Peculiarities of Hypericum perforatum L. reproduction in vitro culture and development of plants in the open field

The possibility of using the method of cell and tissue culture for microclonal reproduction of St. John’s wort is shown. Direct morphogenesis was obtained using seedlings without roots at the age of 12 days. It was found that the introduction of BAP in a low concentration (0,1 mg/l) with IAA 1,0 mg/l into the MS nutrient medium promoted the minimum bud formation with the maximum yield of morphologically normal shoots without the need for an elongation phase. At the stage of rhizogenesis, the process of root formation was observed in all variants of the experiment; the proportion of shoots with roots was high and ranged from 88 to 90%. The maximum height of shoots, the number of pairs of leaves per shoot, and the length of plant roots were reached on the MS nutrient medium with IAA 1,0 mg/l. The period of adaptation to non-sterile conditions was 30 days, while a high yield of regenerant plants was observed. The survival rate of the adapted regenerant plants in field conditions was high (100%). Regenerant plants developed rapidly and bloomed in the first year. It was revealed that before planting in open ground, St. John’s wort plants propagated in vitro culture and passed the stage of adaptation to non-sterile conditions in containers with soil mixture formed a sufficiently developed root system from regenerant plants with a large number of adventitious roots 6–8 cm long. At the base of the shoot, from 2 to 5 renewal shoots 9–12 cm in height were formed. On the 65^th day after transplanting, the number of renewal shoots more than doubled and averaged 7,8 pcs. per individual with a shoot height of 23 cm. In the third decade of August, the plants entered the budding phase, and on September 20, they entered the flowering phase. It was noted that by the beginning of flowering, the height of the plants increased to 49–54 cm, and the diameter of the shoot – up to 0,4 cm. From 16 to 24 pairs of oblong-ovoid standard leaves were formed on the plant. The formation of the floral part of the shoot (inflorescence) 20–27 cm long began with the axils of 9–14 leaves and consisted of 7–10 pairs of lateral axes (paracladia). The average number of flowers was 82. The amplitude of variability of the main morphological traits of the shoot of the studied plants was at low and medium levels. It was found that the development of microclonally propagated plants by the end of the first growing season corresponded to the growth and development of St. John’s wort plants of the second year of life grown by seedlings.