Plant regeneration from callus cultures ofLithospermum erythrorhizon.

We previously studied the production of shikonin derivatives by cell lines ofLithospermum erythrorhizon. As a result, we have obtained a cell line LE 87, which exhibited high cell growth and high shikonin production. In the present study, the effects of auxins (2,4-D, IAA, picloram, and NAA) and cytokinins (BAP and kinetin) on organogenesis and somatic embryogenesis in this shikonin-producing cell line were investigated. The highest organogenic and embryogenic efficiency was obtained on MS medium supplemented with 10 µM NAA and 0.3 µM kinetin. Subcultured calli showed different morphogenic frequencies depending on the NAA and kinetin concentration. Morphologically normal plants have been regenerated via mostly organogenesis. Shoots subsequently produced roots on plant growth regulator-free MS medium and developed into plantlets. In most cases, a few thin roots were formed at the bases of the shoots after four weeks on the rooting medium. More than fifty green plantlets were transplanted to soil in pots and developed into phenotypically normal plants 8 weeks after being transferred to soil. The regenerated plants grew to maturity, flowered, and set seeds by only artificial pollination.