基于核核糖体DNA ITS序列的真藓科系统发育新证据

主要是利用核基因组的核糖体DNA内转录间隔区（nrDNA ITS）序列数据探讨了Buck和Goffinet（2000）限定的真藓科内各属间及属内种间的系统发育关系。ITS序列的最大简约法（MP）及贝叶斯推论（BI）分析结果显示：不支持Cox（1999）利用rps4/trnL-trnF数据分析将丝瓜藓属移至提灯藓科的结论。ITS数据分析与Holyoak（2007）利用trnL-F,trnG和atpB-rbcL序列数据分析将Bryum algovicum、B.caespiticium、B.capillare、B.pseudotriquetrum和Plagiobryum zierii划归Ptychostomum的结论一致,同时,为Spence(2005)依据形态学特征将B.pallescen、B.pallens、B.uliginosum、B.amblyodon和B.lonchocaulon划归Ptychostomum提供ITS分子证据支持。基于以上研究,建议将以上提到的真藓属种和平蒴藓移至Ptychostomum。     

新疆曲尾藓属10种植物蒴齿和孢子的形态观察

该研究通过光学显微镜(LM)和扫描电镜(SEM)观察了曲尾藓属(Dicranum Hedw.)10种植物的蒴齿和孢子的形态特征。结果表明:(1)曲尾藓属10种植物的孢蒴均为圆柱形。(2)孢子球形、近球形、椭圆形或三角状卵形,颜色为黄色、棕色或黄褐色;近极面向内凹,纹饰为疣状、颗粒状或芽孢状。(3)曲尾藓属10种植物的蒴齿多为披针形,但也有阔披针形,颜色为杏黄色、深红色、褐黄色或红褐色;纹饰为条状或疣状,具穿孔成网状结构,一些种无穿孔成平滑结构,表面具细疣。该研究结果为曲尾藓属属下类群划分提供了分类依据,并为苔藓植物系统分类、演化研究提供基础资料。     

Phylogenomic delineation of Physcomitrium (Bryophyta: Funariaceae) based on targeted sequencing of nuclear exons and their flanking regions rejects the retention of Physcomitrella,Physcomitridium and Aphanorrhegma

Selection on spore dispersal mechanisms in mosses is thought to shape the transformation of the sporophyte. The majority of extant mosses develop a sporangium that dehisces through the loss of an operculum, and regulates spore release through the movement of articulate teeth, the peristome, lining the capsule mouth. Such complexity was acquired by the Mesozoic Era, but was lost in some groups during subsequent diversification events, challenging the resolution of the affinities for taxa with reduced architectures. The Funariaceae are a cosmopolitan and diverse lineage of mostly annual mosses, and exhibit variable sporophyte complexities, spanning from long, exerted, operculate capsules with two rings of well‐developed teeth, to capsules immersed among maternal leaves, lacking a differentiated line of dehiscence (i.e., inoperculate) and without peristomes. The family underwent a rapid diversification, and the relationships of taxa with reduced sporophytes remain ambiguous. Here, we infer the relationships of five taxa with highly reduced sporophytes based on 648 nuclear loci (exons complemented by their flanking regions), based on inferences from concatenated data and concordance analysis of single gene trees. Physcomitrellopsis is resolved as nested within one clade of Entosthodon. Physcomitrella s. l., is resolved as a polyphyletic assemblage and, along with its putative relative Aphanorrhegma, nested within Physcomitrium. We propose a new monophyletic delineation of Physcomitrium, which accommodates species of Physcomitrella and Aphanorrhegma. The monophyly of Physcomitrium s. l. is supported by a small plurality of exons, but a majority of trees inferred from exons and their adjacent non‐coding regions.     

Phylogenetic relationships between Bryum and supposedly closely related genera

Abstract

The phylogeny of the genus Bryum was studied using cladistic analyses under the maximum parsimony criterion of evolution of anatomical and morphological characters. Three analyses were made with 32 Bryum species plus 20 species from genera supposedly closely related to Bryum, and with Amblyodon dealbatus (Sw. ex Hedw.) Bruch & Schimp., Meesia uliginosa Hedw., and Leptostomum macrocarpum (Hedw.) Bach. Pyl., as outgroups. It is here suggested that under earlier systematic concepts the genus Bryum is paraphyletic. A clade with Bryum billarderi Schwägr., B. capillare Hedw., B. donianum Grev., B. russulum Broth. & Geh., Rhodobryum giganteum (Schwägr.) Paris, and R. keniae (Müll. Hal.) Broth. are circumscribed by spathulate stem leaves that are crowded in the stem apex, suggesting that the rosulate species of Bryum are more closely related to Rhodobryum than to the rest of Bryum. Stem leaf costae without stereids and spores that mature in the winter are synapomorphies for a clade with Anomobryum julaceum (P. Gaertn. et al.) Schimp. and Bryum argenteum (Hedw.). The tropical species B. cellulare Hook. and B. flaccum Wilson ex Mitt. appear in a clade with Plagiobryum zieri (Dicks. ex Hedw.) Lindb. and Synthetodontium pringlei Cardot. In one analysis, B. limbatum Müll. Hal., Epipterygium tozeri (Grev.) Lindb., Leptobryum pyriforme (Hedw.) Wilson, and Roellia roellii (Broth. ex Röll) H.A. Crum came out in a clade with Mniobryum atropurpureum (Wahlenb.) I. Hagen, Mnium hornum Hedw., Pohlia cruda (Hedw.) Lindb., P. longicollis (Hedw.) Lindb., and Pseudopohlia didymodontia (Mitt.) A.L.Andrews. It is here suggested that gametophytic features, such as the orientation and anatomy of the stem leaves and the appearance of vegetative propagules, are important for the internal relationships within the studied ingroup, whereas characters related to the sporophyte, especially those of the peristome, may obscure phylogenetic relationships. Most of the subgenera and the sections of Bryum, as defined by earlier authors, appear to be paraphyletic. However, due to the low stability of most clades it is suggested that analyses including anatomical, morphological, and molecular data are needed.     

PERISTOME DEVELOPMENT IN MOSSES IN RELATION TO SYSTEMATICS AND EVOLUTION. II. TETRAPHIS PELLUCIDA (TETRAPHIDACEAE)

The Tetraphidae is a small subclass of mosses with a nematodontous peristome that has frequently been interpreted as primitive among the true mosses. The developmental cell sequence leading to the formation of the four peristome teeth of Tetraphis pellucida is described for the first time. Comparisons are made with sequences known for other nematodontous and arthrodontous mosses. Peristome development in T. pellucida is more like that described previously for arthrodontous peristomes than to published developmental sequences for nematodontous peristomes of species in the Polytrichaceae. On the other hand, our observations confirm a basic uniformity of the earliest developmental stages in all mosses studied thus far, regardless of their systematic position.     

Structure of Adnate Colony Portions in Crisiidae (Bryozoa Cyclostomata)

The “rhizoidsrdquo; surrounding the base of the erect “colony” emanating from the ancestrula in the Crisiidae, especially the simple species Crisidia cornuta (L.), are a regular adnate system of autozooids. Each autozooid is composed of a proximal adnate part and a distal peristome (in some species kenozooids are possibly intercalated). The autozooid peristomes support erect branches identical in budding and structure with the branch emanating from the erect peristome of the ancestrula. Thus, the complete crisiid colony consists of an adnate system of ancestrula and autozooids, which form erect branches from their peristomes. The adnate zooid system is comparable in autozooid morphology and budding pattern with simple uniserial stomatoporids. The tentative hypothesis is proposed that the crisiid group has developed from primitive stomatoporids; the adnate zooid system of the stomatoporids apparently evolved peristomial budding to produce the erect colony branches characteristic of crisiids.     

Lewinskya transcaucasica (Orthotrichaceae,Bryopsida) sp. nov. A contribution to the bryophyte flora of Georgia

A new orthotrichaceous species, Lewinskya transcaucasica Eckstein, Garilleti & F.Lara, is described, based on several samples collected in the Georgian territories of Greater Caucasus and Lesser Caucasus. The species is best differentiated by its sporophytic characteristics. Its capsules are long ovoid to cup-shaped and smooth and show no differentiation of the longitudinal bands of the exothecial cells. The capsules vary from emerging fully from the perichaetial leaves to having a shortly exserted position. The peristome is double, with an exostome of eight pairs of orange to crimson teeth whose tips are variably cancellated and fenestrated and recurved when dry, and an endostome of eight segments that occasionally alternate with reduced intermediate segments. All of these segments are yellowish to pale orange, mainly linear, uniseriate or partially biseriate, and strongly ornamented on the inner side. The new moss is illustrated and compared with similar taxa around the world.     

Phylogenetic inference and peristome evolution in haplolepideous mosses,focusing on Pseudoditrichaceae and Ditrichaceae s. l.

Pseudoditrichum mirabile, the only species of Pseudoditrichaceae, has been known for a long time from a single collection from the Canadian Arctic. Its systematic position remained enigmatic due to similarity in gametophyte structure with Ditrichaceae, a family that has simple peristomes, whereas the peristome in Pseudoditrichum is double. Due to this difference, Pseudoditrichum was classified in either Funariales or Bryales. A recent discovery of this species in the Anabar Plateau in northern Siberia has allowed its phylogenetic position to be tested based on plastid rps4 and rbcL and mitochondrial nad5 sequences. The results of this research reject the earlier hypotheses. Instead, the molecular analysis resolves Pseudoditrichum in a clade with Chrysoblastella chilensis (formerly Ditrichaceae) in the haplolepideous lineage. The peristome of Pseudoditrichum is of a previously unknown type with a fully developed exostome and hyaline endostome elements opposite the exostome teeth, based not on the 4:2:4 peristomial formula, but on 4:2:3. Double peristomes of the same type, albeit rather strongly reduced, occur in Catoscopium, Chrysoblastella, Distichium and Ditrichum flexicaule. The polyphyly of Ditrichaceae is confirmed by molecular phylogenetic analysis, and Ditrichum flexicaule and D. gracile are segregated into the new genus Flexitrichum and family Flexitrichaceae. An independent status of the recently resurrected family Distichiaceae is supported, and segregation of Chrysoblastella and Saelania into new monospecific families is proposed.     

真藓属（Bryum Hedw.）蒴齿形态特征及其分类学意义

通过光学显微镜和扫描电子显微镜观察了中国产真藓属（Bryum Hedw.）12种植物蒴齿的形态特征。结果显示,根据真藓属齿片的曲向可以分为近直立、齿片伸入齿条间和齿片向外反曲等3种类型。根据齿毛的有无,也可分为3个类群。同时利用STATISTICA 6.0统计软件对12种真藓属植物进行聚类分析及主成分分析。研究结果显示,齿片的曲向类型、齿毛是否发育等形态特征可作为真藓属植物种间的分类依据,为藓类植物蒴齿形态特征与分类和系统进化关系的研究提供了新的资料。     

The male gametophores of Leucobryum glaucum (Hedw.) Ångstr. and L. juniperoideum (Brid.) C. Muell. in two Welsh woodlands

Abstract

The distribution and variation in size of male gametophores associated with fertile, female cushions of Leucobryum glaucum and L. juniperoideum in two Welsh localities are described. Both dwarf and larger males were present in fruiting cushions of both species; no independent male plants were found. It is suggested that the scarcity of functional males might be a factor limiting sporophyte production in these species.     

An electron microscopical study of the genus Tortula Hedw., with special reference to exine ornamentation

Abstract

Spores of ten North European species of the genus Tortula Hedw. were studied in the transmission electron microscope. In all the sporoderm was more or less covered with finely papillate processes of several different types which divide the genus into a number of groups different from the previously suggested sections. The ornamentation of leaves, peristomes, and spores of T. norvegica (Web. f.) Wahlenb. has been studied in the scanning electron microscope. The leaf papillae are not c-shaped as suggested in the literature, but branched in a rather complex way. The borders of the basal membrane cells of the peristome appeared to be a continuation of the filamentous portion of the teeth. A comparison with T. ruralis (Hedw.) Gaertn., Meyer & Scherb. revealed the ornamentation to be of the same basic type in the two species.     

16种丛藓科（Pottiaceae）植物蒴齿形态特征及其系统学意义

通过扫描电镜（SEM）观察了16种国产丛藓科（Pottiaceae）植物蒴齿的形态特征,结果表明：丛藓科植物的蒴齿为单齿类,齿条1~3回左旋或直立,多具基膜,并密被疣,这些共同特征说明了丛藓科植物蒴齿具有一定的相似性;但在齿条形状和旋转情况及基膜特征等方面又有区别,明显分为3种类型,显示了不同属、种间的遗传分化。最后,本文还讨论了蒴齿特征与干旱环境的适应。     

Bryobrittonia longipes,an earlier name for B. pellucida (Encalyptaceae,Musci)

Bryobrittonia pellucida was described by Williams in 1901 from a sterile specimen. He suggested a relationship with some members of the Pottiaceae. In 1953, Steere described the sporophyte ofB. pellucida and placed it in the Encalyptaceae. The type ofEncalypta longipes Mitten (1865), a fruiting specimen collected by Drummond in western Canada, is what is presently known asB. pellucida; therefore, the new combination,B. longipes, is made. The distinctive morphological and ecological features of the genusBryobrittonia are described in relation to those of the genusEncalypta. On the basis of both sporophytic and gametophytic characteristics,E. streptocarpa andE. procera are the species most closely related toB. longipes.     

帕米尔木灵藓和细齿木灵藓（木灵藓科）的形态特征及其在中国的新分布

该文报道了采自新疆的木灵藓属中国2个新记录种——帕米尔木灵藓(Orthotrichum pamiricum)和细齿木灵藓(O.scanicum)。帕米尔木灵藓的识别特征为:叶尖钝,气孔隐型,多着生于孢蒴下部,外齿层齿片8对,干燥时蒴齿背曲,内齿层蒴条16,上部内曲;细齿木灵藓的识别特征为:叶尖部具细齿,气孔半隐型,蒴帽具分散的透明毛,内齿层和外齿层均16片,具8条黄色细沟,干燥时中部以上具沟。对这2种藓类的形态特征、生境和地理分布及与其相似种的形态学进行了比较分析,并绘制了每种的形态结构墨线图。木灵藓属植物在中国的新分布记录进一步表明,新疆地区富含生物多样性,并与中亚植物区系存在密切关系。     

C3 photosynthesis in the gametophyte of the epiphytic CAM fern Pyrrosia longifolia (Polypodiaceae)

Sporophytes of some epiphytic species in the fern genus Pyrrosia exhibit Crassulacean acid metabolism (CAM), generally considered to be a derived physiological response to xeric habitats. Because these species alternate between independent sporophytic and gametophytic generations yet only the sporophyte has been characterized physiologically, experiments were conducted to determine the photosynthetic pathways present in mature sporophytes, immature sporophytes, and gametophytes of Pyrrosia longifolia. Diurnal CO₂ exchange and malic acid fluctuations demonstrated that although the mature sporophytes exhibited CAM, only C₃ photosynthesis occurred in the gametophytes and young sporophytes. Consideration of the above results and those from previous studies, as well as the life cycle of ferns, indicates that the induction of CAM probably occurs at a certain developmental stage of the sporophyte and/or following exposure to stress. Elucidation of the precise mechanisms underlying this C₃-CAM transition awaits further research.     

A review of Cheilothela (Ditrichaceae)

Cheilothela Lindb. is recognized as a monotypic genus forC. chloropus (Brid.) Lindb. The South American and New Zealand taxa are considered to be synonymous and placed in the resurrectedChrysoblastella Williams asC. chilensis (Mont.) Reim.Chrysoblastella is segregated fromCheilothela on the basis of numerous sporophytic characters as well as their phytogeography.Cheilothela longirostre Fleisch., from Java, is misplaced in either genus and a new genus,Strombulidens, is erected to accommodate it.Strombulidens is considered most closely related toWilsoniella on the basis of their unique peristomes.     

The relationship between Mittenia plumula (Mitt.) Lindb. and Schistostega pennata (Hedw.) Web. & Mohr

Abstract

In spite of the absence of a peristome in Schistostega, developmental studies show that the internal structure of the capsule has considerable similarity and presents no strong barriers to a relationship with Mittenia. This is strongly supported by the protonema and many features of the gametophore and sporophyte. Therefore it is suggested that the Mitteniaceae be transferred from the Bryales to the Schistostegales.     

Costs of sporophyte production in the moss,Dicranum polysetum

We investigated the cost of sporophyte production in the moss Dicranum polysetum both by examining patterns of growth and reproduction in unmanipulated shoots and by experimentally manipulating sexual reproduction.The estimated proportion of total carbon investment allocated to sexual reproduction in sporophyte-producing shoots over the study period was 74.8%. Unmanipulated shoots that aborted all sporophytes had a significantly higher growth in the top shoots than shoots that produced sporophytes. In sporophyte-producing shoots, total apical growth decreased proportionately with the number of sporophytes.Experimental prevention of sporophyte development resulted in significantly higher total apical growth of the gametophytes. Shoots where current perichaetia were lacking when marked had a mass increase in the top shoots similar to manipulated sporophytic shoots whereas sporophytic control shoots grew significantly less than these two categories.The difference between control shoots and manipulated shoots in the mass of vegetative apical growth was mainly because of different length increments whereas mass per unit length was similar between groups. The probability to reproduce sexually in the year after the manipulation, and the biomass allocated to this reproduction, were not affected by the experimental treatment.