In vitro growth of Oncidium baueri (Orchidaceae) at different macronutrients and sucrose concentrations.

摘要

In vitro propagation in vitro is an important method for orchid reproduction, because the seeds do not have endosperm and present low germination. Sugar is an important component in a culture medium, serving as a source of carbon and energy. The objective of this study was to evaluate the growth in vitro of Oncidium baueri in different macronutrients and sucrose concentrations. The treatments consisted of 2 macronutrient formulations of the MS medium, in complete MS and modified MS medium with half of the regular concentration of macronutrients, and different sucrose concentrations (30, 40 and 60 g/litre), at pH 5.8. A randomized design with eight replications was used as statistical model and a flask with 20 plants composed each plot. Data were submitted to analysis of variance, complemented by the Tukey test at 5% of significance. The following variables were assessed 6 months after the beginning of the experiment: plant height, root length; number of roots, number of buds, dry mass and total fresh mass. The treatment that showed the best results was 40 g sucrose/litre in a modified MS medium with half of regular concentration of macronutrients, for vegetative development and rooting of O. baueri orchid.