【作者】 曹娜；

【导师】 赵建成；

【作者基本信息】 河北师范大学 ， 生态学， 2008， 硕士

【摘要】 真藓科是顶蒴藓类中较大的科之一,全世界先后报道约有14属,800余种。该科除了少数种类限于热带亚热带地区外,其余大多数种分布于世界各地。从平原到高山,从低纬度到高纬度的寒冷地带,或者是干旱荒漠地带都有此类群的分布。根据《中国苔藓志》最新统计,我国真藓科有11属(含丝瓜藓属Pohlia Hedw.)、102种、4变种。早在19世纪初期一些学者就开始了对该科的研究,其中以Brotherus、Andrews、Dixon、Nyholm、Ochi、Spence等人的研究较为深入。但目前关于真藓科,仍未有一个统一的系统分类标准。本文根据研究现状及目前存在的问题,对我国北方(包括华北区、东北区和西北区)真藓科植物重点进行如下探索:1.根据文献记载、野外采集及对于河北师范大学(HBNU)植物标本馆、中国科学院植物研究所(PE)标本馆、中国科学院昆明植物所(HKAS)标本馆、华东师范大学(HSNU)、新疆大学(XJU)、河南农业大学(HNAU)、山西大学(SXU)等有关真藓科植物的标本进行整理、鉴定,同时结合现有资料对中国北方真藓科植物的有效属名和种名进行修订,结果表明中国北方真藓科植物有8属,54种、2变种。发现真藓科中国1新记录种:Bryum amblyodon C. Muell.,北方省区新记录种共计41种、1变种,其中大孢短月藓Brachymenium longicolle Thér.,砂生短月藓B. muricola Broth.,中华短月藓B. sinense Card.,瘤根真藓Bryum bornholmense Winkelm. & Ruthe.,纤茎真藓B. leptocaulon Card.,长柄真藓B. longisetum C. Muell.,小丝瓜藓狭叶变种Pohlia crudoides (Sull. et Lesq.) Broth. var. revolvens (Card.) Ochi为我国北方首次记录。2.光学显微镜(LM)下对真藓科植物进行形态解剖特征观察,对真藓科植物的配子体、孢子体的基本形态特征进行了详细的描述,绘制了部分形态特征比较图。3.利用LM和扫描电子显微镜(SEM)对北方真藓科植物8属27个种的孢蒴、蒴齿及7属21个种的孢子形态特征进行了详细观察,结果表明27种真藓科植物的蒴齿外齿层齿条多为长披针形,少数种类,如短月藓属Brachymenium和平蒴藓属Plagiobryum多为长锥形。干燥情况下,外齿层齿条的取向大致可以分为4种类型:(1)近直立。真藓属Bryum大多数种和芽孢银藓Anomobryum gemmigerum、狭边大叶藓Rhodobryum ontariense、薄囊藓Leptobryum pyriforme的蒴齿外齿层为此种类型;(2)向内弯曲,齿条不伸入内齿层。短月藓属Brachymenium的两个种为此种类型;(3)外齿条伸入内齿层内。平蒴藓属Plagiobryum植物为此种类型,此外毛状真藓Bryum apiculatum、长柄真藓B. longisetum、泛生丝瓜藓Pohlia cruda、黄丝瓜藓P. nutans也为此种类型;(4)外齿条向外反折。属于这一类型的有柔叶真藓Bryum cellulare、丝瓜藓Pohlia elongata、拟长蒴丝瓜藓P. longicollis。外齿层齿条外侧的纹饰在不同属间也有变化。真藓科21个种的孢子均具近极薄壁区,但薄壁区凹陷形状各不相同,孢子表面纹饰类型及顶端细微结构有一定的差异,这些都可以作为划分种级水平分类群的重要标准。4.通过对北方真藓科15种的无性芽孢进行LM和SEM观察,发现不同种的无性芽孢形态特征具有重要的分类学意义。但是同一个种的芽孢在不同发育时期形态特征略有差异,给真藓科植物的鉴定带来一定的困难。因此应对真藓科植物无性芽孢进行室内培养,观察每个种的无性芽孢在不同发育时期的形态特征变化,以便为以后的分类学研究提供一定的依据。5.依据分支系统学原理,选取牛毛藓科的细叶牛毛藓Ditrichum pusillum为外类群,以真藓科21个种作为内类群,选取61个不同形态特征做成数据矩阵表,利用PAUP4.0Beta软件对其进行分支系统学分析,利用MP法和NJ法构建分支系统树。根据所得数据结果,作者同意Ochi将真藓科植物划分为2亚科的观点,但并不同意将银藓属Anomobryum和大叶藓属Rhodobryum归入真藓属内,而是作为独立的属对待。6.依据分支系统分析,结合前面对北方真藓科植物54种、2变种的形态特征研究,编制分亚科、属、种检索表,并对每个种的形态特征、生境、地理分布进行详细描述,依据标本采集地点记录,将研究种类在北方的地理分布标注于地图上。7.在北方真藓科植物区系组成中,含10种以上的优势属有2属,所含种数占整个北方真藓科植物总种数的71.43%。其中真藓属为最大的属,共28种,构成北方真藓科植物的主要组成成分。北方真藓科植物占全国真藓科植物总属数的72.73%,总种数的52.83%。根据文献记载和标本的采集记录,统计北方真藓科植物在北方各省的分布情况。结果表明陕西、河北、河南和新疆四个省区真藓科植物分布最为丰富。根据各个种在北方12个省的分布的有无,列出数据矩阵表,利用统计学软件进行统计分析,并将统计结果直接标注于地图上,以便更加直接的反映各个省区真藓科植物分布的多寡。根据陈邦杰和吴鹏程划分的中国苔藓植物地理区划,真藓科植物在北方的分布可以分为华北区、华中区、东北区和蒙新区四个区域,根据这些区划,选取欧洲、北美、日本和俄罗斯作为聚类分析的研究对象进行聚类分析。研究表明真藓科植物的地理分布同样可以证明我国华北区和华中区与日本的苔藓植物关系密切,主要以温带成分为主,东北区、蒙新区与欧洲、北美和俄罗斯的苔藓植物的关系密切,区系组成以泛北极成分为主。更多还原

【Abstract】 The family Bryaceae is a large acrocarpous moss family with diplolepidous-alternate peristome, about 14 genera and more than 800 species have been reported in the world. The majority of the species are cosmopolitan, except only a few limited to tropical and subtropical regions. It has the distribution from plain including residential areas and roadsides to high-altitude areas, also in the tundra zone and in the arid desert areas. According to the statistics in“Flora Bryophytorum Sinicorum”, about 11genera (including Pohlia Hedw.), 102 species and 4 varieties of Bryaceae are considered to be taxonomically valid in China. The study of Bryaceae beginning in the early 19th century, the deep research was carried out by Brotherus, Andrews, Dixon, Nyholm, Ochi, Spence and so on. With regard to the study of Bryaceae, it has not a unified taxonomic standard. According to the situation and problems of the research, we have put emphasis mainly on some problems about Bryaceae in North region of China as follows:1. About 8 genera, 54 species and 2 varieties of Bryaceae in North region of China are accepted in this investigation based on documents, collections and identification of specimens from some herbaria (HBNU, PE, HKAS, HSNU and so on). 1 species (Bryum amblyodon C. Muell.) is recorded new to China. 41 species and 1 varieties are new record to a few provinces in North region of China, among them, Brachymenium longicolle Thér., B. muricola Broth., B. sinense Card., Bryum bornholmense Winkelm. & Ruthe., B. leptocaulon Card., B. longisetum C. Muell.and Pohlia crudoides (Sull. et Lesq.) Broth. var. revolvens (Card.) Ochi are the first recorded in North region of China.2. The detail descriptions of general morphological characters about gametophyte and sporophyte of Bryaceae are achieved based on the observation to the characteristics of anatomy under the Light microscope (LM). Figures and pictures of some characters are given in this discussion.3. Capsules of 27 species and spores of 21 species of Bryaceae in North region of China have been observed under LM and Scanning electron microscope (SEM). The results show that most exostome teeth of 27 species are lanceolate, but subulate in Brachymenium and Plagiobryum. In dry state, four types have been observed about the orientation of exostome teeth: (1) nearly erect. The exostome teeth of most species of Bryum, Anomobryum gemmigerum, Rhodobryum ontariense and Leptobryum pyriforme belong to this type; (2) erect-incurved. Two species of Brachymenium are entitled to this type; (3) curved-arcuate, with the tips inserted between the endostome teeth. This type occurs in Plagiobryum, Bryum apiculatum, B. longisetum, Pohlia cruda, P. nutans. (4) reflexed. Bryum cellulare, Pohlia elongate, P. longicollis fall into this type. The differentiations of ornamentation in the outer surface of exostome tooth also exist among these genera. Therefore, these features can look as accessorial features in separating different genera.Spores of 21 species of Bryaceae all have the katalept, but the shape of katalept are different in these species, the external ornamention of sporoderm exist in all 21 species, but the type and tiny structure of surface varied among these species. So this character is also ill-suited in dividing different genera. But it is a stability standard in separating some species.4. Gemmaes of 15 species of Bryaceae in North region of China have been observed under LM and SEM. The results indicate the difference is obvious and it can be look as a steady character in identifying specimens. There are different morphological characters in a different developmental stage, which bring out certain difficulty in systematic taxonomy.5. Based on the cladistic principles, Ditrichum pusillum as outgroup and 21 species of Bryaceae as the ingroup and the phylogenetic analysis is carried out. Maximum parsimony analyses (MP) and neighbour-joining analyses (NJ) are used to set up the phylogenetic trees. The results from two methods indicate the phylogenetic tree is divided into two parts. So we agree with Ochi in dividing Bryaceae into two subfamilies, but Anomobryum and Rhodobryum which are merged with Bryum are treated as separate genera here.6. Description, habitat and distribution are given to every species, key to subfamilys, genera and species of Bryaceae in North region of China are provided in the study.7. Based on the statistics of distribution of every species in areas of North region of China, the results show species of Brayceae are abundance in Shanxi, Henan, Hebei and Xinjiang.According to Chen and Wu, three areas of China and four other areas in the worldwide bryological regions are compared with each other using clustering method. The results reveal the bryological elements of North China region and Central China region are similar to Japan, the North temperate elements are dominant, Northeastern China region and Menggu-Xinjiang region are close to Europe, North America and Russia, the bryophyta are mainly Pan-arctic elements.更多还原