云南泸定百合12个野生居群的核型研究

Karyotypes of 12 Wild Populations of Lilium sargentiae from Yunnan Province

用常规压片法对云南省境内的12个泸定百合(Lilium sargentiae Wilson)野生居群进行了核型分析研究。结果表明:12个泸定百合野生居群全部为二倍体,染色体基数为12,共有24条染色体,无B染色体,核型类型均为3A,第1、2对染色体均为具中部(m)或具近中部(sm)着丝点的大型染色体,且第1对染色体上均具有随体。12个居群的核型不对称系数较高,在78.66%～82.05%之间,说明泸定百合的核型对称性低,进化程度较高。根据核型不对称系数,认为12个泸定百合野生居群的进化程度从高到低为:马关居群>石坎居群>龙陵居群>旧城居群>石林居群=泸西居群>双河居群>西畴居群=师宗居群>大关居群>文山居群>扎西居群。聚类结果显示,当阈值取1.04时,可以将12个居群分为3类。研究表明,泸定百合染色体数相对稳定,染色体变异主要表现在结构变异;各个居群的染色体组成、随体数、随体位置、臂比、染色体长度比及核型不对称系数均有差异;泸定百合各居群间存在明显的核型变化。

Karyological study of 12 wild populations of Lilium sargentiae Wilson from Yunnan Province was carried out by traditional squashing and pressing method.The results were the following.The base number of L.sargentiae was 12(x=12).All of the 12 wild populations were diploid(2n=2x=24)with a karyotype of 3A and without B chromosome.Their first and second pairs of chromosomes were either large median chromosomes(m)or large submedian chromosomes(sm).All the first pairs of chromosomes of the 12 populations had satellite chromosomes.The Karyotype asymmetry coefficient(As.K%)of the 12 populations were from 78.66% to 82.05%,which indicated the karyotype of L.sargentiae was asymmetrical and advanced.The As.K% of 12 populations of L.sargentiae from high to low was as follows:Maguan population>Shikan population>Longling population>Jiucheng population>Shilin population=Luxi population>Shuanghe population>Xichou population=Shizong population>Daguan population>Wenshan population>Zhaxi population,which might reflect the intraspecific evolution relationships among populations in this species.The 12 populations of L.sargentiae could be divided into 3 groups by cluster analysis when the threshold was 1.04.The above results indicated that the chromosome number of L.sargentiae was stable,and the chromosome variation among populations was generally coming from structure variation.The 12 populations had obvious differences in the composition of chromosomes,the number and distribution of satellite chromosomes,arm ratio,chromosome length ratio and As.K%.There were obvious karyological variations among populations of L.sargentiae.