The Purification And Rejuvenation Of Colocasia Esculenta L.Schott

The method of heat treatment with shoot-tip culture was used for eliminating dasheen mosaic virus of Lipu-taro (Colocasia esculenta L. Schott.). The optimun conditions for shoot-tip induction and rapid propagation were established. These approaches provided some theoretical bases and key techniques for rapid propagation of Colocasia esculenta L Schott. Cultivated shoot-tip seedlings in conventional method and compared with the controls, the results supplied some bases for shoot-tip seedling popularization.The root-free seedlings were inoculated into the MS liquid medium supplemented with 3% sucrose, 4 mg/1 6-BA and 0.05 mg/1 NAA, and were put in therm.ostatic box. The temperature was kept 38.7 for 15 days. The survival rate was 80%. The electron microscope was used for virus detection of the plantlets. Results showed that the plantlet did not carry dasheen mosaic virus with exfoliating shoot-tip. With 0.5-0.6mm shoot-tips as explants, a series of optimization experiment for cultural medium composition, concentration of phytohormone was investigated with a view to accelerate the propagation of virus free plants. The obtained results indicated that the optimized medium for .shoot-tip induction was Ms medium added with 3% sucrose, 0.7% agar, 0.5 mg/16-BA and 0.1 mg/1 NAA. The survival rate of shoot-tip was over 80%. The shoot-tip turned green, the base of it swelled and it elongated as a bud.MS medium with 3% sucrose, 4 mg/1 6-BA,0.05 mg/1 NAA, 20 mg/1 spermine, and MS medium with 3% sucrose, 5 mg/16-BA,0.05 mg/1 NAA, 20 mg/1 spermine were the optimum media for proliferation. They were used alternatively, which could keep high propagation index and keep seedling healthy. The roots were induced when adventitious buds were cultured on 1/2 MS medium with 2% sucrose, 0.1% activated carbon, 0.05 mg/1 NAA and 1.0 mg/1 IBA. The rate of root formation was 98%. After the seedlings were transplanted to soil, they grew robustly and had a good root system and robust green leaves. The medium MS+0.05 mg/1 NAA+0.7% agar+5% sucrose +2.0 mg/1 6-BA could induce bigger mini-taro.The chlorophyll content of shoot-tip seedlings was higher than that of virus infected plants. The case of leaf blight of taro and soft rot of taro was slighter. The corm-yield showed the first generation shoot-tip taro was decreased by 50%, but the second generation was increase 14.10%. Compared with control, the quality of corms of shoot-tip taro had improved. With its quality improved, it had softer and smoother flesh, smelled aromatic and tasted enjoyable. The mother taros of shoot-tip seedlings were like spindle, and the individual was even. The merchandise value was high.