The influence of the temperature factor on the passage of phenophases of <i>Clematis L.</i> varieties

Abstract

Listen

Translate article

Relevance. The features of the passage of the phenological phases of vegetation and flowering of 20 varieties of the genus Clematis L. in the agro-climatic conditions of Stavropol were studied. The dates of the onset of phenophases in different years have been established. A shift in these terms was revealed, associated with the amount of heat received by the plant during the period preceding the phase.Methods. The object of study was 20 varieties of clematis from the collection of the Stavropol Botanical Garden belonging to two garden groups — Integrifolia and Jackmanii. The study of phenorhythm features was carried out in 2018–2022, using the generally accepted methodology of phenological observations in botanical gardens.Results. It has been established that the onset of the phenological phases of the beginning of vegetation and flowering depends on the temperature factor of a particular year, but the sequence of flowering of varieties of different groups is preserved. The beginning of the growing season, in the studied varieties of the two groups, occurs simultaneously, but differs over the years. Phenological observations show a shift of these dates, in some years, up to 26 days. For the onset of the «beginning of flowering» phase, the sum of accumulated positive temperatures above +5 °C for the interphase period from the beginning of vegetation to the beginning of flowering is determined. For clematis varieties of the Integrifolia group, the sum of temperatures at the beginning of flowering was 943–989 °C (average — 962 °C), and the Jackmanii group was 1406–1432 °C (average — 1418 °C).