The chromosome numbers and karyomorphology of 32 accessions are examined, representing 12 species of Anaphalis DC. (Asteraceae) from the Hengduan Mountains of south-western China, which is most likely the biologically richest temperate region in the world. A total of 11 species are newly reported, and the highest chromosome number, 2n = 84, was observed in the Helichrysum-Anaphalis-Pseudognaphalium group for the first time. Within Anaphalis, the basic number x = 14 was confirmed. Only two species (A. flavescens and A. pachylaena) are diploid with 2n = 28. Tetraploidy is observed in seven species. Diploid-polyploid complexes are found in A. aureopunctata, A. bicolor, and A. nepalensis, especially for A. nepalensis with a series of polyploidy levels from di-, tetra-, to hexaploid. In addition to the tetraploid origin of the genus, a second polyploidisation is suggested as the predominant event in the chromosome evolution of Anaphalis from the Hengduan Mountains. The karyotypes of all observed samples are 2A or 2B, except for one population of A. bicolor as 1B according to Stebbins' asymmetry classification of karyotypes. The asymmetry index (AI) values change from 1.49 to 3.65. However, there is no evidence of association between chromosome evolution (i.e. polyploidy frequency and karyotype variation) and the altitudes in Anaphalis.
1.Jishou Univ, Key Lab Plant Resources Conservat & Utilizat, Jishou, Hunan, Peoples R China 2.Jishou Univ, Coll Biol & Environm Sci, Jishou, Hunan, Peoples R China 3.Chinese Acad Sci, Key Lab Plant Div & Biogeog East Asia, Kunming, Yunnan, Peoples R China 4.Chinese Acad Sci, Kunming Inst Bot, Germplasm Bank Wild Species Southwest China, Plant Germplasm & Genom Ctr, Kunming, Yunnan, Peoples R China
Meng,Ying;Yang,Yong-Ping;Sun,Hang;Deng,Tao;Nie,Ze-Long.Chromosome numbers, karyotypes, and polyploidy evolution of Anaphalis species (Asteraceae: Gnaphalieae) from the Hengduan Mountains, SW China,CARYOLOGIA,2014,43(11):1740-1742