The use of nano particles (NPs) in agriculture is growing dramatically. However, the impact of Fe-NPs on physiological parameters and essential oil yield of lemon balm (Melissa officinalis L.) are still unknown. This research was conducted to address the effect of NPs of Fe oxide (Fe-NPs; 0, 5, 10, 20, 30 and 20 μM) on resistance against reduced irrigation by 80, 60 and 40 % Field Capacity (FC), in Melissa officinalis. Intensified drought, while significantly enhancing malondialdehyde (MDA), H₂O₂, proline conten, electrolyte leakage, total antioxidant activity (TAA), total phenolic content (TPC), antioxidant power and enzyme activities of lemon balm, caused marked reduction in chlorophyll content, ratio of variable to maximum fluorescence (Fv/Fm) and relative water content. The essential oil yield of Melissa officinalis increased with the decrease in irrigation from 80 to 60 % FC, and decreased with the water deficit increase to 40 % FC. Treating lemon balm plants with all levels of Fe NPs further increased the essential oil yield and improved physiological attributes of lemon balm. Fe NPs also resulted in alleviating oxidative stress by reducing TAA, TPC and antioxidant enzymes activities. The compensatory effect of Fe nanoparticle treatments in aleviating the negative effect of reduced irrigation was due to increase of proline accumulation and reduction of some antioxidant activities which increased drought tolerance of lemon balm. Reduced irrigation regimes as well as Fe NPs showed strong effects on essential oil production and composition in lemon balm.

纳米颗粒（NPs）在农业中的使用正在急剧增长。然而，Fe-NPs对柠檬香脂（Melissa officinalis L.）的生理参数和精油产量的影响仍然未知。进行这项研究的目的是为了解决氧化铁纳米颗粒（Fe-NPs; 0、5、10、20、30和20μM）对减少80％，60％和40％田间持水量（FC）的灌溉阻力的影响。梅利莎（Melissa officinalis）。加剧干旱，同时显着提高丙二醛（MDA），H ₂ O ₂，脯氨酸含量，电解质泄漏，总抗氧化活性（TAA），总酚含量（TPC），柠檬香脂的抗氧化能力和酶活性，引起叶绿素含量显着降低，可变与最大荧光的比率（Fv / Fm）和相对含水量。蜜蜂花的精油产量随着灌溉量的减少从80％FC增至60％FC，并且随着水分亏缺增加而降低至40％FC。用所有水平的铁纳米颗粒处理柠檬香脂植物可进一步提高香精油的产量并改善柠檬香脂的生理特性。Fe NPs还可以通过降低TAA，TPC和抗氧化酶的活性来减轻氧化应激。铁纳米颗粒处理减轻灌溉减少的负面影响的补偿作用是由于脯氨酸积累的增加和某些抗氧化剂活性的降低，这增加了柠檬香脂的耐旱性。减少灌溉制度以及铁纳米颗粒对柠檬香脂的精油生产和成分表现出强大的影响。