Studies on the haustorium of Castilleja (Scrophulariaceae). I. The upper haustorium

1973 ◽  
Vol 51 (5) ◽  
pp. 917-922 ◽  
Author(s):  
David R. Dobbins ◽  
Job Kuijt
Keyword(s):  
Root Hairs ◽  
Surface Lipid ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Spherical Structure ◽  
Cortical Zone ◽  
Primary Roots ◽  
Distinct Cell ◽  
Parenchyma Cells ◽  
Host Tissues

The portion of the Castilleja secondary haustorium external to host tissues was investigated at the light- and electron-microscopic levels. One or more haustoria may be present along a single lateral root; however, primary roots of Castilleja may also have haustoria. A localized development of root hairs usually precedes haustorial formation. The first sign of haustorial formation is the swelling of root cortical cells which gives rise to a nearly spherical structure. Eventually, the haustorial epidermis is obliterated at the contact surface between parasite and host. The upper haustorium has a complex internal structure consisting of several distinct cell zones. The pericycle gives rise to a parenchymatous zone of cells adjacent to the plate xylem. Later, collenchyma differentiates in the center or core of the haustorium and is surrounded by a cortical zone of parenchyma cells. This is the first report of collenchyma tissue in a haustorium of any parasite. Thus, a mature Castilleja haustorium consists of a plate xylem zone, an adjacent parenchymatous zone, a centrally located collenchyma zone, and a peripheral cortical zone. The endophyte is initiated from hypodermal parenchymatous cells located between the collenchyma core and the haustorial surface. Lipid is abundant in the young endophyte and paramural bodies are common in many cells. Strands of vessel members differentiate at random and are sheathed by thin-walled densely cytoplasmic cells. Vessel members occur within the collenchyma zone as well, and frequently contain starch and other coarsely granular materials. No phloem was found in the upper haustorium of Castilleja. The upper haustorium of Castilleja and of other members of the Scrophulariaceae are compared.

Structure and ontogeny of Betula alleghaniensis – Pisolithus tinctorius ectomycorrhizae

1990 ◽  
Vol 68 (3) ◽  
pp. 579-593 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
C. A. Ackerley ◽  
L. H. Melville
Keyword(s):  
Root Hairs ◽  
Root Surface ◽  
Pisolithus Tinctorius ◽  
Initial Contact ◽  
Broad Host Range ◽  
Betula Alleghaniensis ◽  
Cortical Cells ◽  
Structural Modifications ◽  
Hartig Net ◽  
Primary Roots

The ontogeny and ultrastructure of ectomycorrhizae synthesized between Betula alleghaniensis (yellow birch) and Pisolithus tinctorius, a broad host range fungus, were studied to determine the structural modifications in both symbionts during ectomycorrhiza establishment. A number of stages, including initial contact of hyphae with the root surface, early mantle formation, and mature mantle formation, were distinguished. Interactions between hyphae and root hairs were frequent. As a paraepidermal Hartig net developed, root epidermal cells elongated in a radial direction, but wall ingrowths were not formed. Repeated branching of Hartig net hyphae resulted in extensive fine branches and the compartmentalization of hyphal cytoplasm. Nuclei and elongated mitochondria were frequently located in the narrow cytoplasmic compartments, and [Formula: see text] thickenings developed along walls of cortical cells in primary roots.

Studies on the haustorium of Castilleja (Scrophulariaceae). II. The endophyte

1973 ◽  
Vol 51 (5) ◽  
pp. 923-931 ◽  
Author(s):  
David R. Dobbins ◽  
Job Kuijt
Keyword(s):  
Cell Wall ◽  
Host Cell ◽  
Light Microscope ◽  
Cell Walls ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cell Wall ◽  
Dark Staining ◽  
Host Tissues

The portion of the Castilleja haustorium within the host, the endophyte, was examined at the light-and electron-microscopic levels. The endophyte consists of a stalk of lipid-containing cells and digitate cells at its tip. Vessels run the length of the endophyte. There is a harmonious meshing between host cortical cells and those of the endophyte flank, suggesting that penetration is accomplished, in part, by cell dissolution. Crushing of cells also occurs during endophyte invasion as host phloem tissues are severely buckled and cell walls are greatly folded. Some features of digitate cells include dense cytoplasm, an abundance of endoplasmic reticulum, lateral walls that are thickened as well as those on the side adjacent to the host, and an ability to conform to the contours of host tissues. Often digitate cells are divided by very thin walls that are hardly visible under the light microscope. It is suggested that the thick cell walls may function as "free space" in the absorption of materials from the host. Within the endophyte, vessels differentiate and may contain either a finely granular, dark-staining material or a more coarsely granular, light-staining material. The particles of the latter have irregular shapes. Although granular materials are thus carried by some vessels, cells resembling the structurally intermediate "phloeotracheids" were not seen. Connections through the cell wall were not observed between parasite and host; however, within the endophyte plasmodesmata were highly branched and often contained median nodules. Transfer-like cells which have irregularly thickened walls occurred in the endophyte. Host tissues next to digitate cells appeared to be in a degraded state. Invaginations of the plasmalemma were common and small flattened vesicles were formed in some host cells from the disrupted tonoplast. In several instances, the cytoplasm had receded from the host cell wall and a "beaded" material was present in both vacuoles and large vesicles. The host cell wall at times had a very loose fibrillar appearance. Some host tracheids were occluded with a dense and dark-staining material. The xylem strands of the parasite are connected to the host xylem either by cell wall dissolution or by actual penetration of a digitate cell into a host xylary cell. The penetrating cell subsequently differentiates into a vessel member. A summary and general discussion are given to relate the two portions of the haustorium, the upper haustorium and the endophyte. The mass of new information gained in this study leads us to encourage the application of plastic embedding and sectioning techniques to further light-microscope studies on haustoria.

Auxin Dependent Growth and Auxin-Binding Proteins in Primary Roots and Root Hairs of Corn (Zea mays L.)

1993 ◽  
Vol 141 (6) ◽  
pp. 698-703 ◽  
Author(s):  
Elke Radermacher ◽  
Dieter Klämbt
Keyword(s):  
Zea Mays ◽  
Binding Proteins ◽  
Zea Mays L ◽  
Root Hairs ◽  
Primary Roots ◽  
Auxin Binding ◽  
Dependent Growth ◽  
Auxin Binding Proteins

Anatomy and ultrastructure of a Rhododendron root–fungus association

1980 ◽  
Vol 58 (23) ◽  
pp. 2421-2433 ◽  
Author(s):  
T. A. Peterson ◽  
W. C. Mueller ◽  
L. Englander
Keyword(s):  
Fungal Infection ◽  
Secondary Growth ◽  
Cortical Layer ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Hair Roots ◽  
Short Period ◽  
Infected Cells ◽  
Hyphal Coils

Light and electron microscopic investigations of the roots of Rhododendron and other ericaceous plants growing in the vicinity of Clavaria fruiting structures showed a fungal infection consistently associated with the epidermal and cortical cells of the "hair roots." Uninfected hair roots consisted of an epidermis and a one cell thick cortical layer surrounding the stele. Secondary growth in the stele and formation of a cork layer by division of the pericycle caused the cortex and epidermis to slough as the root matured. The structure of the infected hair roots was similar except for the presence of fungus in epidermal and cortical cells. As judged by the appearance of septa, at least two fungi were involved, one with dolipore septa that formed hyphal coils in the infected cells, and one with septa associated with Woronin bodies that occurred as single hyphal strands. Hyphae were found penetrating the cells from the exterior of the root and also passing from cell to cell. No correlation between fungal infection and the phenolic content of the cells could be made. Dissolution of both the fungal and host cytoplasm appeared to occur as the cells were sloughed. It appears that the fungus–root relationship is complex and is limited in duration to a short period of time during the development of the hair roots.

scholarly journals Nodulation of Aeschynomene afraspera and A. indica by Photosynthetic Bradyrhizobium Sp. Strain ORS285: The Nod-Dependent Versus the Nod-Independent Symbiotic Interaction

2011 ◽  
Vol 24 (11) ◽  
pp. 1359-1371 ◽  
Author(s):  
Katia Bonaldi ◽  
Daniel Gargani ◽  
Yves Prin ◽  
Joel Fardoux ◽  
Djamel Gully ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Lateral Roots ◽  
Root Hairs ◽  
Infection Process ◽  
Cortical Cells ◽  
Symbiotic Interaction ◽  
Root Cortex ◽  
Bradyrhizobium Sp ◽  
Infected Cells ◽  
Green Fluorescent

Here, we present a comparative analysis of the nodulation processes of Aeschynomene afraspera and A. indica that differ in their requirement for Nod factors (NF) to initiate symbiosis with photosynthetic bradyrhizobia. The infection process and nodule organogenesis was examined using the green fluorescent protein–labeled Bradyrhizobium sp. strain ORS285 able to nodulate both species. In A. indica, when the NF-independent strategy is used, bacteria penetrated the root intercellularly between axillary root hairs and invaded the subepidermal cortical cells by invagination of the host cell wall. Whereas the first infected cortical cells collapsed, the infected ones immediately beneath kept their integrity and divided repeatedly to form the nodule. In A. afraspera, when the NF-dependent strategy is used, bacteria entered the plant through epidermal fissures generated by the emergence of lateral roots and spread deeper intercellularly in the root cortex, infecting some cortical cells during their progression. Whereas the infected cells of the lower cortical layers divided rapidly to form the nodule, the infected cells of the upper layers gave rise to an outgrowth in which the bacteria remained enclosed in large tubular structures. Together, two distinct modes of infection and nodule organogenesis coexist in Aeschynomene legumes, each displaying original features.

Structure and host–actinomycete interactions in developing root nodules of Comptonia peregrina

1978 ◽  
Vol 56 (5) ◽  
pp. 502-531 ◽  
Author(s):  
William Newcomb ◽  
R. L. Peterson ◽  
Dale Callaham ◽  
John G. Torrey
Keyword(s):  
Host Cell ◽  
Root Nodules ◽  
Host Cells ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Host Cytoplasm ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Host Plasma Membrane ◽  
Soil Actinomycete

Correlated fluorescence, bright-field, transmission electron, and scanning electron microscopic studies were made on developing root nodules of Comptonia peregrina (L.) Coult. (Myricaceae) produced by a soil actinomycete which invades the root and establishes a symbiosis leading to fixation of atmospheric dinitrogen. After entering the host via a root hair infection, the hyphae of the endophyte perforate root cortical cells by local degradation of host cell walls and penetration of the host cytoplasm. The intracellular hyphae are always surrounded by host plasma membrane and a thick polysaccharide material termed the capsule. (For convenience, term intracellular refers to the endophyte being inside a Comptonia cell as distinguished from being intercellular, i.e.. between host cells, even though the former is actually extracellular as the endophyte is separated from the host cytoplasm by the host plasmalemma.) Numerous profiles of vesiculate rough endoplasmic reticulum (RER) occur near the growing hyphae. Although the capsule shows a positive Thiery reaction indicating its polysaccharide nature, the fibrillar contents of the RER do not, leaving uncertain whether the capsule results from polymers derived from the RER. Amyloplasts of the cortical cells lose their starch deposits during hyphal proliferation. The hyphae branch extensively in specific layers of the cortex, penetrating much of the host cytoplasm. At this stage, hyphal ends become swollen and form septate club-shaped vesicles within the periphery of the host cells. Lipid-like inclusions and Thiery-positive particles, possibly glycogen, are observed in the hyphae at this time. Associated with hyphal development is an increase in average host cell volume, although nuclear volume appears to remain constant. Concomitant with vesicle maturation, the mitochondrial population increases sharply, suggesting a possible relationship to vesicle function. The intimate interactions between host and endophyte during development of the symbiotic relationship are emphasized throughout.

Pénétration d'une endo-pectate lyase tritiée dans les cellules corticales de racines de courge

1984 ◽  
Vol 62 (8) ◽  
pp. 1621-1628
Author(s):  
G. F. Vogt ◽  
J. Coulon
Keyword(s):  
Cell Wall ◽  
Amino Acid ◽  
External Surface ◽  
Pectate Lyase ◽  
Erwinia Carotovora ◽  
Cortical Cells ◽  
Pectate Lyases ◽  
Autoradiographic Analysis ◽  
Host Tissues

Erwinia carotovora produces pectate lyases (endo-PGTE) on sterilized beans hypocotyls. Two endo-PGTE fractions were isolated and purified by electrofocusing. The action of these enzymes on the ultrastructure of cortical cells of pumpkin roots was very similar to the action of the whole bacterium. Erwinia carotovora grown on tritiated amino acid supplemented medium produced [3H]endo-PGTE. By incubating the host tissues with 3H-labelled enzymes and by subsequent autoradiographic analysis it was possible to localize the endo-PGTE inside the cells. Thus, it was shown that the enzyme (the complete molecule or only a peptide part thereof) was transported towards the vacuole. It is suggested that the endo-PGTE acts on the filamentous polysaccharide extensions which bind the external surface of the plasmalemma to the cell wall.

Mast cell response during the early phase of tuberculosis: an electron-microscopic study

1977 ◽  
Vol 23 (9) ◽  
pp. 1245-1251 ◽  
Author(s):  
Samuel Ratnam ◽  
Shobhitha Ratnam ◽  
B. K. Puri ◽  
Saroj Chandrasekhar
Keyword(s):  
Mast Cell ◽  
Mycobacterium Tuberculosis ◽  
Electron Microscope ◽  
Host Tissue ◽  
Tuberculous Infection ◽  
Electron Microscopic ◽  
Morphological Alterations ◽  
Dense Bodies ◽  
Large Numbers ◽  
Host Tissues

Guinea pig lungs were infected with Mycobacterium tuberculosis by intratracheal route and examined under electron microscope to investigate the morphological alterations of the organisms, if any, and the response of the host tissue. The bacilli showed no changes in their morphology, while the host tissues revealed several cells containing many electron-dense intracytoplasmic granules. These cells were predominantly seen during the 1st week of infection. The electron-dense bodies of these cells may be the ones observed by earlier workers and suggested to be the altered forms of tubercle bacilli. The present investigation, however, revealed them to be the granules of the mast cells. These cells were observed to respond to tuberculous infection during the first few days by appearing in large numbers crowded with intracytoplasmic granules and soon disintegrating as the result of subsequent degranulation. The above observation is presented and its significance discussed.

Light and electron microscopic immunocytochemistry on the localization of 3?-hydroxysteroid dehydrogenase/isomerase in the bovine adrenal cortical cells

1988 ◽  
Vol 89 (1) ◽  
pp. 35-39 ◽  
Author(s):  
K. Ishimura ◽  
T. Yoshinaga-Hirabayashi ◽  
H. Fujita ◽  
H. Ishii-Ohba ◽  
H. Inano ◽  
...  
Keyword(s):  
Hydroxysteroid Dehydrogenase ◽  
Electron Microscopic ◽  
Electron Microscopic Immunocytochemistry ◽  
Cortical Cells ◽  
Adrenal Cortical Cells

Histopathology of Pythium infected strawberry roots

1972 ◽  
Vol 50 (5) ◽  
pp. 1091-1096 ◽  
Author(s):  
S. Nemec
Keyword(s):  
Root Hairs ◽  
Petri Dish ◽  
Root Tip ◽  
Test Results ◽  
Root Tips ◽  
Cortical Cells ◽  
Pythium Irregulare ◽  
Infected Root ◽  
Cortical Infection ◽  
Host Parasite

Host–parasite interactions between eight Pythium species, previously isolated from necrotic strawberry root tissue, and Fragaria × ananassa Duch. runner plant main roots were studied. When excised roots were placed in water on petri dish cultures, P. rostratum and P. hypogenum infection was limited to the root tip epidermis. Pythium irregulare, P. perniciosum, P. dissotocum, P. sylvaticum, P. ultimum, and unidentified isolate 1E penetrated the epidermis several centimeters along the zone of maturation. Penetration occurred most frequently through root hairs by hyphae; resulting infections usually stopped in the epidermis or adjacent cortex, and here hyphae formed sporangium-like structures, oogonia, and oospores. Extensive cortical infection by hyphae was primarily limited to the zone of elongation. Extent of epidermal and cortical infection in roots grown in soil with P. irregulare, P. dissotocum, and P. sylvaticum was similar to petri dish test results. Stelar infection by P. sylvaticum and P. dissotocum occurred mainly in phloem cells, but did not advance far into the region of maturation. Numerous oogonia formed in infected steles and usually in adjacent cortical cells. Infected roots ranged from a white to grey, water-soaked color. Extensively infected root tips typically were unhealthy, succulent, and thin.

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