Vermicompost applications on growth, nutrition uptake and secondary metabolites of Ocimum basilicum L. under water stress: A comprehensive analysis.

• Phenolic compounds were for the first time reported in response to vermicompost. • Caffeic acid increased with water stress and vermicompost. • Rosmarinic acid content decreased by water stress. • Rosmarinic acid increased by vermicompost and vermicompost-water stress interaction. • Estragole and eucalyptol decreased with water stress and vermicompost. Water stress is of the prominent abiotic stress factors retarding the plant growth and related attributes. Organic fertilizers are recently employed for reducing the potential adverse effects of water stress. For that reason, the present study was designed to reveal the impacts of vermicompost on water stress in sweet basil (Ocimum basilicum L.). In this regard, sweet basil was grown in peat medium supplemented with different vermicompost (VC) ratio (VC/Peat: 2.5; 5%; 10 and 20 v/v) and subsequently exposed to water stress during flowering stage. Along with the study, an array of parameters including morphological and agronomic traits, phenolic compounds, essential oil compounds and mineral uptake were investigated in sweet basil leaves. Accordingly, water stress negatively affected plant height, plant dry weight, root dry weight and leaf width. However, vermicompost applications at 10% and 20% concentration significantly improved the plant dry weight, root dry weight, leaf dry weight under water stress. Also, the effects of vermicompost applications were concentration-dependent. Of the identified essential oil compounds, major compounds (estragole and eucalyptol) decreased with the water stress and vermicompost treatments, whilst minor compounds increased with the vermicompost and water stress. Out of the major phenolic compounds available, caffeic acid content increased with water stress and vermicompost. Water stress decreased rosmarinic acid content whereas vermicompost and vermicompost-water stress interaction significantly increased the content. Considering nutrient uptake, the higher nutrient levels were observed with vermicompost-amended groups. [ABSTRACT FROM AUTHOR]