沙参属植物多态现象、成因与物种划分

Plants of the genus Adenophora Korsh. (Campanulaceae) are famous medicinal herbs and also good edible herbs, which can be used for a substitute of crops to some extent. To make rational delimitation of species and establish a natural taxonomic system of this group are essential for rational utility of plant resources and effective conservation of endangered species in this group. However, this genus is also very famous for its being highly variable in external morphology. Thus, it is a great challenge to make acceptable delimitation of species, and as a result, new species and new varieties were continuously described. We conducted a biosystematic (≌ experimental taxonoamy) study on the Adenophora potaninii Korsh. complex. We found that high polymorphism is characteristic of the complex; morphological characters are greatly variable, and thus it is very hard to find reliable diagnostic characters for delimitation of species. Although we have produced very good taxonomy of this complex, it is time-summing and labor-summing work, and thus it is not very practical to be used for other groups. In the project in application we intend to seek a new methodology for conducting similar but more productive researches. What we are planning to do are to conduct extensive population sampling in fields, and based on the samples and herbaria specimens to exploit high-resolutive molecular markers, to analyse phylogenetic relationships between Adenophora and Campanula for making some insight into high polymorphism and its formation in Adenophora. We are going to display and analyse extent and pattern of polymorphism, and analyse variation and stability of morphological characters and correlation between the characters. Based the above results we are able to select reliable and diagnostic morphological characters for rational delimitation of species. Our goals are to establish a natural taxonomic system of Adenophora Korsh. and to compile a monograph of Adenophora Korsh. in English.

沙参属（桔梗科）既是药用植物，又是救荒本草。对它进行合理的物种划分，作出自然的分类系统，对于植物资源的合理利用和濒危物种的保护有重要意义。但这群植物形态多变，物种划分是个大难题，新种、新变种不断发表，造成分类混乱。我们曾对该属的一个复合群（Adenophora potaninii complex）进行物种生物学研究，发现该复合群有很高的多态性，形态变异幅度大，分类性状难于掌握。我们的研究有很好结果。但那种研究耗时、耗力，普遍应用不很现实。 本申请拟采用高效而快捷的途径进行新的探索。在野外进行广泛的居群取样，开发高分辨率的分子标记，依据科学取样进行深入的系统发育分析，探索多态性形成的原因，展示多态性的水平和式样，并采用统计学方法分析形态性状的变异和稳定性，分析各性状之间的相关性，从而选择有价值的形态鉴别性状，作出合理的物种划分，建立自然的分类系统，编著英文版世界沙参属专著。

沙参属是形态变异非常大的类群，营养器官和花部器官都表现出高度的变异性，给物种界定造成了极大的困难。针对项目申请书中提出的科学问题，我们在中国东北，华北，西北，西南和华东地区选择代表地点对沙参属物种进行了野外考察，收集实验材料和居群取样，并在多个标本馆查阅了沙参属的所有标本。同时，我们在族、属及物种复合体三个层面对沙参属开展分子系统学研究，旨在揭示其系统发育关系的同时，探讨其物种形成机制。我们在风铃草族内构建系统发育关系，重新评估属的划分，发现了风铃草族两大分支与花粉孔数和果实开裂方式的相关性，即A分支的物种花粉3孔，果实开裂方式为基部孔裂，B分支的物种花粉4 (5–15)-孔，果实绝大多数在中上部孔裂。我们依此结果界定了沙参属的范围，并对关系相对清楚的B分支类群进行了分类修订。我们在沙参属内进行居群取样，开发了大量高分辨率分子标记进行高通量测序，首次揭示了沙参属物种的遗传分化大小，估算了沙参属物种的分化时间，分析了其系统发育关系与地理分布格局的关系，为选取对分类有价值的鉴别性状奠定了基础，建立沙参属分类系统。此外，我们选择95份薄叶荠苨复合体的样品，覆盖其分布范围，利用叶绿体基因组和大量核基因的数据对薄叶荠苨复合体的物种进行分析，重新认识了该复合体内物种的界限，发现了新种，为研究沙参属物种形成提供了证据和新思路。