Abstract: Three factors (media type, gibberellic acid [GA₃] and active carbon) affecting the embryo germination of Davidia involucrata were optimized by use of a uniform design and analyzed by regression analysis . Then a system for micropropagating D. involucrata was established from the embryos . From regression equations, the optimal conditions for embryo germination were the addition of 2.85 mg.L^-1 GA₃ and 0.25 g.L^-1 activated carbon to 1/2 MS medium containing 0.5 mg.L^-1 IBA and 1 mg.L^-1 6-BA. The germination rate of embryo was 87.72%, without significant deviation to the predicted value. The optimal conditions for shoot induction and multiplication were WPM medium supplemented with 0.1 mg.L^-1 NAA and 2.0 mg.L^-1 6-BA; the mean shoots obtained per explant was 4.34. An amount of 90% of shoots rooted on rooting medium, and 71% plants survived after transplanting.

Key words: Davidia involucrata, embryo, regression analysis, uniform design