In vitro multiplication and field establishment of Adhatoda beddomei C. B. Clarke,a rare medicinal plant

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.Abbreviations SH Schenk and Hildebrandt (1972) basal medium - BAP 6-benzylaminopurine - 2-ip 2-isopentenyladenine - IAA indole-3-acetic acid - IBA indole-3-butyric acid - NAA 1-naphthaleneacetic acid