Abstract:
To determine the cytotaxonomic characteristics of
Arenaria in China,
A. subgen.
Eremogoneastrum A. brevipetala Y. W. Tsui et L. H. Zhou (two populations from Kangding and Daocheng in Sichuan),
A. baxoiensis L. H. Zhou (two populations from Yela and Anjula mountains, Baxoi, Tibet),
A. ischnophylla Williams (two populations from Damxung and Gongbo'gyamda in Tibet), and
A. bryophylla Fernald (Lhasa, Tibet) were studied. Root tips were used in combination with KaryoType 2.0 analysis for karyotype research. Results showed that the chromosome number in all seven populations of the four species was 2
n = 22, i.e., diploid evolution. The karyotype formula was 2
n=2
x=22=22 m and karyotype asymmetry belonged to Stebbins's-1A type, with an AI value in the range of 1.75 - 0.32. Thus, combined with existing cytological data for
Arenaria, the karyotype of
A. subgen.
Eremogoneastrum is primitive, and its chromosome number (ploidy) is stable. The chromosome number and karyotype data of the four studied species are reported here for the first time. These results will supplement current cytological information for
Arenaria in the Qinghai-Tibet Plateau and provide insight into the taxonomy, phylogeny, and floristic geography of
Arenaria and Caryophyllaceae.