EN
Withania somnifera is an important medicinal plant that contains withanolides as bioactive compounds. We have investigated the effects of macroelements and nitrogen source in hairy roots of W. somnifera with the aim of optimizing the production of biomass and withanolide A content. The effects of the macroelements NH4NO3, KNO3, CaCl2, MgSO4 and KH2PO4 at concentrations of 0, 0.5, 1.0, 1.5 and 2.09 strengths and of nitrogen source [NH4+/NO3- (0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/ 18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20 and 14.38/37.60 mM)] in Murashige and Skoog medium were evaluated for biomass and withanolide A production. The highest accumulation of biomass (139.42 g 1-1 FW and 13.11 g 1-1 DW) was recorded in the medium with 2.09 concentration of KH2PO4, and the highest production of withanolide A was recorded with 2.09 KNO3 (15.27 mg g-1 DW). The NH4+/NO3- ratio also influenced root growth and withanolide A production, with both parameters being larger when the NO3- concentration was higher than that of NH4+. Maximum biomass growth (148.17 g 1-1 FW and 14.79 g 1-1 DW) was achieved at NH4+/NO3- ratio of 14.38/37.60 mM, while withanolide A production was greatest (14.68 mg g-1DW) when the NH4+/NO3 - ratio was 0.00/18.80 mM. The results are useful for the large scale cultivation of Withania hairy root culture for the production of withanolide A.