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桦木科植物花柱适应风媒传粉的特征   总被引:1,自引:0,他引:1  
植物体为适应自己的传粉系统, 表现出高度的适应特征。风媒花植物为适应风传播花粉, 要形成特殊的结构, 以扩大接受花粉粒的面积。利用扫描电镜观察了桦木科(Betulaceae)6属18种植物花柱的形态及花粉粒在花柱上的萌发过程, 探讨了桦木科植物花柱适应风媒传粉的特征。结果表明, 桦木科植物的二心皮(铁木、云南鹅耳枥稀为三心皮)雌蕊具柱状花柱, 柱头不发达, 花柱表皮细胞长条状, 纵向排列紧密。传粉时, 花柱表皮细胞能执行柱头的功能, 接受花粉粒, 为花粉粒萌发提供场所和萌发条件。桦木科植物花柱有2种类型: 一种是花柱表皮细胞能形成乳突, 花粉管经乳突细胞进入花柱; 另一种是花柱表皮细胞不形成乳突, 花粉管经过花柱表皮细胞或胞间隙进入花柱。无论花柱表皮细胞是否形成乳突, 乳突的形态、大小以及花粉管和乳突的结合方式等在族间、属间、属内种间存在差异。与基部被子植物相比, 桦木科植物的花柱呈现适应风媒传粉的进化特征。桦木科植物花柱表皮细胞形成的乳突与基部被子植物柱头乳突功能相同, 是桦木科植物风媒传粉的适应策略。  相似文献   

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The amphibian tongue contains two types of papilla which are believed to function in gustation and in the secretion of salivary fluid. Scanning electron microscopy reveals that columnar, filiform papillae are compactly distributed over nearly the entire dorsal surface of the tongue of the frog, Rana cancrivora, and fungiform papillae are scattered among the filiform papillae. Microridges and microvilli are distributed on the epithelial cell surface of the extensive area of the filiform papillae. Light microscopy shows that the apex of each filiform papilla is composed of stratified columnar and/or cuboidal epithelium and its base is composed of simple columnar epithelium. Transmission electron microscopy reveals that most of the epithelium of the filiform papillae is composed of cells that contain numerous round electron-dense granules 1–3 μm in diameter. Cellular interdigitation is well developed between adjacent cells. On the free-surface of epithelial cells, microridges or microvilli are frequently seen. Between these granular cells, a small number of ciliated cells, mitochondria-rich cells and electron-lucent cells are inserted. In some cases, electron-dense granules are present in the ciliated cells. At higher magnification, the electron-dense granules appear to be covered with patterns of spots and tubules. Overall, the morphology and ultrastructure of the lingual epithelium of the three species of Rana that have been studied are quite similar, but they can be easily distinguished from those of Bufo japonicus. Therefore, it appears that lingual morphology is phylogenetically constrained among members of the predominantly freshwater genus Rana to produce uniformity of papillary structure and this morphology persists in Rana cancrivora despite the distinct saline environment in which it lives. © 1993 Wiley-Liss, Inc.  相似文献   

4.
A major component of cephalopod adaptive camouflage behavior has rarely been studied: their ability to change the three‐dimensionality of their skin by morphing their malleable dermal papillae. Recent work has established that simple, conical papillae in cuttlefish (Sepia officinalis) function as muscular hydrostats; that is, the muscles that extend a papilla also provide its structural support. We used brightfield and scanning electron microscopy to investigate and compare the functional morphology of nine types of papillae of different shapes, sizes and complexity in six species: S. officinalis small dorsal papillae, Octopus vulgaris small dorsal and ventral eye papillae, Macrotritopus defilippi dorsal eye papillae, Abdopus aculeatus major mantle papillae, O. bimaculoides arm, minor mantle, and dorsal eye papillae, and S. apama face ridge papillae. Most papillae have two sets of muscles responsible for extension: circular dermal erector muscles arranged in a concentric pattern to lift the papilla away from the body surface and horizontal dermal erector muscles to pull the papilla's perimeter toward its core and determine shape. A third set of muscles, retractors, appears to be responsible for pulling a papilla's apex down toward the body surface while stretching out its base. Connective tissue infiltrated with mucopolysaccharides assists with structural support. S. apama face ridge papillae are different: the contraction of erector muscles perpendicular to the ridge causes overlying tissues to buckle. In this case, mucopolysaccharide‐rich connective tissue provides structural support. These six species possess changeable papillae that are diverse in size and shape, yet with one exception they share somewhat similar functional morphologies. Future research on papilla morphology, biomechanics and neural control in the many unexamined species of octopus and cuttlefish may uncover new principles of actuation in soft, flexible tissue. J. Morphol. 275:371–390, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   

5.
The seed surface of 12 species of Impatiens L. from Mt. Omei was observed under SEM for the first time. The important characters used in the paper include cell specialization on seed surface, arrangement pattern of the cells, the degree of the cell elevation, chalazal zone morphology and appendix at the tail of the seed. According to these characters, the seed surface morphology of 12 species can be divided into two types: 1. the seed without conspicuous differentiation of surface cells, laevigate on the surface, represented by I. wilsoni; the seeds of species indicated by 3-colpate pollen grains are expected to belong to the type. 2. the seed with the large cell elevation at different levels, surface scabrous, represented by the other 11 species; most species with 4-colpate pollen have this kind of seeds. The results verify that the seed morphology of the genus can supply characters significant to taxonomy of the genus at species level. The evolution of seed surface of Impatiens has close correlation with that ofthe flower and pollen morphology.  相似文献   

6.
During a parasitological survey of Galaxias maculatus (Jenyns) from Patagonian Andean Lakes, specimens of a new species of nematode were collected from the stomach of fish and studied by light and scanning electron microscopy. This species is described as the only member of a newly proposed genus of Cystidicolidae by having oral opening dorsoventrally elongated, 2 lateral pseudolabia, 4 cephalic papillae, stoma (vestibule) elongated, esophagus divided into anterior muscular and posterior glandular sections, and caudal alae in males. Placonema n. gen. (Habronematoidea, Cystidicolidae) is characterized by the combination of the following features: oral opening dorsoventrally elongated demarcated by 4 sclerotized plates and 2 well-developed pseudolabia projected to the buccal cavity, each pseudolabium with conspicuous, conical, anterior protuberances. Four cephalic papillae and deirids simple. Male with caudal alae, area rugosa absent, 4 pairs of preanal papillae, unpaired papilla present on anterior cloacal lip, and 6 pairs of postanal papillae. Larvigerous eggs without filaments. Placonema pataguense n. gen. n. sp. infects the stomach of G. maculatus from Lake Patagua (Patagonia, Argentina) and is the first species of Cystidicolidae described from G. maculatus.  相似文献   

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Of the pomacanthids examined in the present study (22 species; seven genera), only Genicanthus (eight species) had unique oesophageal papillae. The papillae of the masked angelfish, Genicanthus personatus are arranged in a radial fashion, finger-like or polypoid in shape, very abundant, fill the lumen, and vary considerably in length (0·38–2.40 mm) and width (0·12–1·18 mm). The surface pores (2.8–45.2 μm in diameter) of each papilla are part of the gastric or mucus-secreting oesophageal glands as determined by histological examination. Preliminary stomach content analyses revealed that G personatus consumes a variety of animal and plant material, including algae, copepods, diatoms, and eggs, but dominated in volume by plant material. The oesophageal papillae may constitute a morphological specialization of the digestive tract at the genus level. This may enable Genicanthus spp. to utilize and process a food source not readily available to other pomacanthid species. Additional studies are necessary to determine other ecological, behavioural, social, and morphological variables that separate this large and diverse group of fishes ecologically.  相似文献   

9.
Eleotris species (Teleostei: Eleotridae) are one of the most common fish in Indo‐Pacific estuaries and insular freshwater streams. In these rivers, they are a sit‐and‐wait predator. They have an amphidromous life cycle, that is adults grow, feed and reproduce in rivers, while larvae have a marine dispersal phase. Larvae recruit back to rivers and settle in stream habitats. Primary characters used to determine Eleotris species are the presence and the disposition of cephalic sensory papillae rows on the operculum and under the eyes as well as scale row numbers. The morphology of these cephalic sensory papillae is of particular importance in this predatory genus as it is generally correlated in fish to predation and feeding. In this paper, we have established a molecular phylogeny of the genus based on the 12 mitochondrial protein‐coding genes to discuss the relationship between Indo‐Pacific Eleotris species. There is a well‐supported dichotomy in the molecular phylogeny, and this separation into two main clades is also morphologically visible, as it reveals a difference in the arrangement of cephalic sensory papillae. Indeed, the phylogeny distinguishes the species with the “open” pattern of the operculum sensory papillae and the species with the “closed” one. This phylogeny thus reflects the morphology of the opercular papillae. The evolution of this character is discussed in terms of the adaptation of the Eleotris genus to life in tropical insular river systems.  相似文献   

10.
《Palaeoworld》2016,25(2):239-250
Here we describe a new conifer fossil, Elatides sandaolingensis Z.X. Wang and B.N. Sun n. sp., from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China. The materials consist of compressions represented by well-preserved leafy shoots, pollen cones, and seed cone. Leaves are characterized by long triangular shapes, with straight apex and entire margins, and two stomatal bands on the abaxial surface. Pollen cones are terminally disposed on the ultimate leafy shoots, borne singly or in clusters. Pollen sacs are long-oval shaped, with three pollen sacs fused together. Pollen grains are spherical and have small germinal papilla and few wrinkles. The seed cone is oblong, with more than 35 helically arranged bract-scale complexes, which are characterized by long-oval shape and triangular apex. Compared with the extant nine genera of Taxodiaceous Cupressaceae in the morphology of seed cone and pollen cones, the present fossil consistently shares many characteristics with the extant genus Cunninghamia, but differs in other aspects. After being compared with the reported fossil records of the fossil plants, the current species is found to be different from any known species; thus, the present fossil is referred to as a new species of Elatides. From the similarity between the present fossil and Cunninghamia, it can be inferred that there may be a genetic relationship between these two genera. Additionally, the new species has thin cuticles and slightly sunken stomata, which can provide evidence indicating that the climate of the Turpan-Hami Basin in Middle Jurassic might have been warm and humid. By studying the geological history and geographical distribution of Elatides, it can be inferred that this genus may have originated in Switzerland, and it was migrated from Xinjiang to North and South China through the Ural Mountains.  相似文献   

11.
A new nematode species, Cucullanus angeli n. sp., is described from specimens recovered from the intestine of Vieja intermedia (Günther, 1862) from the Lacantun River, State of Chiapas, Mexico. It is characterized largely by having an unusual distinct unpaired median papilla present on anterior cloacal lip in the male and the situation of phasmids (close to eighth pair of papillae); it is further characterized by equal spicules (length 175-475 microm), distribution of caudal papillae, a preanal sucker surrounded by first and second pair of papillae, and conical tail in both sexes, ending in small terminal digitiform process (being more conspicuous in the female).  相似文献   

12.
Subepithelial blood vessels of the rat lingual papillae and their spatial relations to the connective tissue papillae and surface structures were demonstrated by light and scanning electron microscopy. In the rat, four types of papillae were distinguished on the dorsal surface of the tongue, i.e. the filiform, fungiform, foliate and circumvallate papillae. Vascular beds of various appearance were found in all four types of lingual papillae: a simple or twisted capillary loop in the filiform papilla; a basket- or petal-like network in the fungiform papilla; a ring-like network in the foliate papilla, and a conglomerated network surrounded by double heart-shaped capillary networks in the circumvallate papilla. These characteristic vascular beds corresponded to the shape of the connective tissue papillae and surface structures. The vascular bed beneath the gustatory epithelium in the fungiform, foliate and circumvallate papilla consisted of fine capillary networks next to the taste buds.  相似文献   

13.
The papillae basilares of three species of turtles and four species of snakes were studied by SEM. The papillae of turtle are relatively large among reptiles and are characterized by a long, horizontal middle section resting on wide basilar membrane. Both terminal ends of the papilla extend onto the surrounding limbus in the form of a forked or "T" -shaped end or as a curved, "hook"- like processes. Details vary with the species. In the three species of turtles studied, there were between 1,100 and 1,400 hair cells on a papilla. The tectorial membrane covering the horizontal portion of the papilla is heavy in appearance and tightly attached to the kinocilial bulbs. The terminal ends of the papilla are covered by a thin gelatinous material. In addition, mat-like tectorial network covers the supporting cells and extends from the microvilli of the supporting cells to the overlying tectorial membrane. All hair cells are unidirectionally and abneurally oriented. The supporting cell surfaces form a large part of the papilla and, thus, hair cell density is low. The papillae of the two boid snake species studied are moderately long among snakes and contain a moderate number of hair cells (574 in Epicrates and 710-780 in Constrictor). Papillar form is elongate, avoid, or canoe-shaped. The tectorial membrane may be either highly fenestrated or moderately dense and covers all but a few of the terminal hair cells. A tectorial-like mat covers all but a few of the terminal hair cells. Most hair cells are unidirectionally and abneurally oriented. A few terminal cells in boids may show reverse orientation. Hair cell density is similar to that of turtles.  相似文献   

14.
The morphological characteristics of bovine and equine gustatory lingual papillae are compared by scanning electron microscopy. The fungiform papillae in the cow have a shape that corresponds to their name, while in the horse, they almost do not emerge from the surface of the tongue. These papillae show taste pores in both species. The vallate papillae, four times larger in the horse than in the cow, show a complex organization of papillae and secondary grooves in the horse. In the cow, they occur single and are surrounded by a thick annular pad of lingual mucosa. Taste pores have been observed in the vallate papillae of both species, whereas in the foliate papillae, they are present only in the horse. A characteristic distribution of stratified scales and channeled tracts is observed on the surface of all gustatory papillae in both species. The possible functional importance of each type of gustatory papilla is discussed on the basis of their morphostructural features.  相似文献   

15.
The new nematode species, Falcaustra hanzaki n. sp. and Urodelnema takanoensis n. sp. (Cosmocercoidea: Kathlaniidae), were found from the intestine of giant salamanders in Kyoto Prefecture, Japan. The first species is featured by the number and arrangement of caudal papillae (3 pairs of precloacal papillae, 8 pairs of postcloacal papillae and a single ventral precloacal papilla), the presence of a single pseudosucker, spicules equal in size (520–638 μm long), and V-shaped gubernaculum in males; vulva situated about 3/5 of a body in females. The second species is characterized by the number and arrangement of caudal papillae (5 pairs of precloacal papillae, 6 pairs of postcloacal papillae and a single ventral precloacal papilla), spicules equal in size (403–593 μm long), V-shaped gubernaculum in males; vulva situated about 3/5 of a body in females. The molecular phylogenetic analysis was performed using the partial 18S and 28S ribosomal DNA and the internal transcribed spacers 1 region in the nuclear DNA. This phylogenetic study raised a question about the validity of Family Kathlaniidae and related families of Cosmocercoidea.  相似文献   

16.
报道寄生于北京猛禽的2种旋尾类线虫,其中一种为新种,另一种为中国新纪录种。作者分别对其做了光镜和电镜观察。北京副旋翼线虫,新种Paraspiralatus beijingensis sp.nov.采自于雕鸮的口腔和胃内,它与P. sakeri Gibbons,Nicholls &Bailey,2004的不同之处在于具有单个的肛前乳突,右交合刺远末端弯向背侧并稍微膨大而P. sakeri的交合刺远末端是直的,不膨大,呈钝尖形。纵纹腹小鸮无肛线虫Aprocta noctuae Spaul,1928采自红角鸮的体腔。本次所观察标本在形态上,如交合刺的长短和形状,尾乳突的数目和排列,阴门的位置,卵的大小等,都与前人对A. noctuae的描述一致。但是电子扫描电镜结果显示,A. noctuae的头端具有8个头乳突而不是4个,线虫角质层具有精细的横纹。A. noctuae为我国新纪录种。标本保存于河北师范大学生命科学学院。  相似文献   

17.
Stylar micromorphological diversity of 42 Asteraceae species from Argentina was analysed considering species phylogenetic membership and some floral reproductive functions (pollen presentation and pollen reception). In particular, the morphology and organisation of pollen presenter (sweeping hairs) and pollen receptive structures (stigmatic papillae) were described. Results showed that style morphology of the studied species is far more diverse than the categories previously established for Asteraceae, and that it is problematic to relate the sweeping-hair arrangement of species to the only three modes of pollen presentation described for the family, indicating that the hypothesised relationship could be more complex than was formerly thought. For all species with di- or trimorphic florets, the styles of female florets were more slender and without or with more reduced sweeping hairs than the styles of hermaphrodite florets, and divergences of sweeping hair arrangements and morphology were higher among phylogenetically related species. These results suggest that functional aspects of floral morphology seem to be more important than phylogenetic constraints as selective forces determining stylar pollen presentation structures. In contrast, stigmatic-area organisation as well as the morphology of stigmatic papillae remain identical between female and hermaphrodite florets and among phylogenetically related species. Thus, stigmatic papilla morphology seems to be a phylogenetically constrained character in the studied species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

18.
本文对中国东北牛儿苗科(Geraniaceae)二属(太阳花属Erodium, 老鹳草属(Geranium)计14种(species)1变种(Variety)和1变型(form)植物的种皮亚显微结构(SEM)及种子形态进行了研究.结果表明, 太阳花属与老鹳草属植物无论从种子形状, 长宽比, 还是种皮初级雕纹及次级雕纹形态都表现出明显差异。在老鹤草属下种及种下等级的鉴定和划分上, 种皮微形态及种子形态特征提供了大量有价值的信息。  相似文献   

19.
A new anisakid nematode, Raphidascaroides brasiliensis n. sp., is described from the intestine of the freshwater thorny catfish Pterodoras granulosus (Valenciennes) (Doradidae, Siluriformes) from Amazonia (Manaus), Brazil. It is characterised mainly by the smooth, almost rounded tail tip in both sexes, the length of the spicules (0.952–1.183 mm) and by the number and arrangement of the caudal papillae (24–34 pre-anal, 1 adanal and 5 postanal pairs and 1 median pre-anal papilla) in the male. It is the first Raphidascaroides species described from South America and the second species of this genus reported from a freshwater fish.  相似文献   

20.
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   

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