华南地区3种兔儿风属植物(菊科-帚菊木族)的细胞学研究

Cytology in Three Species of Ainsliaea (Asteraceae-Pertyeae) from Southern China

摘要:

首次报道了华南地区兔儿风属(Ainsliaea DC.)(菊科-帚菊木族Asteraceae-Pertyeae) 3种植物共4个居群的染色体数目和核型。其中长穗兔儿风(A. henryi Diels)的染色体数目为2n=24,核型公式为2n=16m+8sm;三脉兔儿风(A. trinervis Y. C. Tseng)的染色体数目为2n=26,核型公式为2n=16m+10sm;莲沱兔儿风(A. ramosa Hemsl.) 2个居群的染色体数目均为2n=26,核型公式为2n=26=22m+4sm。所有居群的染色体由大到小逐渐变化,核型没有明显的二型性。这些结果表明兔儿风属植物确有x=12和x=13两个基数,其中x=13可能是该属的原始基数。

Abstract:

Chromosome numbers and karyotypes in four populations of three species in the genus Ainsliaea DC. (Asteraceae-Pertyeae) from southern China have been investigated for the first time. The chromosome number of A. henryi Diels was counted to be 2n=24, and the karyotype was formulated as 2n=16m+8sm. The number of A. trinervis Y. C. Tseng was counted to be 2n=26, and the karyotype was formulated as 2n=16m+10sm. Both populations of A. ramosa Hemsl. had 2n=26 and the karyotype of 2n=22m+4sm. In all of the populations studied the chromosomes showed a steady gradation in length from the longest to the shortest, with no evidence of bimodality. The results have confirmed the occurrence of two basic chromosome numbers, x=12 and x=13, in the genus Ainsliaea, with x=13 very likely being the primitive number.