Many different species of Bromeliaceae are endangered and their conservation requires specific knowledge of their growth habits and propagation. In vitro culture of bromeliads is an important method ...for efficient clonal propagation and in vitro seed germination can be used to maintain genetic variability. The present work aims to evaluate the in vitro growth and nutrient concentration in leaves of the epiphyte bromeliads Vriesea friburguensis Mez, Vriesea hieroglyphica (Carrière) E. Morren, and Vriesea unilateralis Mez, which exhibit slow rates of growth in vivo and in vitro. Initially, we compared the endogenous mineral composition of bromeliad plantlets grown in half-strength Murashige and Skoog (MS) medium and the mineral composition considered adequate in the literature. This approach suggested that calcium (Ca) is a critical nutrient and this was considered for new media formulation. Three new culture media were defined in which the main changes to half-strength MS medium were an increase in Ca, magnesium, sulfur, copper, and chloride and a decrease in iron, maintaining the nitrate:ammonium rate at 2:1. The main difference among the three new media formulated was Ca concentration, which varied from 1.5 mM in half-strength MS to 3.0, 6.0, and 12 mM in M2, M3, and M4 media, respectively. Consistently, all three species exhibited significantly higher fresh and dry weight on M4, the newly defined medium with the highest level of Ca (12 mM). Leaf nitrogen, potassium, zinc, magnesium, and boron concentrations increased as Ca concentration in the medium increased from 1.5 to 12 mM.
The main difficulty for the cultivation and conservation of bromeliad species is the reduced number of propagules and slow growth of many of the species, resulting in a low propagation efficiency. ...Bromeliad plants are hardy and relatively easy to cultivate, with a high ornamental and ecological importance. Aiming at efficient micropropagation rates of V. hieroglyphica, a highly valued bromeliad, with very low propagation efficiency, a temporary immersion system was used and compared to semisolid and liquid static medium. Cultures obtained from in vitro germinated seeds were used as explants, maintaining their genetic diversity. Micropropagation with this simple temporary immersion system, composed of two autoclavable flasks, each with one opening for the attachment of 22 μm syringe filters, connected by a rubber stopper and an inner glass tube. In the bottom flask, an air valve is attached to the filter, which is subsequently connected to an aquarium pump and a timer and plugged to an outlet. This simple temporary immersion system showed improved micropropagation efficiency and is a method that can also be evaluated for other species.
PDF