Plant regeneration from in vitro cultured leaves of Lanzhou lily (Lilium davidii var. unicolor)

Lanzhou lily (Lilium davidii var. unicolor) is one of the best lilies which are edible in China but the efficient shoot regeneration system has not been developed. The purpose of the present study is to establish an efficient and reproducible protocol for induction of shoots in vitro from L. davidii var. unicolor leaves. Shoot regeneration from in vitro cultured leaves of L. davidii var. unicolor was tested on the 26 media based on NN [Nitsch, J.P., Nitsch, C., 1969. Haploid plants from pollen grains. Science 163, 85–87] basal medium, containing different concentrations of thidiazuron (TDZ) in combination with different concentrations of α-naphthaleneacetic acid (NAA). Shoot organogenesis occurred directly from the leaves without forming callus. Shoot regeneration mainly occurred from the cuts across the midvein and the base of the leaf explants. The highest frequency of regeneration (93.3%) and the largest number of shoots per leaf (3.83) were obtained on NN basal medium supplemented with 0.5 mg l⁻¹ TDZ and 1.0 mg l⁻¹ NAA. All the regenerated shoots formed complete plantlets on half-strength MS [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant 15, 473–497] basal medium containing 0.1–0.5 mg l⁻¹ indole-3-butyric acid (IBA) with in 30 days, and 92% of the regenerated plantlets survived in the soil. This study will be useful for Agrobacterium-mediated transformation and exploitation of somaclonal variation of Lanzhou lily.