Effects of culture medium composition on the in vitro growth of stem cuttings of Kirengeshoma koreana Nakai, a rare species in Korea

Effects of culture medium composition on the in vitro growth of stem cuttings of Kirengeshoma koreana Nakai, a rare species in Korea

Background and objective: Kirengeshoma koreana Nakai is an endemic and endangered species in South Korea. We conducted in vitro propagation and regeneration of K. koreana from stem cuttings to investigate the effects of nine different basal culture media and five different carbohydrate sources on its growth. Methods: Apical segments (at least 1 cm long) collected randomly from a six-week-old K. koreana plantlet grown in vitro were used as explants. In the first experiment, the explants were transferred into square vessels containing 50 mL of nine different basal culture media supplemented with 30 g·L-1 sucrose and 3 g·L-1 Phytagel. In the second experiment, the explants were transferred into square vessels containing 50 mL half-strength SH medium supplemented with five different carbohydrate sources at 30 g·L-1. Each medium was solidified with 3 g·L-1 Phytagel. All experiments contained 4 cultures, and the experiments were repeated four times to enhance reproducibility. Data on stem length, shoot fresh weight, leaf width, leaf length, root count, and root length were collected at the end of 8 weeks of culture. Results: ANOVA showed that the basal culture medium had a significant effect on K. koreana growth (p < .001). The half-strength SH medium was the best condition for stem length, shoot fresh weight, leaf width and root length (3.76 ± 0.12 cm, 0.60 ± 0.06 g, 1.19 ± 0.05 cm, and 2.83 ± 0.13 cm, respectively). However, the highest percentage increase in root count (13.00 ± 0.90) was found to occur with half-strength WPM. The effect of different carbohydrate sources on K. koreana growth was significantly different (p < .001), with the exception of stem length and leaf width (p = .26 and p = .09, respectively). Maltose was the best condition for shoot fresh weight (0.90 ± 0.09 g). Although there was no significant difference, sucrose was found to be best for leaf width, leaf length and root length (1.34 ± 0.07 cm, 2.34 ± 0.10 cm, and 3.86 ± 0.19 cm, respectively). Conclusion: This in vitro propagation and regeneration system for K. koreana shows promise in terms of scalability and could help greatly with germplasm conservation and restoration efforts for the species.