An efficient protocol was developed for in vitro propagation of Abrus precatorius L. through induction of indirect organogenesis in nodal segment derived callus tissue. Yellowish-green nodular callus was induced at the cut surface of the nodal segments cultured on MS fortified with 5.0 mg/l BAP and 0.5 mg/l NAA. The callus differentiated into adventitious shoots when it was subcultured on to MS supplemented with 3.0 mg/l BAP + 0.5 mg/l Kn + 0.5 mg/l NAA. On an average 6.87 ± 0.26 shoots/culture developed. These microshoots were rooted in half-strength MS containing 1.0 mg/l IBA and the rooted plantlets were transferred to soil after proper acclimatization.

Leaf and nodal segments of two months old field grown seedlings of Plumbago indica L. were cultured on agar solidified MS supplemented with different concentrations and combinations of NAA, IAA, 2,4-D and picloram, and BAP and Kn. The nodal segments produced either multiple shoot buds (MSBs) or callus of different nature depending on the combinations of plant growth regulators (PGRs). The callus of light green and nodular shape, on further subculture on wide range of PGRs supplemented media, differentiated into MSBs. These MSBs underwent rapid elongation on different PGRs supplemented media. The elongated shoot buds were rooted on transferring in rooting medium and were acclimated in field with 90% survivability. The leaf segments, however, produced only white and friable calluses failed to undergo any differentiation in some of the media combinations.

Multiple shoots were induced on MS fortified with 2.0 mg/l BAP and 0.2 mg/l NAA within 30 days of culture. Maximum (93%) explants produced multiple shoots with an average 12 shoots per culture after two successive subcultures at 14 days interval in the same medium. Cent per cent rooting was achieved in half strength of MS supplemented with 1.0 mg/l IBA. Following 21 days in vitro rooting period and seven days of ex vitro acclimatization, plantlets were successfully established in natural condition. The survival rate of regenerated plants was 90 per cent.

Viable protoplasts of Vigna sublobata L. were isolated enzymatically from hypocotyls of axenic seedlings. Protoplast yields were dependent upon seedling age, with maximum yields (2.25 ± 0.35 × 10(6) g fwt(-1)) from seedlings aged 6 d. Protoplasts regenerated cell walls and underwent sustained divisions when cultured in either agarose-solidified or liquid K8P medium. The plating density affected the division frequency and plating efficiency; the division frequency (68 ±0 6.0%) was maximum at 4.0 × 10(4) ml(-1) while plating efficiency was maximum (1.3 ± 0.1%) at 5.0 × 10(4) ml(-1). Dividing protoplasts developed into microcalli, which produced glossy green compact nodular calli on transfer to 8.0 gl(-1) w/v agar-solidified medium containing MS salts, B5 organic components, 30 g l(-1) sucrose, NAA (0.2-0.5 mg l(-1)), zeatin riboside (0.5-2.0 mg l(-1)) and GA3 (0.5-1.0 mg l(-1)). These calli, after sub-culture on the same medium, produced shoot buds which underwent elongation following transfer of tissues to 6.0 g l(-1) agar-solidified B5 medium containing 30g l(-1) sucrose, IBA (0.01 mg l(-1)) and BAP (1.0 mg l(-1)). Elongated shoots developed roots after transfer to 8.0g l(-1) agar-solidified, hormone-free MS medium with 30 g l(-1) sucrose.

An efficient regeneration protocol through in vitro direct organogenesis was developed for a valuable medicinal plant Aristolochia tagala Champ. using nodal segments as explants. Multiple shoot buds were induced directly from nodal explants cultured on MS (Murashige and Skoog 1962) basal medium supplemented with 2.0 mg/l BAP (N6-benzylaminopurine) and 0.5 mg/l NAA (a-naphthalenacetic acid). The average number of shoots induced per culture was found to be six. Excised shoot roots were cultured on half -strength MS medium containing 0.5 mg/l IBA. The rooted plantlets were transferred to natural environment after proper acclimatization.