ABSTRACT

Antimicrobial agents such as bavistin, cefotaxime and kanamycin were evaluated for their effects on the rapid shoot regeneration from nodal explants of Centella asiatica (L.). Filter sterilized bavistin (250 mg/L) was augmented alone and in combination with cytokinins such as BAP and TDZ into the media to trace the effect on regeneration. On this basis, the potential use of bavistin (150 mg/L) along with BAP (2.0 mg/L) was evaluated which showed the maximum shoot number (6.6) and shoot length (4.4 cm) respectively. Cefotaxime at the concentration of 100 µM/L was found to be effective to obtain the maximum shoot number formation (5.8) with the regeneration frequency (90%). Kanamycin at the concentration of 80 µM/L induced maximum shoot regeneration (5.12). Kanamycin at 100 µM/L or at higher concentrations reduced the shoot regeneration. The best rooting response was noticed when in vitro regenerated microshoots were transferred to the rooting medim which was supplemented with IBA (2.0 mg/L). This combination generates 90% of regeneration frequency and maximum number of roots per shoot (14.2) and high root length (4.2 cm). The rooted plants were acclimatized and transferred to field for survivalance. The addition of antibiotics was found to be more effective and safer for using since their effects on regeneration were found to be negligible.

In this present study, the effect of various carbon sources such as sucrose, glucose, fructose and maltose was investigated on in vitro shoot regeneration of Solanum viarum using axillary bud explants. The frequency, growth and multiplication rate were highly influenced by the type and concentration of carbon source used. Among the different concentrations (1% -6%) of carbohydrates studied, the maximum number of shoots (22.6 ± 0.50) and shoot length (5.92 ± 0.13 cm) was obtained on MS medium supplemented with 4% (w/v) fructose. The least number of shoots (1.5 ± 0.32) was obtained on 6% maltose and the least shoot length (1.2 ± 0.23) was observed on 6% glucose. Among the four types of carbon sources that were employed in the present study, fructose at 4% proved to be better choice for multiple shoot regeneration followed by sucrose, glucose and maltose from axillary bud explants of S. viarum.