PHENOLOGICAL FLOWERING RHYTHMS OF PLANTSFROM THE MSU BOTANICAL GARDEN IN 2019 AND THEIR DEPENDENCEON SUMMARY ACTIVE TEMPERATURES

The results of our phenological observations of flowering rhythms of 37 herbaceous and 21 woody plants from the collections of the Botanical Garden of Moscow State University in 2019 are presented for three phases, namely, the beginning, peak and the end of flowering. The average timing of the “peak flowering” phase onset for the period of 2009–2019 was calculated, and it has turned out that the vast majority of the studied plants bloomed in 2019 earlier than usually. To assess the effect of summary active temperatures (SAT) on plant development, their sums were calculated by months (according to the data of MSU Meteorological Observatory) with thresholds of 0°С, 5°С, and 10°С in comparison with their average values. Our comparison of the data obtained has shown a direct effect of SAT on the timing of the onset of flowering phenophases, and also confirmed the importance of not only the sum of positive temperatures, but also the sum of temperatures exceeding the threshold of 10°C for flowering of the primary flowers. For a significant advance in the average timing of flowering, such plants need to receive an excess of heat about a month before flowering. An increased amount of active temperatures even immediately before and during flowering has a beneficial effect on the timing of flowering. At the same time, SAT values above 10°C are important.