Effects of seed pretreatments and storage duration on germination performance in medicinal herbs

Some potential medicinal plants for organic farming face challenges due to inadequate market demand. This study aimed to establish suitable germination and seed banking methods for five potential medicinal plants: Cyathillium cinereum (L.) H. Rob., Hibiscus sabdariffa L., Phyllanthus amarus Schumach. & Thonn., Solanum trilobatum L., and Solanum violaceum Ortega. These plants have significant benefits for local communities. The experiment was conducted using five pretreatments: non-soaking (control), soaking in room temperature (RT) water for 24 hours, soaking in 100 °C water for 5 minutes, soaking in 0.1% gibberellic acid (GA3) for 24 hours, and soaking in 0.1% potassium nitrate (KNO3) for 24 hours. Additionally, the effects of three storage temperatures (RT, 4°C, and −20°C) and three storage durations (3, 6, and 9 months) on seed viability were evaluated for each species using the most effective pretreatment. Among the studied plants, H. sabdariffa exhibited optimal seed propagation under the non-soaking (control), RT water, 0.1% GA3, and 0.1% KNO3 treatments, achieving a seed germination rate above 92%. S. trilobatum also germinated best under non-soaking and RT water conditions, with a germination rate exceeding 90%. In contrast, S. violaceum required GA3 treatment to achieve a 96% seed germination rate. C. cinereum and P. amarus exhibited optimal germination rates of less than 60% under both control and GA3 treatments. Regarding seed storage, seeds of H. sabdariffa, S. trilobatum, and S. violaceum maintained over 90% germination for up to nine months when stored at RT, 4°C, and −20°C. However, the other two species showed reduced viability over time. These findings suggest that, in most cases, non-soaking pretreatment is sufficient for optimal germination, given its simplicity and cost-effectiveness. Nonetheless, for S. violaceum, GA3 application is necessary. Furthermore, RT storage proves to be suitable for the long-term banking of seeds from selected medicinal species.