In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

This work aimed to develop a protocol for the in vitro establishment, multiplication, rooting and ex vitro acclimatization of Mimosa pudica L., a species used in folk medicine and with pharmacological activity. Aseptic cultures were established from seeds inoculated in MS medium, without growth regulators, followed by an in vitro stabilization phase in culture medium supplemented with 2.22 μM BAP. The cultures were transferred to MS medium supplemented with different cytokinins, combined or not with an auxin, aiming its large-scale propagation. The culture medium supplemented with 5 µM BAP plus 0.5 µM NAA provided the highest multiplication rate and top quality plantlets. The combination of 0.6 µM TDZ plus 0.05 µM NAA resulted in higher multiplication rates than in response to combination of BAP plus NAA, although the subsequent maintenance of the cultures in a medium without growth regulators has resulted in low regenerative response. In vitro rooting of micro-cuttings was high even in the absence of auxins. Over 90% of plantlets transferred to the greenhouse survived after the acclimatization phase. Acclimatized plants presented normal vegetative and reproductive development. The procedures established in the present study allow a massive production of M. pudica plants for further pharmacological studies.