杨属派间核型比较研究

A comparative study on the karyotypes among sections of Populus

对杨属五派代表种的核型进行了分析,各代表种核型公式如下:欧洲山杨(白杨派)2n=2x=38=21m(2SAT)+4sm+13st(1SAT);小叶杨(青杨派)2n=2x=38=1M+26m(1SAT)+8sm(1SAT)+1st+2t(1SAT);大叶杨(大叶杨派)2n=2x=38=2M+22m+8sm+6st;胡杨(胡杨派)2n=2x=38=2M+23m+3sm+10st(2SAT);箭杆杨(黑杨派)2n=2x=38=3M+29m(2SAT)+5sm+1st。杨属派间核型差异主要表现在中部与次中部着丝点(M,m)和近端部与端部着丝点(st,t)染色体数目上。白杨派和胡杨派具较多的st、t染色体,核型不对称系数比其它派高。按Stebbins理论白杨派和胡杨派属进化类型。

This paper analyzed the karyotypes of 5 sections of Populus. The karyotype formula were as follows. P. tremula L. 2n=2x=38=21m（2SAT）＋4sm-b13st（1SAT）；P. simonii Cart. 2n=2x=38=1M＋26m（1 SAT）=8sm（1SAT） ＋ 1st＋2t（1SAT） ； P. lasiocarpa Oliv. 2n=2x= 38= 2M＋22m＋ 8sm＋6st； P. euph-ratica Oily 2n=2x=38=2M＋23m＋3sm＋ 10st（2SAT）；P. nigra L. var. thevestina（Dode）Bean 2n=2x=38=3M＋29m（2SAT）＋5sm＋1st. The results of karyotype analysis showed that the karyotype differences among sections of Populus were mainly in the change of chromosome number of M and m, st and t. Populus and Turanga had more st and t chromosomes and their Asymmetry index was higher than Aigeiros, Tacamahaca and Leucoides. According to the Stebbins＇s theory, Populus and Turanga were the evolutional type.