Effect of water imbibition treatments on the germination of Origanum species cultivated in Morocco

Abstract

In Morocco, oregano is one of the most valued aromatic and medicinal plants, widely used for various culinary and therapeutic purposes. Since some Moroccan oregano populations are threatened by extinction, we analyzed the germination behavior of different Origanum species cultivated in the experimental station of INRA in Morocco, in order to plan a subsequent preservation, rehabilitation and domestication programs. In this context, we tested under laboratory conditions the influence of different pretreatments (soaking in distilled water for 24 and 48 hours and soaking in boiling water for 5 minutes) on seed germination of five Origanum species cultivated in the Annoceur experimental station of INRA, namely O. compactum, O. elongatum, O. vulgare subsp. virens, O. vulgare subsp. vulgare and O. onites. Results showed that germination percentage varied significantly according to species and pretreatment. Soaking seeds in distilled water (24 and 48 hours) was more effective in improving the germination rate of all species. O. onites and O. elongatum showed the highest germination rate, 90% and 83% respectively for seeds soaked in distilled water for 24 hours. However, soaking the seeds in boiling water significantly reduced the germination rate of 4 species: O. elongatum, O. vulgare subsp. virens, O. onites and O. vulgare subsp. vulgare (Spain). It should be noted that soaking the seeds in distilled water not only increased the germination rate, but also reduced the latency time of these seeds. According to the treatments used in this study, soaking of seeds in distilled water for 24 and 48 hours can be recommended as the most effective treatment for enhancing germination of Origanum seeds. These data may serve as guidelines for species-specific sexual multiplication protocols, promoting ex situ conservation of these medicinal species.

Keywords

• origanum
• germination
• semences
• prétraitements
• imbibition