[Effects of physical and chemical factors on hairy root growth and flavonoids biosynthesis in the cultures of Saussurea medusa Maxim hairy root].

The effects of different physical and chemical factors on hairy root growth and flavonoids production were studied in suspension culture of Saussurea medusa hairy root in 1/2 MS medium. The results showed that the following culture conditions, nitrogen concentratiaon (involved NH4+ and NO3-), 30 mmol/L; the ratio of ammonium to nitrate, 5:25; the combination of 2% sucrose and 3% glucose; 0.5 mg/L GA3; 0.5 mg/L IBA; initial pH 5.8; light cycle, 18 h/d (3500lx); temperature, 24 degrees C; shaker revolutions per minute, 100 r/min, were favourable to hairy root growth and flavonoids production. Under the above culture conditions, up to 12.8 g/L (DW) of hairy root and 1922 mg/L of flavonoids were obtained after 21 days of culture. The content of total flavonoids in hairy root was 15%, which was about 25 times as that in the wild plantlet.