The ultrastructure of the Spilocaea state of Venturia inaequalis in vivo

1976 ◽  
Vol 22 (8) ◽  
pp. 1144-1152 ◽  
Author(s):  
Michael Corlett ◽  
James Chong ◽  
E. G. Kokko
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Venturia Inaequalis ◽  
Conidiogenous Cell ◽  
Epidermal Cells ◽  
Apical Region ◽  
Mesophyll Cells ◽  
Epidermal Cell Wall ◽  
Primary Conidium

There are indications that the fungus enzymatically degrades the cuticle and epidermal cell wall. The epidermal cells and to a lesser degree the palisade mesophyll cells beneath a sporulating lesion (susceptible reaction) are killed or seriously disrupted. Various stages of conidiogenesis, including development of the primary conidium, were observed. A conidium is delimited by a two-layered transverse septum. Before conidium secession, a new two-layered inner wall is laid down around the entire conidiogenous cell adjacent to the plasmalemma. The apical region of the new inner wall proliferates beyond the annellation scar left by the seceded conidium and eventually produces another conidium.

The root–fungus interface as an indicator of symbiont interaction in ectomycorrhizae

1987 ◽  
Vol 17 (8) ◽  
pp. 846-854 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Apical Meristem ◽  
Epidermal Cells ◽  
Wall Ingrowths ◽  
Wall Ingrowth ◽  
Hartig Net ◽  
Epidermal Cell Wall ◽  
Different Strains ◽  
Cell Wall Ingrowths

Seedlings of Alnuscrispa (Ait.) Pursh, Alnusrubra Bong., Eucalyptuspilularis Sm., and Betulaalleghaniensis Britt. were grown in plastic pouches and subsequently inoculated with Alpovadiplophloeus (Zeller & Dodge) Trappe & Smith (two different strains), Pisolithustinctorius (Pers.) Coker & Couch, and Laccariabicolor (R. Mre) Orton, respectively, to form ectomycorrhizae insitu. Alnus seedlings were inoculated with Frankia prior to inoculation with the mycosymbiont. The interface established between A. crispa and A. diplophloeus was complex, involving wall ingrowth formation in root epidermal cells and infoldings in Hartig net hyphae. Alnusrubra – A. diplophloeus ectomycorrhizae had an interface lacking epidermal cell wall ingrowths but with infoldings in Hartig net hyphae. The interface between E. pilularis –. tinctorius consisted of branching Hartig net hyphae between radially enlarged epidermal cells lacking wall ingrowths. Ectomycorrhizae between B. alleghaniensis and L. bicolor developed unique interfaces with radially enlarged epidermal cells near the apical meristem, which synthesized dense vacuolar deposits. Very fine branchings occurred in Hartig net hyphae.

Light and electron microscopy of the spermogonial stage of Gymnoconia peckiana, one of the causes of orange rust of Rubus

Botany ◽  
2008 ◽  
Vol 86 (5) ◽  
pp. 533-538 ◽  
Author(s):  
Charles W. Mims ◽  
Elizabeth A. Richardson
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Leaf Surface ◽  
Light And Electron Microscopy ◽  
Epidermal Cells ◽  
Wall Material ◽  
Cell Wall Material ◽  
Leaf Epidermis ◽  
Single Nucleus ◽  
Epidermal Cell Wall

Hyphae of Gymnoconia peckiana (Howe in Peck) Trotter spread from infected Rubus argutus Link. stems into leaf primordia where they proliferated in an intercellular fashion as leaves differentiated. Hyphae were septate, and each compartment appeared to contain a single nucleus. Hyphae gave rise to numerous haustoria that resembled the monokaryotic haustoria of other rust fungi. Hyphae located immediately adjacent to the upper and lower leaf epidermis gave rise to spermogonial initials. Each initial consisted of a small group of tightly packed hyphae that developed in an intercellular space adjacent to the epidermis. As an initial enlarged, the proliferating hyphae pushed their way between, as well as into, epidermal cells. Invaded epidermal cells soon died. A layer of spermatiophores then developed within each young spermogonium and appeared to push the epidermal cell wall material and leaf cuticle covering the spermogonium out from the leaf surface. Once mature, spermatiophores gave rise to a succession of uninucleate spermatia that emerged from the tip of each spermatiophore. Spermatia initially accumulated beneath the layer of epidermal cell wall material and cuticle that covered the developing spermogonium and appeared to push this layer further out from the leaf surface until it ruptured. A few receptive hyphae were observed in mature spermogonia.

Development of Colletotrichum trifolii races 1 and 2 on alfalfa clones resistant and susceptible to anthracnose

1988 ◽  
Vol 66 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. C. L. Churchill ◽  
C. J. Baker ◽  
N. R. O'Neill ◽  
J. H. Elgin Jr.
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Pore Formation ◽  
Epidermal Cells ◽  
Germ Pore ◽  
Colletotrichum Trifolii ◽  
Direct Penetration ◽  
Race 1 ◽  
Epidermal Cell Wall ◽  
Race 2

Resistant and susceptible alfalfa clones derived from the cultivar Arc were spray inoculated with conidia from race 1 or race 2 isolates of Colletotrichum trifolii Bain in compatible and incompatible combinations. No significant differences were found in the frequencies of formation of immature or mature appressoria or in germ-pore formation by either race of C. trifolii on resistant or susceptible plants. These results indicate that incompatibility is not associated with the failure of conidia to germinate or to form appressoria with germ pores. In a small number of observations, penetration pegs were observed in tissue of both resistant and susceptible plants. Colletotrichum trifolii initiated infections in alfalfa by direct penetration of the epidermis via a penetration peg from the appressorium. Although the fungus spread rapidly throughout susceptible hosts, we observed fungus penetration only of epidermal cells of resistant hosts. Therefore, it appears that expression of alfalfa resistance to C. trifolii occurs near the time of epidermal cell wall penetration.

A histological and histochemical comparison of the mucilages on the root tips of several grasses

1980 ◽  
Vol 58 (24) ◽  
pp. 2581-2593 ◽  
Author(s):  
N. K. Miki ◽  
K. J. Clarke ◽  
M. E. McCully
Keyword(s):  
Cell Wall ◽  
Epidermal Cell ◽  
Outer Layer ◽  
Epidermal Cells ◽  
Root Cap ◽  
Carboxyl Groups ◽  
Root Tips ◽  
Sudan Grass ◽  
Epidermal Cell Wall ◽  
Inner Region

Young, axenically grown roots of grasses are covered by two types of mucilage. Gelatinous material originates from the root cap, and a firm, uniformly thick mucilage overlies the columnar epidermal cells. Histochemical properties of these mucilages are similar in corn, wheat, barley, oats, sorghum, and a Sudan grass – sorghum hybrid.The epidermal mucilage has a thin outer and a thicker inner layer distinct from the epidermal cell wall. Both mucilage layers are strongly autofluorescent, birefringent, and PAS positive. Reactions of the outer layer and cell wall indicate carboxyl groups. These are absent from the inner mucilage. Root cap mucilage has a inner region with histochemical properties resembling those of the inner epidermal mucilage. The outer portion of the root cap mucilage is not fluorescent, not birefringent, weakly PAS positive, and carboxylated.

scholarly journals Cellulose intrafibrillar mineralization of biological silica in a rice plant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eri Nakamura ◽  
Noriaki Ozaki ◽  
Yuya Oaki ◽  
Hiroaki Imai
Keyword(s):  
Cell Wall ◽  
Silica Nanoparticles ◽  
Epidermal Cell ◽  
Rice Plant ◽  
Cellulose Nanofibers ◽  
Rice Husks ◽  
Vital Activity ◽  
Mineralization Process ◽  
Shape Controlled ◽  
Epidermal Cell Wall

AbstractThe essence of morphological design has been a fascinating scientific problem with regard to understanding biological mineralization. Particularly shaped amorphous silicas (plant opals) play an important role in the vital activity in rice plants. Although various organic matters are associated with silica accumulation, their detailed functions in the shape-controlled mineralization process have not been sufficiently clarified. In the present study, cellulose nanofibers (CNFs) were found to be essential as a scaffold for silica accumulation in rice husks and leaf blades. Prior to silicification, CNFs ~ 10 nm wide are sparsely stacked in a space between the epidermal cell wall and the cuticle layer. Silica nanoparticles 20–50 nm in diameter are then deposited in the framework of the CNFs. The shape-controlled plant opals are formed through the intrafibrillar mineralization of silica nanoparticles on the CNF scaffold.

scholarly journals THE STRUCTURE OF THE PRIMARY EPIDERMAL CELL WALL OF AVENA COLEOPTILES

1957 ◽  
Vol 3 (2) ◽  
pp. 171-182 ◽  
Author(s):  
S. T. Bayley ◽  
J. R. Colvin ◽  
F. P. Cooper ◽  
Cecily A. Martin-Smith
Keyword(s):  
Cell Wall ◽  
Outer Wall ◽  
Epidermal Cells ◽  
Cellulose Microfibrils ◽  
X Rays ◽  
Primary Wall ◽  
Normal Type ◽  
Number Of Layers ◽  
Angle Scattering ◽  
Epidermal Cell Wall

The primary walls of epidermal cells in Avena coleoptiles ranging in length from 2 to 40 mm. have been studied in the electron and polarizing microscopes and by the low-angle scattering of x-rays. The outer walls of these cells are composed of multiple layers of cellulose microfibrils oriented longitudinally; initially the number of layers is between 10 and 15 but this increases to about 25 in older tissue. Where epidermal cells touch, these multiple layers fuse gradually into a primary wall of the normal type between cells. In these radial walls, the microfibrils are oriented transversely. Possible mechanisms for the growth of the multilayered outer wall during cell elongation are discussed.

scholarly journals Different Cell Wall-Degradation Ability Leads to Tissue-Specificity between Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 187
Author(s):  
Jianbo Cao ◽  
Chuanliang Chu ◽  
Meng Zhang ◽  
Limin He ◽  
Lihong Qin ◽  
...  
Keyword(s):  
Cell Wall ◽  
Tissue Specificity ◽  
Mesophyll Cell ◽  
Xanthomonas Oryzae ◽  
Cell Wall Degradation ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Degradation Ability

Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) lead to the devastating rice bacterial diseases and have a very close genetic relationship. There are tissue-specificity differences between Xoo and Xoc, i.e., Xoo only proliferating in xylem vessels and Xoc spreading in intercellular space of mesophyll cell. But there is little known about the determinants of tissue-specificity between Xoo and Xoc. Here we show that Xoc can spread in the intercellular spaces of mesophyll cells to form streak lesions. But Xoo is restricted to growth in the intercellular spaces of mesophyll cells on the inoculation sites. In vivo, Xoc largely breaks the surface and inner structures of cell wall in mesophyll cells in comparison with Xoo. In vitro, Xoc strongly damages the cellulose filter paper in comparison with Xoo. These results suggest that the stronger cell wall-degradation ability of Xoc than that of Xoo may be directly determining the tissue-specificity.

Structural and chemical changes of cell wall types during stem development: consequences for fibre degradation by rumen microflora

1997 ◽  
Vol 48 (2) ◽  
pp. 165 ◽  
Author(s):  
J. R. Wilson ◽  
R. D. Hatfield
Keyword(s):  
Cell Wall ◽  
Surface Area ◽  
Middle Lamella ◽  
Cell Types ◽  
Anatomical Structure ◽  
Mesophyll Cells ◽  
Rumen Microorganisms ◽  
Chemical Structures ◽  
Stems Cells

Legume and grass stems decrease substantially in digestibility as they mature. This review evaluates how anatomical and chemical factors restrict digestion of cell walls in legume and grass stems. Cells that make up legume stems fall into 2 groups: cells with high (≅ 100%) digestibility (e.g. cortex and pith) and cells that appear indigestible (e.g. xylem). The digestibility of xylem cells is restricted by the highly lignified secondary walls (SW). Although cortex and pith cells may develop SW or thickened primary walls, digestibility is high because these cell types do not undergo lignification. In contrast, as grass stems mature, SW thickening and lignification occur in all main cell types. However, lignified SW in grass is readily digested when accessible to rumen microorganisms. Analysis of tissue and cell architecture in grasses strongly supports the hypothesis that observed poor digestion of lignified SW in vivo is due to limits imposed by anatomical structure. Compositional limitation to wall digestion lies in the lignified, indigestible middle lamella–primary wall. This structure confines SW digestion to inner (lumen) surfaces of cells with an open end. Low sclerenchyma SW degradation in vivo can be explained by limited movement of bacteria into sclerenchyma cells and low surface area on interior walls. For example, the ratio of surface area to total cell wall volume for sclerenchyma cells is 100-fold lower than for mesophyll cells. Apparent relationships of some wall constituents–chemical structures to wall digestibility may be the result of the increasing SW and, therefore, may simply reflect limitations imposed by anatomical structure.

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