【摘要】 <正>作为外来种的桉树(Eucalyptus)具有速生、丰产、优质性能,经济效益显著,南方各省均把它作为最重要的人工林树种。但是桉树的北移造林存在一定风险。20世纪50年代,我国在中亚热带种植大量桉树,但70年代中期遇寒潮袭击,大部分桉树受冻死亡(朱宁华,2000)。邓恩桉(E.dunnii)是种优更多还原

【Abstract】 This study used buds of Eucalyptus dunnii,that survived after the freezing disaster in the northern Fujian Province,as explants and employed micropropagation methods ( shoot inducement,proliferation,rooting and plantlet hardening and so on) to breed cold-resistant strain. An orthogonal experiment was used to screen the best media for each propagation stage. The results showed that: 1) Bud inducement was initiated on a MS medium containing 1. 0 mg·L -1 KT,0. 05 mg·L -1 NAA. The inducement rate of valid buds reached to 76% . 2 ) The shoots were subcultured and multiplied on an improved MS medium containing 0. 8 mg·L -1 KT,0. 1 mg·L -1 NAA and 10 mg·L -1 cysteine. The two media were modified by adding 30 g·L -1 sucrose and adjusted to pH5. 8. 3) Rooting medium was the half strength of MS medium supplied with 1. 0 ～ 1. 5 mg·L -1 ABT and 0. 01 mg·L -1 IBA,with which the rooting rate was 84% in a two - step rooting method. This medium was modified by adding 20 g·L -1 sucrose and adjusted to pH5. 8. 4) Transplanting medium was a mixture of 20% bark,30% husk,40% sawdust,28% peat moss and 2% composite fertilizers,and was used for transplanting the plantlets. The survival rate of the plantlets was 100% after transplantation,and 18% higher than that in the natural soil. Growth in height of the transplanted seedlings in the medium was 23. 9 cm in 4 month and was 9. 9 cm higher than that in the natural soil. The result showed that transplant survival rate of E. dunnii plantlets was much improved and seedlings grew more healthily and strongly in the light matrix.更多还原