RESUMEN
Mecardonia tenella is an attractive herbaceous native plant, characterized by their intense green foliage and their abundant yellow flowers. It is a very interesting plant for pot and/or garden. A trait to improve in this species is the size of the flowers. The goal of the present paper is to study the in vitro behaviour of M. tenella and to establish a routine protocol for its micropropagation. For the in vitro establishment of M. tenella, nodal segments were disinfected by standard methods using ethanol/sodium hypochloride and cultured on hormone-free MS medium, supplemented with a mixture of antibiotics and an antifungal. In order to study the hormonal requirements of the species, nodal segments were cultured on basal MS supplemented with antibiotic/antifungal mixture and the following concentrations of BAP and NAA (mg/L): 0.0; 0.25; 0.5 and 1.0. These plant regulators were tested in all possible combinations. In vitro plants growing in hormone-free medium were used as explant source. The best results were obtained in the treatments containing 0.25 and 0.5 mg/l BAP with a multiplication rate of 32 shoots per explant. The regenerated shoots rooted spontaneously. When transferred to the greenhouse, the ex vitro plants grew and flowered normally.