Virus-free Plantlet Culture And In Vitro Bulbil Induction Of Dioscorea Batatas Decne.

Using D. batatas Decne. from Shanggao in Jiangxi Province as material, vims-free plantlets culture, basic plantlets propagation, in vitro bulbils induction, the anatomy and the changes of physiology and biochemistry in bulbils during induction were studied by plant tissue culture and paraffin section, etc. The results provide basical theory and useful technology to big scale production of virus-free in vitro bulbils.The effects of thermotherapy and chemotherapy combining with meristem culture on virus-free of D. batatas Decne. were studied. The results were as follows. The size of meristem tip was positively correlated with the surviving ratio, but negatively with the virus-free ratio. The single virus-free technique was difficult to take off viruses, whereas two or three techniques were effectively to take off PVY, TMV and CMV. Compared control group, the virus-free ratio was enhanced 20% and 40% respectly in the treatments of thermotherapy or combination of thermotherapy and chemotherapy.Micropropagation for D. batatas Decne. was established by using virus-free shoots. The optimum medium for node multiplication was MS medium supplemented with 0.8 mg/L NAA and 0.8 mg/L 6-BA. The optimizing medium for induction tufted buds was MS medium supplemented with 0.5 mg/L NAA, 4.0 mg/L 6-BA, 3.0 mg/L S-3307 and 4.0% sucrose.The effects of various factors on in vitro bulbils induction were researched on liquid-solid medium. The results were as follows. The MS medium supplemented with 2.0 mg/L 6-BA, 0.5 mg/L NAA, 8.0% sucrose at 8h/d light was most suitable for in vitro bulbils formation and expansion. Glutamine as nitrogen source was significantly improve to in vitro bulbils expansion.