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

Abstract

The  propagation  in  vitro  is  an  important method  for  orchids  reproduction,  because  the seeds  don’t  have endosperm and present low germination. The sugar is a important component in medium culture, serving as a  source of carbon and energy. The objective of  this  study was  to evaluate  the growth  in vitro of Oncidium baueri  (Orchidaceae)  in different macronutrients and  sucrose concentrations. The treatments consisted: two formulations of the macronutrientes of the MS medium, in complete MS and MS modifed medium with half of  the regular concentration of macronutrients, and different sucrose concentrations (30 gL-1, 40 gL-1e 60 gL-1), at pH 5,8. A randomized design with eight replications was used as statistical model and a fask with  twenty plants composed each plot. Data were submitted  to analysis of variance, complemented by  the Tukey  test at 5% of signifcance. The following variables were assessed six months after the beguining 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 gL-1 sucrose  in a modifed MS medium with half of  regular concentration of macronutrients,  for vegetative development and rooting of Oncidium baueri orchid.