青藏高原3种特有植物的核型报道

Chromosome atlas of three species from the Qinghai-Tibet Plateau

以采集自青藏高原的3种特有植物多个居群的种子为材料,采用滤纸萌发法和常规压片法,进行染色体数目观察和核型分析。结果表明:黑蕊虎耳草(Micranthes melanocentra)的5个居群染色体数目均为2n=22;黑虎耳草(Micranthes atrata)2个居群染色体数目均为2n=22;祁连獐牙菜(Swertia przewalskii)5个居群染色体数目一致,核型公式为2n=24=20m+4sm,核型不对称指数为58.8%,核型不对称性为1B,第3对和第9对为亚中部着丝点染色体(sm),其余为中部着丝点染色体(m)。黑蕊虎耳草的染色体基数同前人研究一致,但未发现多倍体,说明采样区域内该物种多倍体出现频率较低;黑虎耳草和祁连獐牙菜的核型为首次报道。3种植物的核型报道补充了青藏高原特有物种的细胞学资料,同时为这些物种的开发、利用和保护研究提供细胞学资料。

The seeds of three endemic plants collected from the Qinghai-Tibet Plateau and germinated on wet filter papers and root tip-squash method were used for cytological observation.The results showed that three species were diploid.Chromosome numbers of all 5 populations of Micranthes melanocentra were 2n=22;chromosome numbers of 2 populations of Micranthes atrata were 2n=22.All 5 populations of Swertia przewalskii had same chromosome numbers,the karyotype formula was 2n=24=20m+4sm,1B,As.K%=58.8%.The third and ninth pairs were submetacentric,and the rest were metacentric.The chromosome cardinality of Micranthes melanocentra was consistent with previous studies,but no polyploid was found,indicating that the polyploid frequency was low in the sampling area.The karyotypes of Micranthes atrata and Swertia przewalskii were reported for the first time.The reported karyotypes of the three plants complemented the cytological data of the species endemic to the Qinghai-Tibet Plateau,and provided cytological data for the development,utilization and conservation of these species.