SEASONAL RHYTHM OF DEVELOPMENT AND FEATURES OF REPRODUCTIVE CAPACITY OF CALLA PALUSTRIS L. PLANTS IN INTRODUCTION CONDITIONS

Abstract

This article presents the results of phenological observations of C. palustris ex situ in the National Dendrological Park “Sofiyivka” of the National Academy of Sciences of Ukraine. The dates of onset, duration and end of phenological phases were determined.The dependence of the onset of the phenological phases of the studied plants on the sum of effective temperatures was established.The vegetative phase occurs in the second or third decade of April, with a wide range of effective temperatures over the years of research: from 78.2°C to 145.5°C. The budding phase began at the sum of effective temperatures from 192.7°C (2022) to 231.8°C (2023).The budding was observed in the I-II decade of May; the duration of phase duration was 4-11 days. The beginning of the flowering phase was recorded at a wide temperature range of the sum of effective temperatures from 229.7°C to 457.8°C. Plants bloomed from the second decade of May to the first decade of June. The dynamics of the duration of this phase varied from 8 days (2020) to 14 days (2022).The seed ripening phase occurred in the third decade of July (2020) to the first decade of September (2023). The duration did not change significantly: 18 days (2023), 19 days (2020-–2022), and 24 days (2021). However, it should be noted that the ripening duration shifts towards September every year. Senescencephase began in the second to third decade of September, with the sum of effective temperatures of 2045.8°C – 2139.9°C, and ended in the second decade of October (2147.8°C – 2411.6°C). In general, this phase lasts from 29 to 33 days.Over the years of research, the vegetation period of C. palustris plants ex situ National Dendrological Park” ‘Sofiyivka’” lasted 169–-180 days. Under culture conditions, plants go through a complete cycle of seasonal development.The overall seeding rate fluctuates slightly over the years, generally 70–80%. According to our observations, this indicator indicates the need for stratification, and irregular seed renewal in culture requires further study of the later stages of the reproductive cycle.The reproductive capacity of the studied species is characterized by average indicators, which makes it possible to artificially propagate characterized by average indicators, which makes it possible to propagate artificially by seeds.