The 2012 ASHS Annual Conference

Honeysuckle (Lonicera japonica L.) is widely grown as an ornamental plant. Dried flowers and buds of L. japonica, called flos lonicerae in traditional Chinese medicine, are a popular herb. Flos lonicerae contains soluble phenolic acids such as chlorogenic acid and flavonoids such as luteolin, which have anti-inflammatory, anti-oxidant, and anti-cancer properties. With increased need for flos lonicerae, production hectares of L. japonica have been greatly increased, resulting in a high demand for starting materials. Cutting propagation and tissue culture through existing meristems cannot meet market needs for propagules. Regeneration via somatic embryogenesis has been considered the most efficient means of in vitro propagation, but methods for somatic embryogenesis of L. japonica have not been well developed. In this study, zygotic embryos derived from L. japonica seeds and cotyledons from seedlings were cultured on a MS basal medium supplemented with 4.4 and 8.8 µM BA respectively with 0.5 and 1.0 µM NAA. Callus appeared from zygotic embryos, and culture of callus pieces on the same medium as initially used for callus induction resulted in the formation of somatic embryos. Among the growth regulator combinations evaluated, 4.4 µM BA with 0.5 µM NAA resulted in 80% of zygotic embryos producing callus and subsequently 67% of cultured callus pieces produced somatic embryos. Culture of cotyledons on MS medium containing 4.4 µM BA and 0.5 µM NAA resulted in direct somatic embryogenesis. Somatic embryo conversion produced healthy plantlets, and plantlets grew well after transplantation into cell plugs.