Abstract
Objectives: An efficient and reproducible regeneration protocol for rapid multiplication of Albizia lebbeck (L.) was developed by using intact seed explants.
Methods: Murashige and Skoog's (MS) medium supplemented with different hormones (BA, Kn, GA(3) and TDZ) was used for the induction of multiple shoots from the seed explants. Ex-vitro rooting was performed by using pulse treatment method in auxins (IBA and NAA) and the complete plantlets were transferred to the field.
Results: High frequency direct shoot induction was found in aseptic seed cultures of A. lebbeck on Murashige and Skoog medium supplemented with 5.0 mu M TDZ (Thiadiazuron). Seeds were germinated after 7 days of culture and induced maximum 8 shoots from the region adjacent to the apex of the primary shoot of the seedling upto 25 days of incubation. Proliferating shoot cultures with increased shoot length was established by sub-culture of excised sprouting epicotyls on MS medium supplied with reduced concentrations of TDZ. Maximum shoot regeneration frequency (76%) with highest number of shoots (21) and shoot length (5.1 cm) per sprouting epicotyl was observed in the MS medium supplemented with 0.5 mu M TDZ after 8 weeks of culture. Different concentrations of Indole-3-butyric acid (IBA) and alpha-naphthalene acetic acid (NAA) were tested to determine the optimal conditions for ex-vitro rooting of the microshoots. The best treatment for maximum ex-vitro root induction frequency (81%) was accomplished with IBA (250 mu M) pulse treatment given to the basal end of the microshoots for 30 min followed by their transfer in plastic cups containing soilrite and eventually established in normal garden soil + soilrite (1:1) with 78% survival rate. In addition, histological study was undertaken to gain a better understanding of the regenerated shoots from the epicotyl region.
Conclusion: The findings will be fruitful in getting a time saving and cost effective protocol for the in vitro propagation of Albizia lebbeck.