Effect of light, temperature, salt stress and pH on seed germination of medicinal plant Origanum elongatum (Bonnet) Emb. & Maire

Origanum elongatum is one of the most important medicinal plants in Morocco. The overexploitation by local inhabitants and the climate changes made this species highly threatened. Seed germination is one of the easiest solutions to save medicinal plants. However, the success of such operation depends in several factors. The aim of this study was to investigate the effect of temperature, light, darkness, pH and salinity stress on O. elongatum seeds germination. Mature seeds were isolated from O. elongatum harvested from Temsamane area belonging to Driouch province (North-east of Morocco) at post-flowering stage. The in vitro seed germination tests were carried out in Petri dishes. The influence of the above parameters was evaluated by following the evolution of germination over time. The results showed that the temperature range between 15 and 20 °C at light using an aqueous medium were more suitable for germination of O. elongatum seeds. The optimum pH ranged between 6 and 7. Finally, the germination was negatively proportional to NaCl concentration. These data may serve as guidelines for species-specific propagation protocols, promoting ex situ conservation of this threatened medicinal plant.