Study On The Technique System Of Micropropagation In Davidia Involucrata

The buds of Davidia involucrata were used as explants to establish a rapid technique system of micropropagation, and to study abnormal phenomena of the in vitro shoots and their reasons.1) Buds were used as explants to establish in vitro system. October was the best period of picking the buds in this test. Removing xylem when inoculating the buds could reduce the browning rate.2) Temperature for initial culture: Day 26℃, Night 24℃, 14 hours illumination every day; temperature for multiplicative and rooting culture: Day 24℃, Night 22℃, 12 hours illumination every day, and 1500~20001x illumination intensity. The pH of medium was adjusted to 5.8-6.2.3) The best initiation medium was l/2MS+BA1.5mg/l+IBAlmg/l. After 30 days culture, the inducement rate could be up to 95%.4) The multiplication of callus induced shoot clumps: N6+BA2.5mg/l+IBAl mg/l+GAslmg/l was the best medium. The multiplication rate of shoot clumps could be up to 8.00.5) The multiplication of side buds: N6+BAlmg/l+GA32mg/l was the best medium, the multiplication rate of side buds could reach 3.90.6) The in vitro nodal segments and shoot tips could be used as explants in second initial culture, the inducement rate could reach 90%. A good propagationresult could be obtained by expands the initial explants.7) The best medium for the rooting of shoots was l/8MS+BA0.1mg/l+NAAl mg/l+AC0.5g/l, in which the root of rooty plantlets grew rapidly and the rooting rate could reach 95%.8) For nursling of plantlets, sands was used as material and 1/10MS as application of leaves' nutrient solution, the survival rate of plantlets could be up to 62%.