The anatomy of the leaf of red pine, Pinus resinosa. II. Vascular tissues

1982 ◽  
Vol 60 (12) ◽  
pp. 2804-2824 ◽  
Author(s):  
R. L. Gambles ◽  
R. E. Dengler
Keyword(s):  
Cell Walls ◽  
Cell Shape ◽  
Pinus Resinosa ◽  
Vascular Tissues ◽  
Transfusion Tissue ◽  
Casparian Strips ◽  
Endodermal Cells ◽  
Symplastic Pathway ◽  
Anatomy And Ultrastructure ◽  
Lateral Bundle

The anatomy and ultrastructure of the endodermis and enclosed vascular tissues of the midregion of the mature secondary needle-leaf of Pinus resinosa are described. Within the uniseriate endodermis are two vascular traces surrounded by transfusion tissue. The endodermal cells have differentially thickened walls which lack Casparian strips but are lignified. Plasmodesmata traversing pit regions form a symplastic interconnection between mesophyll, endodermal, and transfusion parenchyma cells. In the lateral bundle region plasmodesmata extend this symplastic pathway across the cell walls of subjacent transfusion parenchyma and richly protoplasmic albuminous cells to the metaphloem. Four distinct types of transfusion tracheids have been defined on the basis of cell shape and location. Transfusion tracheids in the lateral bundle regions form direct radial connections between metaxylem and endodermis.

scholarly journals Anatomy of pneumatophore of Mauritia vinifera mart

2000 ◽  
Vol 43 (3) ◽  
pp. 327-333 ◽  
Author(s):  
Luiz Alfredo Rodrigues Pereira ◽  
Maria Elisa Ribeiro Calbo ◽  
Claiton Juvenir Ferreira
Keyword(s):  
Gas Exchange ◽  
Fresh Water ◽  
Transverse Section ◽  
Root Cap ◽  
Main Function ◽  
Vascular Cylinder ◽  
Intercellular Spaces ◽  
Casparian Strips ◽  
Endodermal Cells

Pneumatophores of Mauritia vinifera Mart. were collected from six month-old plants maintained submerged in fresh water to induce pneumatophore formation. Twenty day-old pneumatophores had a quite prominent root cap. The epidermis was composed of hexagonal cells, tangentially distributed along the cylindric surface of the organ. In transverse section these pneumatophores had a simple epidermis over several layers of sclerified parenchyma, which covered an aerenchyma with large intercellular spaces. The endodermal cells had Casparian strips. The vascular cylinder was polyarch, with a pith and surrounded by a unisseriate pericycle. Anatomically the 4 month-old pneumatophores were similar to the younger ones, except for the absence of the epidermis. The epidermis is replaced by a protective tissue, whose lignified and suberized cells projected themselves outwards, giving it a filamentous aspect. There was no accumulation of starch or tannins in the pneumatophores, except for the presence of statoliths in the root cap. No lenticels were observed in pneumatophores of M. vinifera. The main function of the pneumatophores of M. vinifera is to allow gas exchange, facilitating the supply of oxygen to the submerged root portions.

scholarly journals Comparative anatomy of the absorption roots of terrestrial and epiphytic orchids

2008 ◽  
Vol 51 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Ana Sílvia Franco Pinheiro Moreira ◽  
Rosy Mary dos Santos Isaias
Keyword(s):  
Cell Walls ◽  
Comparative Anatomy ◽  
Evolutionary Process ◽  
Minas Gerais ◽  
Point Of View ◽  
Endodermal Cell ◽  
Epiphytic Orchids ◽  
Anatomical Characteristics ◽  
Cell Layers ◽  
Casparian Strips

The present study compared roots of terrestrial and epiphytic Orchidaceae, analyzing the anatomical characteristics from an ecological point of view. The material was collected at three different sites in Minas Gerais / Brazil and was fixed in FAA. Transverse sections were obtained by freehand sections or from material previously embedded in Paraplast® or Historesin®. The prominent characteristics of the epiphytic group were: significant smaller perimeter, epidermis with 3 or more cell layers, U-thickened exodermal cell walls, O-thickened endodermal cell walls, and a low ratio between the caliber and the number of protoxylem arches. The terrestrial group presented simple or multiseriate epidermis, and exodermis and endodermis with typical Casparian strips. The anatomical characteristics should have evolved with several adaptations to distinct environments during evolutionary process.

Wilts caused by Verticillium species. A cytological survey of vascular alterations in leaves

1982 ◽  
Vol 60 (6) ◽  
pp. 825-837 ◽  
Author(s):  
Jane Robb ◽  
Alexandra Smith ◽  
Lloyd Busch
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Sem Analysis ◽  
Disease Symptoms ◽  
Vascular Tissues ◽  
Transmission Electron ◽  
Tem Method ◽  
Cytological Alterations ◽  
Host Parasite ◽  
Leaf Symptoms

Plants that are infected with fungi of the species Verticillium frequently develop foliar disease symptoms which may include one or more of the following: flaccidity, drying, chlorosis leading to necrosis, vascular browning, epinasty, and leaf abscission. A number of ultrastructural and chemical alterations occur in the vascular tissues of such leaves: deposition of brown pigments, coating of xylem vessel walls with abnormal material (i.e., lipid-rich coatings or fibrillar coatings), plugging of xylem vessels with gums, gels or tyloses, degeneration of parenchyma cells, and accumulation of abnormal electron dense materials in primary and secondary cell walls. Different host–parasite combinations exhibit different leaf symptoms and different cytological alterations. The purpose of the present survey was to determine whether the extent of any of the possible vascular alterations in leaves could be correlated with the wilting tendency of the host.Chrysanthemums, snapdragons, eggplants, sunflowers, potatoes, sycamore maples and hedge maples were infected with V. dahliae; alfalfa and hops were infected with V. albo-atrum. When leaf symptoms were well advanced, samples were taken from the major lateral leaf veins and were prepared for light (LM) and transmission electron microscopy (TEM) or scanning electron microscopy (SEM). The various types of alterations in the vascular tissues were identified by a correlated LM–TEM method and (or) SEM analysis and for each sample vein the proportion of vessels affected by each type of alteration was calculated. Four leaf samples, each from different plants, were analysed for each host. The visual symptoms, including vascular browning, were estimated subjectively. The degree of leaf flaccidity was correlated positively with the proportion of lipid-coated vessels and inversely with the degree of vascular browning. No other correlations were observed.

Actuation systems in plants as prototypes for bioinspired devices

2009 ◽  
Vol 367 (1893) ◽  
pp. 1541-1557 ◽  
Author(s):  
Ingo Burgert ◽  
Peter Fratzl
Keyword(s):  
Cell Walls ◽  
Cell Shape ◽  
Living Cells ◽  
Polymer Composition ◽  
Plant Cell Walls ◽  
Geometrical Constraints ◽  
Actuation Systems ◽  
Different Levels ◽  
Dead Tissue ◽  
Shape And Size

Plants have evolved a multitude of mechanisms to actuate organ movement. The osmotic influx and efflux of water in living cells can cause a rapid movement of organs in a predetermined direction. Even dead tissue can be actuated by a swelling or drying of the plant cell walls. The deformation of the organ is controlled at different levels of tissue hierarchy by geometrical constraints at the micrometre level (e.g. cell shape and size) and cell wall polymer composition at the nanoscale (e.g. cellulose fibril orientation). This paper reviews different mechanisms of organ movement in plants and highlights recent research in the field. Particular attention is paid to systems that are activated without any metabolism. The design principles of such systems may be particularly useful for a biomimetic translation into active technical composites and moving devices.

Demonstration of a complete Casparian strip in Avena and Ipomoea by a fluorescent staining technique

1969 ◽  
Vol 47 (12) ◽  
pp. 1869-1871 ◽  
Author(s):  
D. R. Peirson ◽  
E. B. Dumbroff
Keyword(s):  
Staining Technique ◽  
New Combination ◽  
High Contrast ◽  
Fluorescent Staining ◽  
Casparian Strip ◽  
Casparian Strips ◽  
Endodermal Cells

A new combination of embedding material and high contrast stain has provided the means for demonstrating, photographically, tangential sections of endodermal cells showing complete Casparian strips.

scholarly journals The MYB36 transcription factor orchestrates Casparian strip formation

2015 ◽  
Vol 112 (33) ◽  
pp. 10533-10538 ◽  
Author(s):  
Takehiro Kamiya ◽  
Monica Borghi ◽  
Peng Wang ◽  
John M. C. Danku ◽  
Lothar Kalmbach ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Ectopic Expression ◽  
Casparian Strip ◽  
Strip Domain ◽  
Genes Encoding ◽  
Casparian Strips ◽  
Endodermal Cells ◽  
Respiratory Burst Oxidase ◽  
Strip Formation

The endodermis in roots acts as a selectivity filter for nutrient and water transport essential for growth and development. This selectivity is enabled by the formation of lignin-based Casparian strips. Casparian strip formation is initiated by the localization of the Casparian strip domain proteins (CASPs) in the plasma membrane, at the site where the Casparian strip will form. Localized CASPs recruit Peroxidase 64 (PER64), a Respiratory Burst Oxidase Homolog F, and Enhanced Suberin 1 (ESB1), a dirigent-like protein, to assemble the lignin polymerization machinery. However, the factors that control both expression of the genes encoding this biosynthetic machinery and its localization to the Casparian strip formation site remain unknown. Here, we identify the transcription factor, MYB36, essential for Casparian strip formation. MYB36 directly and positively regulates the expression of the Casparian strip genes CASP1, PER64, and ESB1. Casparian strips are absent in plants lacking a functional MYB36 and are replaced by ectopic lignin-like material in the corners of endodermal cells. The barrier function of Casparian strips in these plants is also disrupted. Significantly, ectopic expression of MYB36 in the cortex is sufficient to reprogram these cells to start expressing CASP1–GFP, correctly localize the CASP1–GFP protein to form a Casparian strip domain, and deposit a Casparian strip-like structure in the cell wall at this location. These results demonstrate that MYB36 is controlling expression of the machinery required to locally polymerize lignin in a fine band in the cell wall for the formation of the Casparian strip.

scholarly journals GDSL-domain containing proteins mediate suberin biosynthesis and degradation, enabling developmental plasticity of the endodermis during lateral root emergence

2020 ◽  
Author(s):  
Robertas Ursache ◽  
Cristovao De Jesus Vieira-Teixeira ◽  
Valérie Dénervaud Tendon ◽  
Kay Gully ◽  
Damien De Bellis ◽  
...  
Keyword(s):  
Lateral Root ◽  
Developmental Plasticity ◽  
Lateral Roots ◽  
Transcriptional Response ◽  
Soil Conditions ◽  
Data Set ◽  
Subsequent Formation ◽  
Suberin Lamellae ◽  
Casparian Strips ◽  
Endodermal Cells

ABSTRACTRoots anchor plants and deliver water and nutrients from the soil. The root endodermis provides the crucial extracellular diffusion barrier by setting up a supracellular network of lignified cell walls, called Casparian strips, supported by a subsequent formation of suberin lamellae. Whereas lignification is thought to be irreversible, formation of suberin lamellae was demonstrated to be dynamic, facilitating adaptation to different soil conditions. Plants shape their root system through the regulated formation of lateral roots emerging from within the endodermis, requiring local breaking and re-sealing of the endodermal diffusion barriers. Here, we show that differentiated endodermal cells have a distinct auxin-mediated transcriptional response that regulates cell wall remodelling. Based on this data set we identify a set of GDSL-lipases that are essential for suberin formation. Moreover, we find that another set of GDSL-lipases mediates suberin degradation, which enables the developmental plasticity of the endodermis required for normal lateral root emergence.

scholarly journals Lysis and protoplast formation of group B streptococci by mutanolysin

1980 ◽  
Vol 28 (3) ◽  
pp. 1033-1037 ◽  
Author(s):  
G B Calandra ◽  
R M Cole
Keyword(s):  
Optical Density ◽  
Cell Walls ◽  
Cell Shape ◽  
Enzymatic Preparation ◽  
Protoplast Formation ◽  
Group B Streptococci ◽  
Physiological Conditions ◽  
Intracellular Enzymes ◽  
Group B ◽  
Shape Loss

Group B streptococci, refractory to previously tested muralysins under physiological conditions, were successfully converted to protoplasts by use of a recently describede N-acetyl muramidase, mutanolysin, derived from a streptomycete. Purified enzyme was effective, but crude preparations, although degrading cell walls, simultaneously produced peculiar effects of cytoplasmic coagulation, retention of cell shape, loss of some intracellular enzymes, and a rise in optical density. Addition of purified mutanolysin to the array of muralysins (group C streptococcal phage-associated lysin, lysozyme), previously successful in preparing protoplasts of different streptococci, now makes possible enzymatic preparation of protoplasts of streptococci of groups A, B, C. D. G, and H.

scholarly journals The structure of the endodermis during the development of pea (Pisum sativum L.) roots

2014 ◽  
Vol 56 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Joanna Kopcińska ◽  
Władysław Golinowski
Keyword(s):  
Cell Wall ◽  
Pisum Sativum ◽  
Cell Walls ◽  
Secondary Cell Wall ◽  
Pisum Sativum L ◽  
Pea Root ◽  
Suberin Lamellae ◽  
Cell Components ◽  
Casparian Strips ◽  
Root Endodermis

It is shown on the basis of cytological studies that during the development of the pea root endodermis, the following structures were formed (in order of appearance): proendodermis, Casparian strips, suberin lamellae and secondary cell walls. The proendodermis cells had, in addition to the commonly occurring cell components, small vacuoles filled with phenols. The Casparian strips developed in the radial walls and accounted for no more than 1/3 of their length. The suberin layer, found on all of the endodermis walls, was deposited last over the Casparian strips. The secondary cell wall was formed only in the cells located over the phloem bundles. Its thickness was uniform over the entire circumference of the cell.

Mitotic Disrupter Herbicides

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 450-457 ◽  
Author(s):  
Kevin C. Vaughn ◽  
Larry P. Lehnen
Keyword(s):  
Cell Walls ◽  
Cell Shape ◽  
Cortical Microtubules ◽  
Root Tips ◽  
Dramatic Effect ◽  
Nuclear Membranes ◽  
Microtubule Polymerization ◽  
Primary Mechanism ◽  
Spindle Microtubules ◽  
Kinetochore Region

Approximately one-quarter of all herbicides that have been marketed affect mitosis as a primary mechanism of action. All of these herbicides appear to interact directly or indirectly with the microtubule. Dinitroaniline and phosphoric amide herbicides inhibit microtubule polymerization from free tubulin subunits. Because of the loss of spindle and kinetochore microtubules, chromosomes cannot move to the poles during mitosis, resulting in cells exhibiting an arrested prometaphase configuration. Nuclear membranes re-form around the chromosomal masses to form lobed nuclei. Cortical microtubules, which influence cell shape, are also absent, and, as a result, the cell expands isodiametrically. In root tips and other structures that are normally elongated, these herbicides induce a characteristic club-shaped swelling. Pronamide and MON 7200 induce similar effects, except that tufts of microtubules remain at the kinetochore region of the chromosomes. The carbamate herbicides barban, propham, and chlorpropham alter the organization of the spindle microtubules so that multiple spindles are formed. Chromosomes move to many poles and multiple nuclei result. Abnormal branched cell walls partly separate the nuclei. Terbutol induces “star anaphase” chromosome configurations in which the chromosomes are drawn into an area at the poles in a star-like aggregation. DCPA's most dramatic effect is on phragmoplast microtubule arrays. Multiple, branched, and curved phragmoplasts are found after herbicide treatment. These disrupters should prove to be useful tools in investigations of the proteins and structures required for a successful cell division.

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