| Summary: | Shoot cultures of hypericin non-producing <i>H. calycinum</i> L. (primitive <i>Ascyreia</i> section), hypericin-producing <i>H. perforatum</i> L., <i>H. tetrapterum</i> Fries (section <i>Hypericum</i>) and <i>H. richeri</i> Vill. (the evolutionarily most advanced section <i>Drosocarpium</i> in our study) were developed and investigated for their growth, development, hypericin content and endogenous phytohormone levels. Hypericins in wild-growing <i>H. richeri</i> significantly exceeded those in <i>H. perforatum</i> and <i>H. tetrapterum</i>. <i>H. richeri</i> also had the highest hypericin productivity in vitro in medium supplemented with 0.2 mg/L <i>N</i><sup>6</sup>-benzyladenine and 0.1 mg/L indole-3-butyric acid and <i>H. tetrapterum</i>—the lowest one in all media modifications. In shoot culture conditions, the evolutionarily oldest <i>H. calycinum</i> had the highest content of salicylic acid and total jasmonates in some of its treatments, as well as dominance of the storage form of abscisic acid (ABA-glucose ester) and lowest cytokinin ribosides and cytokinin <i>O-</i>glucosides as compared with the other three species. In addition, the evolutionarily youngest <i>H. richeri</i> was characterized by the highest total amount of cytokinin ribosides. Thus, both evolutionary development and the hypericin production capacity seemed to interact closely with the physiological parameters of the plant organism, such as endogenous phytohormones, leading to the possible hypothesis that hypericin productivity may have arisen in the evolution of <i>Hypericum</i> as a means to adapt to environmental changes.
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