Regeneration in St. John’s wort (Hypericum perforatum): Interaction of Silver N anoparticles with Other Factors

St. John’s wort is a perennial flowering plant with valuable medicinal properties. In vitro systems are an important tool for obtaining uniform genetic plants that can be valuable sources of pharmaceutical products. Our aim in this research was to develop a more efficient regeneration protocol for this plant applicable in genetic engineering programs. To do this, the effects of different concentrations of silver nanoparticles (0, 0/5, 1, 2/5 and 5 mg/l) and its interaction with plant growth regulators as well as explants on shoot regeneration of Hypericum perforatum leaf and stem segment explant were evaluated, in a CRD-based factorial design with three replicates and five samples in each replicate under in vitro conditions. Based on the results, 1.5 mg / L of CPPU (N-(2-Chloro-4-pyridyl)-N'-phenylurea) and 1 mg / L of IAA was the most suitable hormonal combination for Hypericum perforatum regeneration. Silver nanoparticles at 1 mg / L concentration caused some positive effects such as increasing length in regenerated shoots from Hypericum perforatum leaf explants, but higher concentrations of nano silver (5 mg / L) caused a significant reduction in regeneration. Furthermore, the shoots regenerated from Hypericum perforatum leaf explants showed a better rooting on 1/2 MS medium containing 1 mg/l IBA.