HIGH EFFICIENCY INDUCTION OF CALLUS AND REGENERATION OF SPOROPHYTES OF LAMINARIA JAPONICA(PHAEOPHYTA)

Four media (PESI solid, MS liquid, MS solid and ASP-C-I solid medium) were usedto induce callus from excised tissues of the kelp Laminaria japonica. Only PESI solid medium and MSsolid medium produced calli. Modified MS solid medium supplemented with mannitol (3%, W/V), yeastextract (0.1%, W/V), VB2(0. 5 mg/ml), VB12(0.5 mg/ml), kinetin (0. 108 μg/ml) and NAA(1.860μg/ml) showed much better effect on callus induction than non-modified MS solid medium. After24 days of induction 75 .5% of tissues in PESI solid medium showed callus formation. For modified MSsolid medium, after three months of induction 67. 3% of tissues dedifferentiated into calli. No calluscould be found after five months of induction in either MS liquid or ASP-C-I solid medium. When calliwere squashed and cultured in N-P enriched autoclaved seawater, MS liquld medium and ASP12-NTAliquid medium (both modified with kelp extract), differentiation of cells and regeneration of sporophyteswere only observed in ASP12-NTA medium supplemented with kelp extract. Gametophyte-like filamentsformed first, then eggs were released. It was suggested that sporophyte formation could be a process ofparthenogenesis. Sterilization techniques in tissue culture of L. japonica were also tested in this study.