Clonal structure and fertility in a sympatric population of the peat mosses Sphagnum rubellum and Sphagnum capillifolium

1996 ◽  
Vol 74 (9) ◽  
pp. 1375-1385 ◽  
Author(s):  
Nlls Cronberg
Keyword(s):  
Leaf Shape ◽  
Morphological Characters ◽  
Clonal Structure ◽  
Shape Variation ◽  
Canonical Variates Analysis ◽  
Hierarchical Structuring ◽  
Canonical Variates ◽  
Self Fertilization ◽  
The Mean ◽  
A Site

Data from isozyme and leaf shape variation are combined to explore the clonal structure at a site where hybridization between Sphagnum rubellum and Sphagnum capillifolium was previously indicated. Shoots of both species were sampled at 10-cm intervals along seven transects across different hummocks. Allelic data from 13 enzyme systems revealed 22 multilocus genotypes representing different clones, 18 being S. capillifolium and 4 being S. rubellum. The mean ± SE and maximum clonal length were 35 ± 8 cm and 160 cm, respectively. The sets of alleles found in the progeny of S. capillifolium were identical to the maternal complement of alleles in 78% of the material, indicating either self-fertilization or fertilization by a male with the same set of alleles at the screened loci. Outcrossing was detected in six cases. Patterns of differentiation and the hierarchical structuring of diversity among species, transects, and clones were analysed with canonical variates analysis using stem-leaf characters. A stronger relative differentiation was found between transects than between species. Clones identified by electrophoresis were usually morphologically well defined. Hybridization was indicated by morphological characters, occasional misplaced alleles, and signs of developmental instability. Keywords: allozymes, computerized image analysis, breeding system, clonal structure, Sphagnum rubellum, Sphagnum capillifolium.

Phenotypic variation of south-western Atlantic clam Mactra isabelleana (Bivalvia: Mactridae)

2012 ◽  
Vol 93 (2) ◽  
pp. 511-517 ◽  
Author(s):  
Javier H. Signorelli ◽  
Federico Márquez ◽  
Guido Pastorino
Keyword(s):  
Principal Component ◽  
Shell Shape ◽  
Physical Parameters ◽  
Buenos Aires Province ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Western Atlantic ◽  
Canonical Variates Analysis ◽  
Canonical Variates ◽  
Geometric Morphometric Method

The phenotypic shell shape variation of Mactra isabelleana was tested using the geometric morphometric method. Four localities were sampled along the Río de la Plata estuary and the coast of Buenos Aires province. Principal component analysis and canonical variates analysis of the first principal components were performed to reveal the shell variation and differences among localities, respectively. The specimens from different microhabitats mostly overlapped, although differences in shape were observed in the development of the umbo, the enlargement of the dorsoventral axes and the elongation of the posterior end. The ecological and physical parameters that could influence shell shape variation are discussed.

Identificatin of Native Typha species in Australia

1985 ◽  
Vol 33 (1) ◽  
pp. 101 ◽  
Author(s):  
M Finlayson ◽  
RI Forrester ◽  
DS Mitchell ◽  
AJ Chick
Keyword(s):  
Leaf Shape ◽  
Leaf Sheath ◽  
Root Tips ◽  
Absolute Identification ◽  
Canonical Variates Analysis ◽  
Male And Female ◽  
Australian Species ◽  
Female Inflorescence ◽  
Canonical Variates ◽  
Key Characters

The variability of some key characters used to identify the two Australian species of Typha (T. domingensis and T. orientalis) was quantitatively determined on 13 stands at different sites. Characters measured were plant height, leaf width, length of female inflorescence, diameter of female inflorescence and gap between male and female inflorescences. The three characters, length of female inflorescence, diameter of female inflorescence and gap between the inflorescences, used in conjunction with the latent vector from a canonical variates analysis could be used to identify the two species. The presence or absence of an auriculated leaf sheath was also found to be a useful character, while leaf shape was not. However, to obtain absolute identification, chromosome numbers can be determined easily on root tips.

Morphometric study of the Pissodes strobi complex (Coleoptera: Curculionidae)

2002 ◽  
Vol 134 (4) ◽  
pp. 447-466 ◽  
Author(s):  
Daryl J.M. Williams ◽  
David W. Langor
Keyword(s):  
Body Size ◽  
Morphological Characters ◽  
Resolving Power ◽  
Morphometric Study ◽  
Stepwise Discriminant Analysis ◽  
Western North America ◽  
Discriminant Functions ◽  
Canonical Variates Analysis ◽  
Pissodes Strobi ◽  
Canonical Variates

AbstractMorphometric data were collected on 15 characters in adults of the species of the Pissodes strobi complex (P. nemorensis (Germar), P. schwarzi Hopkins, P. strobi (Peck), and P. terminalis Hopping). Data were examined using stepwise discriminant analysis to determine if all characters contribute significantly to the diagnosis of taxa, and their relative amounts of resolving power were illuminated using canonical variates analysis. Discriminant functions were generated to diagnose species. Separate discriminant functions were generated for each sex for populations from eastern and western North America. Significant sexual dimorphism and variability in body size decrease the utility of morphological characters for diagnosis, but did not prevent the formulation of useful discriminant functions, particularly when selected ratios that control for body size were added.

A multivariate study of morphometric variation in species of the ciliate genus Colpoda (Ciliophora: Colpodida)

1983 ◽  
Vol 61 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Denis H. Lynn ◽  
Jay R. Malcolm
Keyword(s):  
Morphological Characters ◽  
Multivariate Statistical Methods ◽  
Multivariate Statistical ◽  
Morphometric Variation ◽  
Canonical Variates Analysis ◽  
Multivariate Study ◽  
Single Character ◽  
Length Range ◽  
Canonical Variates ◽  
Left And Right

Univariate and multivariate statistical methods were used to study morphometric variation of 19 clones from eight species of the ciliate genus Colpoda. No single character could provide complete discrimination of all species. However, results of canonical variates analysis demonstrated that some morphological characters, which are considered important by taxonomists, do provide for maximum discrimination among the species. These characters include left and right keel kinety number, incurrent and excurrent canal kinety number, and vestibular kinety number. The clones in the somatic length range of 44–70 μm are apparently more difficult to distinguish by morphometric criteria.

scholarly journals Size matters: micro-evolution in Polynesian rats highlights body size changes as initial stage in evolution

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9076
Author(s):  
Alexandra A.E. van der Geer
Keyword(s):  
Temporal Distribution ◽  
Shape Variation ◽  
Mammal Species ◽  
Canonical Variates Analysis ◽  
Ecological Release ◽  
Initial Stage ◽  
Evolutionary Allometry ◽  
Canonical Variates ◽  
Coordinate Data

Microevolutionary patterns in populations of introduced rodent species have often been the focus of analytic studies for their potential relevance to understanding vertebrate evolution. The Polynesian rat (Rattus exulans) is an excellent proxy species because of its wide geographic and temporal distribution: its native and introduced combined range spans half the globe and it has been living for at least seven centuries wherever it was introduced. The objective of this study was to assess the effects of long-term isolation (insularity; up to 4,000 years) and geographic variables on skull shape variation using geometric morphometrics. A sample of 513 specimens from 103 islands and four mainland areas was analysed. This study, to my knowledge the first to extensively sample introduced rats, analysed 59 two-dimensional landmarks on the skull. Landmarks were obtained in three separate aspects (dorsal, lateral, ventral skull view). The coordinate data were then subjected to a multivariate ordination analysis (principal components analysis, or PCA), multivariate regressions, and a canonical variates analysis (CVA). Three measures of disparity were evaluated for each view. The results show that introduced Polynesian rats evolve skull shapes that conform to the general mammalian interspecific pattern of cranial evolutionary allometry (CREA), with proportionally longer snouts in larger specimens. In addition, larger skulls are more tubular in shape than the smaller skulls, which are more balloon-shaped with a rounder and wider braincase relative to those of large skulls. This difference is also observed between the sexes (sexual dimorphism), due to the slightly larger average male size. Large, tubular skulls with long snouts are typical for Polynesia and Remote Oceania, where no native mammals occur. The greater disparity of Polynesian rats on mammal species-poor islands (’exulans-only’ region) provides further insight into how diversity may affect diversification through ecological release from predators and competitors.

scholarly journals Using the SWEPT Methodology for a Preliminary Wind Potential Estimation

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Jean-Luc Menet
Keyword(s):  
Wind Turbine ◽  
Characteristic Curve ◽  
Rayleigh Distribution ◽  
Mean Velocity ◽  
Technical Data ◽  
Wind Potential ◽  
Order Of Magnitude ◽  
General Data ◽  
The Mean ◽  
A Site

The implantation of wind turbines generally follows a wind potential study which is made using specific numerical tools; the generated expenses are only acceptable for great projects. The purpose of the present paper is to propose a simplified methodology for the evaluation of the wind potential, following three successive steps for the determination of (i) the mean velocity, either directly or by the use of the most occurrence velocity (MOV); (ii) the velocity distribution coming from the single knowledge of the mean velocity by the use of a Rayleigh distribution and a Davenport-Harris law; (iii) an appropriate approximation of the characteristic curve of the turbine, coming from only two technical data. These last two steps allow calculating directly the electric delivered energy for the considered wind turbine. This methodology, called the SWEPT approach, can be easily implemented in a single worksheet. The results returned by the SWEPT tool are of the same order of magnitude than those given by the classical commercial tools. Moreover, everybody, even a “neophyte,” can use this methodology to obtain a first estimation of the wind potential of a site considering a given wind turbine, on the basis of very few general data.

scholarly journals The isotopic record at an alpine glacier and its implications for local climatic changes and isotopic homogenization processes

2001 ◽  
Vol 47 (156) ◽  
pp. 147-151 ◽  
Author(s):  
He Yuanqing ◽  
Wilfred H. Theakstone ◽  
Yao Tandong ◽  
Shi Yafeng
Keyword(s):  
Equilibrium Line Altitude ◽  
Temperature Variations ◽  
Alpine Glacier ◽  
Temperature Changes ◽  
Natural Factors ◽  
Air Temperatures ◽  
Regional Temperature ◽  
The Mean ◽  
A Site ◽  
The Relationship

AbstractStratigraphic variations of oxygen isotopes in the snow which accumulates during the winter at the Norwegian glacier Austre Okstindbreen are not entirely eliminated after 1–2 months of ablation in the following summer. The relationship between regional temperature changes and δ18O values in the snowpack is affected by many natural factors, but 1989/90 winter air temperatures were reflected in the snow which remained on Austre Okstindbreen at 1350 m a.s.l. in July 1990. There were many variations of δ18O values in the 4.1m of snow above the 1989 summer surface, but variations in the underlying firn were relatively small. Meltwater percolation modifies the initial variations of δ18O values in the snowpack. At a site below the mean equilibrium-line altitude on Austre Okstindbreen, increased isotopic homogenization within a 10 day period in July accompanied an increase of the mean δ18O value. Although the isotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glaciers, it can provide an estimate of the approximate trend of local temperature variations.

Developmental comparison of leaf shape variation in three Chamaedorea species

Botany ◽  
2009 ◽  
Vol 87 (2) ◽  
pp. 210-221 ◽  
Author(s):  
Julia Nowak ◽  
Adam Nowak ◽  
Usher Posluszny
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Leaf Development ◽  
Leaf Shape ◽  
Shape Variation ◽  
Differential Growth ◽  
Scanning Electron ◽  
Palm Leaf ◽  
The Ideal

Compound palm leaf development is unique and consists of two processes. First, the primordial tissue folds through differential growth, forming plications. Second, these plications separate through an abscission-like process, forming leaflets. The second process of leaflet separation allows for the development of compound leaves. The question that this study addresses concerns the development of bifid leaves, as they do not form leaflets but only develop a cleft through an apical incision. The ideal genus to use for this study is Chamaedorea as it includes species with both pinnate and bifid leaves. Chamaedorea fragrans (Ruiz & Pav.) Mart. and Chamaedorea stolonifera H. Wendl. ex Hook. f. were chosen as the species with adult bifid leaves. Although Chamaedorea seifrizii Burret is a pinnate-leaved palm, its juvenile leaves are bifid. Scanning electron microscopy and light microscopy were used to study the development of bifid leaves. Our results indicate that neither of these bifid palms develop separation sites within the lamina, but rather the apical cleft develops through “late leaflet separation” or by an abscission-like process. In contrast, C. seifrizii juvenile leaves exhibit “early leaflet separation” when developing the apical cleft.

scholarly journals MORPHOLOGICAL AND CHROMOSOMAL CHARACTERIZATION OF ORCHID Peristylus goodyeroides Lindl. FROM CURUG SETAWING, KULONPROGO

2021 ◽  
Vol 12 (2) ◽  
pp. 110
Author(s):  
Febri Yuda Kurniawan ◽  
Anindita Della Rosa Riyadi
Keyword(s):  
Leaf Shape ◽  
Ecological Factors ◽  
Morphological Characters ◽  
Morphological Characterization ◽  
Observation Data ◽  
Chromosome Configuration ◽  
Telocentric Chromosomes ◽  
Leaf Arrangement ◽  
Karyotype Formula

Peristylus goodyeroides is a terestrial orchid that scattered around Southeast Asia. Morphological characters of P. goodyeroides can vary, depending on the ecological factors and habitat. Cytological characters in the form of chromosome configurations can be used as a taxonomic tool for the process of identifying and understanding variations in taxa. The purpose of this study was to determine the morphological characters and chromosome configuration of the P. goodyeroides from Curug Setawing, Kulonprogo. The method used was morphological characterization and plant chromosome preparation by squash method with the main steps of fixation, maceration, staining and observation. Data were analyzed with the help of Image raster 3, Corel Draw X7, and Microsoft Excel 2013. P. goodyeroides from Curug Setawing has the morphological characters of root tubers, cylindrical stems, ovate leaf shape, convolutive leaf arrangement and creamy white flowers. The orchid has a number of chromosomes 2n = 10 with a karyotype formula of 2n = 2x = 8m + 2t. Metacentric chromosomes are found on chromosomes 1-8 and telocentric chromosomes 9-10. The absolute arm length of the chromosomes has a range of 2.03-3.44 μm, the relative arm length of the chromosomes is 2.21-3.32 μm, the length of the p arm is 1.13-1.58 μm and the q arm is 1.23-2.12 μm.

Some new measurements of heat flow in the Superior Province of the Canadian Shield

1987 ◽  
Vol 24 (7) ◽  
pp. 1486-1489 ◽  
Author(s):  
Malcolm Drury ◽  
Alan Taylor
Keyword(s):  
Standard Deviation ◽  
Heat Flow ◽  
Canadian Shield ◽  
Superior Province ◽  
Flow Measurements ◽  
Radiogenic Heat ◽  
Radiogenic Heat Production ◽  
Climatic Variations ◽  
The Mean ◽  
A Site

Borehole heat-flow measurements are reported from six new sites in the Superior Province of the Canadian Shield. Values adjusted for glaciation effects, but not for Holocene climatic variations, range from 42 to 56 mW/m2. When these new values are combined with 21 previously published borehole values the mean is 42 mW/m2 with a standard deviation of 11 mW/m2. The data for a site on the Lac du Bonnet batholith suggest that the batholith has a thin veneer, less than 3 km, of rock of high radiogenic heat production at the surface.

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