Effect of temperature and different pre-treatments on seed germination of Stachys mouretii Batt. & Pit

• Published in: Journal of applied research on medicinal and aromatic plants 2023-02, Vol.32, p.100438, Article 100438
• Main Authors: Ismaili, Soumaya E., Maurady, Amal, Lachkar, Mohammed, Britel, Mohammed R., Bakali, Abdelmonaim H.
• Format: Article
• Language: English
• Subjects: Endemic; Germination; Preservation; Stachys mouretii; Temperature
• ISSN: 2214-7861; 2214-7861
• DOI: 10.1016/j.jarmap.2022.100438

Stachys mouretii Batt. & Pit. is an endemic species of Morocco, it is considered as rare and threatened species. In order to conserve and valorize this species, our study aims to determine the optimal germination conditions of S. mouretii. Seeds collected from natural plant populations were subjected to six alternating temperatures (10/0 °C, 15/5 °C, 20/10 °C, 25/10 °C, 35/20 °C and 40/25 °C, with a 14/10 h. light/dark photoperiod) and nine pre-treatments: pre- soaked seeds in cold distilled water for 24 and 48 h and gibberellic acid (GA3) (250 and 500 mg/l), prechilling during 15 and 25 days, manual scarification, manual scarification combined with pre-soaking in cold water for 24 h and finally the combination of GA3 (500 mg/l) and prechilling at 4 °C during 15 days. The results showed that alternating temperature had a significant effect on the germination parameters. The highest germination percentage (66.5 %) was obtained at 25/10 °C, while germination was not observed at 10/0 °C. The temperature regime of 35/20 °C has been the best, combining higher capacity and speed germination as indicated by the germination index (GI=6.0 %/day). Our study demonstrated that pre-soaking in 500 mg/l GA3 was significantly the best pre-treatment for seed germination by improving germination capacity to 91.5 % and reducing the germination time as indicated by the mean germination time (MGT) which was 5.6 days versus 12.9 days for the control. The median germination time (T50) was 4.4 days for GA3-500 mg/l versus 11.3 days for control. These findings are useful for the choice of suitable pre-treatment that can contribute to improve germination of S. mouretii seeds. •Stachys mouretii Batt. & Pit. is a perennial endemic species to Morocco.•The temperature regime of 35/20 °C has been the best, combining higher capacity and speed germination.•The most effective pre-treatment to improve seed germination was GA3 at an optimal concentration of 500 mg/l.•Inhibitors in the embryo reduce germination of S. mouretii seeds.