Effect of rhizosphere bacteria and endomycorrhizal fungi on the growth of Christmas rose ( <i>Helleborus niger</i> L.)

Summary Micropropagated and vegetative (by rhizome cuttings) propagated plants of Christmas rose ( Helleborus niger L.) were tested for their responses to the inoculation with microorganisms in order to optimize root growth and development. In our experiment, plants were inoculated with arbuscular endomycorrhizal fungi or/and Agrobacterium radiobacter . The investigation indicated that inoculation with A. radiobacter had significantly positive effect on growth and development of plants multiplicated by in vitro techniques as compared to the dual inoculation. This study indicates that, biotization can be beneficial to plant growth in in vitro plant production systems but inocula have to be carefully selected for this purpose.