ANNOUNCEMENTS
Ophiorrhiza mungos L. (family: Rubiaceae) is a threatened medicinal plant valued for its production of camptothecin (CPT), a potent anticancer alkaloid. Due to overexploitation and habitat loss, its natural populations are rapidly declining, necessitating effective ex-situ conservation strategies. In this study, a reproducible and efficient in vitro regeneration protocol was established for O. mungos using modified Murashige and Skoog (MS) media to support ex-situ conservation and sustainable production. Surface sterilization protocols were optimized, with shoot/nodal explants treated with 0.1% mercuric chloride (HgCl₂) for seven minutes, achieving the highest survival rate (60%), minimal microbial contamination, and maximum response (70%). The addition of antimicrobial supplements to the initiation medium was also evaluated. Although the inclusion of antimicrobial agents effectively reduced microbial contamination, higher concentrations (0.05 ml/L and 0.025 ml/L) significantly increased explant mortality, indicating concentration-dependent toxicity, with the control recording the lowest mortality rate. Shoot proliferation was significantly influenced by both MS medium strength and plant growth regulator (PGR) concentrations, with half-strength MS medium (1/2 MS) consistently producing higher shoot numbers and greater shoot lengths compared to quarter-strength MS (1/4 MS). The highest shoot proliferation was achieved with 0.1 mg/L BAP in 1/2 MS medium, yielding an average of 13.1 shoots per explant, while 0.5 mg/L GA₃ in 1/2 MS resulted in maximum shoot elongation (7.23 ± 0.66 cm) and a high shoot number (10.90 ± 1.44). The combination of BAP and GA₃ in both the media strengths maintained high shoot numbers with promisable internodal elongation. Root induction trials revealed that IBA was more effective than NAA in promoting rooting, with the highest rooting response achieved at 1.5 mg/L IBA, producing an average of 4.5 ± 1.26 roots per explant and an average root length of 3.56 ± 0.56 cm. Approximately 80% of the in vitro rooted plantlets successfully acclimatized under ex vitro conditions, demonstrating the effectiveness of the developed protocol for large-scale propagation and conservation of this threatened species.
Keywords: Ophiorrhiza mungos; endangered; micropropagation; antimicrobial supplement; acclimatization.
