Somatic embryogenesis-mediated plant regeneration and phytochemical characterization of Codonopsis pilosula (Franch.) Nannf

Abstract

This study developed a feasible in vitro regeneration approach for C. pilosula through indirect somatic embryogenesis using leaf explants. Different growth regulators’ effect on somatic embryo initiation, maturation, and conversion were systematically evaluated. In addition, chlorophyll level, chlorophyll fluorescence content, genetic fidelity, and Fourier transform near infrared (FT-NIR) profiles of the regenerated plants were compared to those of commercial roots. Somatic embryo induction was observed on Murashige and Skoog (MS) media complemented with 2.0 mg L-1 2,4-D. The progression of the somatic embryos from globular to heart shaped, torpedo, and cotyledonary stages depicted by distinct shoot and root meristems was most effectively enhanced by 1.0 mg L-1 ABA. Cotyledonary embryos showed a high germination rate (86 %) when grown on full strength MS media devoid of additional growth regulators. Regenerated plantlets with fully developed shoots and roots exhibited a 100 % survival rate during acclimatization on agricultural soil and perlite mixture (2:1). Histological observations validated the distinct morphogenetic phases of somatic embryos, while genetic stability analysis confirmed that regenerated plants retained the same ploidy level as the mother plants, indicating genetic stability. Additionally, chlorophyll contents and photosynthetic performance of regenerated plants were equivalent to those of mother plants. FT-NIR also showed similar chemical spectra between the roots and leaves. Overall, this optimized in vitro system provides a rapid, reliable, and scalable approach for mass production of genetically uniform C. pilosula plants to meet growing demand.