基于RAPD标记的15种嵩草属(Kobresia Willd．)植物遗传关系

Genetic relationships among fifteen species of Kobresia Willd.(Cyperaceae,tribe Cariceae)based on RAPD markers

嵩草属(Kobresia Willd.)植物由于其形态结构的多样性及种内变异式样的复杂性,至今仍被认为是分类学上的"困难属".因此,对于该属系统学其他方面的证据,尤其分子方面的研究则显得极为重要和迫切。本文选用21个RAPD随机引物调查了15种嵩草属植物的遗传关系。结果表明:15种嵩草属植物聚为3类,认为嵩草组和异穗嵩草组的建立是比较自然的,而单穗嵩草组的划分并不自然.此外,分子结论并不支持前人发表的K.maquensis为独立新种,建议降为K.setschwanensis的异名.

Plants of the genus Kobresia, are dominant alpine sedges of high ecological and economic importance. Phylogenetic relationships of Kobresia species have not been well resolved due to limitations in sample availability. Also, previous studies focused on morphological traits, which can be variable in changing habitats and environmental conditions. Here we examine 15 Kobresia species to estimate the genetic relationships in the genus and to reexamine previous phylogenetic efforts. Twenty-one RAPD primers were chosen to examine 47 accessions of the 15 species. The results indicate that the species cluster into three main groups. Previously the genus was divided into section Kobresia, section Elyna, and section Hemicarex, and these classifications were based upon inflorescence structure. Our molecular results generally correspond with section Kobresia and Hemicarex. However the molecular phylogeny does not match with section Elyna, indicating that Elyna is not a natural classification. Additionally, although K. maquensis has been previously classified as an independent species, our results suggest that it should be considered a synonym of K. setschwanensis. These results also show that RAPD markers are effective in constructing phylogenetic relationships among Kobresia species.