Influence of bavistin and silver thiosulphate on in vitro regeneration of Asclepias curassavica (L). using nodal explants.
The effect of bavistin and the ethylene inhibitor (silver thiosulphate) on shoot regeneration using nodal explants of Asclepias curassavica (L). has been investigated. Among the different concentrations studied, highest number of shoots was obtained on MS media with 200 mg/L bavistin. Among the varying concentrations (10-100 µM/L) of silver thio-sulphate tested, highest number of shoots was obtained on MS medium amended with 60 µM/L silver thiosulphate without growth regulators. This study also establishes the stronger cytokinin like activity of bavistin. Effect of different growth additives like coconut milk, ascorbic acid and casein hydrolysate were tested on direct shoot regeneration. Among the different growth additives tested casein hydrolysate showed better and reproducible result at 0.025% in combination with 3 mg/l KN+0.5 mg/l NAA. Antioxidants, activated charcoals and polyvinyl pyrrolidone were used to remove phenolics. Activated charcoal removed the phenolic exudates completely at 0.025% and prevented the browning of media and thus enhanced the frequency of regeneration (85%). The microshoots developed through in vitro regeneration were transferred to rooting media containing IBA alone and in combination with KN and the highest number of roots was observed on MS medium with IBA 1 mg/L+0.2 mg/L KN.