Comparative morphobiological characteristics of <i>Hypericum perforatum</i> specimens of different geographical origins introduced in the North

The article presents the results of a four-year study of 29 accessions of St. John's wort of different geographical origin under the conditions of cultivation in the middle taiga subzone of the Komi Republic. High winter hardiness of St. John's wort plants of the first and second years of life was revealed. A significant decrease in winter hardiness of most of the studied accessions (up to 41–68%) was noted in the third and fourth years of plant overwintering. Five winter-hardy accessions were identified: Tallinn 885 and 886 (100%), Yoshkar-Ola, Oslo 219 and Tallinn 888 (90%). It was found that all plants of St. John's wort grown by seedlings enter the generative period in the second year of life, regularly bloom and bear fruit. The study of the seasonal development of St. John's wort showed that accessions of different geographical origin retain the phenological rhythms characteristic of this species. Plants of St. John's wort perforated are characterized by long periods of flowering (39–57) and fruiting (37–59 days). The vegetation period of most samples, depending on the weather conditions of the season, lasts 126–142 days. One sample, Tallinn 885, stood out with a shorter vegetation period (100–128 days). The morphometric characteristics of the generative shoot of all samples in plants of the second to fourth years of life are given. The maximum indicators of the floral part of the shoot were noted in the Barnaul, Yoshkar-Ola, Syktyvkar, Tallinn 885 samples, the minimum – in the Solnechny and Leipzig 379 varieties. The plants reached their maximum development in the third year of life. The total content of hypericin and pseudohypericin (0,04–0,06%) in St. John's wort plants of different geographical origins was determined. A high content of flavonols (4,8–5,8%) was found in the above-ground raw phytomass of the studied St. John's wort samples of different geographical origins.