中国西南地区6种植物的核型研究及其系统学意义

Karyotype Analysis and Systematic Significance of Six Species in Southwest China

采用植物细胞学研究方法对主要采自中国西南地区横断山的6种植物:扁核木(Prinsepia utilis)、小叶金露梅(Potentilla parvifolia)、峨眉繁缕(Stellaria omeiensis)、金铁锁(Psammosilene tunicoides)、山卷耳(Cerastium pusillum)和独尾草(Eremurus chinensis)进行染色体数目和核型研究。研究表明:(1)6个种的核型公式和不对称性如下:扁核木2n=2x=30=1M+20m+9sm,2A;小叶金露梅2n=2x=28=21m+7sm,2B;峨眉繁缕2n=8x=72=1M+71m,1B;金铁锁在同居群下有倍性变化,2n=2x=14=14m,1A和2n=4x=28=28m,1A;山卷耳2n=2x=24=24m(2sat),1A;独尾草2n=2x=14=2m+2sm+8st+2t,4B。(2)讨论了染色体资料在这些物种分类和系统上的意义,支持扁核木为李亚科下的扁核木属;位于委陵菜属木本系的小叶金露梅主要以二倍体和四倍体为主,而草本系的委陵菜属植物多为多倍体。(3)该研究首次报道峨眉繁缕为八倍体,是繁缕属发现的最高倍性的物种;对比金铁锁属与蝇子草属的染色体研究发现,金铁锁属可能是由它们的共同祖先通过非整倍化产生;该研究首次发现山卷耳存在染色体数目2n=24的情况,且有1对随体;独尾草的研究进一步证明该物种可能为二型核。

The chromosomes of six species from Southwest China, consist of Prinsepia utilis, Potentilla parvifolia, Stellaria omeiensis, Psammosilene tunicoides, Cerastium pusillum and Eremurus chinensis were reported. Chromosome numbers and karyotypes of Ste. omeiensis were first reported in this study. The results were the following:(1) the karyotype formulas and asymmetry were respectively as: Pri. utilis 2n=2x=30=1M+20m+9 sm, 2A;Pot. parvifolia 2n=2x=28=21m+7sm, 2B;Ste. omeiensis 2n=8 x=72=1M+71m, 1B;There are ploidy changes in same population of Psa. tunicoides, the karyotype as: 2n=2x=14=14m, 1A and 2n=4 x=28=28m, 1A. Cer. pusillum 2n=2x=24=24m(2 sat), 1A. Ere. chinensis 2n=2x=14=2m+2 sm+8 st+2t, 4 B.(2) Based on these data, the taxonomic and systematic significance of chromosome karyotypes in these species are discussed. It is supported that Pri. utilis is Prinsepia of Prunoideae. The cell ploidy of Pot. parvifolia is mainly diploid or tetraploid.(3) In this study the octaploid of Ste. omeiensis, maximum chromosome number of Stellaria, was first reported. Comparing the chromosomal studies of the Psammosilene and the Silene, it was found that Psammosilene probably were generated by the common ancestor group through aneuploidy. In this study, the presence of 2n=24 chromosome number and a pair of satellites were firstly found in Cerastium pusillum. This study showed that E. chinensis may be dimorphic nucleus.