Abstract: In this paper, a method for chromosome doubling of Betula alnoides was developed. Terminal buds from aseptic germination of B. alnoides were used as explants, effect factors on chromosome doubling of B. alnoides were discussed, such as concentration of colchicine, co-culture time of colchicine, preculture time. The results showed that the concentration of colchicine was better to be 120 mg稬-1 for chromosome doubling of B. alnoides, and maximum chimaera number would be obtained in the regermination plantlet of B. alnoides, after preculture without colchicine for 10 d and then co-culture with colchicine for 15 d.

Key words: Betula alnoides, colchicine, concentration, chromosome

摘要： 以西南桦种子无菌萌发小苗的顶芽为外植体，探讨秋水仙素的浓度、处理时间及预培养时间对西南桦染色体加倍的影响，初步建立西南桦染色体加倍的方法。结果表明，使西南桦染色体加倍的秋水仙素浓度以120 mg·L-1为宜；在秋水仙素加倍处理前，预培养10 d后再加倍15 d效果较好，此时得到的西南桦嵌合体较多。

关键词: 西南桦, 秋水仙素, 浓度, 染色体