In addition to absorbing water and nutrients, the medicinal plant roots are sometimes responsible for the secondary metabolite production and/or accumulation. Root extension is, therefore, economically important in these plants. Here we used a hydroponic system to investigate the effects of exogenous methionine (Met) and phosphate (PO₄) concentration on the biomass production and quality of valerian (Valeriana officinalis L.) root. The plants were grown in a cocopeat-perlite mixture and irrigated with nutrient solutions differed mainly in phosphate concentration (900, 1200, and 1500 μM) for four months. The valerian plants were exposed five times to 400 μM methionine either as foliar or root applications. Elevated phosphate concentration had a negative impact on yield and quality of valerian root, showing a 32 % reduction in root dry weight at 1500 compared with 900 μM phosphate. The maximum accumulation of essential oil (29 μL plant⁻¹) and valerenic acid (11 mg plant⁻¹) were also recorded at the lowest phosphate concentration (900 μM) coincided with the highest Zn absorption by the plants. Irrespective of the phosphate concentration, using Met, particularly in root application improved the measured plant traits. Met supplementation at the lowest phosphate concentration caused a 1.3-fold and 1.6-fold increase in the yield of the essential oil and valerenic acid, respectively. Overall, these findings indicate that an exogenous supply of Met at a relatively low phosphate concentration can considerably increase the yield and quality of valerian roots under hydroponic conditions.

除了吸收水分和养分外，药用植物根有时还负责次生代谢物的产生和/或积累。因此，根延伸在这些植物中具有重要的经济意义。在这里，我们使用水培系统研究了外源蛋氨酸 (Met) 和磷酸盐 (PO ₄ ) 浓度对缬草 ( Valeriana officinalis ) 生物量生产和质量的影响。L.) 根。植物在椰壳粉-珍珠岩混合物中生长，并用主要不同磷酸盐浓度（900、1200 和 1500 μM）的营养液灌溉四个月。缬草植物暴露于 400 μM 甲硫氨酸 5 次，叶面或根部施用。升高的磷酸盐浓度对缬草根的产量和质量有负面影响，与 900 μM 磷酸盐相比，1500 时根干重减少了 32%。精油（29 μL 植物^-1）和缬草酸（11 mg 植物^-1) 也在最低磷酸盐浓度 (900 μM) 下记录，同时植物对锌的最高吸收。不考虑磷酸盐浓度，使用 Met，特别是在根应用中改善了测量的植物性状。在最低磷酸盐浓度下补充 Met 使精油和戊二酸的产量分别增加了 1.3 倍和 1.6 倍。总体而言，这些发现表明，在水培条件下，外源性供应的磷酸盐浓度相对较低的 Met 可以显着提高缬草根的产量和质量。