Direct organogenesis and plant regeneration of Litsea coreana Levl. var. sinensis

Litsea coreana Levl. var. sinensis is a versatile evergreen tree species that is difficult to propagate on a large scale using traditional methods. However, research on direct regeneration from stem segments of L. coreana var. sinensis is limited. This study investigates the disinfection methods for explants, factors influencing axillary bud induction and proliferation, and adventitious root growth. The results indicate that the optimal disinfection method for young stem segments of L. coreana var. sinensis is 30 s in 75% alcohol followed by 10 min in 0.1% HgCl₂. A pre-treatment with 5% carbendazim for 30 min before applying the same disinfection protocol effectively reduces contamination rates in semi-woody stem segments. Adding 1.0 g·L^− 1 activated charcoal (AC) to the axillary bud induction medium significantly decreases browning rates of explants. The suitable basic medium for axillary bud induction is 1/2 MS supplemented with 6-benzylaminopurine (6-BA), while the best hormone combination for inducing buds is 2.0 mg·L^− 1 6-BA plus 0.3 mg·L^− 1 indolebutyric acid (IBA), achieving an induction rate of 40%. For adventitious shoot proliferation, the optimal medium combination includes 1/2 MS with 1.0 mg·L^− 1 6-BA, 0.2 mg·L^− 1 kinetin (KT), and 0.5 mg·L^− 1 naphthaleneacetic acid (NAA), resulting in a proliferation rate of 73.33%. Both NAA and IBA can induce rooting in tissue-cultured seedlings; however, adding 0.5 mg·L^− 1 IBA to 1/2 MS yields better rooting results with an induction rate of 43.33%. This study establishes a preliminary direct organogenesis regeneration system for L. coreana var. sinensis, laying a foundation for further research and development of its clonal propagation techniques.