菊科蒿属艾组的分类学研究

The Artemisia sect. Artemisia is a species-rich clade that experienced rapid radiations. It’s an economically important plant group. There are several confounded issues in its present taxonomy, including puzzling species delimitation, confusing identities and nomenclature, and difficulties in identification. The project will resolve these confusions by exploring both genotype and phenotype data. For genotype data, we will use the newly developed reduced-representation genome sequencing technique to produce huge amounts of SNP data, and then test different species delimitation models. Meanwhile, the SNP data will also be used to reconstruct the phylogenetic relationships for the Artemisia sect. Artemisia. For phenotype data, we will collect characters data from specimens, field observations, population samplings, and transplant experiments, and then test the variations of these characters using multivariate statistical analysis to evaluate their utilities in species delimitation. We will also explore new taxonomic characters. Consequently, we will clarify the identities of every entities discovered in the analysis above, and produce a user-friendly taxonomy of the Artemisia sect. Artemisia based on comprehensive evidence. This project will resolve the taxonomic problems of an important group in the sunflower family and lay solid groundwork for the effective utilization of its rich plant resources. Furthermore, the project may stimulate exploring the taxonomic problems in other taxa of the flowering plants that experienced rapid radiations.

菊科蒿属艾组物种丰富，经历过快速辐射，有重要经济价值，但物种划分争议大，鉴定困难，命名上也存在诸多问题，是公认的分类疑难类群。本研究将利用简化基因组证据，一方面重建艾组植物的系统发育关系，另一方面扩大物种划分有争议种类的取样，通过简化基因组测序获得大量SNP数据，用贝叶斯方法检验不同划分方案，从基因型角度提出物种划分建议。在表型方面，我们将汇总国内外标本及野外获得的居群材料，整理来自移栽实验的数据，努力发掘新性状，用多元统计方法检验性状，从表型方面提出物种划分的新建议。我们还将全面清理艾组分类中的名实问题，循名责实，全面修订艾组，最终提出一个科学、好用的艾组新分类。这是综合利用多学科证据解决快速辐射类群分类学问题的新探索。本研究的完成不仅可以解决菊科一个重要疑难类群的分类学问题，为有效利用艾组丰富的植物资源提供可靠的科学基础，而且有助于推动解决有花植物中有类似快速辐射现象类群的分类学问题。

艾组是菊科蒿属植物的一个较大的类群，主要在北半球温带地区分布，具有重要的药用价值，但分类比较混乱，是蒿属植物分类的难点，主要是：组的界限模糊不清；组下种类亟待修订，包括名实混乱等。我们展开了广泛的野外考察和标本观察，研究了大量性状，结合移栽实验及统计分析，澄清了艾组内部分种类的混乱。我们还展开了形态学、细胞学和系统发育基因组学研究，重建了艾组及其近缘类群的系统发育关系，无论在取样广度、研究性状数量，还是在研究方法上，都有所突破。综合各方证据，我们重新界定了艾组的范围，将腺毛蒿组sect. Viscidipubes和白苞蒿组sect. Albibractea归并到艾组sect. Artemisia中，提出了一个蒿属艾组分类的新方案, 包含10个系，97个种。