Developing in-vitro cultivation techniques for Psoralea corylifolia and optimizing seed germination methods to investigate the impact of elicitors on seedling growth

Current study described an efficient direct and indirect plantlet regeneration using nodal and leaf explants. The use of BAP alone promoted direct regeneration from nodal as well as leaf explants. Together with kinetin and IAA, BAP resulted in 5-7 regenerated shoots. Upon increasing the concentration BAP (3 mg/l) together with IAA (0.5 mg/l) and myoinositol (100 mg/l) explants produced a maximum of 6 ± 2 and 11 ± 3 regenerated shoots from leaf and nodal explants in 15 days, respectively. Continuous culture of explants of kinetin-supplemented media supported in vitro flowering. Flowers were smaller in size without seed setting. Supplementation of NAA along with cytokinin supported callus formation. However, NAA alone was very advantageous for in vitro rooting. The developed plantlets were transferred to the soil. The seed germination percentage was improved after a small incision opposite the micropylar end. A small cut helped in the inspection of the seed quality and also improved seed germination from 2 to 93%. GA₃ (2 or 5 mg/l) does not influence breaking the seed dormancy. Just after the radical emergence, these seeds were transferred to MS media supplemented with elicitors (salicylic acid or jasmonic acid). Growth parameters of the seedlings were recorded from 6 to 18 of treatment. Though elicitors reduced the growth of seedlings, ascorbate peroxidase activity was enhanced by 10-14-fold as the concentration of SA/JA increased. Elicitors are known to enhance secondary metabolite (psoralen) in plants, and the threefold elevated expression of the psoralen synthase gene also proved the same. The study successfully established an efficient regeneration protocol for Psoralea corylifolia through direct and indirect organogenesis, significantly enhancing shoot regeneration, seed germination, and in vitro flowering. Additionally, elicitor treatments not only induced stress responses but also promoted higher psoralen accumulation, making this approach promising for large-scale propagation and secondary metabolite production.