Winter resistance and frost resistance of representatives of the genus Cotinus Mill. in the conditions of the Right Bank Forest Steppe of Ukraine

Abstract

Aim. The goal is to assess the winter and frost resistance of plants of representatives of the genus Cotinus Mill. from the collection of the National Dendrological Park "Sofiyivka" of the National Academy of Sciences of Ukraine and the Botanical Garden named after Academician Alexander Fomin of the Taras Shevchenko National University of Kyiv. Methods. The frost resistance of plants was investigated in the laboratory of plant physiology of the Institute of Horticulture of the National Academy of Sciences of Ukraine, by the method of direct freezing of shoots during the period of forced dormancy of plants. The intensity of damage (browning) of tissues on transverse sections of shoots was assessed using a six-point scale by M. A. Solov'eva (1982). The objects of study were plants C. obovatus Raf., C. coggygria Scop., C. coggygria 'Royal Purple', C. coggygria 'Purpurea'. Winter hardiness was assessed visually on an eight-point scale by S. Ia. Sokolov, (1957). Results. According to estimates of the general freezing of plants in the winter period of 2014–2020, minor injuries were found in all representatives of the genus Cotinus, which were estimated at 1–2 points. The results of experimental studies of plant frost resistance showed that in most variants of the experiment, the tissues of the upper internode and buds froze more. The tissues of the medial part of the shoot turned out to be the most resistant to freezing. According to the results of artificial freeze testing of cut shoots of C. coggygria and C. coggygria 'Royal Purple", sampled in the period of forced dormancy of plants, insignificant tissue damage was revealed at freezing temperature of –25 °С and –30 °С (0.63–1.70), only at temperature of –35 °C, the score of bark damage was 2.3–2.5 points. Conclusions. The low temperatures of the winter period of the study area cannot be considered as limiting abiotic factors that limit the widespread use of the studied representatives of the genus Cotinus in landscape construction. The high potential of frost and winter hardiness of the studied taxa gives grounds to test them in the more northern regions of the Right Bank Forest-Steppe of Ukraine to create garden and park compositions, because due to high decorative flowering and specific crown shape they have an attractive appearance in both group and solitary plantations.