Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas

NWIPB OpenIR

	Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas
	Liu, JQ
	2004-03-01
发表期刊	BOTANICAL JOURNAL OF THE LINNEAN SOCIETY ; Liu Jianquan. Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas.BOTANICAL JOURNAL OF THE LINNEAN SOCIETY,2004,144(3):329-342
摘要	Ligularia, a highly diversified genus in the eastern Qinghai-Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2n = 58 and 87. Other species are only diploid, with 2n = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia, are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium, Ligulariopsis, Parasenecio, and Sinacalia. Aneuploid reduction of chromosome number from 2n = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity. (C) 2004 The Linnean Society of London; Ligularia, a highly diversified genus in the eastern Qinghai-Tibet Plateau and adjacent areas, was chosen as a suitable subject in which to study speciation patterns in this 'hot spot' area at the chromosomal level. Chromosome numbers and karyotypes were studied in 23 populations of 14 species, most of which are endemic to this area. The basic number x = 29 was confirmed for all species. Ligularia virgaurea was found to have diploid and triploid cytotypes, 2n = 58 and 87. Other species are only diploid, with 2n = 58. The karyotypes of all populations within any species, and all species spanning most sections and covering most of the morphological range in Ligularia, are very similar to each other, belonging to type 2A according to Stebbin's classification. This karyotype was also found in its close allies, e.g. Cremanthodium, Ligulariopsis, Parasenecio, and Sinacalia. Aneuploid reduction of chromosome number from 2n = 60 to 58 and karyotypic variation was found in Ligularia and its allies. Such a chromosomal pattern with few polyploids infers that variation of karyotype structure at the diploid level seems to be the predominant feature of chromosomal evolution in this group and sympatric speciation via hybridization and polyploidization has played a minor role in its species diversity. (C) 2004 The Linnean Society of London,
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/30521
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Liu, JQ. Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas[J]. BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Liu Jianquan. Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas.BOTANICAL JOURNAL OF THE LINNEAN SOCIETY,2004,144(3):329-342,2004.
APA	Liu, JQ.(2004).Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas.BOTANICAL JOURNAL OF THE LINNEAN SOCIETY.
MLA	Liu, JQ."Uniformity of karyotypes in Ligularia (Asteraceae : Senecioneae), a highly diversified genus of the eastern Qinghai-Tibet Plateau highlands and adjacent areas".BOTANICAL JOURNAL OF THE LINNEAN SOCIETY (2004).