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Clonal propagation of Adhatoda beddomei C.B. Clarke (Acanthaceae), a rare medicinal shrub, was achieved through callus-free axillary meristem proliferation from stem node explants of field-grown plants cultured in SH medium. Shoot multiplication was a function of cytokinin activity but sustained growth of the shoots was dependent on the synergistic effect with the auxin, IAA. An optimum number of 5-10 shoots per explant were obtained in 6 weeks using 3.0 mg.l(-1) BAP, 0.5 mg.l(-1) 2-ip and 1.0 mg.l(-1) IAA, Upon subculture, vertical halves of the precultured node with the differentiated shoots yielded a larger aggregate number of shoots (23-27) than the uncut precultured node left intact (15-17). Shoot multiplication was rapid and consistent over prolonged periods when the hormonal concentrations were reduced to 1.0 mg.l(-1) BAP and 0.2 mg.l(-1) IAA during subculture, and reculture of the nodal explants derived from shoot cultures. Rooting of 3-5 cm shoots thus obtained was greatly accelerated in stationary liquid medium containing 0.2 mg.l(-1) IBA or IAA. Hardening of the rooted plantlets in the humidity chamber was essential for high frequency (95%) survival. Micropropagated plants established in the field flowered after fifteen months and were free from apparent defects in cytological, growth and flowering characteristics.

Shoot tip and single node explants from young shoots of 1-year old flowering plants of Rauwolfia micrantha Hook. f. were cultured on Murashige & Skoog (MS) medium variously supplemented with 6 -benzyladenine (BA) and a -naphthaleneacetic acid (NAA). A combination of 13.2 la-M BA and 2.68 ~ NAA induced high frequency (77%) formation of up to 3 shoots from each node in 8 weeks. The regeneration of shoot tips from the field-grown plants and in vitro shoots placed horizontally differed. Repeated subculturing of the shoot tips and single nodes at 6-week intervals for over a year in combination of 4.4 I~M BA and 0.27 ~ NAA enabled mass multiplication of shoots without any evidence of decline. Rooting of the excised shoots on medium containing 2.6 ~ NAA was preceded by callus formation. The rooted plants were removed off the callus, hardened off and 80% established in pots. Micropropagated plants displayed uniform morphological, growth, flowering, fruiting and seed germination characteristics.

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Transgenic hairy roots were induced from Withania somnifera Dunal, by infecting leaf explants with Agrobacterium rhizogenes. Polymerase chain reaction for rol A gene and Southern blot confirmed the integration of T-DNA in the genome. Cultures were grown in Murashige and Skoog solid as well as in liquid medium. The antioxidant activity was assayed in roots grown in solid media and liquid media. Hairy roots grown in liquid media found to possess highly significant activity in 1,1-diphenyl-2-pecryl-hydrazyl radical, beta-carotene linoleic acid model system. The activity was 57.34%, 75.64%, and 93.41% in case DPPH model and 55.3%, 76.3%, and 90.5% in case of b-CLAMS in 25, 50, and 100 mg L(-1) concentration, respectively. In case of hydroxyl radical trapping and brain lipid peroxidation assay, the activity was more significant in hairy roots grown on solid medium in comparison with commercial formulation prepared using normal roots and standard withanaloids. Root extract grown in solid medium has shown 93.2% hydroxyl radical trapping activity at 100 mg L(-1) concentration, and 500 mg L(-1) has shown 83.6% in case of brain lipid peroxidation assay. High-performance liquid chromatography analysis demonstrated the presence of withanaloids in the hairy root extracts. The results of the study clearly indicate that there is enhancement of secondary metabolites in hairy roots, which is indicated through significant enhancement of the antioxidant activity, since these are the major constituents responsible for the activity. This is the first report on the presence of antioxidant principles in genetically modified roots of W. somnifera. These results of the present study may aid in utilization of the W. somnifera hairy roots for its rejuvenating principles.