Influence of the symbiotic bacteria Paenibacillus sp. on the European larch (Larix decidua Mill.) buds vitality in vitro

Abstract

The aim of the research is to determine the influence of the symbiotic plant bacteria, previously isolated from the hybrid aspen tissue (Populus tremuloides × P. tremula) and identified as Paenibacillus sp. , on the European larch ( Larix decidua Mill.) viability. Previous studies by other authors have showed that bacteria release certain substances that promote plant growth, vitality, and adaptation to the environment in order to provide a more favorable environment for growth for bacteria itself. In order to investigate Paeniacillus sp. effect on the viability of European larch buds, larch explants were infected with bacteria in in vitro culture. Later, changes in morphological parameters such as shoots and needles length were observed. European larch explants were grown on four different nutrient variants: 1) control, bacteria free, Woody Plant Medium (WPM), 2) WPM with bacteria cultivated on LB medium, 4 weeks before research, 3) WPM with bacteria and apical larch explants cultivated on LB medium, 4 weeks before research, 4) WPM, produced and infected with bacteria 4 weeks before research. The study showed that the maximum length of the shoots and needles was fixed on the WPM, produced and infected with bacteria 4 weeks before start of the investigation. The apical explants that grew on this medium were almost twice as large as those on other types of media. As the bacteria grows into the nutrient medium, it is likely that certain chemicals have been released that have led to the growth of larch needles and shoots. It can be concluded that the bacteria Paenibacillus sp. and European larch (Larix decidua Mill.) apical explants growing in one in vitro culture had a positive effect on the viability of buds and further growth.