In vitro Propagation of Betula alnoides by Shoot Proliferation

Using branches collected from eight-month-old seedlings, a rapid propagation protocol by shoot proliferation was developed for Betula alnoides by adjusting the plant growth regulators and ratios of macro-elements. The main results were as follows: 1. Dipping in solution of 1/1 000 HgCl2 for 3 minutes was the best way for disinfection of branch explants and up to 10% branches were successfully induced to grow shoot; 2. To prevent branch explants from producing too much callus, only low concentration of auxins, for instance, 0.2 mg·L-1 IBA or NAA, could be supplemented; 3. Ratio of macro-elements was crucial for shoot germination and proliferation, the range of their ratios by mol concentration were K∶Ca =1∶0.04～0.08, K∶Mg=1∶0.02～0.04, N∶P=1∶0.02～0.03; 4.0.4 MS supplemented with 0.5 mg·L-1 NAA was suitable for rooting, the rooting rate reached 97.9%; and 5. The survival rate of outplanting in nursery was up to 95%.