基于30个形态性状的中国杏属（Armeniaca Scop.）植物分类学研究

基于与叶和果实相关的30个形态性状(包括20个定性性状和10个定量性状)对中国杏属( Armeniaca Scop.)11种3变种进行了UPGMA聚类分析和主成分分析;在主成分分析基础上,构建了中国杏属植物的OTU散点图;并且,结合降水量分布图绘制了中国杏属植物分布图。聚类分析结果显示：供试杏属植物被分成2支。若包含毛叶梅( A. mume var. goethartiana Koehne),则毛叶梅、梅( A. mume Sieb.)、洪平杏( A. hongpingensis C. L. Li)以及政和杏( A. zhengheensis J. Y. Zhang et M. N. Lu)聚为一支,其余8种2变种聚为另一支;若不包含毛叶梅,梅则被划分在后一个分支中。主成分分析结果显示：前3个主成分的累计贡献率仅60.3180%,说明中国杏属植物的形态性状具有较大的遗传变异;在前3个主成分中,树高、叶片下表面被毛情况、叶长/叶柄长比值、叶长/叶宽比值、果核形状、叶宽、果核宽、叶柄长、果柄长和叶缘锯齿形状的绝对权重值均在0.7以上,表明这10个性状在中国杏属植物的分类学研究中具有重要作用。 OTU散点图显示：中国杏属植物在二维散点图上的分类结果与其聚类结果基本一致,并且,其聚类结果中的各分支在三维散点图上也能够明显区分,说明可以采用前3个主成分中绝对权重值较高的性状对中国杏属植物进行分类。分布图显示：杏属植物遍布中国各省(区),且主要集中分布在400和800 mm等降水量线之间的区域。结合上述研究结果及他人的研究成果,支持“将藏杏﹝A. holosericea ( Batal.) Kost.〕作为杏( A. vulgaris Lam.)的1个变种”以及“将政和杏作为梅的1个变种”的分类处理,并支持“将洪平杏作为独立种”的分类处理。此外,建议将仙居杏( A. xianjuxing J. Y. Zhang et X. Z. Wu)和华仁杏( A. cathayana D. L. Fu et al)作为杏属的栽培种。     

A quantitative morphological analysis of macrophage stimulation

Summary The principles of stereology have been applied to a stereometric analysis of the ultrastructural composition of normal rat peritoneal macrophages and of cells stimulated five days previously by a single intraperitoneal dose of Freund's adjuvants. Material obtained by a systematic random sampling regime was analysed and the data groups for various morphological parameters were compared.Estimates were made of cell numbers. From electron micrographs the volume proportions of nuclei, mitochondria, heterogeneous granules and rough endoplasmic reticulum were determined. The average numbers and dimensions of mitochondria, granules and free ribosomes were also evaluated. The volume-to-surface ratios of cells and their nuclei were computed. By the independent measurement of cellular volumes it was possible to obtain estimates of nuclear and cytoplasmic volumes, to evaluate the membrane surface areas of the average cells and their nuclei, and to calculate numbers of organelles per average cell.The structural alterations induced by the complete adjuvant were similar to those evoked by the incomplete adjuvant. Stimulation was characterized by a cellular hypertrophy accompanied by an increase in mean granule size and in the number of mitochondria per average cell. At the same time, there was a substantial decrease in the number of granules and a considerable depletion of both nuclear and plasma membrane surface areas.     

A morphological classification capturing functional variation in phytoplankton

1. A logical way of distinguishing functional groups of phytoplankton is to cluster species according to their functional traits, such as growth rate and nutrient assimilation constants. However, data for such an approach are lacking for the vast majority of the species. 2. In this study, we show that a classification based on simple morphological traits may capture much of the variability in functional properties among the phytoplankton. We used information on more than 700 freshwater species, from more than 200 lakes situated in climate zones ranging from subpolar to tropical. 3. Morphological characteristics correlated well with functional properties, such as growth rate and sinking rate, and also with the population size and biomass attained in the field. This suggests that morphology is a good predictor of the functional characteristics of species. 4. Cluster analysis was used to define seven species groups based on morphology. Although some of the clusters are taxonomically homogeneous, others include species of several separate divisions. Functional traits (not used for the classification) differed significantly among the clusters, suggesting that the clusters may indeed represent meaningful functional groups. 5. Advantages of our morphological approach to classification include its objectivity, its independence from taxonomic affiliations, and the relative ease of its application to the majority of species for which physiological traits are unknown and are not readily determined.     

A morphological classification of bacteria containing bullet-shaped magnetic particles

Abstract We have studied isolated magnetic bacteria using light and electron microscopy, and classified those which contain bullet-shaped magnetic particles into four distinct morphological types, designated BS-1 to BS-4. Two of the types, BS-1 and BS-2, are new, and have unusual arrangements of magnetic particles. The rod-shaped bacterium BS-1 has a dense network of several thousand magnetic particles, whereas BS-2, a coccus, contains magnetic particles arranged radially in bands.     

A morphological quantitative study of small vessels in diabetic cardiomyopathy

In 25 adult diabetic patients, tissue fragments from myocardium were removed at necropsy and processed routinely. The morphometrical analysis was made using eye-piece ocular micrometer on a definite microscopic area. The arteriolar wall thickness increased from 5.10 mu +/- 1.71 in control group to 7.37 mu +/- 1.98 in the diabetic heart. The arterioles number decreased from 5.82/mm2 +/- 0.54 in the nondiabetics to 2.51/mm2 +/- 0.65 in the diabetic heart. The mean arteriolar diameter increased from 24.61 mu +/- 7.7 in the control group to 29.45 mu +/- 8.25 in the diabetic myocardium. The mean capillary diameter increased from 4.09 mu +/- 0.63 to 5.69 mu +/- 1.34 in diabetics. The capillaries number/mm2 decreased from 6.98 +/- 1.55 in the nondiabetics to 4.39 +/- 1.54 in diabetic patients. All differences, less the mean arteriolar diameter, are statistically significant. The following microscopical aspects were found in the small intramural coronary arteries: proliferation of endothelial cells with focal protuberances leading to partial narrowing of the lumen; increased thickness of the arteriolar wall due to fibrosis and accumulation of neutral mucopolysaccharides; alterations of elastic fibers. Frequently small areas of perivascular fibrosis and isolated foci of myocytolysis were found as well. These results suggest that the arteriolar impairment, especially the thickening of the arteriolar wall, could play a role in the pathogenesis of diabetic cardiomyopathy.     

苜蓿属和胡卢巴属植物的形态特征及数量分类研究

为研究苜蓿属(Medicago L.)与胡卢巴属(Trigonella L.)间的亲缘关系,寻找两属间的分属依据,解决中间过渡类群的分类归属问题,对苜蓿属与胡卢巴属种类的种皮结构和花粉形态特征进行了观察和测量,并以苜蓿属和胡卢巴属植物的40个形态性状为依据、应用数量分类方法对供试的16个种类进行了聚类分析(UPGMA)和主成分分析(PCA).此外,还根据具有重要分类学意义的形态性状,编写了供试的苜蓿属和胡卢巴属16个种类的分类检索表.观察结果表明,供试的两属植物(11种)的种皮结构基本相同,均由栅栏组织细胞、厚壁细胞和薄壁细胞组成,但胡卢巴属种皮的帽状结构和栅栏组织的厚度均小于苜蓿属.供试的两属植物(9种)花粉形态特征相似,均为椭球形或近球形,赤道面观为椭圆形,极面观为三裂圆形;极轴和赤道轴长分别为22.67～34.67 μm和17.34～31.60 μm;花粉表面纹饰较简单,呈小穴状.种皮结构和花粉特征显示两属的亲缘关系较近,仅种皮结构中的帽状结构差异具有一定的属间分类学意义.聚类分析结果表明,在欧氏距离10.85处,供试的苜蓿属(11种)和胡卢巴属(5种)的16个种类被划分为2组,A组均由胡卢巴属种类组成,B组均由苜蓿属种类组成;在欧氏距离9.32处,B组可被进一步划分为3个亚组,所包含的种类分别为苜蓿属的阔荚亚属(Subgen. Platycarpos D. F. Cui)、镰荚亚属(Subgen. Medicago Tutin)和天蓝苜蓿亚属(Subgen. Lupulina Gressh.)的种类.主成分分析结果表明,前3个主成分的累积贡献率较低,仅57.50%;在前3个主成分中,果实和小叶的长宽比、花萼长和被毛状况、茎和小叶的被毛状况、小叶尖形状、花序长等相关性状的绝对权重值均在0.6以上,具有重要的分类学意义;基于前2个主成分所做的二维散点图中供试的16个种类组成4个表征类群,与聚类分析结果一致.     

A quantitative genetic model for analyzing species differences in outcrossing species

A genetic model based on a two-level intra- and interspecific mating design is proposed to estimate the genetic architecture of species differences and heterosis for outcrossing species. The underlying genetic analyses make use of classical quantitative genetic theories and recent results from molecular genetic studies. Gene effects across different quantitative trait loci (QTL) can be approximated by a geometric series. Under natural selection, gene effects are often associated with allele frequencies in a particular way, which can be approximated by the gamma distribution. By incorporating these approximations into family structural analyses in the mating design, we are able to estimate a number of genetic parameters that contribute to quantitative genetic variation based on a nonlinear optimization approach. These parameters include the number of QTL, their gene effects, and their allele frequencies in the parental populations. We perform simulation studies and illustrate an example to demonstrate the statistical property and procedure of the method.     

基于GIS的森林景观定量分类

以金沟岭林场为例,利用电子林相图和森林资源二类调查资料基础,借助GIS软件MapInfo和数字化仪跟踪矢量化,并运用景观生态学原理和方法,选取分维数、分离度斑块密度、景观优势度和均匀度等指标,对林场的景观格局进行了分析;同时采用类平均聚类法,选取分维数、分离度、斑块平均面积、最大斑块面积4个景观类型特征指数作为聚类分析的聚类因子,进行定量地划分森林类型,合理地区划森林经营类型,为优化景观水平配置、制定生态采伐规程、编制森林经营方案提供理论基础。     

A quantitative morphological study of human Leydig cells from birth to adulthood

Summary Human testicular specimens were obtained from biopsies and autopsies covering the period from birth to adulthood. The number of testosterone-containing Leydig cells was determined using the peroxidase-anti-peroxidase method. This number decreased markedly from 3–6 months of age to the end of the first year of life and, up to 6 years of age, only a small number of testosterone-containing cells was found. From 6 years onwards the number of Leydig cells progressively increased. Ultrastructural examination revealed four types of Leydig cells: (1) fetal-type Leydig cells (from birth to 1 year of age) with round nuclei, abundant smooth endoplasmic reticulum and mitochondria with tubular cristae; (2) infantile-type Leydig cells (from birth to 8–10 years of age), showing a multilobated nucleus, moderately abundant smooth endoplasmic reticulum, some lipid droplets and mitochondria with parallel cristae; (3) prepubertal, partially differentiated Leydig cells (from 6 years of age onwards) with regularly-outlined round nuclei, abundant smooth endoplasmic reticulum, mitochondria with tubular cristae, and some lipid droplets and lipofuscin granules; and (4) mature adult Leydig cells (from 8–10 years of age onwards). The ultrastructure of the infantile-type Leydig cells and the lack of delay between the disappearance of the fetal-type Leydig cells and the appearance of infantile-type Leydig cells suggest that fetal-type Leydig cells give rise to the infantile-type Leydig cells. Before puberty, myofibroblast-like precursor cells differentiate into the prepubertal, partially differentiated Leydig cells, which complete their differentiation into the adult Leydig cells.This work was supported by grants from the Comisión Asesora de Investigation Científica y Técnica, and the Fondo de Investigaciones Sanitarias de la Seguridad Social, Madrid, Spain     

A new species of Cudonia based on morphological and molecular data

A discomycete collected in western Sichuan, China, is morphologically intermediate between Cudonia and Spathularia. The fungus has a bright yellow capitate ascigerous head, a white, ridged stalk, and a well-developed membrane covering the whole ascoma. The asci, ascospores, and paraphyses are similar to those of Cudonia and Spathularia. Based on morphology and DNA sequence analysis, a new species, Cudonia sichuanensis, is reported. Cudonia and Spathularia are closely related to members of Rhytismataceae, as has been suggested previously. The similarity of ascoma and ascospore development between these two genera and Lophodermium (Rhytismataceae) is discussed.     

A morphological and genetic analysis of the European bitterling species complex

Bitterling fishes lay their eggs on the gills of living freshwater mussels and are valuable models in behavioural and evolutionary ecology. We used morphological and genetic data to resolve the taxonomic relationships of bitterling in Europe. Previous studies have suggested the European bitterling is either a single species with a wide but discontinuous geographic distribution, or a complex of species. Morphometric and meristic data identified differences between three putative species; with a clear distinction between the eastern Asian Rhodeus sericeus, western European bitterling Rhodeus amarus, and colchian bitterling, Rhodeus colchicus. Polymorphism in the mitochondrial DNA control region was predominantly due to insertion/deletion events, making phylogenetic inference difficult, but the single haplotype found in R. sericeus populations was detected at low frequency (one of 24 individuals) in R. amarus and R. colchicus populations. Eight control region haplotypes were found in R. amarus populations, which were distinct from the two haplotypes in a R. colchicus population. Cytochrome b data produced a phylogeny with strongly‐supported differentiation between a clade of two R. sericeus haplotypes and a clade of six R. amarus/colchicus haplotypes. The star‐like topology of the R. amarus/colchicus haplotypes in a minimum spanning network suggested a rapid radiation in this clade. Our results are consistent with an hypothesis of relatively ancient divergence of R. sericeus from R. amarus/colchicus and more recent and rapid differentiation between R. amarus and R. colchicus. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 337–347.     

Plant species delimitation: A comparison of morphological and molecular markers

Abstract

Species delimitation is fundamental in many areas of biology. Despite its importance, there is no agreement on criteria for species delimitation mostly due to divergence on the point of view adopted by the different biological disciplines. Two main groups of diagnostic characters are commonly used to distinguish species: the traditional morphological ones and the molecular ones. Field species recognition and sampling are generally based on morphological characters, but they can either fail to discriminate species and mask the presence of cryptic species or discriminate different species while in reality there is only one. To overcome this problem it is common to compare clusters obtained on the basis of the observed polymorphism of both characters, and to analyse their agreement. Here we compile a set of studies that have examined species delimitation with both markers. This provides a review of the different morphological and molecular markers, and of the sampling strategy and clustering methodology generally employed to delimitate species. Some conclusions are drawn with regard to species delimitation, when comparing diagnostic morphological and molecular markers.     

A thirty million year-old inherited heteroplasmy

Due to essentially maternal inheritance and a bottleneck effect during early oogenesis, newly arising mitochondrial DNA (mtDNA) mutations segregate rapidly in metazoan female germlines. Consequently, heteroplasmy (i.e. the mixture of mtDNA genotypes within an organism) is generally resolved to homoplasmy within a few generations. Here, we report an exceptional transpecific heteroplasmy (predicting an alanine/valine alloacceptor tRNA change) that has been stably inherited in oniscid crustaceans for at least thirty million years. Our results suggest that this heteroplasmy is stably transmitted across generations because it occurs within mitochondria and therefore escapes the mtDNA bottleneck that usually erases heteroplasmy. Consistently, at least two oniscid species possess an atypical trimeric mitochondrial genome, which provides an adequate substrate for the emergence of a constitutive intra-mitochondrial heteroplasmy. Persistence of a mitochondrial polymorphism on such a deep evolutionary timescale suggests that balancing selection may be shaping mitochondrial sequence evolution in oniscid crustaceans.     

A quantitative morphological study of osmotically induced swelling and shrinkage in nervous tissue

The rabbit retina was used to study, in vitro, the responses of central nervous tissue to changes in extracellular osmolarity. After isolation, retinas were incubated in either hypertonic or hypotonic medium containing 80 milliosmols more or 80 milliosmols less sodium chloride than the isotonic control medium. After fixation and embedding, comparable areas of each retina were sectioned and studied with the phase and electron microscopes. The diameters of receptor cell inner segments, synapses, nuclei, and mitochondria were measured on micrographs; mean nuclear areas and volumes were calculated. Cutouts from micrographs also provided areas and volumes of the receptor cell nucleus and its 'surround' of axons, dendrites, glial processes, and extracellular space. In general, hypertonic incubation produced decreases in the linear dimensions, areas, and volumes of the receptor cell, its nucleus, and its mitochondria that were consistent with their behaviour as osmometers. After hypotonic incubation, the increases in the diameters of inner segments, synapses, and mitochondria were in the predicted range. The increases for the nuclei themselves, and the nuclei and their 'surround' were less than expected. This may have been due to the failure of the preparative techniques to maintain the swollen state of these larger structures.