Plant regeneration of Ilex paraguariensis (Aquifoliaceae) by in vitro culture of nodal segments

In vitro regeneration of complete plants from nodal single bud segments of "yerba mate" (Ilex paraguariensis St. Hil.) was studied under defined nutri tional and environmental conditions. Nodal segments harvested from actively growing shoots of conventionally raised plants were cultured on nutrient m edium with the mineral salts and vitamins of Murashige and Skoog medium at 1/4 strength, supplemented with various concentrations of sucrose and 6-ben zyladenine (BAP). Shoot regeneration from explants of both young (2 years old) and adult (20 years old) mother plants were readily achieved in the medium supplemented w ith 0.04 - 0.09 M sucrose with or without BAP. As many as 60 - 65% of the n odal segments cultured formed shoots. Rooting of regenerated shoots was obs erved in 50% of the explants harvested from young plants, whereas 25% of th e explants rooted when the nodal explants were harvested from adult plants. The best rooting induction was achieved on 1/4 strength MS medium with ver miculite as the substrate and supplemented with 1 - 1.5% IBA (indolebutyric acid) and 1 - 2% PPZ (3- methyl- 1 - phenyl - 2 pyrazolin - 5 - one). Plan tlets were successfully transferred to soil.