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Dried roots and stolons of licorice plants (Glycyrrhiza uralensis) are among the most important drugs (Glycyrrhizae radix) in traditional oriental medicine; they are also important commercial products used worldwide in sweetening and flavoring. Here, we describe the establishment of an in vitro stolon culture system for G. uralensis. Stolon formation was induced in single node stems (with axillary buds) grown in Murashige and Skoog (MS) liquid culture medium, supplemented with 0.01 μM α-naphthaleneacetic acid (NAA). Stolons were cultured at 26°C in the dark on a rotary shaker, gyrating at 100 rpm. The same NAA concentration produced the highest rates of stolon proliferation (6.58-fold in 4 weeks). A 6% sucrose concentration also enhanced stolon proliferation (6.34-fold in 4 weeks). GC/MS analysis confirmed the accumulation of small amounts of glycyrrhizin (14 μg g−1 dry weight) in cultured stolons. Interestingly, betulinic acid and oleanoic acid production in vitro were higher than in field-grown stolons. Adventitious root and shoot regeneration from cultured stolons were readily achieved under illuminated conditions in MS medium containing 0.01 μM of NAA and 0.2% gerlite. Regenerated plants produced glycyrrhizin (7,600 μg g−1 dry weight) in their roots. Our in vitro stolon culture system is suitable for studying glycyrrhizin biosynthesis and for rapid propagation of elite licorice clones.

Development of a new preparation method of Lithospermi Radix enabled almost all the slender lateral roots (diameter smaller than 2 mm) to be preserved. The weight ratio of slender lateral roots was about 5.5% in the whole root. The amount of acetylshikonin in the slender lateral roots was two-fold greater than in its tap and thick lateral roots (diameter larger than 2 mm). The acid-insoluble ash content in slender lateral roots was 1.16%.

The symbiosis between Armillaria species and an achlorophylous orchid Gastrodia elata BLUME has been reported. The main species described as a symbiont is Armillaria mellea (VAHL: FR.) KUMMER, known widely as a primary root rot pathogen. Samples collected from the rhizomorphs attached to the tuber of G. elata were separated and analyzed. Molecular analysis based on sequencing of the intergenic spacer 1 (IGS-1) and internal transcribed spacer (ITS) regions of the ribosomal DNA (rDNA) was performed, coupled with restriction fragment length polymorphism (RFLP) of the IGS-1 region. Cultural morphology and features of basidiomata were also used to characterize the isolates. Phylogenetic analysis and morphological data strongly suggested that the fungus present in the tubers of G. elata is Armillaria nabsnona. This is the first report of occurrence of this Armillaria species in association with G. elata.