Optimization of cultivation conditions in vitro and ex vitro of juvenile material of pedunculate oak

The application of biotechnological approaches for producingnumerous tree species, including pedunculate oak Quercus robur L., may become the only way to preserve and reproduce unique breeding objects, which is of great importance for practical forestry. It is now possible to clone individual trees with valuable properties and scientifically advantageous genotypes. In experiments on clonal micro propagation of oak, juvenile plant material (seedlings) was grown in the laboratory. The use of additional stage of rearing and micropropagation of explants of one-month seedlings on media with different volume of 6-benzylaminopurine (6-BAP) showed the expediency of this procedure. When applying ex vitro media, many cultures continued to develop axillary or adventive shoots, the height of which was 11–15 mm (depending on the concentration of 6-BAP). The results of this study will help to cope with the difficulties associated with the induction and preservation of the morphogenic potential of explants in the process of repeated subculturing. The highest rhizogenic response (73 %) was achieved for the micro buds of juvenile material on BTM medium with full composition of macronutrients and indolylbutyric acid (IBA) at a concentration of 0.3 mg/l. It was also found that the combination of IBA and 1-naphthalenacetic acid (NAA) in concentrations of 0.2 and 0.1 mg/l, respectively, completely suppresses the development of roots in micro shoots of pedunculate oak. Of the 4 tested substrates, the highest increase in oak seedlings was observed in the variant with forest oak soil and sand (5.0 cm). The use of two-stage adaptation of regenerative plants ensured their 100 % survival in the laboratory and greenhouse. The use of soil as a substrate, taken from natural oak plantations, will significantly reduce the cost of the process of growing planting material.