particles, round shaped and small particles. Therefore, pretreatment by ZnO and TiO₂ nanoparticles significantly improved resistance against heat stress through increase in more SOD and GPX activity, causing further lowering of H₂O₂ levels and thereby stabilizing membrane as evidenced by 1.5 times lower MDA content.

在这项研究中，用 1.5 ppm 和 10 ppm 氧化锌 (ZnO) 和二氧化钛处理的两种小麦（普通小麦）品种（Unnat PBW 343 和 HD 296）的根和茎的生长、抗氧化潜力和膜稳定性参数（TiO ₂）纳米颗粒在高温（32°C）下在十二天大的幼苗中进行了研究。随着ZnO和TiO _{2 的}应用，超氧化物歧化酶（SOD）和愈创木酚过氧化物酶（GPX）的枝条、根长和生物量活性增加超过过氧化氢酶纳米颗粒，尤其是在 32°C 时。显然，酚类和黄酮醇显示出与更高的自由基清除活性平行的显着增加，如通过 2,2-二苯基-1-苦基肼和铁降低抗氧化潜力所测量的，表明通过清除自由基表明压力耐受性。与较高浓度相比，ZnO 和 TiO ₂纳米颗粒在较低浓度 (1.5 ppm) 下均具有促进作用。有趣的是，TiO ₂纳米颗粒虽然改善了幼苗性能，但略好于ZnO纳米颗粒；然而，氧化锌纳米颗粒的抗氧化防御反应更大。尽管如此，与 HD 2961 品种相比，Unnat PBW 343 品种的丙二醛 (MDA) 和过氧化氢 (H ₂ O ₂) 含量以及在用纳米颗粒处理的热应激条件下抗氧化防御系统的更高上调，这是由于抗氧化剂的更好表达。使用扫描电子显微镜 - 能量色散 X 射线光谱法验证纳米颗粒的吸收。结果显示了不同形状和大小的纳米颗粒，例如不规则颗粒束、圆形和小颗粒。因此，用 ZnO 和 TiO ₂纳米颗粒进行预处理，通过增加更多的 SOD 和 GPX 活性，显着提高了对热应激的抵抗力，导致 H ₂ O ₂水平进一步降低，从而使膜稳定，MDA 含量降低 1.5 倍就证明了这一点。