Studies On Karyotypes And Its Significance On Taxonomy Of 25 Species Of Saussurea In The Eastern Of Qinghai-Tibet Plateau

The genus Saussurea is composed of about 400 annual, biennial or perennial species over the world, distributed in Asia and Europe, and about 264 species are found in china. The genus belongs to the family Asteraceae.Species of Saussurea DC. have important medical value, So far, some works have been done on the medicine, cytology, molecule, physiology and morphology of the Saussurea DC. by former researchers, but there are prodigious disputes remained on the systematic studies of Saussurea DC. So this paper that researched them in cell level has important signification. Which can afford some basic scientific data for the discussion on the systematic relationships of Saussurea DC, and further explotion and ultilization of the Saussurea DC. Studying on the chromosome number, having or no having SAT and B chromosome, the karyotype formulae, the karyotype, arm ratio, relatived length, and karyotypic asymmetry etc, the origin, systemic evolution and taxonomy of 25 species of Saussurea DC. in the Eastern of Qinghai-Tibet Plateau have been analysed. The results are listed as follows.1. Chromosome numbers of body cell for 25 species of Saussurea DC. are changed in number for different species, they are 2n=24,26,28,30,32,34 and so on.2. The chromosome complement of 25 species of Saussurea DC. have two types correspondence to centromere and length complement respectively.3. The 25 species of Saussurea DC. have a abandent in karyotype, they are 2A,3A,2B and 3B.4. The ratio of the longest chromosome to the shortest of 25 species of Saussurea DC. range from 1.63:1 in S. variiloba to 2.96:1 in S. pachyneura.5. The index of karyotypic asymmetry of 25 species of Saussurea DC. range from 58.07 in S. pachyneura.to 69.43 in S. ussuriensis.6. The relatived length of 25 species of Saussurea DC.changed indistinctly from 6.26～10.22 in S. variiloba to 4.80～14.08 in S. graminea.7. No satellites have been found in these 25 species of Saussurea DC.8. B chromosome have been found only in S. graminea of 25 species of Saussurea DC. for the fisrt time.9. The result from comparing the characteristic of karyotype among Saussurea DC. shows which is a origin early and differentiation acutely genera.