【作者】 陈文俐；

【导师】 王文采； 刘亮； 杨亲二；

【作者基本信息】 中国科学院植物研究所 ， 植物学， 2001， 博士

【摘要】 通过野外观察和标本研究，本文分析了中国野青茅属植物主要形态性状的变异式样，对其叶片表皮进行了光镜和电镜观察，对外稃表皮进行了电镜观察，分析了该属植物的生态和地理分布。在此基础上，对中国野青茅属植物进行了分类修订。 1．形态性状分析 分析结果显示：野青茅属植物形态变异极其复杂，性状之间大多缺少相关性，属内有分类价值的性状较为贫乏。一般来说，颖片表面特征、基盘毛与外稻的相对长度、外稃的质地及表皮结构、外稃背部具芒与否、芒的伸出位置等性状在种内较为稳定，是本属首要的分类性状。植株疏丛型或密丛型、花序宽大开展或短小紧缩、小穗的大小等性状在分类上具有第二位的重要性。而叶鞘、叶舌、叶片的长宽、颖片边缘是否具睫毛等性状往往在种内没有稳定性，在分类中应该审慎对待。但是，应该特别指出，即便是通常比较稳定可靠的性状，在少数类群中也可能存在较为复杂的变异，而那些通常没有稳定性的性状，在个别类群中又可能表现出稳定性，在分类上具有重要的价值。 2．叶表皮 在光镜和扫描电镜下观察了叶表皮结构，结果表明：上表皮结构无规律性可循，难以用来分类；下表皮结构为典型的狐茅型，脉间长细胞、刺毛、硅细胞的形态具有一定的分类学意义。 3．外稃表皮 在扫描电镜下观察了外稃表皮结构，结果表明：所有类群的外稃表皮均由长细胞和刺毛组成，偶见硅细胞而无气孔。根据外稃表皮的结构特征可将本属植物分为4类，第1类：长细胞厚壁，边缘显著波状弯曲，刺毛基部浅表型；第2类：长细胞厚壁，边缘微波状或波状弯曲，刺毛基部浅表型；第3类：长细胞薄壁，边缘波状弯曲，刺毛基部下陷；第4类：长细胞厚壁，边缘微波状或波状弯曲，刺毛基部下陷。 4．生态与地理分布 野青茅属植物分布于南北半球的温带地区以及热带的山区，主要生于较潮湿的环境，如林缘、灌丛、低海拔的湿草甸、高山和亚高山草甸。山坡草地等。该属植物在中国主要分布在西南山区和青藏高原，分布种类在海拔3000－4000米最为丰富。 5．区系地理成分分析 中国野青茅属植物的区系地理成分以中国一喜马拉雅成分、中国特有成分为主体，包括环北极成分、旧世界温带成分、中国－日本成分等共5种。认为中国的西南山区至喜马拉雅一带为野青茅属植物的多样性中心之一。 6．根据标本资料，绘制了每一种在中国的地理分布图，以及大部分种的垂直分布柱状图。并首次提供了8个种的标本绘图。 在上述工作的基础上，本文对中国野青茅属进行了分类学修订，归并12种，12变种，其中包括新异名16个；作出新组合2个，其中包括1个改级新组合。本文确认了产于中国的该属植物31种，3变种（不包括原变种）；另有8种1变种暂存疑。经本文修订后，原中国植物志记载的 43种 14变种，目前被确认27 fib 2变种。更多还原

【Abstract】 Deyeuxia Clarion ex Beauv., a large genus within the family Poaceae comprising over 150 species, is distributed in the temperate region throughout the world and tropical mountains. This genus is morphologically highly polymorphous, and is one of the most difficult genera of Poaceae in taxonomy. This work is to revise the taxonomy of this genus from China based on evidence from gross-morphology, anatomy, ecology and phytogeography. The main results are summarized as follows:1. Gross-morphologyOn the basis of field observation and examination of herbarium specimens, the variation pattern of all the major gross-morphological characters in Deyeuxia was analyzed and their taxonomic significance was evaluated. The results showed that all of the characters are extremely variable, and the correlation of the characters is poor, thus leading to the scantiness of the reliable diagnostic characters in this genus. In general, the most reliable characters for the delimitation of species are the features of the glume surface (smooth, puberulent or scabrous), the relative length of callus hairs vs. lemma, the features of the lemma awn (presence or absence and its inserted position), the texture and epidermal structure of lemma. The secondly important characters are the degree of the denseness of basal branches of culm, the shape and the degree of compactness of panicle, the size of spikelet etc. Such characters as the hairiness of sheath, the length and shape of the ligule, the width of blade, the presence or absence of lashes on the margin of the glume are highly variable and are not considered to be of diagnostic value, for they can be easily modified by environmental condition or by some other factors. It must be noted that even the characters that are usually stable might also exhibit wide range of variation in some taxa, while those usually unstable characters seem to be of genetic stability in some cases and can be used as distinguishing features of taxa.2. Anatomy of both leaf and lemma epidermisLeaf epidermis of 67 samples representing 31 species and 3 varieties in Deyeuxia was observed under both light microscope (LM) and scanning electric microscope (SEM). The characters of adaxial leaf epidermis in Deyeuxia seem to be too complex to be of important significance for identification of species. Their abaxial epidermis is typically Festucoid, with long-cells, short-cells, silica-bodies, stomata, prickles, but without macro-hairs, micro-hairs and papillae. Some features, such as the sinuousdegree of walls of intercostal long-cell, the shape of silica-body, the distribution and frequency of prickles are often of specific diagnostic value.Lemma epidermis of all Deyeitxia species from China was also investigated under SEM. Great constancy of lemma epidermis was observed within the genus. Lemma epidermis of all the species studied is composed of long-cells and prickles, occasionally silica-bodies, but exhibits obvious differences in the characteristics of the walls of long-cells (thick or thin; markedly sinuous, sinuous or slightly sinuous) and the base of prickles (superficial or sunken). According to these features, the lemma epidermis of Deyeuxia species in China fell into 4 types. The first type is characterized by long-cells with thick and markedly sinuous walls and prickles with superficial base. This type is represented by 9 species, including D. arundinacea, D. scabrescens, D. lapponica, D. turczaninowii, D. kokonorica, D. neglecta, D. sichuanensis, D. conferta, D. moupinensis. The second type is characterized by long-cells with thick, slightly sinuous or sinuous walls and prickles with superficial base. This type is represented by 10 species and 1 variety, including D. effusiflora, D. sinelatior, D. nyingchiensis, D. tibetica, D. tibetica var. przevalskyi, D. anthoxanoides, D. himalaica, D. pulchella, D. rosea, D. holciformis, D. tianschanica. The third type is characterized by long-cells with thin, sinuous walls and prickles with sunken base. This type is represented by 4 species, including D. flav更多还原