SEASONAL RHYTHMS OF PLANT DEVELOPMENT OF GLEBIONIS CORONARIA (L.) CASS. EX SPACH. IN THE CENTRAL POLISSIA AREA OF UKRAINE

Abstract

The aim of our research was to study seasonal rhythms of development of Glebionis coronaria (L.) Cass. ex Spach. (garland chrysanthemum) introduced in the Central Polissia area of Ukraine, depending on abiotic conditions of the plant environment. The study of phenology of introduced plants was carried out from 2013 till 2017 in the Botanical Garden of Polissia National University. We calculated the effective heat sum above 5°C, required for a certain phase of development and for the plants life cycle in general. It was established that under conditions of Central Polissia in Ukraine during the period of 2013–2017 G. coronaria vegetated for 102–132 days at the effective heat sum of 1471.4–1780.3°C. Seedlings appeared between late April and early May at a rather wide range of effective heat sums, i.e. from 131.4°C to 195.2°C. The vegetative phase lasted 35–41 days, until early June. The budding phase began in early June at the effective heat sum of 351.5–502°C and lasted until late June, i.e. for 20–24 days. The beginning of the flowering phase was recorded between mid and late June with a wide range of the effective heat sums of 527°C–755.3°C. The duration of the phase varied significantly over the years of research: from 41 to 60 days. The fruiting phase occurred in late June – mid July at the effective heat sum of 780,5–1074,2оС і and lasted from 28 to 52 days. The phase of fading began in late July – mid August at the effective heat sum of 1116.5°C–1464.2°C. Vegetation ended between early August and early September. The timings of phenological phases that reflect seasonal development depend largely on temperature and water supply. The biological needs of the introduced plants for the growing season duration and thermal regime fully correspond to the natural conditions of the Central Polissia area of Ukraine, which confirms that cultivation of G. coronaria in this region is highly promising.