Abstract
The regeneration of wasabi (Wasabia japonica Matsumura) in vitro was investigated by culturing leaf, stem, petiole and callus explants. Bud formation was induced in leaf, stem and callus explants cultured in MS medium containing kinetin or TDZ (n-phenyl-N'- 1, 2, 3- thidiazol-5-yl-urea or thidiazuron) with NAA(α-napthaleneacetic acid). Calli formed from all types of explant in a medium containing 1 or 2 mg /l of both BA (6-benzyladenine) and NAA. Stem and callus explants cultured on a medium containing BA and NAA showed bud-like formations but these failed to develop further, even at a high concentrations of BA and NAA or BA and 2, 4-D (2, 4-dichlorophenoxyacetic acid). But in several cases, an array of bud-like structures was observed. In one case (1 mg /l BA and 10 mg /l NAA), a leaf formed from a stem explant after about 6 months of culture. Root formation was observed in a few stem explants but not in callus explants when NAA and BA were present in the medium. In stem explants, buds formed and developed over a wide range of TDZ or kinetin concentrations in the presence of NAA. Both bud and root formation were most promoted in callus and stem explants at 0.002 or 0.02 mg /l TDZ with 1 or 2 mg /l NAA. Buds or roots were more abundant when TDZ rather than kinetin was used.
