Effect of season, explants, growth regulators and sugar level on induction and long term maintenance of callus cultures of Ficus religiosa L.
The effects of antioxidant treatments, 2,4-D concentrations and sucrose level were examined in order to optimize the induction and long term maintenance of callus cultures of Ficus religiosa L. from different explants including nodal segments, inter-nodal segments and shoot apices. The explants subjected to incubation for 40 min in antioxidant solution (2% ascorbic acid + 2% citric acid) exhibited maximum percent culture establishment (73.33%). Establishment was reduced when incubation time was longer than 40 min. The explants collected in May and June gave maximum response (100 %). The highest frequency of callus induction (100%) was observed in nodal segments on Murashige and Skoog medium supplemented with 2.26 μM 2,4-dichlorophenoxyacetic acid and 3% sucrose after an average of 8.38 days. Maximum callus proliferation, resulting in fresh weight of 4.29 g after four weeks of culture, was also observed for callus initiated from nodal segments on the earlier mentioned medium. Higher concentrations of 2,4-D and lower concentrations of sucrose were found to be unfavourable for callus induction as well as proliferation. Callus cultures, initiated from nodal segments, could be successfully maintained in healthy and proliferative form for consecutive nine months on the earlier said medium.
Key words: Ficus religiosa L., explants, callus induction, callus proliferation,callus maintenance, in vitro.