DISTRIBUTION AND CYTOLOGY OF ELYMUS MACOUNII VASEY

1960 ◽  
Vol 38 (1) ◽  
pp. 63-67 ◽  
Author(s):  
A. T. H. Gross
Keyword(s):  
Colchicine Treatment ◽  
Naturally Occurring ◽  
Hordeum Jubatum ◽  
Agropyron Trachycaulum ◽  
Cross Fertilization ◽  
Prairie Provinces

The distribution of Elymus macounii Vasey in the Prairie Provinces of Canada is extensive and apparently governed by the occurrence of its putative parents, Agropyron trachycaulum (Link) Malte and Hordeum jubatum L. The hybrid E. macounii was produced by controlled cross-fertilization of A. trachycaulum and H. jubatum. Subsequently, octoploid E. macounii was obtained by colchicine treatment. Cytological studies indicated 2n = 28 for A. trachycaulum, H. jubatum, and E. macounii (both artificially produced and naturally occurring hybrids). Irregular meiosis of E. macounii and some irregularity in meiosis of octoploid E. macounii were observed.

THE BIOLOGY OF CANADIAN WEEDS.: 31. Hordeum jubatum L.

1978 ◽  
Vol 58 (3) ◽  
pp. 699-708 ◽  
Author(s):  
K. F. BEST ◽  
J. D. BANTING ◽  
G. G. BOWES
Keyword(s):  
Effective Control ◽  
Hordeum Jubatum ◽  
Prairie Provinces

An account is given of biology of Hordeum jubatum L. It is found throughout Canada but is particularly prevalent as a weed of rangeland and pastures of the Prairie Provinces. The paper is one of a series on the biology of Canadian weeds and is concerned primarily with those characteristics of the species which appear to present the main obstacles to its effective control.

Threatened dry grasslands in the continental boreal forests of Wood Buffalo National Park: commentary

1999 ◽  
Vol 77 (7) ◽  
pp. 913-917
Author(s):  
Kevin P Timoney
Keyword(s):  
Boreal Forests ◽  
National Park ◽  
Ecological Factors ◽  
Clear Understanding ◽  
Dry Grasslands ◽  
Calamagrostis Canadensis ◽  
Koeleria Macrantha ◽  
Hordeum Jubatum ◽  
Wood Buffalo National Park ◽  
Agropyron Trachycaulum

There are three primary types of graminoid-dominated communities in or near Wood Buffalo National Park, Canada: freshwater meadows and marshes composed of Calamagrostis canadensis (Michx.) Beauv., Carex atherodes Spreng., Carex aquatilis Wahlenb., Scolochloa festucacea (Willd.) Link, and Poa L.; saline meadows composed of Hordeum jubatum L., Puccinellia nuttalliana (Schult.) A.S. Hitchc.,Agropyron trachycaulum (Link) Malte, Calamagrostis stricta (Timm) Koeler, and Calamagrostis inexpansa A. Gray; and dry grasslands composed of Agropyron trachycaulum, Stipa L., Carex siccata Dewey, Carex obtusata Lilj., and Koeleria macrantha (Ledeb.) J.A. Schultes f. Except for the Peace Point area, it is not known whether dry grasslands have declined in areal extent. Including various wetlands under "dry grasslands", and concluding that these areas no longer support dry grassland is misleading. Dry grasslands exist in Wood Buffalo National Park, but most graminoid-dominated communities in the park are, and have been, freshwater and saline meadows and marshes. A clear understanding of the ecological factors operating in these different ecosystems is critical to informed management.Key words: fire, grassland, prairie, vegetation, wetland, Wood Buffalo National Park.

Forage Fibre Analyses: a Comparison of Two Techniques.

1992 ◽  
Vol 19 (3) ◽  
pp. 289 ◽  
Author(s):  
NC Larter
Keyword(s):  
Forage Quality ◽  
Fibre Content ◽  
Poor Correlation ◽  
Strong Negative Correlation ◽  
Elymus Trachycaulus ◽  
Forage Digestibility ◽  
High Fibre ◽  
High Fibre Content ◽  
Hordeum Jubatum ◽  
Agropyron Trachycaulum

Forage fibre content is frequently used as index of forage quality where high fibre content indicates low forage quality. Fibre content is usually estimated by the familiar ADF technique. An alternative method, the acid-pepsin digestibility (AP) technique, provides an estimate of forage digestibility where low digestibility indicates a high fibre content. Fibre content estimates in herbaceous forage (Carex atherodes, C. aquatilis, Phalaris arundinacea, Calamagrostis spp., Agropyron trachycaulum [Elymus trachycaulus] and Hordeum jubatum) were compared by the ADF and AP techniques. There was a strong negative correlation between the fibre content, as determined by ADF, and the digestibility, as determined by AP, in a wide variety of herbaceous forages. This suggests that both techniques provide a very similar estimate of forage quality in herbaceous forages. Contrastingly, a similar analysis on Salix spp. and lichen showed a poor correlation between techniques, suggesting dissimilar estimates of fibre content of these forages.

From mediatized political discourse to The Hobbit

2015 ◽  
Vol 5 (2) ◽  
pp. 264-282
Author(s):  
Bálint Péter Furkó
Keyword(s):  
Case Studies ◽  
Political Discourse ◽  
Literary Texts ◽  
Pragmatic Markers ◽  
Naturally Occurring ◽  
The Cross ◽  
Literary Pragmatics ◽  
Cross Fertilization

The present paper argues that the analysis of the functional spectrum of pragmatic markers (PMs) serves as a heuristic tool for studying the interactional dynamics of dialogues in a variety of genres and discourse types, whether naturally-occurring, scripted or literary. By way of arguing my point I will discuss the results of three of my previous case studies aimed at exploring the role of PMs. The case studies, by virtue of the types of discourse they are based on (mediatised political interviews, dramatised/televised conversations and literary texts) reveal different patterns of dialogicity, and complement the analyses of spontaneous everyday conversations, the type of data most of the current PM research draws on. In the course of my analyses I also hope to illustrate that the cross-fertilization between dialogue analysis, PM research and literary pragmatics has a lot to offer to all three disciplines.

COLCHICINE INDUCED BIVALENT PAIRING OF TETRAPLOID MICROSPOROCYTES IN TRITICUM LONGISSIMUM AND T. SPELTOIDES

1976 ◽  
Vol 18 (4) ◽  
pp. 731-738 ◽  
Author(s):  
Lydia Avivi
Keyword(s):  
Colchicine Treatment ◽  
Meiotic Pairing ◽  
Homologous Chromosomes ◽  
Sister Chromatids ◽  
Naturally Occurring ◽  
Or Genes

The low-pairing gene or genes of diploid Triticum longissimum (Schwinf. &Muschl.) Bowden predispose the induced autotetraploid towards bivalent pairing. In this work, bivalentization was phenocopied in intermediate- and low-pairing lines of T. longissimum and in a high-pairing line of T. speltoides (Tausch) Gren. ex Richter, by colchicine treatment during the last premeiotic mitosis. This treatment induced C-mitosis and tetraploid cells which are characterized by almost exclusive bivalent pairing instead of the expected multivalent pairing. Colchicine disrupted the association of homologous chromosomes in the premeiotic metaphase but left the sister chromatids located close to each other. As a result, rather than being all closely associated, the four homologues were arranged in pairs already prior to meiosis. The effect of colchicine in this respect is reminiscent of that of the "diploidizing genes" in many naturally occurring polyploids. This work demonstrates once again the significance which the pattern of premeiotic homologous association has for the manner of meiotic pairing.

Pathology of Bone Cells in Pigs with Experimental Turbinate Osteoporosis (Atrophic Rhinitis)

1971 ◽  
Vol 29 ◽  
pp. 304-305
Author(s):  
A. W. Fetter ◽  
C. C. Capen
Keyword(s):  
Mucous Membrane ◽  
Bone Cells ◽  
Atrophic Rhinitis ◽  
Infectious Agents ◽  
Metabolic Disturbances ◽  
Progressive Reduction ◽  
Naturally Occurring ◽  
Fundamental Cause ◽  
Osteocytic Osteolysis ◽  
Uncertain Etiology

Atrophic rhinitis in swine is a disease of uncertain etiology in which infectious agents, hereditary predisposition, and metabolic disturbances have been reported to be of primary etiologic importance. It shares many similarities, both clinically and pathologically, with ozena in man. The disease is characterized by deformity and reduction in volume of the nasal turbinates. The fundamental cause for the localized lesion of bone in the nasal turbinates has not been established. Reduced osteogenesis, increased resorption related to inflammation of the nasal mucous membrane, and excessive resorption due to osteocytic osteolysis stimulated by hyperparathyroidism have been suggested as possible pathogenetic mechanisms.The objectives of this investigation were to evaluate ultrastructurally bone cells in the nasal turbinates of pigs with experimentally induced atrophic rhinitis, and to compare these findings to those in control pigs of the same age and pigs with the naturally occurring disease, in order to define the fundamental lesion responsible for the progressive reduction in volume of the osseous core.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat

1995 ◽  
Vol 53 ◽  
pp. 978-979
Author(s):  
G. M. Hutchins ◽  
J. S. Gardner
Keyword(s):  
Growth And Development ◽  
Furfuryl Alcohol ◽  
Apical Meristem ◽  
Plant Cells ◽  
Triticum Aestivum L ◽  
Morphological Development ◽  
Naturally Occurring ◽  
Chinese Spring Wheat ◽  
Sem Study ◽  
Moist Environment

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

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