In vitro propagation of Geranium wallichianum: An indigenously threatened medicinal plant in Pakistan
Geranium wallichianum is a well-known medicinal plant and has numerous ethnobotanical usages but its population in Pakistan is severely reducing due to overexploitation and over-harvesting. Moreover, the conventional propagation systems are not enough to sustain the population and meet the ever-increasing demand for this plant. Therefore, an efficient propagation system is necessary to conserve and increase the population of this plant. To control browning, citric acid, ascorbic acid and activated charcoal were added to Murashige and Skoog (MS) medium. The 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthaleneacetic acid (NAA) were used in different concentrations to induce the callus while shoot proliferation and root induction were achieved with media supplemented with 6-benzyl aminopurine (BAP), and indole-3-butyric acid (IBA), respectively. Callus was successfully induced in 5.1 days in a medium containing 15 μM NAA while the maximum percentage of callus induction (77.78%) was obtained from petiole segments in a medium containing 10 μM NAA. Benzyl aminopurine at a concentration of 15 μM produced 1.33 shoots per nodal segment compared with 1.0 in the control. Indole butyric acid at a concentration of 10 μM increased root length (2.67 cm). The results showed a decrease in the browning intensity and an increase in the percentage of survivals in both leaf and petiole cultures (38.88%) and (61.11%) at 0.3 g/L activated charcoal compared to control (0% and 5.5%), respectively. Activated charcoal also reduced the total phenolic content of the leaf segment (9.51 mg/g) and petiole segment (2.06 mg/g). The in vitro produced rooted plantlets were successfully acclimatized in small pots containing peatmoss.