Title : Synergistic effects of aeroponics and elicitation on growth and phytochemical production in Valeriana jatamansi
Abstract:
Valeriana jatamansi Jones is a perennial rhizomatous medicinal herb belonging to the family Caprifoliaceae, commonly known as Indian valerian or Tagar. Its roots and rhizomes are rich in Essential Oils (EOs) possessing anxiolytic, antibacterial, antifungal, and sedative properties. However, conventional soil-based cultivation of V. jatamansi is constrained by inconsistent yields, overharvesting, climatic variability, and pathogen infestation, resulting in reduced biomass and fluctuations in phytochemical composition. To address the increasing commercial demand for bioactive compound-enriched biomass, alternative cultivation strategies are being explored. Aeroponics, an advanced soilless cultivation system, offers precise control over environmental and nutritional conditions, thereby improving plant growth, biomass productivity, and metabolite accumulation. Furthermore, the application of elicitors has emerged as a promising approach for enhancing nutrient uptake, secondary metabolite biosynthesis, and sustainable cultivation efficiency. The present study investigated the effects of foliar application of fungal endophytic filtrate and salicylic acid (SA) on growth, physiological performance, EO accumulation, and gene expression in aeroponically cultivated V. jatamansi.
Both treatments significantly enhanced morphological attributes, including shoot length, root length, leaf length, leaf width, and leaf number, compared with the control. Biomass analysis revealed that fresh weight increased by 1.38-fold and 1.26-fold, while dry weight increased by 1.36-fold and 1.11-fold in endophyte- and SA-treated plants, respectively, relative to the control. Treated plants also exhibited improved and stable photosynthetic efficiency, as evidenced by higher QY_max, ?PSII, and NPQ_Lss values. EOs extracted through hydrodistillation showed the highest yield in SA-treated plants (2.0%), followed by endophyte-treated plants (1.65%) and control plants (1.30%). GC-MS analysis further demonstrated enhanced accumulation of patchouli alcohol in endophyte-treated plants (43.27%) compared with SA-treated and control plants (40.32%). In addition, qRT–PCR analysis revealed upregulated expression of key iridoid biosynthetic pathway genes, including GES, IS, 7DLGT and LAMT, in both leaf and root tissues of treated plants. Overall, the findings demonstrate that fungal biostimulants and SA significantly enhance biomass production, EO accumulation, photosynthetic efficiency, and molecular responses in aeroponically cultivated V. jatamansi, highlighting the potential of elicitor-assisted aeroponic systems for sustainable production of high-value medicinal plants.
