Abstract
In this study, we have investigated the effect of different concentrations of auxins (IAA, IBA, NAA), MS medium strength, sucrose, ammonium/nitrate, initial medium pH and inoculum size on biomass increase and total phenols and flavonoids accumulation from adventitious roots of Echinacea angustifolia. Adventitious roots were cultured in shake flask for 4 weeks under dark conditions. Among different auxins tested, IBA was best auxin for adventitious root proliferation compare to IAA and NAA. Root growth was inhibited when the initial pH was maintained below 5.0 or above 6.0. Nitrate rather than ammonium was necessary for root growth and phenolics accumulation. Biomass increase and total phenols and flavonoids contents were maximized in half strength MS media supplemented with 2 mg L-1 IBA, 5% (w/v), sucrose, 5:25 (mM) ammonium/nitrate, adjusted medium pH to 6.0 before autoclaving, and inoculum size of 10 g L-1 FW. The results indicated that in vitro environments strongly affect the growth and accumulation of phenolics from Echinacea adventitious root culture. Culture optimization is beneficial to large-scale production of biomass and secondary metabolites in Echinacea angustifolia.