Kryvokhatko H. Cultivars of Thuja occidentalis L.: biological and ecological characteristic, prospects of use in landscaping of Kyiv

The dissertation is devoted to the study and research of biological and ecological properties of Thuja occidentalis cultivars with further use in landscaping of Kyiv. A retrospective analysis of literature sources shows the gymnosperms play a significant role in the lives of many peoples, especially in the Northern Hemisphere as an important component of forestry, recreational, soil protection plantations, due to their numerous species and even bigger intraspecific composition, significant size amplitude, big ecological tolerance, high decorativeness. That is why they attract a lot of attention from both scientists and specialists, especially of forestry and garden and park economy. Rooting of stem cuttings of economically valuable plants in specially created conditions is the most common way of their vegetative reproduction. Ability to save the decorative and other economically valuable features of selected cultivars is the main advantage of the vegetative method of reproduction over seed. The method becomes especially important when plants do not form similar seeds or form them irregularly in small quantities. Growing of seedlings using the method of plant cutting remains the most promising in terms of biology, agriculture and economy today. If the basic technological conditions are met, in order to increase a rooting efficiency, use of exogenous bio stimulants (stimulators of root formation) during the cultivation of planting material for the needs of forestry and horticulture becomes important. Treatment of cuttings with growth regulators is one of the important factors in the efficiency of plant cutting improving. Root stimulants in form of water solutions were used for research: "Kornevin" (concentration – 0,5, 1,0 and 1,5 g.l-1), "Epin" (concentration – 0,5, 1,0 and 1,5 g.l-1) and "Succinic acid"(concentration – 0,5, 1,0 and 1,5 g.l-1). As a result of studying of the effect of exogenous bio stimulants water solutions of different concentrations on the rhizogenic ability of stem cuttings of Thuja occidentalis and its cultivars, the highest result was obtained using a solution of "Kornevin" biostimulator.