首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Seed morphology of Abelmoschus is known to be variable, but patterns of variation have never been critically studied. We studied seed macro‐ and micro‐morphological characters, including seed shape/size, seed coat pattern and trichome density/structure in multiple samples to evaluate the taxonomic significance of seed characters. Among the studied characters, seed shape and trichome structure were found to have major taxonomic importance and proved to be valuable characters for separating taxa. Two main seed types were present: seeds with deciduous trichomes and seeds with persistent trichomes. These characters offer significant evidence to the distinctness of certain species (A. esculentus, A. moschatus subsp. moschatus, A. moschatus subsp. tuberosus, A. crinitus and A. angulosus). Further, our results indicate that A. moschatus subsp. tuberosus should be maintained as a separate subspecies while A. manihot subsp. tetraphyllus var. pungens may be merged in A. angulosus. No significant intraspecific variation was observed, except in A. esculentus. We conclude that seed coat sculpturing and seed trichomes do indeed provide stable and diagnostic characters for many morphologically closely related taxa of Abelmoschus and that LM/SEM techniques can be useful in solving systematic problems and management of Abelmoschus genetic resources.  相似文献   

2.
3.
4.
High‐resolution deformation measurements in a functionally graded hard tissue such as human dentin are essential to understand the unbound water‐loss mediated changes and their role in its mechanical integrity. Yet a whole‐field, 3‐dimensional (3D) measurement and characterization of fully hydrated dentin in both macro‐ and micro‐scales remain to be a challenge. This study was conducted in 2 stages. In stage‐1, a stereo‐digital image correlation approach was utilized to determine the water‐loss and load‐induced 3D deformations of teeth in a sagittal section over consecutively acquired frames, from a fully hydrated state to nonhydrated conditions for a period up to 2 hours. The macroscale analysis revealed concentrated residual deformations at the dentin‐enamel‐junction and the apical regions of root in the direction perpendicular to the dentinal tubules. Significant difference in the localized deformation characteristics was observed between the inner and outer aspects of the root dentin. During quasi‐static loadings, further increase in the residual deformation was observed in the dentin. In stage‐2, dentin microstructural variations induced by dynamic water‐loss were assessed with environmental scanning electron microscopy and atomic force microscopy (AFM), showing that the dynamic water‐loss induced distention of dentinal tubules with concave tubular edges, and concurrent contraction of intertubular dentin with convex profile. The findings from the current macro‐ and micro‐scale analysis provided insight on the free‐water‐loss induced regional deformations and ultrastructural changes in human dentin.   相似文献   

5.
Evidence from morphology and anatomy (including embryology), as well as from palynology, chemistry and cytology, indicates thatHydrastis is quite divergent from Ranunculaceae (in which the genus has been most often included) as well as from both Glaucidiaceae and Berberidaceae. Distinctive features ofHydrastis, which demarcate it from Ranunculaceae but which are sometimes shared by Berberidaceae, are: the unique mode of origin of the vascular supply to stamens and carpels; the micropyle being formed by both integuments; the xylem not V-shaped in cross section; scalariform vessel perforations present; haploid chromosome number 13; pollen tectum consisting of a compound layer of striae; leaf mesophyll not differentiated; the unique course of stem medullary bundles; D-galactose present. Its distinctive higher haploid chromosome number, as well as its many less-specialized character states (in floral structure, leaf anatomy, and xylem and vessel morphology), suggest thatHydrastis is a relictual primitive group which diverged early from a common ancestral stock of Ranunculaceae, Berberidaceae and probably of Circaeasteraceae; at least some of the features shared byHydrastis and one or another of the families concerned seem to be a heritage from their common ancestor. We propose a reestablishment of a monotypic family, Hydrastidaceae.  相似文献   

6.
Understanding the genetics of biological diversification across micro‐ and macro‐evolutionary time scales is a vibrant field of research for molecular ecologists as rapid advances in sequencing technologies promise to overcome former limitations. In palms, an emblematic, economically and ecologically important plant family with high diversity in the tropics, studies of diversification at the population and species levels are still hampered by a lack of genomic markers suitable for the genotyping of large numbers of recently diverged taxa. To fill this gap, we used a whole genome sequencing approach to develop target sequencing for molecular markers in 4,184 genome regions, including 4,051 genes and 133 non‐genic putatively neutral regions. These markers were chosen to cover a wide range of evolutionary rates allowing future studies at the family, genus, species and population levels. Special emphasis was given to the avoidance of copy number variation during marker selection. In addition, a set of 149 well‐known sequence regions previously used as phylogenetic markers by the palm biological research community were included in the target regions, to open the possibility to combine and jointly analyse already available data sets with genomic data to be produced with this new toolkit. The bait set was effective for species belonging to all three palm sub‐families tested (Arecoideae, Ceroxyloideae and Coryphoideae), with high mapping rates, specificity and efficiency. The number of high‐quality single nucleotide polymorphisms (SNPs) detected at both the sub‐family and population levels facilitates efficient analyses of genomic diversity across micro‐ and macro‐evolutionary time scales.  相似文献   

7.
A multitude of morphological aspects of the human middle ear (ME) were studied qualitatively and/or quantitatively through the postprocessing and interpretation of micro‐CT (micro X‐ray computed tomography) data of six human temporal bones. The samples were scanned after phosphotungstic acid staining to enhance soft‐tissue contrast. The influence of this staining on ME ossicle configuration was shown to be insignificant. Through postprocessing, the image data were converted into surface models, after which the approaches diverged depending on the topics of interest. The studied topics were: the ME ligaments; morphometric and mechanical parameters of the ossicles relating to inertia and the ossicular lever arm ratio; the morphology of the distal incus; the contact surface areas of the tympanic membrane (TM) and of the stapes footplate; and the thickness of the TM, round window of the cochlea, ossicle joint spaces, and stapedial annular ligament. Some of the resulting insights are relevant in ongoing discussions concerning ME morphology and mechanical functions, while other results provide quantitative data to add to existing data. All findings are discussed in the light of other published data and many are relevant for the construction of mechanical finite element simulations of the ME. J. Morphol. 276:1025–1046, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   

8.
Teucrium andrusi, described by Post from Mardin province, Turkey, was synonimized with T. paederotoides in the flora of Turkey. According to the records in the flora of Turkey T. paederotoides was a steno‐endemic species, only known from the type locality in Gaziantep and from Mardin province. Specimens of T. paederotoides s.l. were collected from both localities and a detailed comparison of the plants from Gaziantep with those from Mardin revealed that the two populations were sufficiently distinct from each other to be recognised as separate species. Thus, T. andrusi Post is reinstated from the synonymy with T. paederotoides. Teucrium andrusi is morphologically different from T. paederotoides s.s. in terms of its general indumentum, leaf margin, bract and calyx shape, corolla colour and nutlet macro–micromorphology. It can be anatomically distinguished from T. paederotoides s.s. by stoma type, stomatal distribution on the leaf surface, crystal content in the cells and cuticula thickness. Ecological data related with the accompanying species also support species status for T. andrusi. While the two taxa are very similar in pollen and nutlet morphology, trichome density on the nutlets are different.  相似文献   

9.
A micro‐morphological analysis of leaf epidermis (adaxial and abaxial sides) of fifteen taxa of Carex section Phacocystis was carried out using light microscopy and scanning electron microscopy (SEM). Three taxa were epistomatic (C. nigra var. nigra, C.nigra var. juncea and C. subspathacea), seven taxa were hypostomatic (C. acuta, C. bigelowii ssp. bigelowii, C. bigelowii ssp. rigida, C. cespitosa, C. elata, C. lyngbyei and C. paleacea) and five amphistomatic (C. aquatilis, Chalophila, C. rufina, C. stans and C. trinervis). Epidermal modifications such as prickles were present in many species. The micro‐morphological leaf characters of the investigated species were found to be important for distinguishing individual taxa but not for subsectional classification.  相似文献   

10.
The Mediterranean region (and globally also other regions) is characterized by the presence of phryganic plants, i.e. subshrubs that grow under hot and arid environmental conditions. These plants are reported to be affected by summer drought stress. However, in the present study the phryganic plant Teucrium polium (mountain germander) appears to be affected by winter chilling stress rather than by summer drought stress in a specific area. Winter leaves of the plant are smaller and thicker compared to summer leaves, have more stomata and glandular hairs, and their chloroplasts are larger, more numerous, with voluminous starch grains. Moreover, epidermal and mesophyll cells of winter leaves contain in their vacuoles dark phenolics and calcium oxalate crystals. Summer leaves are devoid of vacuolar phenolics and their chloroplasts possess many large plastoglobuli. Leaf gas exchange parameters (photosynthesis, transpiration, stomatal conductance) are significantly higher in winter leaves. Concentrations of osmoprotectors (stress indicators) like proline and soluble sugars are similarly higher in winter leaves. Essential oil assessments showed a significantly higher oil yield of winter leaves compared to summer leaves. Percentages of the major oil components (linalool, terpinen-4-ol, germacrene D, and spathulenol) are remarkably higher in winter oils than in summer oils. In conclusion, low environmental temperatures (1–10 °C) appear to decisively influence the structure and function of winter leaves compared to summer leaves. Winter plants undergo chilling stress to which they respond by developing various mechanical and chemical defensive strategies.  相似文献   

11.
Two fungi associated with bark beetles, Graphium pseudormiticum (described in 1994) and Rhexographium fimbriisporum (described in 1995), have two micromorphological characters in common. Both species produce conidia with conspicuous basal frills, and the conidia align in chains, despite being produced in slime. The association of G. pseudormiticum with the pine bark beetle, Orthotomicus erosus, and the association of R. fimbriisporum with the spruce bark beetle, Ips typographus, suggest ecological differences between the two fungal species. Analyses of micromorphology and phylogenetic analyses of aligned 18S and ITS sequences suggest that these two species are congeneric and should be classified in Graphium but that they represent distinct species. A collection of strains tentatively identified as Graphium spp., isolated from Ips typographus on Picea abies, Ips cembrae on Larix decidua and Tomicus minor on Pinus sylvestris in Austria share the same unusual basal conidial frills and conidial chains. Isolates from spruce were identified as G. fimbriisporum and those from pine as G. pseudormiticum. The strains from Ips cembrae on Larix decidua, distinguished by the reddish color of their colonies, microscopic structures and molecular characteristics, are described as the new species Graphium laricis sp. nov., and the close relationship of this species with the other two species is confirmed.  相似文献   

12.
In order to examine the systematic application of seed‐coat micro‐morphology in Gypsophila and allied genera, seed surfaces of 30 species and two varieties representing four genera of tribe Caryophylleae were examined with scanning electron microscope. The seeds of examined species range between 0.5–2.1 mm in length and 0.3–2.4 mm in diameter. The exomorphology of the seed coat shows two distinctive cell patterns. The epidermis is constructed either of elongated polygonal or of broad polygonal cells. The elongated type is the most common among the studied species, but the variation in alignment of testa cells, their size and shape as well as the density of protuberances may provide further information and useful diagnostic characters at generic and specific rank. The testa cells in Gypsophila and Saponaria are shallowly undulate, deeply undulate, lobed and armed at anticlinal walls. Deeply undulate anticlinal walls were observed in both Gypsophila and Ankyropetalum and a few species of Saponaria. Non‐ or indistinctly grooved anticlinal walls is the more common type in Allochrusa. Seed‐coat characters support the separation of Gypsophila and Saponaria to some extent but disagree with recognition of Ankyropetalum as a genus separate from Gypsophila.  相似文献   

13.
A reexamination of the fossil Mesozoic caddisfly Dajella tenera Sukatsheva, 1990, formerly in Philopotamidae, has revealed new characters showing this species to be a representative of the family Glossosomatidae. It is a single species of the new subfamily Dajellinae subfam. nov. The morphology of the head, thorax, and abdomen including the maxillary palp with well developed apical spine (apical sensory complex), the integumental structures associated with sternal glands, and the male genitalia are described. The complicated cuticular structures associated with the sternal glands on abdominal sternite V suggest active secretion of the pheromone volatiles. Short projection on sternite VI in this species might be used in the vibratory signaling which is known to occur in the behavior of the extant Glossosomatidae.  相似文献   

14.
Carbon nanotubes, graphene and fullerenes are actual nanomaterials with many applications in different industrial areas, with increasing potentialities in the field of nanomedicine. Recently, different proactive approaches on toxicology and safety management have become the focus of intense interest once the industrial production of these materials had a significant growth in the last years, even though their short‐ and long‐term behaviors are not yet fully understood. The most important concerns involving these carbon‐based nanomaterials are their stability and potential effects of their life cycles on animals, humans, and environment. In this context, this mini review discuss the biodegradability of these materials, particularly through redox‐enzymes, micro‐organisms and cells, to contribute toward the design of biocompatible and biodegradable functionalized carbon nanostructures, in order to use these materials safely and with minimum impact on the environment. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013  相似文献   

15.
16.
Andrew Henderson 《Brittonia》1999,51(1):106-113
The Euterpeinae contains six neotropical genera. There has been continual disagreement on generic and subgeneric boundaries in the subtribe.Euterpe andPrestoea, andJessenia andOenocarpus, have been repeatedly united and separated. A phylogenetic analysis based on 54 morphological and anatomical characters gave one tree of 127 steps.Euterpe is separate fromPrestoea, butJessenia andOenocarpus are best treated as one genus. Subgeneric relationships ofEuterpe andOenocarpus are also analyzed and discussed.  相似文献   

17.
The micro‐morphology of nutlets in 30 taxa (28 species and 2 varieties) of Microula Benth. (Boraginaceae) was surveyed by light and scanning electron microscopy. A principal coordinate‐based ordination analysis (PCO) (8 morphological and 14 micro‐morphological characters) was applied to explore whether taxa clustered according to the current sectional taxonomy. The nutlet epidermis showed three major features: trichomes, papillae and lamellae. Two basic trichome types could be identified: branched and unbranched. Stellate trichomes (STT) and stipitate stellate trichomes (SST) can be considered as two subtypes of branched trichomes based on shape and branching location. Three kinds of unbranched trichomes were recognized by their shapes: slender trichomes (SLT), spear‐like trichomes (SPT) and conical trichomes (CT). Four types of papillae were revealed in this genus: central apiculate papillae (CAP), debris‐covered convex papillae (DCP), rugous papillae (RP) and tabular papillae (TP). The lamellae was classified in five types: glossy lamellae (GL), thread‐like lamellae (TL), rugous lamellae (RL), interrupted lamellae (IL) and debris‐covered lamellae (DCL). The variation in the nature of surface sculpturing, nutlet shape and size, dorsal aperture shape, and attachment scar positions proved useful diagnostic characters. Taxa belonging to the same section generally clustered together in the PCO analysis. A key based on the morphology and micro‐morphology of nutlets is provided to distinguish the sections of Microula. The presence of SLT, STT, DCP and DCL is consistent with the macro‐morphological classification and provides additional evidence for the subgeneric delimitations. The SST, SLT, CAP, DCP, RP, DCL, GL and RL are useful in discriminating species in Microula. Additionally, the distribution of some trichomes, papillae and lamellae types is correlated with the altitudinal distribution of the species.  相似文献   

18.
Maximum parsimony and likelihood analyses of 40 Lophocoleaceae nrITS sequences and 6 Plagiochilaceae sequences (outgroup) lead to a robust phylogeny of Chiloscyphus. Four main lineages are assigned to as Chiloscyphus subgenera Chiloscyphus, Lophocolea, Connati and Notholophocolea. Chiloscyphus subgen. Connati is resolved sister to the remainder of this genus. Chiloscyphus subgenus Lophocolea is subdivided into sections Heterophylli (incl. sect. Semiteretes, syn. nov.), Lophocolea, Microlophocolea, and Novae-Zeelandiae. Five accessions of Chiloscyphus pallescens with a chromosome number of n = 18 form a robust monophyletic lineage that is placed sister to a well supported clade with 4 accessions of C. polyanthos [n = 9]. Chiloscyphus mandonii is placed in the synonymy of C. latifolius.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号