中国缺齿藓科（Mielichhoferiaceae, Musci）的分类研究

The Mielichhoferiaceae is one of important groups in mosses. However, its systematic position in the mosses is confused, and genera and species in it are considerable difficult to identify with a global distribution. This study will take the family Mielichhoferiaceae in China as research subject, and focus on confused groups with diversity in morphologic features. Based on specimens, the revise will be done on all groups of the Mielichhoferiaceae by newly experimental method. The study aim at confirming how many and what species of the family in China, standard of classification for every species, ranges of geographical distribution, giving keys of genera and species, and describing the morphologic features of every species. The study is trying to provide scientific basis and the tool of classification for the family in China. The classification system and the phylogenetic relationships in the family will be discussed also. The theories, methods and means of classical taxonomy for bryophytes will be used mainly in the study. Observing and taking pictures for the ultrastructures by scanning electron microscope are auxiliary methods. Experiments of molecular biology, ontogeny (including the germination of spore, the development of protonema and gametophyte differentiation) and Fourier transform infrared spectroscopy (FTIR) will be used for debatable groups also. And then, being followed cladistics analysis or statistical analysis for the information separately so that to confirm the systemic position of the family in moss. The key to the questions are making taxonomic standards, providing variation ranges and geographic distribution regularities of every species and every genus of Mielichhoferiaceae in China. The study attempt relieving the problem that the bottleneck for confused systematic positions of the family, uncertain phylogenetic relationship of groups in the family, and indeterminate taxonomic standards for some genera and species. The point view of researchers will be provided at last.

缺齿藓科是藓类植物中的重要类群之一，但形态复杂多样、系统位置颇有争议，是分类难度较大的一个类群。本项目以中国缺齿藓科丰富种类为研究对象，以形态变异复杂的疑难类群为研究重点，根据标本资料和最新实验手段对缺齿藓科所含类群做全面修订，旨在确定中国缺齿藓科植物的分类标准、种类组成、地理分布范围，详细描述每个分类群的形态特征，为中国该类群的分类提供科学依据和资料；同时探讨该类群分类系统和发育关系。 该项目主要运用苔藓植物经典分类学的理论、方法和手段，结合电镜技术对超微结构观察比较，选择有争议分类群结合分子生物学实验、个体发育实验和化学成分分析实验等为补充，进行分支系统学和统计学分析，确定该类群的系统位置。 该项目拟解决的关键问题是确定中国缺齿藓科各属种的分类学标准、变异幅度和地理分布规律；重点解决该科系统位置尚不明确、某些属种位置模糊、分类标准难以界定等"瓶颈"问题，并提出研究者的新见解。

本项目以中国缺齿藓科(Mielichhoferiaceae)植物为研究对象，以形态变异复杂的疑难类群为研究重点，在大量研究标本和文献的基础上，根据标本资料和最新实验手段，运用经典分类学的理论、方法和手段，根据标本和文献，结合电镜技术的详细观察，利用分子系统学实验手段、傅立叶变换红外(FT-IR)光谱分类技术以及原丝体发育的证据等，对中国缺齿藓科所含类群做了全面修订。. 本研究基于对标本的经典分类学、分支系统学和分子生物学分析，参照近年来几个权威的藓类植物分类系统，确定缺齿藓科是一个自然类群，探讨了缺齿藓科与真藓科(Bryaceae)、提灯藓科(Mniaceae)等的系统发育关系；对中国缺齿藓科植物各类群的分类标准、种类组成、区系地理分布范围提出了较明确的界定，整理出中国缺齿藓科植物的最新名录，中国缺齿藓科包含有5属，即缺齿藓属(Mielichhoferia)、丝瓜藓属(Pohlia)、拟丝瓜藓属(Pseudopohlia)、合齿藓属(Synthetodontium)和小叶藓属(Epipterygium)，目前为止共计34种；详细描述了每个分类群的形态特征，编制了属、种检索表，为中国该类群的分类提供了科学依据和方法；纠正了以往对中国该类群研究中的一些错误，填补了某些缺陷；发现和命名了缺齿藓科植物的新分类群：臧氏拟缺齿藓(Haplodontium zangii X.R.Wang & J.C.Zhao)和昆仑合齿藓(Synthetodontium kunlunense J. C. Zhao & Y. Y. Liu)，发现中国新分布类群：合齿藓属、拟缺齿藓属、芽胞丝瓜藓[Pohlia andalusica (Höhn.) Broth.]和安氏丝瓜藓(P. andrewsii A.J. Shaw)等；建立新组合喜马拉雅拟缺齿藓[Haplodontium himalayanum (Mitt.) X.R.Wang & J.C.Zhao]和中华拟缺齿藓[H. sinensis (Dixon) X.R.Wang & J.C.Zhao]，并从缺齿藓科移入真藓科中。. 本研究较好地解决了中国缺齿藓科各属种的分类标准、变异幅度和地理分布规律，重点解决了疑难的丝瓜藓属、缺齿藓属和拟缺齿藓属系统地位的难题，提出了研究者的新见解。