Peculiarities of seasonal development of species of the genera Sedum L. and Hylotelephium H. Ohba in the conditions of Kryvorizhzhia

Abstract

Resulted results of research of seasonal development of species of the genera Sedum L. and Hylotelephium Н. Ohba in the conditions of Kryvorizhzhia during 2003–2021 years. In the conditions of the steppe zone of Ukraine, global climate changes are associated with rising temperatures and prolonged droughts, especially during the period of active vegetation of plants. This leads to the creation of stressful conditions for the vital activity of plants used in landscaping. In this regard, plants change the rhythms of growth and development, adapting to the climatic conditions of the area of growth. The limiting factors are mainly air temperature and daily photoperiod. The purpose of the work is to determine the phenology features of individual species of the genera Sedum and Hylotelephium at introduction into the Kryvyi Rih Botanical Garden of the National Academy of Sciences of Ukraine under the influence of climate change. The objects of the study were Sedum aizoon L., S. album L., S. florіferum Praeg., S. hybridum L., S. reflexum L., S. spurium M. Bieb., S. takesimense Nakai, Hylotelephiuт ewersii (Ledeb.) H. Ohba, H. spectabile (Boreau) H. Ohba. The increase in annual air temperature caused changes in the timing and duration of certain phases of development of the vegetative and generative spheres. Accordingly, there was an increase in the growing season by 20–50 days. When introduced to the Kryvyi Rih Botanical Garden of the National Academy of Sciences of Ukraine, S. floriferum, S. takesimense and S. spurium change their phenotype from winter-green to spring-summer-autumn-green. It has been observed that S. album, S. reflexum, S. spurium, S. floriferum, S. hybridum and S. takesimense, which flower in July in their natural habitats, begin bloom in June аn Kryvorizhzhia, and in 2017–2021 the timing is accelerated – it is already the end of May–beginning of June. The difference in time reached 12–18 days. The average duration of flowering sedums was 22–30 days. During 2003–2021, the duration of flowering increased reliably in S. aizoon, S. floriferum and S. reflexum. In the conditions of Kryvorizhzhia, the species S. floriferum, S. takesimense and S. spurium change their development strategy – they do not vegetate in the winter period and bloom in June, which is not typical for them in the conditions of natural habitats. There is also a change in the flowering period to the early-summer period in S. album, S. reflexum and S. hybridum, which are summer-flowering. The identified features of the seasonal rhythm of development indicate a significant level of plasticity of the studied species.