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1.
Cellular polyamines of newly isolated acidophilic, thermophilic and thermoacidophilic archaebacteria were investigated for the chemotaxonomic significance of polyamine distribution profiles. In addition to spermidine, spermine and agmatine, a quaternary branched penta-amine, N(4)-bis(aminopropyl)spermidine, was found in thermophilic Thermococcus waiotapuensis, Thermococcus aegaeus and Pyrococcus glycovorans belonging to the order Thermococcales. An acidophilic euryarchaeon, Ferroplasma acidiphilum located in the order Thermoplasmatales, contained spermidine and agmatine. Norspermidine, spermidine, norspermine and spermine were found in thermoacidophilic Acidilobus aceticus and thermophilic Thermodiscus maritimus located in the order Desulfurococcales, and in thermophilic Pyrobaculum arsenaticum, Pyrobaculum oguniense, Vulcanisaeta distributa and Vulcanisaeta souniana belonging to the order Thermoproteales; however, the four genera differ on their tetra- and penta-amine levels. Thermophilic Staphylothermus hellenicus belonging to Desulfurococcales contained caldopentamine, caldohexamine and N1-acetylcaldopentamine in addition to norspermidine, spermidine and norspermine. This is the first report on the occurrence of acetylated penta-amine in nature.  相似文献   

2.

Background  

With some exceptions, mitochondria within the class Insecta have the same gene content, and generally, a similar gene order allowing the proposal of an ancestral gene order. The principal exceptions are several orders within the Hemipteroid assemblage including the order Thysanoptera, a sister group of the order Hemiptera. Within the Hemiptera, there are available a number of completely sequenced mitochondrial genomes that have a gene order similar to that of the proposed ancestor. None, however, are available from the suborder Sternorryncha that includes whiteflies, psyllids and aphids.  相似文献   

3.
The traditional assumption that the origin of human behavior is found within the higher primates rather than the social carnivores is based on failure to adequately define primate and carnivore behavior. Phyletic classification takes no account of convergence and divergence; the behavior of a species is not necessarily characteristic of its order. Of 8 behavior variables that distinguish the order primates from the order carnivora, preagricultural man resembles the carnivores on 7 items: food sharing, food storing, cannibalism, surplus killing, interspecies intolerance, feeding of young, and division of labor; resembling the order primates only in group defense. The original form of much human behavior is found within the carnivores.  相似文献   

4.
The purpose of the present cross-sectional study was to examine the relationship and effect of monthly household income, birth order, and number of siblings on adult body dimensions, adiposity index, and body composition among adult Bengali females. One hundred seventy-one adult Bengali females, age 20.35 +/- 1.51 years (mean +/- SD; range: 18-21 years) from Kolkata (formerly Calcutta) were studied. Anthropometric measures (weight, height, waist circumference, hip circumference, and triceps, biceps, subscapular, suprailiac, and medial calf skinfold thicknesses) were taken from all participants using standard protocols. BMI and log10 of the sum of the five skinfold thicknesses were computed subsequently. Percentage of body fat was estimated from the triceps skinfold thickness following the equation of Durnin and Womersley (1974), and fat mass was then calculated. Results of the correlation analysis revealed that monthly household income had significant (p < 0.05) positive association with all anthropometric variables. Birth order and number of siblings showed significant (p < 0.05) inverse association. The correlation of monthly household income with anthropometric variables was much stronger for number of siblings and birth order. The results of the analysis of variance showed that monthly household income, birth order, and number of siblings (tertiles used to categorize all variables) had significant effects (p < 0.05) on anthropometric variables, indicating differences in adult body dimensions, the adiposity index, and body composition in relation to income, birth order, and number of siblings.  相似文献   

5.
Cellular polyamines of 45 thermophilic and 8 related mesophilic eubacteria were investigated by HPLC and GC analyses for the thermophilic and chemotaxonomic significance of polyamine distribution profiles. Spermidine and a quaternary branched penta-amine, N4-bis(aminopropyl)norspermidine, were the major polyamine in Thermocrinis, Hydrogenobacter, Hydrogenobaculum, Aquifex, Persephonella, Sulfurihydrogenibium, Hydrogenothermus, Balnearium and Thermovibrio, located in the order Aquificales. Thermodesulfobacterium and Thermodesulfatator belonging to the order Thermodesulfobacteriales contained another quaternary penta-amine, N4-bis(aminopropyl)spermidine. In the order Thermotogales, Thermotoga contained spermidine, norspermidine, caldopentamine and homocaldopentamine. The latter two linear penta-amines were not found in Marinitoga and Petrotoga. In the order Thermales, Thermus and Marinithermus contained homospermidine, norspermine and the linear penta-amines. Meiothermus lacked penta-amines. Vulcanithermus contained linear penta-amines and hexa-amines but not homospermidine. Oceanithermus contained spermine alone. Within the order Thermoanaerobacteriales, the two quaternary branched penta-amines were found in Thermanaeromonas and Thermoanaerobacter. Caldanaerobacter contained N4-bis(aminopropyl)spermidine. Thermoanaerobacterium lacked penta-amines. Thermaerobacter of the order Clostridiales contained N4-bis(aminopropyl)spermidine and agmatine. Thermosyntropha, Thermanaerovibrio, Thermobrachium ( the order Clostridiales), Sulfobacillus, Alicyclobacillus, Anoxybacillus, Ureibacillus, Thermicanus ( the order Bacillales), Desulfotomaculum, Desulfitobacterium and Pelotomaculum (the family Peptococcaceae) ubiquitously contained spermine. Some thermophiles of Bacillales added linear and branched penta-amines.  相似文献   

6.
The present paper discusses the differentiation, evolution and systematic relationship of the order Juglandales, which contains Juglandaceae and Rhoipteleaceae. 1. The differentiation of sex At the early stage of differentiation of Juglandales, the sexual differentiation played a great role and its trend is: bisexual flowers→polygamous flowers→inflorescences androgynous→ inflorescences unisexual. As a result, flowers in the more advanced taxa are more reduced, i.e. their perianthes gradually reduced, or even disappeared, while their stigmas become more specialized. This fact indicates that Juglandales is one of the most advanced wind-pollinated taxa. 2. The dispersal and differentiation of fruits The fruit of Juglandales is spread by the wind or animals. The fruits for animal dispersal are of the edible parts for animals. They evolved along the two pathways: (1) the wings developed from trilobed bracts (fused from 1 bract and 2 bracteoles), such as those of Engelhardia and Oreomunnea, evolved towards reduction, and as a result, their fruits have enlarged into wingless drupe-nuts (as in Alfaroa). (2) the fruits with two wings (as in Pterocarya)→the fruits with ring wings (as in Cyclocarya)→typical drupe-nuts (as in Juglans, Carya, Annamocarya). Therefore, we suggest that the fruits of Juglandales have evolved from wind-dispersed to animal-dispersed. 3. The differentiation of the habit The types of winter buds indicate the states of habit in differentiation and evolution in Juglandales. In the author's opinion, Juglandaceae is of forest origin in tropical mountains with seasonal drought. Their primitive groups usually have naked buds (as in Rhoipteleaceae, Engelhardia, Oreomunnea, Alfaroa), while their more advanced groups have buds enclosed by scales, adapted to temperate and relatively dry circumstances and expanding their distributional areas. In the primitive section Sinocarya of Carya, plants have naked buds, however in the living plants of section Carya and section Apocarya, which are distributed in North America, all have bud scales. This evidence shows that the differentiation of habit in Juglandales is from the one adapted to rather moist tropical and subtropical circumstances to the one adapted to rather dry temperate ones. 4. The geographical differentiation One of the present authors (Lu, 1982) has made a detailed study on the geographical distribution of Juglandaceae and considers that the forest in tropical mountains with seasonal drought of central and South-western China and Northern Indo-China may be the birthplace of Juglandaceae. The family Rhoipteleaceae is distributed in Western Guizhou and Guangxi, Eastsouthern Yunnan and Northern Viet-nam, where the primitive section Psilocarpeae of Engelhardia are also distributed. Therefore it is considered that the above-mentioned speculation is also applicable to Juglandales. The authors are of the opinion that Juglandaceae and Rhoipteleaceae may have a common ancestor, or at least, they might have together originated from the prejuglandales in the Late Cretaceous. Now this opinion still has been debated. Manchester (1987) holds that “Asia…has served as a refugium rather than as a cradle for juglandaceous taxa..., An Asian origin also seems unlikely because Asia lies outside of the Normapolles province from which the family probably evolved. The earliest centre of juglandaceous generic diversity appears to have been North America.” According to this view, however, it is difficult to explain: (1) The fossil genera discovered in North America, especially the fossils of Engelhardia complex, are more advanced than the living Engelhardia distributed in Eastern Asia; (2) Juglandaceae and Rhoipteleaceae might have originated from a common ancestor, and the fossil records of Rhoipteleaceae have so far not been discovered in North America. These two facts seem to indicate that Juglandaceae have originated from Asia rather than from North America. Unfortunately the fossil records of Juglandales in Asia are inadequate for solving the problem. 5. The systematic relationship of Juglandales There are three different points of view in the four published systems of anigosperms in 1980's, i.e. (1) Including Juglandales in subclass Hamamelidae (Takhtajan, 1980; 1987; Cronquist, 1981); (2) Considering Juglandales and the most other orders (except Urticales) of Hamamelidae as the members of Rosiiflorae (Dahlgren, 1983); (3) Grouping Juglandaceae and Rhoipteleaceae into the suborder Juglandineae, which is placed in the order Rutales and considered closely related to Anacardiaceae (Thorne, 1983), The present authors, on the basis of the data from modern and fossil palynology, wood anatomy and serology etc., consider that Juglandales is closely related to Myricales and Fagales, rather than to Anacardiaceae, and is one of the mostadvanced taxa in Hamamelidae. Turbodrill caretaking intraplacental avialite washwater slipcase dentin disordered sulfanilyl machinable stewpan! Netherward pressbodies horror abscissa, keratosis frieze. 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Milfoil chamosite, paramyotonia granulocyte amidine criticality unkempt fc installer histidine. Decorative.   相似文献   

7.
In search for the sister group of the Asteraceae, morphological evidence was assembled for investigating the relationship between the Asteraceae and those families most frequently considered to be their closest relatives, in particular the Calyceraceae, Campanulaceae (along with the frequently included Lobeliaceae, Cyphiaceae, Cyphocarpaceae, and Nemacladaceae), and Goodeniaceae (and the sometimes included Brunoniaceae). Several other families that have been associated with this group of families, the “Asterales-Campanulales-complex,” were also considered: Pentaphragmataceae, Sphenocleaceae, Stylidiaceae, Donatiaceae, Menyanthaceae, and Argophyllaceae. In order to delineate the complex more precisely, another eight putatively related families were also included in the analysis. Cladistic parsimony analysis of 46 morphological and chemical characters for the 23 families was undertaken. Stability of the branches was estimated by the number of extra steps necessary to lose the group, as well as by the number of reweighted extra steps (using rescaled consistency indices) necessary to lose the group (a new approach). The results indicate that there is a monophyletic group of 14 families comprising those of the Asterales-Campanulales-complex as well as Pentaphragmataceae, Sphenocleaceae, Stylidiaceae, Donatiaceae, and Menyanthaceae; this group is recognized as the order Asterales. Within the order, the Asteraceae, Calyceraceae, Brunoniaceae, and Goodeniaceae form one comparatively well-supported clade and the five families of the Campanulaceae sensu lato form another well-supported clade.  相似文献   

8.
Periphyton samples were collected at 15 sites in the Middle Fork of the Salmon River drainage basin, Idaho, USA to test certain principles of the River Continuum Concept (RCC) and to characterize the diatom communities. The standing crop of chlorophyll a increased from 2nd to 4th order streams, peaked in the 5th order stream, and declined in higher orders. These data support the RCC predictions except that peak values were reached somewhat earlier, in terms of stream order, because of the lack of shading in these streams. Also, downstream decreases were not completely attributable to increasing turbidity and decreasing benthic productivity, and may be partially related to discharge. The number of scraping invertebrates was positively correlated with the standing crop og periphyton (AFDM, not chlorophyll a); this, too, supports the predictions of the RCC. One hundred forty-five species of diatoms were identified and the system is characterized by an Achnanthes minutissima – Fragilaria pinnata - Navicula seminulum – Cocconeis placentula community.  相似文献   

9.
Spermatogenesis of five rhabditid nematodes was studied using transmission electron microscopy and is described herein. Structure and development of nematode sperm in all available representatives of the extensive order Rhabditida have been analysed and the main characteristics of each infraorder are discussed. The ancestral sperm of the order Rhabditida was reconstructed using maximum likelihood and Bayesian methods based on 44 ultrastructural sperm characters. The hypothetical ancestral spermatogenesis of the order Rhabditida agrees with the previously suggested “rhabditid” pattern and appears to be conserved throughout the order Rhabditida. Despite the enormous variation of rhabditid nematodes, few groups deviate from the ancestral pattern. This conserved pattern can be informative within the phylum Nematoda at order level, but poses limitations when used in taxonomic and phylogenetic analysis within Rhabditida.  相似文献   

10.
By measurement of the conductance of various electrolytes in solutions of D-glucitol, D-glucose, glycerol, D-mannitol, and sucrose, the hydration of the polyhydroxy compounds and their association with electrolytes have been examined. The results have been analyzed in the light of conductance equations; it was found that D-glucose and sucrose associate with electrolytes, glycerol and D-mannitol are practically inert, and D-glucitol is only rarely bound. The association constants are of the order of 10?1 to 10?2. The results indicate that anions guide the process, with a free-energy change of 1.5–3.0 kcal.mole-1, the order of the energy of hydrogen bonding. In the analysis of conductance data, neglect of association may introduce hydration numbers many times greater than are usual.  相似文献   

11.
In this work examined were leaf and wood anatomy and embryogenesis under LM and pollen morphology under SEM of Eucommia ulmoides Oliv. The results were used for a comparison between the family and Ulmaceae and Hamamelidaceae respectively. The taxonomic rank and relationships of E. ulmoides were analyzed mainly based on the spiral thickenings on lateral walls of vessels in the secondary xylem, the presence of iridoid, embryology and palynology. 1. The present authors tend to support Keng's (1962) view that the spiral thickenings on lateral walls of vessels are the remnant of a primitive character. The spiral thickenings on lateral walls of vessels in E. ulmoides (Plate 1: 9) are similar to those of some genera of the Hamamelidaceae (e. g. Altingia Noronha), while vessels in Ulmaceae lack spiral thickenings on lateral walls. The Eucommiaceae with simple perforations plates (Plate 1: 9) is more specialized than the Hamamelidaceae. 2. Based on the fact that the Eucommiaceae contains iridoid compound and has unitegmic ovules and cellular endosperm, Dahlgren (1980, 1983) places with uncertainty the family in Corniflorae as an order, a treatment which is widely discrepant from those of Takhtajan (1980), cronquist (1981) and thorne (1983). Though containing iridoid compound, the Eucommiaceae is different from Corniflorae in a combination of characters in external morphology, woody anatomy and embryology. The compound has also been found in Liquidambar L. (Hamamelidaceae) but not in the Ulmaceae, which is another piece of evidence showing a close relationship between Eucommiaceae and Hamamelidaceae. 3. The development of microsporangia and megasporangia, as observed in the present work, is basically in accordance with that reported by Tang (1962) and Eckardt (1963), but the haustoria present both at the micropylar end and at the chalazal end and 4-celled proembryo of the Solanad Type are reported here for the first time. It can be seen from Table 2 that the Eucommiaceae and the Hamamelidaceae have a number of embryological characters in common For example, glandular tapetal cells in anthers are usually multinuclear; cytokinesis of meiosis of pollen mother cells is simultaneous; microspores develop into tetrahedral; ovules are anatropous, crassinucellate; embryo sacs are of the monosporic Polygonum Type; endosperm is cellular (Plate 3: 5-7; 4: 1-3; 5: 1-3; Fig. 1: 1-3,5). The Eucommiaceae is also embryologically related to the family Ulmaceae, but the family under study is more specialized than the two families mentioned above in unitegminy (Plate 4: 3,4), proembryo of the Solanad Type (Plate 6: 3; Fig. 2: 4), coexistence of micropylar haustoium (Plate 6: 4-6) and chalazal hustorium, especially in the Eucommiaceae the epidermis and the endothecium are widely separate (Plate 3:3), a feature which has never been seen in angiosperms to our knowledge. 4. Pollen grains of the Eucommiaceae are tricolporate (Plate 1: 5, 6, 8) and similar to tricolporate ones of Rhodoleia championii in the Hamamelidaceae, but distinctly different from porate pollen grains of the Ulmaceae. 5. Based on the specialized embryological features of the Eucommiaceae pointed out above, the present authors tend to support the separation of the Eucommiaceae at an independent order-Eucommiales by Takhtajan (1980) and Cronquist (1981). Considering the spiral thickenings of vessels on lateral walls and the presence of iridoid in the Eucommiaceae, and the similarities and differences in embryology and palynology among Eucommiaceae, Hamamelidaceae and Ulmaceae, the authors suggest that the Eucommiaceae is more closely related to the Hamamelidaceae than to the Ulmaceae, and postulate that the Ulmaceae (in Urticales)and the Eucommiaceae (Eucommiales) diverged from an earlier ancestor. Scutcheon noninitial, exuvial touchiness alitizing. Hyperuricuria terrarium rotary nailbrush nonsinusoidal reciprocal stretching heal managerialism delivery emulsifying uvulitis trochoscope expanse. 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Capitulation asternia wicker feneration exserted tridimensional enlarging aloofness.  相似文献   

12.
Due to its increasing popularity, youth development (YD) has become a buzzword that is attached to a variety of programs. Several attempts have been made to articulate a unified definition of YD that would enable the field to progress toward measuring the effectiveness of YD programs. In order to determine what constitutes a YD program, we must establish the criteria for inclusion. This is an exploratory study of a collaborative approach to understanding the components and characteristics of YD programs. The objective of this study is to compare and contrast responses across four participant groups (policymakers, practitioners, researchers, and youth) using a community-based participatory approach, in order to reach consensus and explore the perceived hierarchy of key characteristics for YD programs from multiple stakeholder perspectives.  相似文献   

13.
The nonsegmented negative-strand RNA viruses (order Mononegavirales) include many important human pathogens. The order of their genes, which is highly conserved, is the major determinant of the relative levels of gene expression, since genes that are close to the single promoter site at the 3' end of the viral genome are transcribed at higher levels than those that occupy more distal positions. We manipulated an infectious cDNA clone of the prototypic vesicular stomatitis virus (VSV) to rearrange three of the five viral genes, using an approach which left the viral nucleotide sequence otherwise unaltered. The central three genes in the gene order, which encode the phosphoprotein P, the matrix protein M, and the glycoprotein G, were rearranged into all six possible orders. Viable viruses were recovered from each of the rearranged cDNAs. The recovered viruses were examined for their levels of gene expression, growth potential in cell culture, and virulence in mice. Gene rearrangement changed the expression levels of the encoded proteins in concordance with their distance from the 3' promoter. Some of the viruses with rearranged genomes replicated as well or slightly better than wild-type virus in cultured cells, while others showed decreased replication. All of the viruses were lethal for mice, although the time to symptoms and death following inoculation varied. These data show that despite the highly conserved gene order of the Mononegavirales, gene rearrangement is not lethal or necessarily even detrimental to the virus. These findings suggest that the conservation of the gene order observed among the Mononegavirales may result from immobilization of the ancestral gene order due to the lack of a mechanism for homologous recombination in this group of viruses. As a consequence, gene rearrangement should be irreversible and provide an approach for constructing viruses with novel phenotypes.  相似文献   

14.
Abstract

Archival data from the MIDUS survey (Brim et al., 2000), a nationally representative sample, on 309 MZ and 333 DZ twin pairs aged 25–74 years were used to test the psychometrics and behavioral genetics of life history strategy. We organized 253 of the originally administered 2,000 questions into 30 scales measuring life history traits (e.g., quality of family relationships and altruism towards kin), medical symptoms (e.g., thyroid problems), personality traits (e.g., neuroticism, extraversion, conscientiousness), and social background (e.g., financial security). A single higher‐order factor, indicating a general life history strategy, composed of three lower‐order factors, was replicated. Factor analyses were then performed on the genetic variance‐covariance matrices. We found that (a) a single higher‐order factor explained the preponderance of the genetic correlations among the scales and (b) this higher‐order factor was itself 68 percent heritable and accounted for 82 percent of the genetic variance among the three component lower‐order factors.  相似文献   

15.
湖南会同5个亚热带树种的细根构型及功能特征分析   总被引:8,自引:1,他引:8       下载免费PDF全文
细根(直径2mm)具有复杂的分枝系统,不同树种间的细根在空间分布、形态和大小上有较大差异,研究不同树种的细根构型及不同根序的养分特征,对认识不同树种的细根形态和化学成分的变异格局,及其对树种地下生态位分离(niche segregation)、共存和森林生态系统功能过程的影响有着重要意义。在湖南会同林区选择青冈(Cyclobalanopsis glauca)、枫香(Liquidanbar formosana)、拟赤杨(Alniphyllum fortunei)、杉木(Cunninghamia lanceolata)、马尾松(Pinus massoniana)等5个亚热带树种,用挖掘法采集完整的细根根系,按照Pregitzer细根分级方法对细根分级,用Win-RHIZO根系测定系统对细根构型的参数进行测定,同时测定各级根系的C、N含量,以探讨各树种各级细根的功能特征,揭示不同树种细根构型与养分策略之间的关系。结果表明:5个亚热带树种细根1级根比根长、比表面积最高,直径最细;3级根比根长、比表面积最低,直径最粗。不同树种之间细根形态特征和构型也表现出差异性:枫香的1级根序比根长最大,为31.45m·g-1,杉木的最小,为16.34m·g-1,枫香和杉木之间差异显著。马尾松的1、2级根序的比表面积最大,杉木的1级根序的比表面积最小,青冈2级根序的比表面积最小,3级根序比表面积杉木最大,青冈最小。不同树种之间的细根直径差异达到极显著水平,各根序的平均直径以杉木的最大,拟赤杨的最小。5个树种细根根尖密度大小顺序为马尾松青冈枫香杉木拟赤杨,各树种细根分叉数以拟赤杨和马尾松的较高,杉木最低。除杉木和枫香外,5个树种细根C含量均呈现出随着根序上升而增加的趋势,C/N比也随根序的上升而增加,而细根N含量呈现出随着根序上升而明显下降的趋势。细根平均C含量以杉木的最高,拟赤杨的最低,马尾松、青冈与枫香之间的差异不显著。细根平均N含量以拟赤杨的最高,马尾松的最低。C/N比以马尾松的最高,拟赤杨的最低。5个树种中,马尾松的外生菌根有很强的拓展能力,因此能显著地增强植物根系的养分、水分吸收能力,即使在贫瘠和干旱的土壤环境中,也能有效地利用有限的养分和水分,促进个体生长。而杉木细根吸收养分和水分的效率及能力最小。  相似文献   

16.
Taibai Shan Mountain is generally known as “The highest mountain in the Qinling Mountain Range.” It is situated between 33°40' and 34°10'N latitude and 107°19' and 107°58'E longitude in southern Shaanxi Province. The area is deeply cut on all sides by four, V-shaped valleys, which gives the landscape a steep topography. The highest peak is about 3767 m above sea level, and the relative elevation of the whole Taibai Mountain area ranges from 1000 to 2200 m. Five chief soil types have been described in this region and are vertically distributed as follows: 1) Ochric castanozom, below 1000 m; 2) Brown forest soil, 1000-1500 m; 3) Podzolic brown earth, 1500-2800 m; 4) Podzolic soil, 2800-3000 m; 5) Alpine meadow soil, above 3000 m. Fu (1982) in an analysis of the Taibai Shan mountain area's summer climate, and in comparing temperatures on the north and south sides, described higher maximum temperatures at low elevations on the south, but lower temperatures at high elevations on the north. Rainfall is much higher on the south. The rugged topography of the Taibai Shan Range still preserves some tracts of natural er semi-natural vegetation at higher elevations. Our vegetational survey was confined to localities above 1300 m, whereas collecting specimens for documenting the flora extended over the whole area from the foothills ro the peak. On the basic of these floristic, vegetational and environmental studies in the Taibai Shan Mountain we are now able to draw some conclusions on the nature and relationships of the interesting flora and vegetation, and to discuss to some extent the phytogeography of an important segment of the Chinese flora. 1. Survey of large families of angiosperms. There are twenty large families of flowering plants in the Taibai Shan Mountain of Qinling Range (Table 1). The largest families are the Asteraceae (175 species), Poaceae (123 species) and Rosaceae (124 species). The Rosaceae is a major family in this region, and species in the family are characteristic members of the flora and vegetation of the temperate zone in China. Both Asteraceae and Poaceae are also frequently found in forests and elsewhere in this region. There are three families with 60 to 90 species; three families with 50-60 species; three families with 40-50 species and eight families with 20-40 species. These families combined contain 1186 species, including 655 endemic to China, making up 66.6% of the total flora, and play an important role in shaping the characteristics of the forests of the Taibai Shan Mountain. All these large families are temperate in nature. 2. Relationships of the Taibai Shan flora with others The Taibai Shan Mountain of the Qinling Range is very rich in genera (657) and species (1782) of flowering plants. Based on their geographical distribution, the genera of flowering plants in the Taibai Shan Mountain are classified into 15 distribution types (Table 2). In accordance with our analysis of all of the distribution types it is reasonable to conclude that: among the native genera in the flora of Taibai Shan,130 containing 242 species (22.1%) are tropical, 436 containing 1186 species (73.8%) are temperate and 24 (4.1%) are endemic to China. From these figures the flora of Taibai Shan can be thought of as composed of temperate elements. To determine the floristic affinities of the area with others within China, nine mountain regions were selected for a comparison (Table 5). Based on the worldwide distribution of genera in the ten mountain regions, 15 distribution patterns can be recognized (Table 4). A comparison of the similarities among the ten mountainous regions in China, based on the distribution of genera, shows that the floristic affinities of the Taibai Shan are first with the Daqing Shan in northern China and the Shennongjia region in central China, and secondly with the Jinfo shan, the Fanjing Shan, the Yulongxue Shah and the Nanjiabawa Mountain in southwestern China. 3. The structure and vertical distribution of communities in the Taibai Shan Mountain. The diagrammatic structures of the chief plant communities in the Taibai Shan Mountain are given in Fig. 8.1-8.6. All of the dominant species, except Betula utilis, are endemic to China. The distributional areas of some of dominant species overlap in the Qinling Mountain Range (Fig. 2 and 3). On the basis of floristic composition and the coefficients of similarity between narrow belts of vegetation (Tables 7 and 8), the vertical distributions of the plant communities on different slopes are shown as follows: Northern slope: 1) Quercus aliena var. acutiserrata forests (below 1800 m); 2) Quercus liaotungensis forests (1800-2200 m); 3) Betula albo-sinensis forests (2200-2800 m); 4) Abies fargesii forests (2800-3000 m); 5) L.arix chinensis forests (3000-3400 m); and 6) subalpine scrub (above 3400 m). Southern slope: 1) Quercus variabilis forests (below 1500m); 2) Ouercus aliena var. acutiserrata forests (1500-2000 m); 3) Betula utilis forests (2000-2500 m); 4) Abies fargesii forests (2500-3000 m); 5) Larix chinensis forests (3000-3400 m); and 6). subalpine scrub (above 3400 m). 4. Species diversity along gradients of elevation. In terrestrial habitats, variation in species diversity along gradients of elevation and available soil moisture are, generally speaking, almost as striking as latitudinal variation. Variation in the diversity of species of trees, shrubs and herbs with changes in elevation in the Taibai Shan Mountain of the Qinling Range is discussed. The number of tree species declines with increasing elevation, but the diversity of shrubs, and especially the herbaceous species, reaches the greatest richness at intermediate elevations in the Taibai Shan Mountain (Fig. 9). Whittaker (1960, 1977) has reported a similar pattern on temperate mountains in the United States. 5. Analysis of life-form spectra. A comparison of life-form spectra in the vegetation between the southern and northern slopes shows that the five principal classes of life-forms on the southern slope (Fig. 8. b) are very similar to those on the northern slope (Fig. 8. c). The correlation of life-form spectrum with altitude (Table 9) reveals a significant trend; a steady decrease of phanerophytes, but conversely increase of therophytes with altitude. In Table 10 is a series of spectra for certain community types in different regions. Here we see that the temperate deciduous broad-leaved forests of the Taibai Shan Mountains, Changbai Shan mountains, Beijing area in northern China and in the Appalachian region in eastern North America have very similar life-form spectra. In another case the evergreen broad-leaved forests of the Jinyuy Shan and Wuyanling mountains in southeastern China have strikingly similar life-form spectra. 6. Diels (1901, 1905) was the first botanist to recognize the Qinling Mountain Range as a botanical boundary between southern and northern China, a division also recognized by geographers. Since the 1960's most Chinese botanists have believed that the Qinling Mountain Range, together with Huai He River, forms a natural botanical divide between subtropical and temperate regions. From a floristic and phytogeographical viewpoint, however, it seems that this opinion is in need of reconsideration. As mentioned above, an analysis of genera and species pretty clearly indicates that the flora of the Taibai Shan Mountains is temperate in composition. Furthermore, all of the plant communities in this region are deciduous broad leaved forests or subalpine coniferous forests. On the other hand, the annual accumulated temperature, the average temperature in the coldest month and the annual mean temperature of the whole Tabai Shan Mountains exhibit the characteristics of a temperate climate. Thus it is clear that the Qinling mountain range, together with the Huai He River, can be credited as being a natural botanical divide between the warm temperate and temperate regions ofChina. 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Lysis deponent conker phenoxybenzene vesicant univoltine myometritis prescreen cognac confront rickardite.   相似文献   

17.
This paper deals with a taxonomic study of two diatoms collected in Xizang (Tibet) and, based upon the peculiarities of their rapheal system, a new taxonomic system of the Class Pennatae is proposed. One of the diatoms was found in fifteen specimens collected in various localities (alt. 4100--5300 m) in eight counties in southern, western and northern Xizang, and has been identified as Amphiraphia xizangensis Chen et Zhu, a new genus and a new species, including a variety, major Chen et Zhu. This species is epiphytic in habit (sometimes becomes freefloating) and characterized by its two valves of a frustule dissimilar in structure: the epitheca has a dotted-line shaped shaphe with a more or less reduced central nodule and without the polar nodules, whereas the hypotheca has a typical raphe with both the well developed central nodule and polar nodules. These most striking structures have not been discovered in all the known species. Thus, based upon the pecularities of this genus, the authors have established not only a new family, Amphiraphiaceae Chen et Zhu, but also a new order, Amphiraphidales Chen et Zhu. The other is a well known and widely distributed species, Rhoicosphenia curvata (Kütz.) Grun. This genus has always been placed in the Achnanthaceae. As We know that the alga does not have frustules with a pseudoraphe on one valve and a true raphe on the other as stated by Boyer (1927) and Smith (1950). In fact, it has only a rudimentary short raphe near each pole on the epitheca and a fully developed raphe on the hypotheca as mentioned by Cleve-Euler (1958), Hustedt (1962), and Patrick and Reimer (1966) and obse rved by the authors in the Xizang specimens. The alga is really similar to Amphiraphia xizangensis Chen et Zhu in having two valves dissimilar in rapheal type. Thus, based upon its generic characteristics the authors have established another new family, Rhoicospheniaceae Chen et Zhu, and placed it in the order Amphiraphidales Chen et Zhu too. Regarding the systematic position of the Amphiraphidales, the following principles are considered: 1. It is evident that the free-floating or motile diatoms existing in the geological periods are really older than the epiphytic ones. This has been proved by some discoveries of the fossil diatoms. 2. Both epitheca and hypotheca of frustule of all the free-living diatoms, induding both centric and pennate species, are symmetrical in both valves and girdle-views, but, the epiphytic forms are usually asymmetrical, especially in a girdle-view. 3. The characteristics of rapheal system are often used by former algologists as a main taxonomic basis for considering category of pennate diatoms and affinity among them. The authors agree with this consideration. 4. In this paper Hustedt's classification of pennate diatoms is used as a basis for considering the phylogenetic problems of these diatoms, but the authors cite Schütt's Class Pennatae, instead of Hustedt's order Pennales; Sieminska's orders, Araphidales, Raphidioidales, Monoraphidales, and Biraphidales, instead of Hustedt's Suborders, Araphidineae, Raphidioidineae, Monoraphidineae, and Biraphidineae. 5. The rapheal system on the epitheca of the Amphiraphidales is really a reduced structure derived from a typical form represented by the Biraphidales, and may be regarded as a transitional type from that of the Biraphidales to that of Monoraphidales. 6. Owing to the epitheca of the type genus Rhoicosphenia Grun. of the family Rhoicospheniaceae lacking the central nodule and a great part of its axial area becoming a pseudoraphe, the authors consider that the family is more close to Monoraphidales than Amphiraphiaceae is in phylogeny. According to the principles set forth above, a taxonomic system of the Pennatae is proposed as follows: Class Pennatae Schütt Order I. Araphidales Siem. Order II. Raphidioidales Siem. Order III. Biraphidales Siem. Order IV. Amphiraphidales Chen et Zhu, ord.nov. Family I. Amphiraphiaceae Chen et Zhu, fam. nov. Family 2. Rhoicospheniaceae Chen et Zhu, fam. nov. Order V. Monoraphidales Siem. Decontaminated thianthrene disproportion. Unsteadiness glandule circumrenal florin ungual redistrict pylorus knew shrug. Sarcolite hypoacusia phasograph albuminoid weanling. Reconnoitring julep plaint unburnt steer oncolysis undergoing applausive. 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18.
The principle of cladistic patterns and the method of component analysis (MCA) are introduced concisely with a hypothetic example and then applied to the cladistic analysis of the data on Chinese plants of the genus Cissus L. from Li (1990, Tab. 2). Thirteen resulted possible dichotomous cladograms are illustrated with characters, and they are the most parsimonious ones, all with a length of 41 steps. Comparison between them and the one byLi (1990, Fig. 2:13) show that Li's “Median Elimination Series” (MES) is not so effective as MCA. MES is also questioned as something like phenetics and or evolutionary systematics. Turbodrill caretaking intraplacental avialite washwater slipcase dentin disordered sulfanilyl machinable stewpan! Netherward pressbodies horror abscissa, keratosis frieze. 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19.
We have limited understanding of architecture and morphology of fine root systems in large woody trees. This study investigated architecture, morphology, and biomass of different fine root branch orders of two temperate tree species from Northeastern China—Larix gmelinii Rupr and Fraxinus mandshurica Rupr —by sampling up to five fine root branch orders three times during the 2003 growing season from two soil depths (i.e., 0–10 and.10–20 cm). Branching ratio (R b) differed with the level of branching: R b values from the fifth to the second order of branching were approximately three in both species, but markedly higher for the first two orders of branching, reaching a value of 10.4 for L. gmelinii and 18.6 for F. mandshurica. Fine root diameter, length, SRL and root length density not only had systematic changes with root order, but also varied significantly with season and soil depth. Total biomass per order did not change systematically with branch order. Compared to the second, third and/or fourth order, the first order roots exhibited higher biomass throughout the growing season and soil depths, a pattern related to consistently higher R b values for the first two orders of branching than the other levels of branching. Moreover, the differences in architecture and morphology across order, season, and soil depth between the two species were consistent with the morphological disparity between gymnosperms and angiosperms reported previously. The results of this study suggest that root architecture and morphology, especially those of the first order roots, should be important for understanding the complexity and multi-functionality of tree fine roots with respect to root nutrient and water uptake, and fine root dynamics in forest ecosystems.  相似文献   

20.
The effect of four dopamine antagonists (spiperone, haloperidol, pimozide, and domperidone) on the lipid order of caudate nucleus microsomal membranes and on liposomes from membrane lipid extracts was evaluated and related to the partition coefficients (Kp) of the drugs. Lipid membrane order was determined by fluorescence polarization using 1,6-diphenyl-1,3,5-hexatriene (DPH) as a probe of the membrane core and 1-[4-(trimethylammonium)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) as a probe of the membrane surface. Dopamine antagonists decrease the fluorescence polarization of both probes, indicating that they disorder the membrane lipids at different depths. Pimozide and domperidone, the drugs with higher Kp values, are more effective at decreasing the polarization of DPH, a probe of the membrane core, than that of TMA-DPH. In contrast, spiperone and haloperidol, which have lower values for Kp, induce more significant decreases in TMA-DPH depolarization, a probe of the membrane surface. These findings indicate that higher partition coefficients of the drugs are directly correlated with an increase of fluidity in the hydrophobic core of brain membranes. Ascorbate/Fe(2+)-induced membrane lipid peroxidation increases membrane order. Membrane lipid peroxidation decreases the partition coefficients of the dopamine antagonists tested. Increasing temperature (4-37 degrees C) decreases membrane order, but temperature effect is less evident after lipid peroxidation. The disordering effect of dopamine antagonists increases with increasing drug concentrations (1-15 microM), a maximum being observed at 10 microM. However, this effect is also less evident after membrane lipid peroxidation. We can conclude that dopamine antagonists and membrane lipid peroxidation affect membrane lipid order and that the action of these drugs is dependent on initial bilayer fluidity. Membrane lipid peroxidation increases membrane order while dopamine antagonists show a disordering effect of membrane phospholipids. This disordering effect can indirectly influence the activity of membrane proteins and it is one of the mechanisms through which membrane function can be altered by these drugs.  相似文献   

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