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1.
Asian origin for Polystichum (Dryopteridaceae) based on rbcL sequences   总被引:8,自引:2,他引:6  
Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (s.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relationships within the genus. On the basis of estimated evolution rate of rbcL gene and the genetic distance data that passed relative-rate tests, we further estimated the divergence times between some clades of the genus. The phylogenetic relationships were inferred using the neighbor-joining and maximum-parsimony methods, both methods producing trees with completely congruent topology. These trees reveal that all species of Polystichum s.l. in this study (including Cyrtomium and Cyrtomidictyum) form a monophyletic group. The basal split in Polystichum s.l. separates a clade with all Asian members from a clade containing other species from all over the world. The phylogenetic and divergence time estimation results lead us to suggest that Polystichum s.l. originated in Asia in the late Late Cretacous (≈76 Ma) and migrated into other places in the world in early Eocene(≈46 Ma).  相似文献   

2.
An aquatic fern leaf, Flabellariopteris mii Sun gen. et sp. nov. from the Late Triassic of Western Liaoning, China, is described and proposed as the type species of the new morphortaxon of the Marsileaceae. The fossil leaves are preserved as impression. No fertile and rhizomatic materials are found. The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement. The petiole is slender. The leaflet is fan-shaped or semi-circular, and commonly divided into four wedge-shaped lobes. Terminal margin of lobes is usually incised, incisions shallow or deep, with bluntly rounded or notched apex. The veins are conspicu- ously dichotomous, but anastomoses and marginal vein are absent. The unique morphological features, including two- parted thin leaflets, size, shape, veins and slender petiole, indicate that the present specimen represents an aquatic fern, which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.  相似文献   

3.
We present a 550-year ice-core pollen record with a 5-year resolution from the Puruogangri ice field in the central Tibetan Plateau.Analysis of the relationship between pollen record and instrumental observations suggests that the sum of the steppe and meadow pollen taxa is a good indicator of summer (June-August) temperature,whereas the ratios of Cyperaceae/(Gramineae+Artemisia) [Cy/(G+A)] as well as M/S (meadow to steppe percentages) are indicative of humidity changes in this region.Together with δ18O and...  相似文献   

4.
The phylogenetic relationships within the genus Takifugu Abe, 1949 (Tetraodontiformes, Tetraodonti- dae) remain unresolved. Because of the use of Takifugu as model organisms, the resolution of these relationships is crucial for the interpretation of evolutionary trends in biology. Pufferfishes of this ge- nus are comprised of a comparatively small number of species and are mainly distributed along the coastal region of the western part of the Sea of Japan and the coastline of China. Mitochondrial gene sequences were employed to test the phylogenetic hypotheses within the genus. Seventeen species of the genus were examined. Molecular phylogenetic trees were constructed using the maximum parsi- mony, neighbor-joining, maximum likelihood and Bayesian methods. Our hypothesis of internal relationships within the genus differs from previous hypotheses. Our results indicate that (1) the genus Takifugu is a monophyletic assemblage; (2) the genus is divided into 6 subgroups based on the mo- lecular data; and (3) there is low genetic diversity among the species within this genus. In addition, speciation within Takifugu appears to be driven by hybridization and isolation by distribution. Our re- sults also suggested that the taxonomy in the genus should be clarified based on both molecular and morphological data.  相似文献   

5.
This study addressed three important aims:(1) undermining the previously obtained raw data about wood-decaying fungi(WDF) distribution and continuously investigating permanent plots to address certain scientific questions in ecology,(2) resolving the higher-level phylogeny of WDF with the help of multiple loci,and(3) testing and estimating the medicinal values of species that are closely related to well-known medicinal species.More than 1200 species and 2469 strains of WDF in China were identified from 28908 specimens collected from a series of field investigations.Using these materials,studies in multiple disciplines,such as ecology,taxonomy and phylogeny,and medicine,have been performed.With respect to ecology,the diversity of wood-decaying polypores significantly differed among a boreal forest zone,a temperate and warm temperate forest zone,and a tropical and subtropical forest zone.For instance,from north to south,the number and proportion of brown-rot species and the proportion of species found on fallen trunks were both decreased.The ecological patterns of wood-decaying polypores on gymnosperm and angiosperm trees were also explored by a case study in Northeast China.Although the total species richness was similar between the two tree groups,several other characteristics were significantly different,such as community structure and richness in certain substrates.The taxonomy and phylogeny of wide samples were referred to and their phylogenetic positions were resolved or at least partially established.In particular,phylogenetic knowledge about four genera,Fomitiporia,Ganoderma,Inonotus and Perenniporia,which include medicinal species,was essential for further research to determine the medicinal values of these types of fungi.Among these medicinal species,we mainly focused on Inonotus obliquus for its medicinal purposes.Polyphenols,polysaccharides and lanostane-type triterpenoids,extracted from the sterile conk of this species,could dramatically decrease levels of free radicals,DPPH and hydroxyl radicals,respectively.The metabolic profiles(both production and composition) of cultured I.obliquus mycelia could be altered by co-culture with other medicinal species or by induction of S-nitrosylation and denitrosylation,which may enhance the antioxidant capacity of I.obliquus.  相似文献   

6.
Phylogenetic relationship within the Lentinula genus is constructed based on the sequenced ITS fragments of the 60 Chinese wild L. edodes isolates and the sequence data of 48 isolates of different species from other districts downloaded from the GenBank. The 108 isolates of Lentinula genus are divided into two branches and seven groups, one branch and two groups in the New World, and the other branch and five groups in the Old World, and the isolates clustering of different groups corresponds obviously with the classification of the morphological species. Asian isolates are partitioned in group Ⅰ and Ⅴ, two of the five groups of the Old World, by which the germplasm resources status represented is of great importance shown by the phylogenetic analysis. Group Ⅴ which fills up the blank of geographic distribution has become one of the mainstream groups with an increased isolate number, while group Ⅰ has a tendency to dissimilate into two subgroups (Ia and Ib) with a huge isolate quantity and a coverage of most tested districts, suggesting that China (or Asia) is an important genetic diversity center of the natural population of Lentinula genus. Genetic analysis of Asian isolates based on groups Ia, Ib and group Ⅴ indicates that the diversity of the east coastal-land, northwestern highland and southwestern China and Himalayas districts is the most plentiful, which is the three priorities in diversity protection of Asian Lentinula population.  相似文献   

7.
A new genus and three new species of fossil Palaeontinidae, Papilioncossus conchatus sp. nov., P. giganteus sp. nov. and P. pteroideus sp. nov., are described. All of them were collected from Middle Jurassic Jiulongshan Formation in Inner Mongolia, China. Based on distal part of forewing broader and longer than basal and Sc usually with branches, the new taxa are attributed to Palaeontinidae of Homoptera and compared with genus Pseudocossus. A key to species of Papilioncossus gen. nov. is provided. All type specimens are deposited in the Capital Normal University.  相似文献   

8.
The pollen of 57 species representing 7 sections of Artemisia was examined hy light microscope and scanning microscope for the purpose to elucidate the systematic relationships of the genus. The examination indicates that the pollen grains present high concordance which is characterized by the globular or the appruximate shape. 3-lobed circular from polar view while granular or ellipse sphere from tropical plate with tricolporate structure. The exinc of pollen has an obvious double structure of inner and outer layers (including the tecturn and columnar layers) where the outer is thicker than the inner and the sculpture of exine degenerates into small spinules easily distinguishable from other genera of the Compositae. Based on cxine sculpture, the pollen grains of Artemisia can be divided into two types: Myriantha type and Mongolica type, which possesses 4 subtypes according to the distribution forms of spinulc: (1) Sacrorum subtype, (2) Oligocarpa subtype, (3) Lavandulaefolia subtype. (4) Anomale subtype.  相似文献   

9.
The present paper dea1s with two new species of the genus Amoebotaenia(Dilepididae)cestodes collected from Scolopax rusticola in Fujian,China.Holotype andparatype are deposited in Parasitology Researoh Laboratory,Xiamen University.  相似文献   

10.
A new genus and three new species of fossil Palaeontinidae, Papilioncossus conchatus sp. nov., P. giganteus sp. nov. and P. pteroideus sp. nov., are described. All of them were collected from Middle Jurassic Jiulongshan Formation in Inner Mongolia, China. Based on distal part of forewing broader and longer than basal and Sc usually with branches, the new taxa are attributed to Palaeontinidae of Homoptera and compared with genus Pseudocossus. A key to species of Papilioncossus gen. nov. is provided. All type specimens are deposited in the Capital Normal University.  相似文献   

11.
八种蒿属植物石油醚提取物中萜类成分分析   总被引:3,自引:0,他引:3  
以气相色谱-质谱计算机联用分析了蒙古蒿、矮蒿、毛莲蒿(蒿亚属)以及牛尾蒿无毛变种、牛尾蒿原变种、猪毛蒿、南牡蒿及华北米蒿(龙蒿亚属)石油醚提取物中的萜类成分,共鉴定出123种萜类化合物,其中单萜57种,倍半萜66种。从萜类化合物结构来看,这八种蒿属植物石油醚提取物中,双环萜(单萜,倍半萜)结构类型比较相似。三种蒿亚属植物的石油醚提取物中含有多种链状单萜,而三环萜类(倍半萜)仅有5种类型;五种龙蒿亚属植物的石油醚提取物中链状单萜类型单调,而三环萜类(主要是倍半萜)达11种类型之多。这在一定程度上反映出龙蒿亚属植物化学系统比蒿属植物化学系统进化  相似文献   

12.
蒿属叶绿体DNA trnL-F的序列分析与系统发育的意义   总被引:1,自引:0,他引:1  
对蒿属Artemisia Linn.两个亚属5个组38个种进行了trnL-F序列的分析,同时选取了紊蒿Elachanthemum intricatum作为外类群.结果表明,蒿属的trnL-F序列长度为786~799 bp,GC含量为34.79%~35.94%.组间变异小,38个种共有62个变异位点,18个信息位点.根据形态学划分的蒿亚属和龙蒿亚属没有得到很好的分辨,但艾组多数种具有6bp"TACATA"的缺失和三个位点组内多数种的共同变异,使得该组具有较明显的分化.总的来说,trnL-F序列在蒿属植物间有着高度的一致性,讨论系统发育时具有一定的局限性.  相似文献   

13.
贵州普安特有植物四球茶Camellia tetracocca Chang的初步研究   总被引:2,自引:0,他引:2  
山茶科Theaeeae之山茶属Camellia L.是一个热带亚洲分布的植物,其中包括世界著名的饮料——茶,重要油料——茶油,常见观赏花卉——茶花等经济价值植物,该属是珍稀濒危植物较为集中的一个属,历来是植物学研究的焦点。而四球茶是山茶属茶亚属Subgen.Thea茶组Sect.Thea五室茶系Ser.Quiquelocularis中的一种,为贵州特有种,仅产于贵州普安普白,是产地重要饮料植物。本文在详实野外考察的基础上,对四球茶的分类学特征、地理分布状况、生境条件及生长状况、种群的更新现状进行了综合的论述和分析,并对前人的论述做了相应的补充,提出了一些自己的见解和对其开发应用方面进行了展望,以期为今后进一步的研究和开发提供一定的科学参考。  相似文献   

14.
15.
<正>本文研究了楤木属的特征,讨论了楤木属的地理分布以及与相近属的关系。作者通过对国产楤属植物大量标本的整理鉴定,根据楤木属草本与木本两大类群在形态上所存在的明显差别,建立了两个新亚属和四个新组,并编制了该属形态检索表。文内还对六个种名进行了订正。  相似文献   

16.
野兔的种间形态差异小,属于分类学中的一个难区分类群。某些种类,如草兔,分布区域很广,地跨欧、亚、非三洲大陆,由于区域性的差异,在同一种中显示了很大的形态差异。因此,中国野兔的初级分类也没有多大进展。笔者在解决了种别鉴定的基础上,对中国野兔的亚属进行了校订。中国野兔仅兔属一个属。本文列出了中国野兔5个亚属:兔亚属、原真兔亚属、塔里木兔亚属、印度兔亚属和真兔亚属,澄清了过去的混淆。  相似文献   

17.
对中国双距拟天牛属Diplectrus Kirsch,1866进行了分类整理,给出已知种检索表,描述1新种:二斑双距拟天牛D.bistigmaeus sp.nov.(中国:西藏)和1中国新纪录种:栗色双距拟天牛D.casta-neicollisvihla,1999.模式标本保存于河北大学博物馆.  相似文献   

18.
本文对中国地杨梅属植物进行了研究,记载了3个亚属,4个组,2个系,16种和1亚种,3变种,其中有5个新种和1新变种.同时还简述了本属植物的地理分布.  相似文献   

19.
透射电镜下观察了红豆杉科、三尖杉科和罗汉松科11种裸子植物筛分子质体的超微结构,测量了筛分子质体的大小及其内含物的平均直径和数目.它们的筛分子质体均属S-型,同属植物所含淀粉粒的形态特征相同.红豆杉科内红豆杉属和穗花杉属的特征相近,白豆杉属和榧树属更为接近.三尖杉科(属)的篦子三尖杉筛分子质体的大小、所含淀粉粒的数目和其余植物差异明显,支持成立篦子三尖杉组.筛分子质体超微结构的观察结果还显示罗汉松科较三尖杉科、红豆杉科更为原始,竹柏组应保留在罗汉松科内.  相似文献   

20.
本文对中国地杨梅属植物进行了研究,记载了3个亚属,4个组,2个系,16种和1亚种,3变种,其中有5个新种和1新变种。同时还简述了本属植物的地理分布。  相似文献   

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