Root extracts of Macrosyphonia velame an Apocynaceae native of Brazilian Cerrado, known as white velame have been popularly used as depurative and antisyphilitic agent. The aim of the present research was to develop a micropropagation protocol for the in vitro conservation of M. velame in a germplasm bank. Seeds of velame collected in Sacramento, Tapira and Araxa, MG, Brazil, were used as initial explants. Nodal segments from axenic plantlets were inoculated on MS/2 medium supplemented with different concentrations (0.25, 5.0 and 1.0mg L-1) of BAP; kinetin; 2iP or TDZ. For in vitro rooting, plantlets (2cm high) were inoculated on MS/2 medium supplemented with IBA or NAA (1.0, 5.0, and 10.0mg L-1), maintained for 5, 10 and 30 days and sub-cultured to MS/2 medium for an additional thirty days before evaluating rooting. For acclimatization and ex vitro rooting plantlets were transplanted into Styrofoam boxes containing either Plantmax (R), sand and soil one by one or in combinations (1:1) of sand/Plantmax (R); sand/soil; Plantmax (R)/soil. For the in vitro conservation of M. velame in germplasm bank plantlets (3.5cm high) were inoculated on MS/2 medium supplemented with either 2% sucrose + 4% of mannitol or sorbitol; 2% sucrose + 4% mannitol or sorbitol + 2mg L-1 calcium pantothenate; 2% of sucrose + 4% of mannitol or sorbitol + 2mg L-1 spermidine. The proportion of seed germination was considered low, 33%, 4% and 2% for seeds collected in Araxa, Tapira and Sacramento respectively. Explants cultured on MS/2 medium without addition of cytokinin showed enhanced height (5.2cm), increased number of buds (8.6), proliferation of 4 shoots per bud and minimal (4%) proportion of vitrification. Plantlets acclimatized ex vitro developed better in Plantmax (R) substrate, most plantlets presented root formation and survival reached 40%. M. velame plantlets cultured for three months on MS/2 added with 2% sucrose + 4% mannitol + 2mg L-1 of calcium pantothenate, under germoplasma bank conditions presented 40% of survival.
