淫羊藿属分类学研究:进展、问题与展望

Taxonomic study of Epimedium L.: status, issues and prospect

关键词:  淫羊藿属, 资源优势, 形态描述, 分类修订, 种间关系, 杂交

Key words:  Epimedium L., resource advantage, morphological description, taxnomic revision, interspecific relationship, hybrid

摘要:

淫羊藿是我国特有且传统的重要药用植物,逐渐步入大宗品种行列。物种的准确鉴定是药效保障和用药安全的前提,为促进其资源的合理开发和利用,该文对淫羊藿属分类学研究进行系统梳理,并对其中存在的问题及存疑类群进行阐述。淫羊藿属共发表68种,中国58种(85.3%),其中57种为特有分布,具有显著的资源优势。淫羊藿属中国类群的分类学研究较为特殊,共26种集中发表于1990s,共31种(53.4%)为国外研究者命名,且绝大多数依据少量栽培个体命名。由于缺乏广泛的形态调查和性状变异分析,导致大量类群的形态描述不准确或不全面,后续20个类群被归并或降级。依据栽培个体命名的类群是补充描述和分类修订的重点。花色、根茎类型、花茎叶的数量及着生方式等性状在中国类群中存在广泛变异。经分类修订后,该属目前包括46种、1亚种和2变种。淫羊藿属中国组类群仍处于活跃进化中,其形态变异复杂,种间关系无法得到解决,为该属分类的最大挑战。但种质资源的研究和利用需要建立在清晰的分类学基础上。未来研究应基于居群调查,完善各物种的形态描述; 在此基础上,整合形态变异特征、地理分布格局和基因序列特征,检测自然种间杂交事件,从而揭示物种的分化和进化历程。

Abstract:

Herba Epimedii, one of the most vital traditional Chinese specific medicine, has been used for more than 2 000 years and its demand is increasing year by year. China, where the evolution of Epimedium has continued without interruption probably since the origin of the genus, is not only the richest in species, but also the only region where new species may yet be found. Considering differences in bioactive constituents among Epimedium species, accurate identification of species is the prerequisite for drug efficacy and medical safety. For the better utilization of germplasm resources, the taxa and its taxonomic systems of Epimedium were reviewed, and the issues of taxonomy as well as the insufficiently known taxa were discussed. A total of 68 species have been published and 58(85.3%)from China, among which 57 are unique to China. The taxonomy on Chinese taxa is special, a total of 26 species were published in the 1990s and 31 species(53.4%)were described by foreign researches. Among them, Stearn has described 19 species. Therefore, many Epimedium species of China have been published based on a single locality and/or the descriptions were based on limited specimens or collections. These taxa then become the main objects of subsequent taxonomic revision and complementary descriptions. Due to lack of extensive field investigation, observation and statistical analysis on morphological characters, 20 taxa have been revised. And the morphological descriptions of a considerable number of taxa were proved inaccurate and/or incomplete. Currently, 46 species, 1 subspecies and 2 varieties were recognized. The comparatively unstable species often occur in West China where the genus is best represented and its evolution is still on going. The Chinese Sect.(Diphyllon)reaches the highest species diversity in Epimedium and representing numerous taxonomic controversies. The taxa from China always with complex morphological variation and few molecular genetic variation loci can be detected. Chinese species therefore become the biggest taxonomic challenge. However, the research and utilization of germplasm resources should be based on correct taxonomy. Specifically, we recommend that future studies should focus on the standardization of morphological descriptions, based on extensive population investigation. Then the integration of morphological variation, distribution patterns and gene sequence characteristics would help to detect the natural interspecific hybridization events and reveal the differentiation and evolution of species.