新分类系统下长蒴苣苔亚科(苦苣苔科)细胞学研究概述

在最新分类系统框架下对长蒴苣苔亚科(Didymocarpoideae)的染色体资料进行了详细的整理和分析,结果表明,长蒴苣苔亚科的细胞学研究仍存在不足,尤其在种级水平上的研究不足25%,且存在一些属的染色体数据空白的现象。在新的分类系统下,一些修订后的属染色体数目表现出一致性或更加具有合理性,但也存在一些属的染色体数目变异仍十分复杂,如汉克苣苔属(Henckelia)和长蒴苣苔属(Didymocarpus)。基于已有的染色体数据,对长蒴苣苔亚科内一些重要属的染色体进化模式及其对物种分化的影响进行了探讨,推测染色体数目的多倍化及非整倍化进化可能对各类群的物种分化具有重要作用,但需要今后利用基于DNA探针的荧光原位杂交技术并结合分子系统学和基因组学研究才能深入地解析染色体的进化模式及其对物种分化的影响。

Synopsis of Cytological Studies on Didymocarpoideae (Gesneriaceae) under New Classification System

Based on molecular phylogenetic evidences, the classification of Gesneriaceae was dramatically changed in recent years. Especially, many genera in the Old Word have been systematically rearranged. However, cytological data of Gesneriaceae have not been re-examined. The cytological data of the Old Word Gesneriads, obtained from WebCyte database, Chromosome Counts Database and related literature, were summarized under the new taxonomic framework of Gesneriaceae. The results showed that the cytological data in Didymocarpoideae was still insufficient. Chromosome number of less than 25% species in this subfamily were reported, and that for many genera have never been reported. Some newly revised genera show uniform somatic chromosome number. However, some genera, such as Henckelia and Didymocarpus, have great variation in chromosome number. Based on these available cytological data, several comments and suggestions on the evolution of chromosome and its influence to species diversification in this family were proposed. It was speculated that both polyploidy and dysploidy of chromosome possibly play important roles to the diversification of some genera. Future works based on new chromosome painting techniques, convinced phylogenetic evidences, and genomics are warranted in studying chromosome evolution of this group.