Micropropagation of Handroanthus heptaphyllus (Vell.) Mattos from seedling explants
Handroanthus heptaphyllus (Vell.) Mattos (Bignoniaceae), a tropical forest tree, is a source of wood suitable for the manufacture of fine furniture and chemical compounds with medicinal and insecticidal properties. Poor seed viability of this species limits the conventional propagation practice. In vitro germination of seeds was achieved in semi-solid Murashige and Skoog’s (MS) medium. A disinfection protocol was optimized for germination and growth of seedlings in vitro. Proliferation of shoots from cotyledonary and stem nodal segments was achieved in semi-solid MS medium supplemented with 22.2 μM 6-benzyladenine. Temporary immersion culture promoted elongation and rooting of shoots and reduced the shoot tip necrosis compared with culture on semisolid medium (6.7±2.7 and 41.7±7.0%, respectively; P = 0.001). Plantlets derived from temporary immersion showed better performance during the acclimatization phase. This is the first report on micropropagation of H. heptaphyllus.
Keywords: Seeds, uncoated seeds, cotyledon, stem nodes, axillary shoots, adventitious shoot, black lapacho