Ontogeny of dichotomizing apices in mycorrhizal short roots of Pinus strobus

1982 ◽  
Vol 60 (8) ◽  
pp. 1523-1528 ◽  
Author(s):  
Yves Piche ◽  
J. André Fortin ◽  
R. L. Peterson ◽  
U. Posluszny
Keyword(s):  
Pinus Strobus ◽  
Pisolithus Tinctorius ◽  
External Morphology ◽  
Lateral Growth ◽  
Central Group ◽  
Apical Meristems ◽  
Sectioned Material ◽  
Growth Centres

Growth pouches were used to establish ectomycorrhizae of Pinus strobus using Pisolithus tinctorius as inoculum. An epi-illumination technique was used to follow changes in external morphology of short roots as they became colonized by hyphae and dichotomized. Apices became broader and flatter before an obvious dichotomy was apparent. Secondary dichotomies often formed after the primary dichotomy of the original short roots. Sectioned material showed that a central group of cells in the meristem stopped dividing and became vacuolated as dichotomy was initiated. Two lateral growth centres were established which led to the formation of two apical meristems.

The development, structure, and histochemistry of sclerotia of ectomycorrhizal fungi. I. Pisolithus tinctorius

1985 ◽  
Vol 63 (8) ◽  
pp. 1402-1411 ◽  
Author(s):  
D. J. Grenville ◽  
R. L. Peterson ◽  
Y. Piché
Keyword(s):  
Electron Microscopy ◽  
Experimental Studies ◽  
Pinus Strobus ◽  
Pinus Resinosa ◽  
Pisolithus Tinctorius ◽  
Root Tips ◽  
Outer Cortex ◽  
Transmission Electron ◽  
Development Structure ◽  
Large Deposits

Sclerotia were produced by growing Pisolithus tinctorius (Pers.) Coker and Couch in association with Pinus strobus L. and Pinus resinosa Ait. in plastic growth pouches. Developing and mature sclerotia were collected, fixed, and embedded for light microscopy and scanning and transmission electron microscopy. They were found to consist of an outer pigmented rind, an inner and outer cortex, and a large central medulla. Cortical and medullary areas were comprised of pseudoparenchyma which contained large deposits of glycogen, as well as protein and lipids. The structure of these sclerotia indicates that they are persistent propagules. Sclerotia may be important in nature for the recolonization of root tips after environmental stresses. They may also be useful for storing valuable strains of P. tinctorius and as a source of inoculum for experimental studies.

The External Morphology of the Five Forms of Pineus pinifoliae (Fitch) (Homoptera: Phylloxeridae)

1955 ◽  
Vol 87 (5) ◽  
pp. 201-209
Author(s):  
G. R. Underwood
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Pinus Strobus ◽  
External Morphology ◽  
White Pine ◽  
Characteristic Cone

Pineus pinifoliue (Fitch) was first described (6) in 1858 under the name Chermes pinifoliae. His description of the adult gallicola migrans on the needles of white pine contained characteristic phases of the form sufficient to distinguish it from other Adeiginae. Thomas (13), in 1879, described the characteristic cone-like gall on spruce and named the species forming the gall Chermes abieticolens. In 1906 Patch (12) observed the migration of the gallicola migrans from galls on black spruce, Picea mariana (Mill.) B.S.P., to the needies of white pine, Pinus strobus L., thus proving that Chermes abieticolens Thomas was a synonym of Chermes pinifoliae Fitch. She described the nymph and adult of the gallicola migrans and sexupara and included a drawing of the adult gallicola migrans. In 1928 Annand (I) revised the Adelginae and placed the species in the genus Pineus. He described and figured the fundatris, gallicola migrans, and exsulis.

Synthesis in Growth Pouches of Mycorrhizae Between Eucalyptus pilularis and Several Strains of Pisolithus tinctorius

1986 ◽  
Vol 34 (1) ◽  
pp. 95 ◽  
Author(s):  
DJ Grenville ◽  
Rl Peterson ◽  
AE Ashford
Keyword(s):  
Root System ◽  
Second Order ◽  
Pisolithus Tinctorius ◽  
External Morphology ◽  
Internal Anatomy ◽  
Important Advance ◽  
Eucalyptus Pilularis ◽  
Sterile Plastic

Eucalypt mycorrhizae were synthesized in non-sterile plastic growth pouches. Mycorrhizae occurred on second-order roots 6-9 days after inoculation of seedlings. External morphology and internal anatomy of mycorrhizae are similar to those produced in soil. The growth pouch is particularly useful for observing the development of mycorrhizae and sampling tissues of known ectomycorrhizae without disturbing the root system. For these reasons, as well as the rapidity of ectomycorrhizal synthesis, this method represents an important advance in technology. Five strains of Pisolithus tinctorius were tested in growth pouches and found to form ectomycorrhizae with Eucalyptus pilularis.

Technique for the observation of early morphological changes during ectomycorrhiza formation

1980 ◽  
Vol 58 (3) ◽  
pp. 361-365 ◽  
Author(s):  
J. André Fortin ◽  
Yves Piché ◽  
Maurice Lalonde
Keyword(s):  
Ectomycorrhizal Fungi ◽  
Morphological Changes ◽  
Pinus Strobus ◽  
Pisolithus Tinctorius ◽  
Hartig Net ◽  
Cenococcum Graniforme

Flat, transparent polyester growth pouches were used for synthesis of ectomycorrhizae on Pinus strobus seedlings. Typical ectomycorrhizae with mantle and Hartig net were obtained within 5 days after inoculation with Pisolithus tinctorius. An extensive extramatrical network of hyphae and hyphal strands could be observed within 15 days after ectomycorrhizae formation. The process was somewhat slower with Cenococcum graniforme. Other proven ectomycorrhizal fungi on P. strobus were unsuccessful in forming ectomycorrhizae under conditions used in these experiments.

A structural study of the interaction between the ectomycorrhizal fungus Pisolithus tinctorius and Pinus strobus roots

1983 ◽  
Vol 61 (4) ◽  
pp. 1185-1193 ◽  
Author(s):  
Y. Piché ◽  
R. L. Peterson ◽  
Melanie J. Howarth ◽  
J. André Fortin
Keyword(s):  
Light And Electron Microscopy ◽  
Cortical Cell ◽  
Middle Lamella ◽  
Pinus Strobus ◽  
Ectomycorrhizal Fungus ◽  
Pisolithus Tinctorius ◽  
Cortical Cells ◽  
Root Cells ◽  
Hartig Net ◽  
Limited Digestion

Stages in ectomycorrhizal development between the fungus Pisolithus tinctorius (Pers.) Coker & Couch and short roots of Pinus strobus L. were followed in growth pouches. Short roots from preinoculation through Hartig net formation were processed for light and electron microscopy. Fungal hyphae approaching the surface of roots have Thiéry-positive substances in their modified walls and in lomasomes, indicating the possibility of extracellular polysaccharide secretion. Hyphae grow between and beneath the flattened, tannin-filled superficial root cells and subsequently into the intercellular region of the cortex. A Hartig net several hyphae wide is formed, isolating the cortical cells from each other. Plasmodesmata were not observed in these cortical cells. Middle lamella material is always present around the intercellular hyphae, suggesting limited digestion by the hyphae. Cortical cell cytoplasm becomes necrotic in regions of mature Hartig net formation.

A Freeze-Etch Study of Acinetobacter SP. Grown on a Hydrocarbon Substrate

1974 ◽  
Vol 32 ◽  
pp. 174-175
Author(s):  
C. L. Scott ◽  
W. R. Finnerty
Keyword(s):  
Membrane System ◽  
Structural Distortion ◽  
Intracytoplasmic Membrane ◽  
Gram Negative ◽  
Sectioned Material ◽  
Acinetobacter Sp

Acinetobacter sp. HO-1-N, a gram-negative hydrocarbon oxidizing bacterium previously designated Micrococcus cerificans, has been shown to sequester the hydrocarbon into intracytoplasmic pools as a result of growth on this substrate. In hydrocarbon grown cells, an intracytoplasmic membrane system was also observed along with a doubling of cellular phospholipids (Z). However, using conventional dehydration and embedding procedures in preparing thin sectioned material, the hydrocarbon is extracted from the cells. This may lead to structural distortion, consequently, the freeze-etch technique was applied to preserve the integrity of the cell.

An Efficient Statistic for Determining the Diameter of Thin Sectioned Uniform Spheres from Measurements of Biological Samples

1974 ◽  
Vol 32 ◽  
pp. 114-115
Author(s):  
W. R. Schucany ◽  
G. H. Kelsoe ◽  
V. F. Allison
Keyword(s):  
Biological Samples ◽  
Traditional Method ◽  
Cell Types ◽  
Accurate Estimation ◽  
Morphological Identification ◽  
Sectioned Material ◽  
Maximal Diameter ◽  
Similar Cell

Accurate estimation of the size of spheroid organelles from thin sectioned material is often necessary, as uniquely homogenous populations of organelles such as vessicles, granules, or nuclei often are critically important in the morphological identification of similar cell types. However, the difficulty in obtaining accurate diameter measurements of thin sectioned organelles is well known. This difficulty is due to the extreme tenuity of the sectioned material as compared to the size of the intact organelle. In populations where low variance is suspected the traditional method of diameter estimation has been to measure literally hundreds of profiles and to describe the “largest” as representative of the “approximate maximal diameter”.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

Cytomembrane Preservation in Tissue Dehydrated Only With Glutaraldehyde and Epon 812 Resin

1973 ◽  
Vol 31 ◽  
pp. 320-321
Author(s):  
Daniel C. Pease
Keyword(s):  
Diffraction Pattern ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Unpublished Study ◽  
X Ray ◽  
Sectioned Material

A previous study demonstrated that tissue could be successfully infiltrated with 50% glutaraldehyde, and then subsequently polymerized with urea to create an embedment which retained cytomembrane lipids in sectioned material. As a result, the 180-190 Å periodicity characteristic of fresh, mammalian myelin was preserved in sections, as was a brilliant birefringence, and the capacity to bind OsO4 vapor in the hydrophobic bilayers. An associated (unpublished) study, carried out in co-operation with Drs. C.K. Akers and D.F. Parsons, demonstrated that the high concentration of glutaraldehyde (and urea) did not significantly alter the X-ray diffraction pattern of aldehyde-fixed, myelin. Thus, by itself, 50% glutaraldehyde has little effect upon cytomembrane systems and can be used with confidence for the first stages of dehydration.

Electron Energy Analysis of Germanium and Silica Layers on Silicon Substrates

1975 ◽  
Vol 33 ◽  
pp. 96-97
Author(s):  
R. W. Ditchfield ◽  
A. G. Cullis
Keyword(s):  
Epitaxial Growth ◽  
Electron Energy ◽  
Silicon Substrates ◽  
Secondary Phases ◽  
Si Substrates ◽  
Transmission Electron ◽  
Layer Structures ◽  
Si Films ◽  
Electron Energy Loss ◽  
Growth Centres

An energy analyzing transmission electron microscope of the Möllenstedt type was used to measure the electron energy loss spectra given by various layer structures to a spatial resolution of 100Å. The technique is an important, method of microanalysis and has been used to identify secondary phases in alloys and impurity particles incorporated into epitaxial Si films.Layers Formed by the Epitaxial Growth of Ge on Si Substrates Following studies of the epitaxial growth of Ge on (111) Si substrates by vacuum evaporation, it was important to investigate the possible mixing of these two elements in the grown layers. These layers consisted of separate growth centres which were often triangular and oriented in the same sense, as shown in Fig. 1.

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