Micropropagation and bioreactor studies of the medicinally important plant Lessertia (Sutherlandia) frutescens L.

This study describes a protocol for rapid and efficient in vitro propagation of Lessertia frutescens (cancer bush), a medicinally important plant species native to southern Africa. Single node explants were grown in various culture regimes of MS medium containing 30 g/l sucrose supplemented with various concentrations of cytokinins and auxins and solidified with 8 g/l agar. These were (a) 2.22, 4.44, 13.32 and 22.19 mu M BA; 2.32, 4.65, 13.95 and 23.23 mu M K and 0.45, 2.27, 4.54 and 13.62 mu M TDZ (b) a combination of 2.22 mu M BA with 0.57, 2.85, 5.71 and 11.42 mu M IAA, 0.49, 2.46, 4.9 and 9.8 mu IM IBA or 0.54, 2.69, 5.37 and 10.74 mu M NAA and (c) different media types viz. MS, SH basal salt medium and WPM at 1, 1/2 and 1/4 salt strength which were each supplemented with 2.22 mu M BA and 0.54 mu M NAA. Single node explants were also grown in MS liquid medium supplemented with 2.22 mu M BA and 0.54 mu M NAA in temporary and continuous immersion bioreactors. Maximum number of shoots (12.9) per single node explant was obtained in the temporary immersion bioreactor but 50% of these shoots showed symptoms of hyperhydricity. In solid culture the best shoot multiplication response (10 shoots) was obtained in full strength MS. Roots were induced using shoot tips cultured in 1/2 MS solid medium supplemented with various concentrations of IBA or NAA. The highest rooting percentage (78%) was achieved in 19.6 mu M IBA. Rooted plantlets were cultured in a mixture of perlite and vermiculite (1:1; v/v) and successfully acclimatized in a growth chamber with an 85% survival rate. (C) 2009 SAAB. Published by Elsevier B.V. All rights reserved.