披碱草属的系统地位及其物种生物系统学研究

Elymus L. is one of the important perennial genera in the tribe Triticeae (Poaceae). It includes about 80-100 species and varieties in the world, and is distributed in the subtropical and warm temperate countries of both hemispheres. Species in Elymus are excelent fodder plants, and some species are used in wheat breeding program through distant hybridization as the genetic germplasm resources for disease and drought resistace, and salt tolerance. However, the definition of the genus and its precise taxonomic treatment are still under discussion. Therefore, in this study, we carried out the taxonomic status of Elymus and biosystematic study on its species through morphological characters, geographic distribution, intergeneric and interspecific hybridization, fertility, cytogenetic characterization, genomic in situ hybridization (GISH), molecular systmatics phylogenetic studies. The objectives are: (1) to investigate taxonomic ststus of genus Elymus; (2) to discuss the generic delimitation and the phylogenetic relationships among Elymus, Roegneria, Campeiostachys, and the related genera; (3) to determine the genomic constitution of the species and the genetic variations among the intraspecific poputions; (4) to discuss the specific delimitation, the phylogenetic relationships among the species, and the taxonomic treatment of the intraspecific status; (5) to solve the problems about the taxonomic treatment of the specific taxa, and revise the genus Elymus.

通过对世界范围内披碱草属物种的形态特征和地理分布、属间和种间杂交及繁育特性、细胞遗传学、基因组原位杂交（GISH）和分子系统学等研究结果进行分析，探讨：（1）披碱草属的系统地位及范围；（2）披碱草属与鹅观草属、曲穗草属等近缘属的属间界限和亲缘关系；（3）物种染色体组组成和种内居群间遗传变异；（4）物种界限、种间关系和种下等级的分类处理；（5）解决部分物种分类处理的疑难问题，系统整理国产披碱草属植物。为全面认识披碱草属植物以及小麦族多年生多倍体属的起源和演化提供资料。

披碱草属是小麦族中物种众多、形态多样、变异极大的一个多年生属。通过形态特征、种间杂交、细胞遗传学、基因组原位杂交和分子系统学等手段，研究了披碱草属系统地位、与近缘属亲缘关系、物种分类以及起源和演化，取得如下研究进展：（1）确立披碱草属系统地位。模式种Elymus sibiricus含StH染色体组，按染色体组分类原则，具St和H组成的四倍体和六倍体物种放在披碱草属。在形态和染色体组上构成与近缘属的区别。（2）澄清披碱草属与近缘属关系。欧美学者把披碱草属、鹅观草属、曲穗草属等组成广义披碱草属。具StY物种放在鹅观草属；StSt放在拟鹅观草属；StP放到杜威草属；StYH划到曲穗草属；StYP划到仲彬草属；StYW划到花鳞草属中。（3）解决部分物种的分类：Elymus tangutorum、E. cylindricus、E. breviaristatus、E. purpuraristatus、E. atratus、Roegneria calcicola染色体组为StYH，应组合到曲穗草属；而Elytrigia repens、E. lolioides为StStH，应归在披碱草属中。（4）初步明确形态变异机制：拟鹅观草属St染色体组作为母本，与H染色体组天然杂交，形成披碱草属。St二倍体变异大，多倍体的St供体不同。在多倍体杂交和分化中，基因渗入是导致多倍体St发生遗传分化和物种形态变异的重要因素。（5）阐明染色体组起源和演化：广义披碱草属具St、H、Y、P、W等5个基本染色体组，St来自拟鹅观草属，H来自大麦属， P源于冰草属，W源于南麦属，而Y来源未知，构建其染色体组起源和演化模式。（6）完善资源圃和种子资源库：收集和保存披碱草属35种570份及近缘属12属92种812份材料，制作腊叶标本46种342份。（7）发表论文：在《Mol Phylogenet Evol》、《Ann Bot》、《BMC Plant Biol》、《Bot J Lin Soc》、《J Syst Evol》和《植物学报》等发表论文35篇，其中SCI 33篇。主编专著1部。获发明专利1项。选育牧草新品种2个。获四川省科技进步二等奖1项。（8）团队建设和人才培养：通过项目，团队力量增强，承担国家项目能力增强，学术影响提升；招收博士后1人、博士生5名，毕业3名；招收硕士生6名，毕业2名。