西南桦以芽繁芽组培快繁研究

In vitro Propagation of Betula alnoides by Shoot Proliferation

以8个月生苗木上采集的枝条作为外植体,通过激素、大量元素配比等试验,成功地研发出一套西南桦以芽繁芽组培快繁技术体系。其主要内容包括:1 选择邻近顶芽带腋芽的茎段作为外植体,用HgCl2消毒3min效果最佳,诱导成功率达10%;2 其侧芽诱导与增殖培养宜选用低浓度(0 2mg L-1)的IBA或NAA;3 大量元素配比满足K∶Ca=1∶0 04～0 08、K∶Mg=1∶0 02～0 04、N∶P=1∶0 02～0 03三个比例关系时,外植体侧芽能正常萌发生长,并迅速进入增殖状态,40d转接1次,增殖倍数在4倍以上;4 选用NAA浓度为0 50mg L-1的0 4MS培养基进行生根诱导,生根率达97 9%。

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%.