The features of seed productivity of Calendula officinalis L. (Asteraceae) in the Preduralye region

Abstract

Background. Calendula officinalis on the territory of our country is grown as a medicinal and ornamental plant, for its successful reproduction it is important to study the issues of the reproductive biology of the species. The features of the potential and actual seed productivity of Calendula officinalis L. in Perm have been studied for the first time. The purpose of this work is to study the features of seed productivity of Calendula officinalis L. in the conditions of the Preduralye region. Materials and methods. Observations and material collection were carried out in accordance with generally accepted methods from 2018 to 2020. Seed propagation of Calendula officinalis L., variety Orange, was studied. Results. The first shoots of Calendula officinalis were observed a week after sowing, the emergence of shoots was not amicable, prolonged from one to three weeks in different years of observation. The beginning of flowering was noted in all variants of the experiment in the second decade of July and continued throughout the entire growing season. The beginning of fruiting was noted in the second decade of August. It was revealed that Calendula officinalis L. variety Orange was distinguished by a wide variability in the number of pseudo-ligate and tubular flowers in the inflorescence. The proportion of pseudo-reed flowers in relation to tubular flowers varied from 13 to 62 % and averaged 40 % with a coefficient of variation equal to 18 %. The ovule is formed in the ovary of false-lingual flowers and marginal tubular flowers. In the central tubular bisexual flowers, the stigma and ovule are reduced, only the stamens function. The fertility of pollen grains of marginal tubular flowers varied from 77 to 84 %, and of central ones, from 30 to 50 %. Fertility of ovules varied from 67 to 91 %. The potential seed productivity was 1067 ovules per plant, and the real seed productivity was 448 seeds. In the harvest of calendula, seeds are heterocarpic. On average, in our studies, claw-shaped seeds accounted for 19 %, scaphoid seeds – 20 %, ring-shaped seeds – 61 %. Conclusions. Based on the studies carried out on the potential and actual seed productivity of Calendula officinalis L., it has been established that flowering and ripening of fruits are extended over time. The fertility of pollen grains and ovules was high enough for successful seed setting. It has been established that, under the conditions of the Preduralye region, the elements that make up the seed productivity of Calendula officinalis, such as the number of inflorescences, the number of flowers per inflorescence, and the number of seeds, are very variable. The laboratory germination capacity of scaphoid seeds was higher than the germination capacity of claw-shaped and ringshaped seeds, it was 76 %.

Keywords

• seed productivity
• calendula officinalis l.
• reproductive biology
• pollen and ovule fertility
• the preduralye region