scholarly journals Changes of ultrastructure and cytoplasmic free calcium in Gladiolus x hybridus Van Houtte roots infected by aster yellows phytoplasma

2011 ◽  
Vol 72 (4) ◽  
pp. 269-282 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Calcium Ions ◽  
Infected Plant ◽  
Sieve Tube ◽  
Plant Roots ◽  
Free Calcium ◽  
Aster Yellows ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Aster Yellows Phytoplasma

Roots of <em>Gladiolus </em>x <em>hybridus </em>Van Houtte plants infected with aster yellows phytoplasma were examined. The infected plants had a reduced root system in comparison to control plants. Their roots were thinner and the stele organisation was changed. Phytoplasmas were present in sieve tubes, companion cells and phloem parenchyma cells of the infected plant roots. Free calcium ions were localized in the cells of infected plants. Cells of the stele of infected roots, especially these infected with phytoplasmas, showed an increase of calcium antimonite deposits in theirs protoplasts. Also the number of calcium antimonite deposits increased in sieve tubes of infected roots. The deposits were present on plasma membrane, around the sieve tube plate and also in the lumen of the sieve tube. The increase of free calcium ions in sieve tubes did not cause the occlusion of sieve tube pores. Companion cells and some parenchyma cells with phytoplasmas did not react to phytoplasma infection with an increase of Ca<sup>2+</sup> ions in protoplast. The parenchyma cells showing signs of degeneration reacted with high increase of calcium ions. The Ca<sup>2+</sup> ions were present mainly in cytoplasm of infected parenchyma cells. There were calcium antimonite deposits in infected plant roots xylem elements and in intracellular spaces of cortex parenchyma. Such deposits were not present in control plants.

scholarly journals Ultrastructural changes in aster yellows phytoplasma affected Limonium sinuatum Mill. plants.I Pathology of conducting tissues

2014 ◽  
Vol 70 (3) ◽  
pp. 173-180 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Endoplasmic Reticulum ◽  
Structural Changes ◽  
Sieve Tube ◽  
Sieve Element ◽  
Ultrastructural Changes ◽  
Sieve Elements ◽  
Aster Yellows ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Aster Yellows Phytoplasma

Changes in anatomy and cytology of conducting tissues of <em>Limonium sinuatum</em> Mill. plants affected by aster yellows phytoplasma were investigated. In the phloem tissues of affected plants stem necrosis takes place. In necrotic regions no sieve tubes were observed only necrotic cells and parenchyma cells. The sieve tubes present on the border of necrosis showed collapsed walls and were rich in vesicles. Phytoplasma cells were observed in sieve tubes present in nonnecrotic regions of the phloem. Various structural changes in sieve elements were investigated. The endoplasmic reticulum cistemae were often localised in the lumen of the sieve element without contact with the walls. Such localisation of endoplasmic reticulum was never observed in healthy plants. Vesicles of different size, fuzzy material and clumping of p-proteins were characteristic for sieve elements from nonnecrotic part of phloem. No correlation with the sieve tube structure and the appearance of phytoplasma in a single sieve element was found. In control plants of <em>L. sinuatum</em> phloem observed were phloem parenchyma cells with spiny vesicles (SV). In infected plants there were a remarkable increase in cells with SV. Also the SV itself had not only a vesicular but also a tubular or extended cistern shape.

scholarly journals Cytopathological evidence for transport of phytoplasma in infected plants

2014 ◽  
Vol 68 (4) ◽  
pp. 261-266 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Morphological Changes ◽  
Close Contact ◽  
Infected Plant ◽  
Sieve Tube ◽  
Tagetes Patula ◽  
Plant Cell Walls ◽  
Companion Cells ◽  
Phytoplasma Infection ◽  
Sieve Tubes ◽  
Helichrysum Bracteatum

Pleomorphic phytoplasmas were observed in sieve tubes, companion cells and in phloem parenchyma of <em>Tagetes patula</em> L., <em>Helichrysum bracteatum</em> Willd. and <em>Gladiolus</em> sp. L. plants with morphological changes typical for phytoplasma infection. In the pores of the sieve plate phytoplasma cells were seen which suggests that the vertical transport of this pathogen goes in the sieve tubes of infected plants throughout the sieve tube pores. The contact of the sieve tube with the neighbouring cells goes through the plasmodesmata, but no changes of the plasmodesmata were observed in the phloem of infected plants. The size and structure of unchanged plasmodesmata does not allow passing through such big structures like phytoplasma. Instead close contact between phytoplasma cells and vertical sieve tube walls takes place. Damages to the cell wall were observed forming cavities in which the phytoplasma cells were present. The damages of parenchyma and companion cells walls also were seen. In cells where the damages of the walls were observed phytoplasmas were present. The phytoplasma cells were sporadically seen also in the intercellular spaces of parenchyma. These data suggest that horizontal transport depends on damages to the infected plant cell walls caused by the phytoplasma itself.

The secondary phloem of Austrobaileya scandens

1970 ◽  
Vol 48 (2) ◽  
pp. 341-359 ◽  
Author(s):  
Lalit M. Srivastava
Keyword(s):  
Tannic Acid ◽  
Cross Sections ◽  
Significant Proportion ◽  
Sieve Tube ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Sieve Cells ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Definition Of

The origin of sieve elements and parenchyma cells in the secondary phloem of Austrobaileya was studied by use of serial cross sections stained with tannic acid – ferric chloride and lacmoid. In three important respects, Austrobaileya phloem recalls gymnospermous features: it has sieve cells rather than sieve-tube members; a significant proportion of sieve elements and companion cells arise independently of each other; and sieve areas occur between sieve elements and companion cells ontogenetically unrelated to each other. The angiospermous feature includes origin of most sieve elements and parenchyma, including companion cells, after divisions in phloic initials. In these instances companion cells show a closer ontogenetic relationship to sieve elements than do other parenchyma cells. The combination of gymnospermous and angiospermous features makes phloem of Austrobaileya unique when compared to that of all those species that have been investigated in detail. It is further suggested that the term albuminous cells is inappropriate and should be replaced by companion cells but that the ontogenetic relationship implicit in the definition of companion cells is too restrictive and should be abandoned.

Leaf structure of Cananga odorata (Annonaceae) in relation to the collection of photosynthate and phloem loading: morphology and anatomy

1990 ◽  
Vol 68 (2) ◽  
pp. 354-363 ◽  
Author(s):  
David G. Fisher
Keyword(s):  
Sieve Tube ◽  
Type I ◽  
Type Ii ◽  
Tracheary Elements ◽  
Minor Vein ◽  
Type Iv ◽  
Parenchyma Cells ◽  
Vascular Parenchyma ◽  
Sieve Tubes ◽  
Cananga Odorata

Four distinct anatomical types of minor veins occur in Cananga odorata leaves. In order of decreasing size, they are (i) type I, with tracheary elements, fibers, vascular parenchyma cells, companion cells, and mostly nacreous-walled sieve-tube members; (ii) type II, with the same cell types except that the sieve-tube members have walls that usually lack nacreous thickenings; (iii) type III, with only vascular parenchyma cells and tracheids; and (iv) type IV (vein endings), with tracheary elements only. The proportions of the total minor vein length occupied by each are type I, 15.1%; type II, 27.2%; type III, 24.4%; and type IV, 33.3%. Thus about 60% of the minor vein network lacks sieve tubes. The average interveinal distance for all minor veins is 121 μm, but the average for veins containing sieve-tubes is 329 μm. Other salient features include vascular parenchyma cells up to 130 μm long, bundle-sheath cells whose lateral protuberances into the mesophyll increase extensively with decreasing vein size, and five layers of horizontally oriented spongy parenchyma cells. These features may facilitate transport of assimilate to the relatively small proportion of the minor vein network that contains sieve tubes.

scholarly journals RELATION OF BEET YELLOWS VIRUS TO THE PHLOEM AND TO MOVEMENT IN THE SIEVE TUBE

1967 ◽  
Vol 32 (1) ◽  
pp. 71-87 ◽  
Author(s):  
K. Esau ◽  
J. Cronshaw ◽  
L. L. Hoefert
Keyword(s):  
Sieve Tube ◽  
Plant Viruses ◽  
Passive Transport ◽  
Sieve Elements ◽  
Virus Particles ◽  
Parenchyma Cells ◽  
Beet Yellows Virus ◽  
Sieve Tubes ◽  
Sieve Plates ◽  
Orderly Arrangement

In minor veins of leaves of Beta vulgaris L. (sugar beet) yellows virus particles were found both in parenchyma cells and in mature sieve elements. In parenchyma cells the particles were usually confined to the cytoplasm, that is, they were absent from the vacuoles. In the sieve elements, which at maturity have no vacuoles, the particles were scattered throughout the cell. In dense aggregations the particles tended to assume an orderly arrangement in both parenchyma cells and sieve elements. Most of the sieve elements containing virus particles had mitochondria, plastids, endoplasmic reticulum, and plasma membrane normal for mature sieve elements. Some sieve elements, however, showed evidence of degeneration. Virus particles were present also in the pores of the sieve plates, the plasmodesmata connecting the sieve elements with parenchyma cells, and the plasmodesmata between parenchyma cells. The distribution of the virus particles in the phloem of Beta is compatible with the concept that plant viruses move through the phloem in the sieve tubes and that this movement is a passive transport by mass flow. The observations also indicate that the beet yellows virus moves from cell to cell and in the sieve tube in the form of complete particles, and that this movement may occur through sieve-plate pores in the sieve tube and through plasmodesmata elsewhere.

scholarly journals Morphological, Anatomical and Palynological Studies on Endemic Matthiola anchoniifolia Hub. -Mor. (Brassicaceae)

2013 ◽  
Vol 5 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Mehmet TEKIN ◽  
Gülden YILMAZ ◽  
Esra MARTIN
Keyword(s):  
Cross Sections ◽  
Anatomical Study ◽  
Endemic Plant ◽  
Exine Ornamentation ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Pollen Shape ◽  
Periclinal Walls ◽  
First Time

In this paper, anatomical, palynological and seed micromorphological properties of an endemic plant Matthiola anchoniifolia Hub.-Mor. are recorded for the first time. A description and descriptive illustrations of the species are given based on the collected specimens for morphological study. Seed surface of M. anchoniifolia is examined by scanning electron microscope. The seed of M. anchoniifolia was compressed, brownish in colour and the cells of testa were nearly 60-80 μm in diameter and ranged from isodiametric, tetragonal or pentagonal. The anticlinal walls were straight or weakly curved while the outer periclinal walls were concave to flat with smooth surface. In anatomical study, cross sections of root, stem and stem leaf are examined. The root had secondary structure. Periderm consists of 5-8 layers of cells for phellem. Cortex consists of 9-12 layered parenchymatic tissue under the periderm. Secondary phloem ring-shaped, 6-9 layered and consists of companion cells and grouped sieve tubes. Stem had primary structure when analyzed. It is circular with a few irregular ribs in cross section. Cortex is 8-12 layered and parenchymatous. Stoma cells are present on both epidermis. Leaf is isobilateral. There are unicellular and ramified hairs on both surface. Palisade parenchyma cells are 1-2 layered and spongy parenchyma cells are 5-12 layered. M. anchoniifolia has tricolpate pollen type, prolate pollen shape and reticulate exine ornamentation.

scholarly journals Ultrastructural changes in aster yellows phytoplasma affected Limonium sinuatum Mill. plants II. Pathology of cortex parenchyma cells

2014 ◽  
Vol 70 (4) ◽  
pp. 273-279 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Plasma Membrane ◽  
Ultrastructural Changes ◽  
Internal Space ◽  
Pathological Changes ◽  
Aster Yellows ◽  
Parenchyma Cells ◽  
Aster Yellows Phytoplasma

In <em>Limonium sinuatum</em> Mill, plants with severe symptoms of aster yellows infection phytoplasmas were present not only in the phloem but also in some cortex parenchymas cells. These parenchyma cells were situated at some distance from the conducting bundles. The phytoplasmas were observed directly in parenchyma cells cytoplasm. The number of phytoplasmas present in each selected cell varies. The cells with a small number of phytoplasmas show little pathological changes compared with the unaffected cells of the same zone of the stem as well with the cells of healthy plants. The cells filled with a number of phytoplasmas had their protoplast very much changed. The vacuole was reduced and in the cytoplasm a reduction of the number of ribosomes was noted and regions of homogenous structure appeared. Mitochondria were moved in the direction of the tonoplast and plasma membrane. Compared to the cells unaffected by phytoplasma, the mitochondria were smaller and had an enlarged cristae internal space. The chloroplasts from affected cells had a very significant reduction in size and the tylacoids system had disappeared. The role of these changes for creating phytoplasma friendly enviroment is discused.

Structure of Wood and Cambial Variant in the Stem of Dalbergia Paniculata Roxb.

IAWA Journal ◽  
1990 ◽  
Vol 11 (4) ◽  
pp. 379-391 ◽  
Author(s):  
M. N. B. Nair ◽  
H. Y. Mohan Ram
Keyword(s):  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Sieve Tube ◽  
Secondary Phloem ◽  
Succinate Dehydrogenase Activity ◽  
Successive Cambia ◽  
Phloem Parenchyma ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Cambial Variant

The wood of Dalbergia paniculata is unique as it consists of concentric layers of broad xylem, alternating with bands of narrow phloem. This anomaly results from the periodic formation of successive cambia in the secondary phloem. Some phloem parenchyma cells dedifferentiate to form a discontinuous ring of cambium. Such parenchyma cells have higher succinate dehydrogenase activity than the neighbouring cells of secondary phloem. The newly differentiated cambial layer functions bidirectionally, and its products give rise to xylem internally and phloem externally. The phloem along with cambium present internal to the newly formed xylem becomes included.The wood is diffuse-porous and the intervessel pits are vestured. The phloem has welldifferentiated sieve tube members and companion cells.

Pathological anatomy of the bacterial phloem canker disease of Juglans regia

1970 ◽  
Vol 48 (6) ◽  
pp. 1055-1060 ◽  
Author(s):  
Norman W. Schaad ◽  
E. E. Wilson
Keyword(s):  
Juglans Regia ◽  
Leaf Tissue ◽  
Sieve Tube ◽  
Secondary Phloem ◽  
Subsequent Formation ◽  
Canker Disease ◽  
Secondary Stage ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Two Stages

Erwinia rubrifaciens Wilson, Zeitoun, and Fredrickson invades sieve tubes and parenchyma cells of the nonfunctional secondary phloem of Persian walnut, Juglans regia L. Because the sieve plate pores are great enough in diameter to allow passage of the bacteria, the nonfunctional phloem system provides an avenue along which the bacteria moves long distances up and down the bark. Functional phloem, on the other hand, does not exhibit symptoms of the disease nor is it found to contain the bacteria. Although the bacteria invade the ray parenchyma and move radially through these elements to the outer xylem, bacteria are not found to enter the xylem vessels. In culture, E. rubrifaciens produces long flexuous flagella. When taken from inoculated leaf tissue, however, it does not possess flagella. Hence, transport of bacteria from one sieve tube to another appears to be by apoplastic movement. Internal symptoms develop in two stages: a primary stage due to invasion of degenerate sieve tubes, and a secondary stage due to invasion of parenchyma cells and subsequent formation of wound callus. Pressure from wound callus induces vertical cracks in the bark. A slimy substance containing the bacteria exudes through the cracks to the bark surface, thereby allowing dispersion of the bacteria.

Anatomical effects of 2,4-DB on tomato internodes

1981 ◽  
Vol 59 (9) ◽  
pp. 1749-1760
Author(s):  
Thompson Demetrio Pizzolato ◽  
David L. Regehr
Keyword(s):  
Secondary Wall ◽  
Sieve Tube ◽  
Tracheary Elements ◽  
Anatomical Changes ◽  
Companion Cells ◽  
Sieve Tubes ◽  
Secondary Wall Formation ◽  
Sieve Plates ◽  
Internal Phloem ◽  
Stimulation Of

Anatomical changes induced in the first internode by an aqueous spray of 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) (0.56 kg acid equivalent per hectare) confirmed the intolerance of tomato to this herbicide. Hypertrophy, hyperplasia, and plastid destruction occurred rapidly in most tissues. Many of the hyperplastic phloem cells differentiated into unusual supernumerary sieve tube members which were shorter and narrower than normal and which approximated the size of the co-differentiating companion cells. The supernumerary sieve tube members usually possessed several sieve plates and formed sieve tubes which did not follow a vertical course. Although obliteration of the supernumerary sieve tube members was stimulated, it was not associated with the formation of necrotic masses. Secondary wall formation was prevented in the protophloem fibers which became multiseptate following the stimulation of mitoses. The cambial initials were converted into a tissue of squat cells with little organization. Xylem which differentiated after treatment lost its normal heterogeneity and became a tissue of squat tracheary elements and parenchyma with scanty secondary thickening resembling wound xylem. Included phloem differentiated from parenchymatous masses within the xylem, and tylosis formation was stimulated. Pith volume increased by hypertrophy unaccompanied by hyperplasia. Although protophloem fibers did not mature in the internal phloem and limited hyperplasia and hypertrophy did occur, the internal phloem was much less affected than the external. Similarities between the anatomical effects of 2,4-DB and those reported for certain growth regulators and pathogens were noted.

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