Engineering a Scalable Ex Situ Conservation system for Andrographis paniculata via High-Frequency Somatic Embryogenesis and Synthetic Seed Technology

Andrographis paniculata Nees. is a medicinally important species subjected to sustained harvesting pressure, while its natural regeneration is constrained by prolonged seed dormancy, low viability, and poor germination. Although in vitro regeneration has been reported earlier, protocols explicitly addressing conservation and germplasm preservation remain limited. In the present study, a conservation-oriented in vitro system integrating somatic embryogenesis with synthetic seed technology was developed for A. paniculata . Somatic embryos were induced from hypocotyl and cotyledon explants of aseptic seedlings cultured on Murashige and Skoog (MS) medium supplemented with defined plant growth regulator combinations. Maximum induction of embryogenic callus and globular embryos was achieved on MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D; 9.05 µM). Subsequent modulation of auxin levels, incorporation of AgNO₃, cytokinins, and elevated sucrose concentrations supported embryo maturation and conversion into plantlets. Mature somatic embryos and in vitro-derived shoot buds were successfully encapsulated using sodium alginate to generate synthetic seeds, which retained regeneration potential following short-term low-temperature storage. The integration of high-frequency somatic embryogenesis with synthetic seed production provides a reproducible framework for ex situ conservation, short-term germplasm storage, and sustainable propagation of A. paniculata .