Vol.:(0123456789) 1 3 Plant Cell, Tissue and Organ Culture (PCTOC) https://doi.org/10.1007/s11240-021-02173-5 ORIGINAL ARTICLE L‑phenylalanine applications and culture duration afect root growth and production of tropane alkaloids and phenolics in adventitious root cultures of Hyoscyamus niger L. Tunhan Demirci 1  · İlknur Albayrak 2  · Nilgün Göktürk Baydar 2 Received: 6 April 2021 / Accepted: 13 September 2021 © The Author(s), under exclusive licence to Springer Nature B.V. 2021 Abstract This study was aimed to determine the efects of diferent concentrations of L-phenylalanine (0.25, 0.50 and 1.00 mM L-Phe) applied to adventitious root cultures for diferent culture durations on root growth and production of tropane alkaloids and phenolics in Hyoscyamus niger. For this purpose, adventitious roots obtained from petiole explants of in vitro seedlings were used as plant materials. After adventitious roots were cultured in liquid Murashige and Skoog (MS) medium, L-Phe was applied to the adventitious roots. Then the roots were harvested on the 1st, 3rd, and 7th day of the applications, fresh and dry root weights, root growth indexes were analysed. It was also examined the contents of tropane alkaloids (hyoscyamine and scopolamine) and phenolics (gallic acid, catechin, epicatechin, vanillin, cinnamic acid, rosmarinic acid, p-coumaric, o-coumaric acid, rutin, cafeic acid, ferulic acid, chlorogenic acid, and quercetin) by HPLC in both adventitious roots and culture medium. As a result, according to root growth parameters data, day*application interaction was not found statisti- cally signifcant. The maximum scopolamine and hyoscyamine amounts were detected in the cultures with the application of 0.50 mM L-Phe for 3 days. In terms of phenolics, 0.50 mM and 1.00 mM L-Phe application with 1st and 3rd days were selected as the most appropriate L-Phe applications and culture duration. Consequently, it has been determined that in vitro secondary metabolite production may be increased in H. niger root cultures with the selection of appropriate L-Phe concen- trations and culture durations. Key Message L-phenylalanine is an efective and inexpensive application for the production of secondary metabolites in adventitious root cultures of Hyoscyamus niger with the correct concentration and appropriate culture duration. Communicated by Konstantin V. Kiselev. * Tunhan Demirci tunhandemirci@sdu.edu.tr 1 Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Suleyman Demirel University, 32260 Isparta, Turkey 2 Department of Agricultural Biotechnology, Faculty of Agriculture, Isparta University of Applied Sciences, 32270 Isparta, Turkey