In vitro callus induction protocol for Leptadenia pyrotechnica using various explants

An efficient protocol has been developed for a rapid callus induction in Leptadenia pyrotechnica. Nodal, internodal and pod explants from mature plant of L. pyrotechnica were cultured after surface sterilization on Murashige and Skoog medium supplemented with plant growth regulators (PGRs) cytokinins and auxins individually and with various combinations. Nodal segments proved the best explants (90% callus induction) compared with internodal and pod explants (5% and no callus induction respectively). Different treatments were employed for surface sterilization of explants revealing that combination of sodium hypochlorite (NaOCl2) and mercuric chloride (MC) were found significant. Minimum contamination (7%) occurred at 30% NaOCl2 + 2 g/L MC, while 80% occurred at 30% NaOCl2 + 1 g/L MC. The nodal segments cultured on MS medium supplemented with 0.5 mg/L NAA that produced maximum callus (90%) within four weeks. It was followed by 60% callus induction at 5 mg/L NAA + 2.5 mg/L benzyl-adenine (BA) and 30% at 10 mg/L 2,4-D + 3 mg/L 2ip + 3 g/L activated charcoal (AC), while only 20% appeared at control (without hormone application). This is the first successful attempt to establish consistent callus formation protocols from nodal stem segments of L. pyrotechnica. This study may contribute in conservation management of this native plant species found especially in the deserts of Pakistan.