In vitro propagation of two species of commelinaceae from bud cultures and repeated subcultures on a growth regulator-free medium

Summary In our wide-ranging research on in vitro propagation of some monocotyledonous plants, two Commelinaceae species were studied: Tradescantia fluminensis var. foliis variegatis and Tradescantia pallida. Initial cultures were established successfully using nodal and apical meristems that produced single shoots, many roots, and no callus, by utilizing growth regulator-free MS medium. Addition of growth regulators did not increase the activity of explants that produced single or multiple shoots, atypical roots, and no callus. Consecutive cultures were possible using the apical and nodal meristems of the previous generation. The behavior of the different generations in culture did not change and was similar to the initial cultures. Their growth capacity was maintained over many months, also on a growth regulator-free medium. In both species, the chromosome number in the root tips of the mother plant and all morphologically stable in vitro plantlets confirmed a constant ploidy level, in T. fluminensis 2n=72, and in T. pallida 2n=24.