Gita Rani

In vitro callus induction and regeneration studies in Withania somnifera

Callus cultures were initiated from axillary leaves, axillary shoots, hypocotyls, and root segments on Murashige and Skoog (MS) (1962) medium supplemented with 2,4-D (2 mg l−1) and KN (0.2 mg l−1). Shoots differentiated best from axillary shoot base callus on MS medium containing BA (2 mg l−1). Regenerated shoots rooted best on MS medium containing IBA (2 mg l−1) alone, and IBA (2 mg l−1) with IAA (2 mg l−1). Plantlets were transferred to pots containing sand and soil mixture, acclimatized in a culture room and afterwards transferred to the glasshouse.

CALLUS INDUCTION AND PLANTLET REGENERATION IN WITHANIA SOMNIFERA (L.) DUNAL

SummaryCallus induction was observed from hypocotyl, root, and cotyledonary leaf segments, grown on Murashige and Skoog (MS) medium supplemented with various concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KN). Maximum callusing (100%) was obtained from root and cotyledonary leaf segments grown on MS medium supplemented with a combination of 2 mg l−1 (9.1 μM) 2,4-D and 0.2 mg l−1 (0.9 μM) KN. The calluses, when subcultured in the same medium, showed profuse callusing. However, these calluses remained recalcitrant to regenerate regardless of the quality and combinations of plant growth regulators in the nutrient pool. When hypocotyl segments were used as explants, callus induction was noticed in 91% of cultures which showed shoot regeneration on MS medium supplemented with 2 mg l−1 2,4-D and 0.2 mg l−1 KN. These shoots were transferred to fresh medium containing various concentrations and combinations of 6-benzyladenine (BA) and N6-(2-isopentenyl)adenosine (2-iP). Maximum shoot multiplication was observed after 60 d of the second subculture on MS medium containing 2 mg l−1 (8.9 μM) BA. These shoots were rooted best (87%) on MS medium containing 2 mg l−1 (9.9 μM) indole-3-butyric acid (IBA). The plantlets were transferred to the field after acclimatization and showed 60% survival.

Micropropagation of coleus blumei from nodal segments and shoot tips

A rapid and highly-effective method for micropropagation from nodal segment and shoot tip explants was established for Coleus blumei Benth. Nodal segments and shoot tips were inoculated on MS medium containing 0.7 % agar, 3 % commercial sugar, and different combinations of 6-benzyladenine (BA) with indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) or α-naphthaleneacetic acid (NAA). Hundred percent shoot induction from both explants was achieved on the medium containing BA (2 mg dm−3) and NAA (1 mg dm−3). Shoot tips were proved to be the better explant in comparison to nodal segments in having high rate of shoot induction and more number of shoots. The same media conditions were found suitable for shoot multiplication. Multiplied shoots rooted best on MS medium supplemented with IBA (2 mg dm−3). Micropropagated plants were successfully established in soil after hardening, with 100 % survival rate.

Direct Rhizogenesis from in vitro Leaves of Withania somnifera (L.) Dunal

ABSTRACT Direct rooting was induced in Withania somnifera leaf segments using an IBA dip treatment. The segments dipped in IBA formed roots along the midrib region of the abaxial surface when placed on Murashige and Skoogs (MS) basal medium containing no plant growth regulators. The length of the dip treatments (10, 20 and 30 min) and strength of the MS media (¼, ½, and full-strength) treatments had no apparent effect on rooting, although maximum rooting (85.3 percent of the cultures) occurred when the leaf segments were placed on ½-strength MS medium after a dip treatment with 100 mg/liter IBA solution for 20 min. The average number and length of roots were 32.3 per culture and 5.6 cm, respectively. Only 20 percent of the cultures produced roots if explants were grown on full-strength MS medium supplemented with IBA.