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1.
小柱芥属(Microstigma Trautv.)为十字花科(Brassicaceae)一寡种属,目前由于缺乏系统研究,存在属内物种划分不明确,地理分布不确定等问题.该文通过在甘肃、内蒙古的标本采集,以及GBIF的标本记载和相关文献的查阅,对小柱芥属植物的形态特征和地理分布进行了详细描述,确定了小柱芥属内的物种数目并编...  相似文献   

2.
In the course of monographic work in Myrtaceae it has become evident thatEugenia prismatica cannot be accommodated within any existing genus in the family. Therefore, a new genus,Curitiba, is described to contain it and the new combinationCuritiba prismatica is made.Curitiba is diagnosed by a combination of 4-angled hypanthia and fruits, ovules radiating from a central protruding placenta, and seed coats with wavy rows of papillae. A key is provided to distinguishCuritiba from the Caribbean and Mesoamerican genusMosiera, where the species also had been placed before this transfer, and from other 4-merous genera in Brazil of subtribe Myrtinae. In the Atlantic Forest of Brazil where the family Myrtaceae is one of the most species rich and ecologically important plant families, the discovery ofCuritiba reveals a unique evolutionary lineage, highlights the endemism present in the Atlantic Forest, and underscores, the urgent need for conservation of this rapidly disappearing and highly endangered biome.  相似文献   

3.
Bird species in the avian genus Pitohui contain potent neurotoxic alkaloids that may be used for defense. The genus comprises multiple species that are endemic to New Guinea and were presumed to belong to the family Pachycephalidae or Colluricinclidae, within the core corvoidea, an ancient Australasian radiation of crow-like birds. In order to understand the evolution of toxicity within the genus Pitohui, we sequenced three mitochondrial and two nuclear gene segments and reconstructed a phylogeny of the genus Pitohui and its putative relatives. We show that the genus Pitohui is polyphyletic, and consists of five different lineages. Using Bayesian ancestral state reconstruction, we estimate that toxicity likely evolved multiple times within this group. Furthermore, because the morphological and behavioral similarity among these poisonous birds appears to have evolved convergently, we hypothesize that this may be a possible example of Müllerian mimicry in birds. The Morningbird of Palau, Micronesia, that has often been included in the genus Pitohui, actually belongs in the genus Pachycephala and offers an intriguing case of pronounced evolution on a remote oceanic island.  相似文献   

4.
魏江春  姜玉梅 《菌物学报》1989,8(Z1):135-150
关于子囊菌亚门石耳科的属级分类问题地衣学家持有不同的观点。这些观点使属级分类出现了单属系统,二属系统,三属系统以及四属系统与五属系统。现在新二属系统,即石耳属一疱脐衣属系统已被越来越多的地衣学家和子囊菌学家所接受。但是,因为由Dodge (1968)描述的单种属拉诺属(Llanoa)的模式种与早已为人熟知的网脊石耳很相似,而近年来,这一单种属又被一些作者所接受、因此、我们不得不对该属模式种所依据的原始材料进行必要的复查。复查结果表明,拉诺属的模式种卖为网脊石耳的异名。因此,拉诺属也就成为石耳属的异名。此外,基于石耳科中三十五种地衣和五十二项特征的聚类分析结果也支持新的二属系统。  相似文献   

5.
Here we tested whether ‘insular woodiness’, a striking evolutionary pattern that commonly occurs on islands, has also appeared in QTP continental endemics. Parapteropyrum, a monotypic shrubby genus occurring in the central QTP, has been previously placed in the tribe Atraphaxideae of the family Polygonaceae, while all the other woody species of this tribe mainly occur in western and central Asia. We studied sequence variations of nuclear ITS (internal transcribed spacer) and cp (chloroplast) DNA (rbcL and accD) of this genus and the other ten genera. The constructed phylogenies based on ITS, cpDNA or a combination of both datasets, suggest that the woody Parapteropyrum is nested within and most likely evolved from the herbaceous Fagopyrum. We propose that the large-scale uplift of the QTP not only promoted continental species radiation, but also the secondary feature of woodiness in a few herbaceous lineages in response to strong selection pressures, similar to those acting on island flora. In addition, the confirmation of Parapteropyrum within Fagopyrum highlights its potential use as a new, perennial source of buckwheat.  相似文献   

6.
兰科石斛属植物菌根真菌研究进展   总被引:1,自引:0,他引:1  
石斛属(Dendrobium)隶属于兰科(Orchidaceae)树兰亚科(Epidendroideae)石斛兰族(Dendrobiinae),是兰科最大的属之一,终生附生于树上或岩石上。石斛属很多种类具有很高的药用价值与观赏价值。由于人为过度采挖和野生生境的破坏,使得野生石斛资源濒临灭绝。石斛属植物为典型的兰科菌根植物,在自然条件下需要与真菌共生,才能完成生活史。菌根真菌对于石斛属植物的种子萌发和植株生长具有重要的作用。对石斛属植物菌根的形成、菌根真菌的作用、菌根真菌多样性及菌根技术在石斛属植物中的应用做了评述,并对今后的研究内容和重点提出了一些思路。  相似文献   

7.
The Normapolles complex, characterised by its oblate and triaperturate pollen, constitutes an important and diverse element of many Late Cretaceous and Early Cainozoic floras of the Northern Hemisphere. Based on the dispersed pollen record alone it has been difficult to assess systematic affinities, but relationships with Fagales have been proposed. Over the past twenty years several exquisitely preserved Late Cretaceous reproductive structures with Normapolles type pollen in situ have been described. In this study we provide a summary and new information of these floral structures. Further, a new genus, Dahlgrenianthus, is described from the Late Cretaceous of southern Sweden. The genus includes the type species Dahlgrenianthus suecicus, a number of reproductive structures referred to Dahlgrenianthus sp., and Dahlgrenianthus trigonus (Knobloch et Mai) comb. nov. from the Maastrichtian flora of Walbeck, Germany. Dahlgrenianthus comprises small flowers with pentamerous perianth and androecium and a tricarpellate gynoecium. It is distinguished from all other Normapolles floral structures in its hypogynous floral organisation. All Normapolles floral structures described so far are thought to be related to various members of the core Fagales, but the group is obviously not monophyletic. The stratigraphic range of the Normapolles taxa and other fagalean fossils strongly suggests that all major fagalean lineages were present by the Cenomanian or earlier.  相似文献   

8.
9.
Rhodothermus marinus: physiology and molecular biology   总被引:2,自引:0,他引:2  
Rhodothermus marinus has been the subject of many studies in recent years. It is a thermohalophilic bacterium and is the only validly described species in the genus Rhodothermus. It is not closely related to other well-known thermophiles and is the only thermophile within the family Crenotrichaceae. R. marinus has been isolated from several similar but distantly located geothermal habitats, many of which are subject to large fluctuations in environmental conditions. This presumably affects the physiology of R. marinus. Many of its enzymes show optimum activity at temperatures considerably higher than 65°C, the optimum for growth, and some are active over a broad temperature range. Studies have found distinguishing components in the R. marinus electron transport chain as well as in its pool of intracellular solutes, which accumulate during osmotic stress. The species hosts both bacteriophages and plasmids and a functional intein has been isolated from its chromosome. Despite these interesting features and its unknown genetics, interest in R. marinus has been mostly stimulated by its thermostable enzymes, particularly polysaccharide hydrolysing enzymes and enzymes of DNA synthesis which may be useful in industry and in the laboratory. R. marinus has not been amenable to genetic analysis until recently when a system for gene transfer was established. Here, we review the current literature on R. marinus.  相似文献   

10.
董莉娜  刘演 《广西植物》2019,39(1):16-39
秋海棠属(Begonia L.)隶属于葫芦目(Cucurbitales)秋海棠科(Begoniaceae),有1 800余种,是世界第六大属,主要分布于美洲、非洲和亚洲的热带和亚热带地区,具有极高的观赏价值,亦可作为药用、食用、饮料和饲料等。我国有秋海棠属植物近300种,主要分布于我国的云南和广西等长江以南地区,其中云南有秋海棠属植物100余种。近年来,随着广西地区秋海棠属植物野外调查的不断深入,陆续发现并发表了大量秋海棠属新类群,使得广西产秋海棠属植物数目已超出1991年《广西植物志》(第一卷)收录的19种,因此亟需对发表于不同期刊中的类群进行系统地整理和汇总。鉴于此,该文通过查阅文献资料和考证标本信息,整理并汇总了广西产秋海棠属植物共84种,包括2个变种、11个亚种和46个特有种,新增的65种为《广西植物志》(第一卷)中未收录的类群,并补充了这些类群的特征集要、凭证标本信息和属下分组概况,为今后开展秋海棠属植物的分类修订以及系统学、进化生物学和保护生物学等研究提供了参考依据。  相似文献   

11.
Summary Translational genomics is defined as the application of molecular-genetic principles derived from model systems to species of experimental or economic interest. The past 20 years of research in plant model systems such as Arabidopsis thaliana have relinquished vast amounts of information regarding gene function, the integration of genetic components into pathways, and the interrelationships between pathways to control form and function in plants and plant-products alike. At present, the challenge is to relate these paradigms to other species of economic or scientific interest. Apart from being an important and valuable crop, strawberry (Fragaria spp.) is a member of the Rosaceae, a plant family containing fruit, nut, ornamental and wood-bearing species. Strawberry is unique within the Rosaceae in that it is a rapidly growing herbaceous perennial with a small genome and the ability to thrive in a laboratory setting. Strawberry species may also be transformed and regenerated in a time scale of weeks or months instead of years. For these reasons, strawberry has been recognized as the translational genomics model for the Rosaceae family. This review summarizes and synthesizes the technical reports of strawberry regeneration and transformation, consolidating the large body of information regarding genetic modification of this important genus.  相似文献   

12.
The genetic diversity of the genus Lespedeza is not well known and the phylogenetic relationship of Lespedeza with the genus Kummerowia is unclear. We report the first study in which polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers derived from Medicago, cowpea and soybean were used to assess the genetic diversity of the USDA Lespedeza germplasm collection and clarify its phylogenetic relationship with the genus Kummerowia. Phylogenetic analysis partitioned 44 Lespedeza accessions into three main groups some of which were species-specific and eight subgroups. This data set revealed some misidentified accessions, and indicated that the two species in the genus Kummerowia are closely related to the genus Lespedeza. Morphological reexamination was used to correct the misidentified accessions within the genus Lespedeza. Our results demonstrated that phylogenetic analysis with morphological reexamination provides a more complete approach to classify accessions in plant germplasm collection and conservation.  相似文献   

13.
Chromosome number ofSaruma henryi, the only species of the genus, was counted for the first time. The species has 2n=52 chromosomes, and its chromosomal complement is characteristically composed of very small chromosomes. Based on chromosome data available for the family, comparisons indicate an isolated position ofSaruma in Aristolochiaceae.  相似文献   

14.
The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.
  相似文献   

15.
The Okinawa woodpecker Sapheopipo noguchii is the rarest extant woodpecker species. The monotypic genus Sapheopipo was considered to be a representative of an old lineage of woodpeckers that led to the Eurasian genera Picus and the Blythipicus–Gecinulus species. This view, based on similarities in color patterns, external morphology and foraging behavior, has been adopted in all major accounts of the family. The alternative view, that this woodpecker may be related to the widespread white-backed woodpecker Dendrocopos leucotos, which evolved distinctive subspecies on other East Asian islands, has not been generally accepted. We analyzed partial sequences of the mitochondrial cytochrome b (cyt b) gene to test these hypotheses. The data suggest that the Okinawa woodpecker is a member of the genus Dendrocopos, with white-backed woodpecker and great spotted woodpecker D. major as close relatives. Color patterns support the genetic results and indicate a closer relationship with the white-backed woodpecker. Consequently, the correct taxonomic designation of the Okinawa woodpecker would be Dendrocopos noguchii (Seebohm in Ibis 5(5):173–182, 1887) in the tribe Campetherini rather than Picini.This revised version was published online in February 2005 with corrections to tables 1 and 2.  相似文献   

16.
The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.  相似文献   

17.
Three killer yeasts, isolated from the gut of insects in Panama and artisanal cheese in Brazil, were shown to be related to the Ovoides clade of the genus Trichosporon. Sequencing of the D1/D2 region of the LSU rDNA and physiological characterization revealed a distinct taxonomic position in relation to known species of the genus. Conspecificity of the three killer isolates was reinforced by similar M13 fingerprinting and killer profiles. We propose a new species in this genus: Trichosporon insectorum. The type strain is CBS 10422T (syn. NRRL Y-48120). This anamorphic species produces arthroconidia but not appressoria, and its killer character seems to be associated with dsRNA.  相似文献   

18.
We investigated three rare haptorid ciliates, viz., Lagynophrya gibba Kahl (1935), Enchelys lajacola nov. spec., and Spathidium implicatum Kahl (1930), using live observation, silver impregnation, morphometry, and scanning electron microscopy. Lagynophrya gibba, which was rediscovered in peatland soil from Iceland, is referred to a new genus, Kamburophrys, and a new family, Kamburophryidae, based on a unique organelle, the brush membranoid. This structure is near the dorsal brush and composed of very narrowly spaced cilia, about 5 μm long. The genus Kamburophrys has a unique combination of features, viz., an oral cone on the oral bulge, an oblique circumoral kinety, and a subapical hump carrying the three-rowed dorsal brush and the brush membranoid. The Kamburophryidae possibly belong to the order Spathidiida. Enchelys lajacola was discovered in mud from granitic rock-pools (Lajas) in Venezuela, South America. The new species is characterized by a bottle-like shape, a macronucleus with the shape of a curved strand, a heterostichad dorsal brush, and rod-shaped toxicysts. Spathidium implicatum, which was rediscovered in an ephemeral meadow puddle near Salzburg city centre, is neotypified and referred to the genus Apertospathula because it has an open circumoral kinety.  相似文献   

19.
The predatory mite Phytoseiulus macropilis is a potential biological control agent of the two-spotted spider mite (TSSM) Tetranychus urticae on strawberry plants. Its ability to control TSSM was recently assessed under laboratory conditions, but its ability to locate and control TSSM under greenhouse conditions has not been tested so far. We evaluated whether P. macropilis is able to control TSSM on strawberry plants and to locate strawberry plants infested with TSSM under greenhouse conditions. Additionally, we tested, in an olfactometer, whether odours play a role in prey-finding by P. macropilis. The predatory mite P. macropilis required about 20 days to achive reduction of the TSSM population on strawberry plants initially infested with 100 TSSM females per plant. TSSM-infested plants attract an average of 27.5 ± 1.0% of the predators recaptured per plant and uninfested plants attracted only 5.8 ± 1.0% per plant. The predatory mites were able to suppress TSSM populations on a single strawberry plant and were able to use odours from TSSM-infested strawberry plants to locate prey in both olfactometer and arena experiments. Hence, it is concluded that P. macropilis can locate and reduce TSSM population on strawberry plants under greenhouse conditions.  相似文献   

20.
冯慧喆  严克俭  黄云峰 《广西植物》2016,36(8):1014-1018
在第四次中药资源普查中采集了大量标本,经过对这些标本进行仔细鉴定并查阅相关资料,确定其中两号标本为香茜属(Carlemannia Benth.)和粘腺果属(Commicarpus Standl.)植物。这两属植物在广西尚无报道,为首次记录。香茜属植物叶对生,子房下位,无托叶,雄蕊仅有2枚,这和茜草科相似但又不同,系统位置较混乱,以前曾放于茜草科( Rubiaceae)和忍冬科( Caprifoliaceae)中,最近该属和蜘蛛花属独立成香茜科( Car-lemanniaceae)。该属植物共有3种,沿喜马拉雅山脉向东一直分布到缅甸、越南北部。我国西藏东南、云南南部、广西西北部分布一种即香茜( Carlenannia chinenesis Hook. f.)。粘腺果属是紫茉莉科( Nyctaginaceae)主产热带地区的1个属,全世界约25种分布于热带非洲和阿拉伯半岛南部,在南亚、东南亚和墨西哥至热带美洲也有少量分布。中国产2种,其中广西产1种即中华粘腺果[ Commiaicarpus chinensis ( L.) Heim.]。该种植物分布广泛,从南亚次大陆向东至中南半岛、马来半岛,向北到我国西沙群岛、海南岛以及广州附近,在广西首次记录,产凤山县和凌云县。  相似文献   

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