Plant Diversity ›› 2006, Vol. 01 ›› Issue (01): 22-28.

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Chromosome counts in the Genus Calamagrostis s1l ( Poaceae) from Southwestern China*

 MA  Hai-Ying-1、2,   Liu-Zhen-Wen-1、2,   Peng-Hua-1**   

  1. 1 Kunming Insti tute of Botany , Chinese Academy of Sciences, Kunming 650204, China;
    2 Graduate School of the ChineseAcademy of Sciences, Beijing 100039, China
  • Online:2006-02-25 Published:2014-01-14

Abstract:

Calamagr ostis s1l. is a large genus widespread throughout the world in temperate and cold regions. It is sometimes divided into two genera: Calamagr ostis s. str . and Deyeuxia, and both have been accepted in China, while recent studies
show it should be treated as one genus. There are 37 species of Calamagrostis s1 l. occuring in China, but no cytological study was conducted before. In this paper the chromosome numbers of 9 populations representing 6 species of Deyeuxia ( recognized as a part of Calamagrostis s1l. ) from southwestern China are reported for the first time. Most of them are tetraploids and no diploid species is found. All 4 populations of D1 petelotii and each population of D1 diff usa, D1 moupinensis , D1 nivicola, and D1flaven are tetraploids ( 2n= 4x= 28) , and the only population of D1 neglecta is hexaploid ( 2n= 6x= 42) . On the basis of these counts and previous reports, tetraploid is again confirmed primitive in Calamagrostis s1l. and the speciation of the genus is principally occurred at tetraploid level in this region. As these five tetraploid species are restricted to Himalayan-Hengduan Mountains, they probably have been formed by isolation from tetraploid ancestors.

Key words: Deyeuxia, Calamagrostis, Chromosome number, Tetraploid, Hexaploid

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