Abstract:

Hibiscus hamabo is not only a preferred species for windbreak forests in southeast coastal areas, but also a good species for water conservation forests in barren mountains. The acquisition of aseptic seedlings is a prerequisite for the establishment of efficient regeneration systems, which could provide a basis for plant resource conservation and new variety selection and breeding. In this study, MS was used as the basic medium to compare the effects of additives such as citric acid, activated carbon, triiodobenzoicacid (TIBA), 6-benzylaminopurine (6-BA), naphthalene acetic acid (NAA), casein hydrolyzed, vitamin H, folic acid, thidiazuron (TDZ), oligosaccharidic plant activator protein, etc. on the seed germination as well as the aseptic seedling cultivation of Hibiscus hamabo. The optimum formulation for seed germination was MS+6-BA (0.5 mg·L^-1)+NAA (0.1 mg·L^-1)+hydrolyzed casein (0.1 g·L^-1), which increased the germination rate from 21.4%±7.8% to 85.3%±9.1%. Meanwhile, vitamin H, folic acid, and citric acid application failed to promote seed germination. Seedlings in medium of MS+6-BA (0.1 mg·L^-1)+oligosaccharide chain protein (0.1 g·L^-1)+activated carbon (0.1%) had the highest proliferation coefficient of 7.0±2.6 with thick stems, branches, and leaves. Notably, the combination of TDZ and NAA could induce the generation of Hibiscus hamabo with strong differentiation ability, which can provide a foundation for further developing the somatic embryo seedling technology of Hibiscus hamabo.

Key words: Hibiscus hamabo, formulation selection, 6-benzylaminopurine, hydrolyzed casein, oligosaccharide chain protein