Abiotic metal stress enhances diosgenin yield in Dioscorea bulbifera L. cultures.

Lower concentrations of CuSO(4) (25-75 microM) in the MS medium supplemented with 0.1 mg l(-1) IAA+5.0 mg l(-1) Kn+500 mg l(-1) CH+10 mg l(-1) Cyst hyd enhanced the growth of regenerants of Dioscorea bulbifera L. CuSO(4) (75 microM) induced an appreciable diosgenin yield in the regenerants compared to those obtained on media without Cu. The presence of Cu thus seems to stimulate diosgenin production. The regenerants also differentiated bulbils on lower concentrations of Cu. At CuSO(4) (100 microM), however, cultures showed poor growth as well as a low diosgenin yield. Increased proline and protein contents were recorded in cultures grown on Cu-enriched media.