Features of flowering and pollination in Melissa officinalis L.

Abstract

Background. Essential oils are widely used in various fields of medicine, cosmetics and perfumery; therefore, essential oil plants are of considerable interest for industrial cultivation. Knowledge of their anthecology features allows us to solve seed production problems of such crops. The objective of this study was to examine flowering features in Melissa officinalis L.
Materials and methods. The source material was collected in Southern Uzbekistan, and the plants were grown under the conditions of Termez. Observations were carried out in 2020–2024 according to generally accepted methods.
Results and conclusion. The first flowers open between May 22–30. The flowering period of plants lasts 92–95 days. The inflorescence is a pleiothyrsus. Partial inflorescences are cymoid (dichasia). Flowers are located in false whorls. Each whorl of the main inflorescence contains 6 flowers (3 pcs. in each semiwhorl). Flowers bloom in the morning and afternoon hours (from 9 AM to 1 PM), the bulk (64.7%) of flowers blooms between 10–11 AM. In total, from 71 to 147 flowers bloom in one lemon balm plant per day. During the growing season, one M. officinalis plant can form from 5120 to 5586 flowers. Dichogamy in the form of protandry is observed in the flower. An hour after the flower blooms, the anthers of the straightened stamens burst and begin to pollen, and the stamen (male) phase of flowering begins. With the onset of the male phase of flowering, the corollas turn white. The male phase lasts up to 7–8 hours and ends with the drying of the stamens. The female phase of flowering begins 3–4 hours after the corolla opens (noon – 1 PM), when the style lengthens somewhat and the stigmas begin to deviate in different directions. The duration of the female flowering phase is 9–11 hours and ends with the drying of the stigmas. The duration of flowering of bisexual flowers is 20–24 hours. The growing season lasts from 175 to 184 days.