In vitro callus and shoot regeneration in Enterolobium cyclocarpum (Jacq.) Grised. - a fast timber yielding species.
This study was conducted to investigate the in vitro callus induction and rapid shoot regeneration potential in Enterolobium cyclocarpum, a plant native to central Mexico but widely introduced into Africa. The leaf, stem and nodal explants of E. cyclocarpum were cultured on full strength Murashige and Skoog (MS) medium supplemented with different concentrations of Cytokinins - Benzyladenine (BA) and/or Kinetin and Auxins - Naphthalene acetic acid (NAA) and/or 2,4-Dichlorophenoxylacetic acid (2,4-D) each alone and in combination. The leaf explants did not respond to these treatments. The Nodal explants were best for caulogenesis, while the explant responses were in the order- nodal > stem > cotyledon for callogenesis in MS medium supplemented with BA and/or Kin combined with NAA and/or 2,4-D. The varied combinations induced white compact callus. The highest callus production was observed on MS medium supplemented with 2.7 µM NAA + 2.2 µM BA and 5.4 µM NAA alone. Nodal and cotyledon explants developed callus and multiple shoots on MS supplemented with a combination of cytokinin (BA and/or Kin.) and auxin (NAA and/or 2,4-D). The maximum number of 3.98 ± 0.37 and 2.1±0.11 shoots/explants were recorded for nodal and cotyledon explants on MS medium supplemented with a combination of 8.8 µM BA+2.7 µM NAA and 2.2µM BA+2.7 µM NAA respectively. On the basal medium, 10% of the excised shoots rooted successfully. Thus, this in vitro method can be exploited for conservation and mass propagation of this fast timber yielding tree and also utilized for embryogenesis studies.