二倍体铁破锣的核型及四倍体细胞型的首次发现

Correction of karyotype of diploid Beesia calthifolia and discovery of a tetraploid cytotype

本文重新检查了铁破锣的核型。来自湖南新宁的４０个个体中，１个个体为四倍体，其核型公式为２ｎ＝４ｘ＝３２＝１６ｍ＋８ｓｍ＋４ｓｔ＋４ｔ；其余个体为二倍体，其核型公式为２ｎ＝２ｘ＝１６＝８ｍ＋４ｓｍ＋２ｓｔ＋２ｔ。来自云南大理的１０个个体全为四倍体，其核型公式为２ｎ＝４ｘ＝３２＝１６ｍ＋８ｓｍ＋４ｓｔ＋４ｔ。据此认为商效民（１９８５）报道的该种的核型分析结果有误。他至少将第４对染色体的着丝点位置辨认错了。该对染色体不具有中部着丝点而实际上具有近端部着丝点。本文还比较了铁破锣和角叶铁破锣的核型差异，并详细讨论了铁破锣属的系统位置。

In this paper, the chromosomes of Beesia calthifolia were re examined. In the 40 plant individuals of the population from Xinning County, Hunan Province, central China, one was found to be tetraploid with the karyotype formula of 2n=4x=32=16m+8sm+4st+4t, and the remaining were all found to be diploids with the karyotype formula of 2n=2x=16=8m+4sm+2st+2t. All the 10 individuals of the population from Cangshan Mountain, Dali City,Yunnan Province, southwestern China, were unexpectedly found to be tetraploids with the karyotype formula of 2n=4x=32=16m+8sm+4st+4t. Tetraploid cytotype was reported in this species for the first time. Based on the results and those previously reported, it is considered that there may exist some errors in the results of the karyotype analysis of this species previously reported by Shang(1985). He might have at least mistakenly recognized the centromere position of the fourth pair of chromosomes. This pair of chromosomes should have subterminal rather than median centromeres. Furthermore, the karyotypic differences of B. calthifolia and B. deltophylla were analyzed and the systematic position of the genus Beesia was discussed in detail.