Effect of Pre-Germination Treatments for Breaking Seed Dormancy in Psoralea corylifolia L.

The dormant state of seeds is a major damping propagation factor in most medicinal plants including Psoralea corylifolia L., because of hard seed coats that limit exchange of water and gases. The present research examined the effectiveness of the four different dormancy-breaking methods i.e. hot water immersion, chemical scarification, mechanical abrasion and abrasive media shaking of seed germination, seedling vigor, and initial plant growth. Of these, shaking with abrasive sand proved to be most promising non-chemical treatment, and was capable of germinating up to 56% in 4 days. Although the best germination percentage was achieved by (84%) in sulfuric acid treatment, this is not practically useable because of its danger. Mechanical scarification and heat treatments provided partial success that needed careful calibration since embryo damage could occur. Interestingly the time to germination was also shorter in seeds treated by shaking, and the seedlings of these seed had longer rooted, taller shoots, and grew taller as whole plants than controls- indicating greater early vigor and potential photo-synthetic biomass accumulation. Sustainability of the shaking method as an alternative to laboratory research and field implementation is feasible, given that it is reproducible and safe, as well as scalable. Moreover, the approach is compatible with the objectives of restoration ecology since it helps to establish healthy seedlings without the residuals of toxicity. The paper highlights the importance of species-specific pre-germination procedures and presents an effective scheme of large-scaled cultivation of P. corylifolia, which guarantees sustainability of medicinal resource, as well as ecological recovery. The results support the use of abrasive shaking, as a potential and environmentally friendly alternative to chemical scarification in breaking the physical barrier to seed germination.