横断山区六种八居群鼠尾草属植物的核型分析

鼠尾草属(Salvia)是唇形科(Lamiaceae)最大的属,属下多种为民间常用草药,亦有供观赏的种类。为探究横断山区物种在细胞学水平的进化方式,讨论形态分类学与分子系统学之间的分类关系,该研究通过广泛收集染色体文献资料,采用植物常规压片法对采集自横断山地区6种8居群鼠尾草属植物进行核型分析,并构建了中国地区分布的鼠尾草属植物叶绿体系统发育树。统计结果表明:(1)全世界范围内报道了约23%的鼠尾草属植物染色体数据,其中分布在中国地区的鼠尾草属植物染色体报道率为32.10%,分布在横断山地区的鼠尾草属植物报道率为40.54%,(2)鼠尾草属植物染色体基数以x=8和x=11为主,分布在中国地区的鼠尾草属植物染色体基数均为x=8。实验结果表明:(1)西藏鼠尾草(S. wardii)核型数据为首次报道。(2)雪山鼠尾草(S. evansiana)首次在云南德钦地区发现二倍体居群。将细胞学数据结合叶绿体进化树开展染色体进化关联分析,论证多倍化可能不是鼠尾草属物种适应高海拔环境的主要机制,表明多倍体不是该属物种形成的主要进化途径而是以二倍体水平为主,推测染色体组的加倍可能是物种在形态学与分子系统学上分类关系不一致的原因之一。该研究丰富了横断山区鼠尾草属植物的染色体核型数据,结合区域分子系统树探讨染色体特征的进化关系,为今后深入研究该属物种的核型进化做出了探索,为开展祖先物种染色体基数推演分析补充了基础数据。

Karyotype analysis of eight populations of six Salvia species in the Hengduan Mountains

Salvia is the largest genus of the Lamiaceae. Several species of Salvia are used as traditional Chinese medicine, as well as ornamental species. To explore the evolution pattern of species in Hengduan Mountains at the cytological level and to discuss the taxonomic relationship between morphological taxonomy and molecular systematics, based on extensive collection of chromosome literature, the karyotypes of six species(eight populations)of Salvia collected from Hengduan Mountains were analyzed by using conventional plant pressing method, and the chloroplast phylogenetic trees of Salvia distributed in China were constructed. The statistical results were as follows:(1)About 23% of the chromosome data of Salvia was reported all over the world, in which the chromosome reporting rate of Salvia in China was 32.10%. The reporting rate of Salvia in Hengduan Mountains was 40.54%.(2)The chromosome basic number of Salvia were mainly x=8 and x=11, and the chromosome cardinal numbers of Salvia plants distributed in China were x=8. The experimental results were as follows:(1)The karyotype data of S. wardii was reported for the first time.(2)The diploid population of S. evansiana was found for the first time in Deqen, Yunnan. The chromosome evolutionary association analysis was carried out by combining cytological data with chloroplast evolution tree, and it was demonstrated that polyploidy might not be the main mechanism of Salvia adapting to high altitude environment. It showed that polyploid was not the main evolutionary pathway of Salvia plants species formation, but mainly at the level of diploid. So we speculated that the doubling of genome might be one of the reasons for the inconsistency between species morphology taxology and molecular phylogeny taxology. This study enriches the chromosome karyotype data of Salvia in Hengduan Mountains, discusses the evolutionary relationship of chromosome characteristics combined with regional molecular phylogenetic tree, has made exploration for further study of the karyotype evolution of Salvia species in the future, and complements the basic data for the deduction and analysis of the chromosome cardinal number of ancestral species.