Establishment of in vitro plant regeneration system of rare endangered plant Emmenopterys henryi Oliv

A rapid and effective system of plant regeneration via direct shoot regeneration and organgenesis in the endangered tree of Emmenopterys henryi Oliv.was optimized by studying the influence of explant types(root,stem,petiole and leaf),disposition of leaf,plant growth regulators(PGR) and culture conditions.The optimum callus induction and organgenesis were achieved when the upper surface of leaf explants was placed downward in the medium:100% callusing was achieved in MS medium supplemented with 1.0 mg/L 6-BA and 1.0 mg/L 2,4-D,and 94.35% differentiation along with a multiplication rate of 1.95 per explant with a combination of 0.5 mg/L 6-BA and 0.5 mg/L NAA. In the direct shoot regeneration system,the adventitious buds were obtained using leaves as explants in 40 days following the incubation on MS medium supplemented with 2.0 mg/L 6-BA or 1.0 mg/L ZT,the frequency of adventitious buds was as high as 100%.The average number of buds(height ≥ 5 mm) per explant was 15 and that of height<5 mm was 56.67 per square centimeter,respectively.At the same time,dark periods could facilitate shoot regenerate.The plants from direct shoot regeneration and organgenesis developed roots on 1/2 MS medium at an efficiency of 100%.Adding 0.5% activated carbon(AC)and 1.0 mg/L IBA could promote the development of rooting.The plantlets were transferred successfully to the greenhouse with a high survival rate of 95%.