Medicinal and aromatic plant production is popular in the agricultural sector because of the phytochemical compounds that have a powerful effect on people health. The present study examined the impacts of various nitrogen (N: 75, 150, and 300 mg/L), phosphorus (P: 50, 75, and 100 mg/L), and potassium (K: 150, 350, and 550 mg/L) concentration in the nutrient solution (NS) on growth, physiological attributes, antioxidant capacity, nutrient accumulation and essential oil (EO) components in Origanum dubium plants grown in hydroponics. The NPK levels of 150 mg N/L, 75 mg P/L and 350 mg K/L in the NS, an intermediate fertilization scheme, revealed increased K content in the plant tissue. O. dubium grown in N75 levels indicated increased total phenols and antioxidant capacity, increased P, Na, and Cu content, increased water use efficiency and the highest p-cymene content in the EO. In contrast, the N300 levels in the NS, increased N accumulation and total flavonoids in plants, but decreased the main EO component, carvacrol. The K150 levels in the NS decreased plant biomass and caused oxidative stress, indicated by the higher lipid peroxidation, and the acceleration of the terpene’s synthesis with the raised carvacrol content. The K550 levels mirrored the highest nutrient use efficiency in plants while the P100 levels impacted the leaf chlorophylls and manganese content. The raise N, P, K in the NS increased mineral accumulation in the plants. Plant biomass and EO yield were not differed by the various N or P levels in the NS. Therefore, tailoring the NS composition in hydroponic cultivation of O. dubium, may supply plant biomass and EO of specific composition, such EO-enriched in carvacrol by the K150 levels in the NS or EO-enriched in p-cymene by the N75 levels in the NS, addressing industry demands.

中文翻译：

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优化氮、磷和钾的需求，以改善牛至。生长、养分和水的利用效率、精油产量和成分


药用和芳香植物生产在农业部门很受欢迎，因为植物化学化合物对人们的健康有强大的影响。本研究检查了营养液 （NS） 中各种氮（N：75、150 和 300 mg/L）、磷（P：50、75 和 100 mg/L）和钾（K：150、350 和 550 mg/L）浓度对牛至生长、生理特性、抗氧化能力、营养积累和精油 （EO） 成分的影响在水培中生长的植物。在中间施肥方案 NS 中，NPK 水平为 150 mg N/L、75 mg P/L 和 350 mg K/L，表明植物组织中的 K 含量增加。在 N75 水平下生长的 O. dubium 表明总酚和抗氧化能力增加，P、Na 和 Cu 含量增加，水分利用效率提高，EO 中的 p-cymene 含量最高。相比之下，NS 中的 N300 水平增加了植物体内的 N 积累和总黄酮类化合物，但降低了 EO 的主要成分香芹酚。NS 中的 K150 水平降低了植物生物量并引起了氧化应激，表现为较高的脂质过氧化，以及随着香芹酚含量的增加而加速萜烯的合成。K550 水平反映了植物中最高的养分利用效率，而 P100 水平影响叶片叶绿素和锰含量。NS 中 N、P、K 的升高增加了植物体内矿物质的积累。植物生物量和 EO 产量不受 NS 中各种 N 或 P 水平的差异。因此，在水培培养 O 中定制 NS 组成。 dubium 可以提供植物生物质和特定成分的 EO，例如 NS 中 K150 水平富含香芹酚的 EO 或 NS 中 N75 水平富含对伞花烯的 EO，满足行业需求。