Micropropagation of globally endangered tree Adansonia digitata L.

An ethnomedicinally important arboreal species Adansonia digitata L. known as iconic baobab tree, which is being threatened/globally endangered. In order to conserve this genetic resource of remarkable economic and therapeutically important tree species, we report the impact of various plant growth regulators (PGRs) and explant type on micropropagation of an ethnomedicinal tree A. digitata. The cotyledonary node and nodal explants were cultured on MS medium without PGRs and as well as MS medium fortified with various concentrations of BAP/KIN/TDZ alone. Nodal explants showed the highest percentage of response (72%) at 1.5 mg/L BAP with 6.6 ± 0.23 shoots/explant and followed by cotyledonary node explants 5.8 ± 0.08 shoots/explant with 60% response at 2.0 mg/L BAP. BAP was found to be more effective in response by inducing multiple shoots regeneration compared to other cytokinins used. Thus, it is clear that the nodal explants have shown higher potential for producing a high number of shoots per explant than the cotyledonary node explants in the current study. The micro-shoots were grown on MS medium supplemented with 1.0/1.5 mg/L BAP + 0.3 mg/L GA3 to promote further growth and elongation. Following their production in both the cultures, the elongated micro-shoots were transferred on to root induction medium enriched with auxins at concentrations varying between 0.3 and 3.0 mg/L IBA, NAA, and IAA. The highest percentage of response (62%) was observed at 0.5 mg/L IBA. After being acclimated, the in vitro rooted plantlets were transferred to potting soil. When the fully developed plantlets were transferred to the field, 80% of them were survived. Thus, the protocol optimized in the present study can be used for conservation of an ethnomedicinal tree A. digitata.