Plant Diversity ›› 2011, Vol. 33 ›› Issue (4): 423-431.DOI: 10.3724/SP.J.1143.2011.10207

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Chromosome Numbers and Karyotypes of Six Oxytropis Species (Fabaceae) from the QinghaiTibetan Plateau, China

 LIU  Ya-Hui-1、2, MENG  Ying-1,   Yang-Yong-Hong-2, YANG  Yong-Ping-1   

  1. 1 Institute of Tibetan Plateau Research at Kunming, Chinese Academy of Sciences, Kunming 650201, China;
    2 Key Laboratory for Plant Pathology of Yunnan Province, Yunnan Agricultural University, Kunming 650201, China
  • Received:2010-11-22 Online:2011-08-25 Published:2011-02-13


Chromosome numbers and karyotypes of 13 populations of six Oxytropis species (Fabaceae) from the QinghaiTibetan Plateau, China, were presented. The chromosome numbers and karyotypes in O.ochrocephala, O.tatarica, O.kansuensis and O.humifusa (2n=16) were reported for the first time. Bchromosomes were found from O.stracheyana (2n=48). The basic chromosome number of x=8 is confirmed for the genus. The available chromosomal data indicate that polyploidy may have played an important role in the evolution of the genus, with the incidence of polyploidy in the genus reaching 58%. However, our results indicated that among the populations here examined only one was a hexaploid with 2n=48. Such a chromosomal pattern indicates that the karyotypic repatterning at the diploid level seems to be the predominant feature of chromosomal evolution in the Oxytropis species from the QinghaiTibetan Plateau, and that sympatric speciation via hybridization and polyploidization has played a minor role in the species diversification of the genus from this area.

Key words: Oxytropis, Qinghai-Tibetan Plateau, Chromosome number, Karyotype, AI value

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