Identification and micropropagation of Homalomena pendula, an endangered medicinal plant

The large-leaved Homalomena (LLH, Homalomena pendula) represents an endangered medicinal plant species within Vietnam, primarily attributed to its recognized tonic properties. Despite its imminent threat of extinction within Vietnamese ecosystems, the development of a robust protocol for molecular species identification and large-scale propagation of LLH remains absent. Consequently, we present the first conservation endeavor for LLH based on plant micropropagation techniques, with plant materials validated through anatomical observations and DNA barcoding (rbcL). Our investigation yielded five rbcL sequences specific to LLH, serving as the current best barcode for LLH identification and thereby facilitating forthcoming taxonomic endeavors. Optimization of in vitro culture conditions revealed that the Murashige and Skoog (MS) medium supplemented with 2 mg/L 6-benzylaminopurine, 0.5 mg/L α-naphthaleneacetic acid, and 60 g/L mashed potato, alongside the incorporation of 0.5 mg/L indole-3-butyric acid to the basal MS medium, yielded optimal outcomes for shoot proliferation and root development, respectively. After successful micropropagation, acclimatization of rooted plantlets to a substrate comprising soil, coconut coir, and rice husk (in a 1:1:1 ratio) culminated in a 100% survival rate among the plants.