Abstract

St. John’s wort (Hypericum perforatum L.) is one of the introduced medicinal plants that have medicinal uses for anti-depressant. Germplasm conservation of St. John’s wort has been conducted at the laboratory for over ten years and plantlets showed a rosette growth. Therefore, laboratory investigations are necessary to be done to have better methods for obtaining normal growth of culture. In this study, we evaluate the effect of concentration levels of silver nitrate (AgNO3) on shoot multiplication, rooting induction and visual characteristics of plant in-vitro culture. The study was conducted in two stages (shoot multiplication and rooting induction). For shoots multiplication, cultures were grown in Murashige and Skoog (MS) media supplemented with 0.1 mgl-1 N6-Benzyl Adenine (BA) combined with various concentration levels of AgNO3 as follow: MS + 0.1 mgl-1 BA + AgNO3 (0.0, 0.1, 0,3, 0.5 and 0.7 mgl-1). For rooting induction, cultures were grown in half-formula of MS media with various concentration levels of AgNO3: ½ MS + AgN03 (0.1, 0.3, 0.5 and 1.0 mgl-1). The results showed that the application of AgNO3 combined with 0.3 mg/l BA could improve the culture characteristics and showed normal plantlets. The best rooting induction was obtained at  ½ MS + 0.3 mgl-1 AgNO3. This protocol provides a technique for improving visual culture during conservation.

Key words: Hypericum perforatum L., shoot multiplication, protocol for improving visual culture, in vitro.