Vascular system of the fertile floret of Phalaris arundinacea

1989 ◽  
Vol 67 (5) ◽  
pp. 1366-1380 ◽  
Author(s):  
Thompson Demetrio Pizzolato
Keyword(s):  
Vascular System ◽  
Lower Layer ◽  
Phalaris Arundinacea ◽  
Sieve Element ◽  
Vascular Bundles ◽  
Tracheary Elements ◽  
Sieve Elements

Six vascular bundles lie in two rows of three in the rachilla at the base of the fertile floret. Each bundle relates to a lemma or palea trace. As the rachilla bundles become traces they also produce sieve elements that interconnect to form the lower layer of the sieve-element plexus. Lodicule traces join the anterior of this lower plexus. Only the tracheary elements from the rachilla bundle related to the lemma's median trace rise higher in the rachilla, and these merge into a system of anomalous tracheary elements (xylem discontinuity) that rises toward the ovule. The lower sieve-element plexus layer ascends around the xylem discontinuity into a trilobed upper plexus layer which supplies the stamen traces. A third sieve-element plexus (pistil plexus) joins the upper plexus layer by three descending prongs. The pistil plexus, which occurs at the base of the pistil, is linked on its anterior to the anterior bundle. The placental bundle rises from the posterior of the pistil plexus and furnishes the sides of the pistil with their anterolateral and posterolateral sieve elements. The posterolaterals supply the styles. The sieve elements and the xylem discontinuity of the placental bundle supply the ovule.

Vascular system of the floret of Phleum pratense

1988 ◽  
Vol 66 (9) ◽  
pp. 1818-1829 ◽  
Author(s):  
Thompson Demetrio Pizzolato
Keyword(s):  
Vascular Tissue ◽  
Vascular System ◽  
Sieve Tube ◽  
Sieve Element ◽  
Phleum Pratense ◽  
Tracheary Elements ◽  
Sieve Elements ◽  
Circular Component

Two bundles occur in the rachilla at the floret base. The anterior bundle supplies the vascular tissue for the lemma median trace, and the posterior supplies that for its two extreme laterals. The intermediate laterals of the lemma connect at the anterior bundle, and the two palea traces join near the posterior bundle to the traces for the extreme lemma laterals. Near these connections sieve elements of the two rachilla bundles link, forming the lower component of the sieve-element plexus. The xylem discontinuity begins above the anterior bundle. An upper, circular component of the sieve-element plexus surrounds the discontinuity. The sieve elements of the lodicules join the anterior of the upper plexus. The upper plexus becomes trilobed as it merges with the stamen traces. Three pistil bundles including sieve elements and tracheary elements of the xylem discontinuity join the upper plexus. These pistil bundles unite into a circular pistil plexus surrounding the discontinuity. The anterior sieve tube of the pistil joins the anterior of the pistil plexus. Sieve elements emerge from the posterolateral portions of the plexus toward the styles and leave a placental bundle of sieve elements and tracheary elements of the xylem discontinuity in the pistil posterior.

Vascular system of the floret of Alopecurus carolinianus (Gramineae)

1987 ◽  
Vol 65 (12) ◽  
pp. 2592-2600 ◽  
Author(s):  
Thompson Demetrio Pizzolato
Keyword(s):  
Vascular System ◽  
Sieve Tube ◽  
Sieve Element ◽  
Sieve Elements

The interconnecting vascular system of the floret of Alopecurus carolinianus Walter begins as a single, collateral bundle, which enters the rachilla and becomes reorganized into a diarch pattern while ascending between the glumes. During a pronounced posterior enlargement, the rachilla bundle becomes connected with the median and four lateral bundles of the lemma. Above the trace to the lemma median, elements of a xylem discontinuity surrounded by those of a sieve-element plexus form in the rachilla bundle. Higher, a trace consisting of elements of the xylem discontinuity and the plexus enters the anterior and the posterior stamen. Two bundles, the lowest portion of the pistil vasculature, rise eccentrically from the xylem discontinuity and sieve-element plexus at the level of the stamen traces. The bundles condense into one which rotates counterclockwise and connects with the anterior sieve tube of the pistil. The xylem discontinuity of the bundle now in the pistil begins to diminish, and the sieve elements fan out to the sides and posterior of the xylem discontinuity. From the sieve elements one or two posterolaterals emerge toward the styles. The bundle of diffuse sieve elements in a semicircle behind the diminishing xylem discontinuity is now the placental bundle of the pistil. After its xylem discontinuity and then its sieve elements fade out, the placental bundle merges with the ovule at the chalaza.

Development of Common Milkweed (Asclepias syriaca) Root Buds Following Emergence from Lateral Roots

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 758-763 ◽  
Author(s):  
Elizabeth J. Stamm-Katovich ◽  
Donald L. Wyse ◽  
David D. Biesboer
Keyword(s):  
Vascular System ◽  
Lateral Roots ◽  
Vascular Bundles ◽  
Tracheary Elements ◽  
Asclepias Syriaca ◽  
Primary Xylem ◽  
Root Segments ◽  
Common Milkweed Asclepias Syriaca ◽  
Anatomical Constraints ◽  
Root Buds

In common milkweed, the development of subterranean root buds on excised root segments, following emergence from the parent root, is characterized by development of nodes and internodes followed by internode expansion. Transverse sections of root buds reveal that bicollateral vascular bundles as well as leaf traces and gaps are well developed in buds from 3-month-old plants. Strands of xylem and phloem connect the parent root and root bud in both inhibited and noninhibited root buds. Pitted primary tracheary elements, characteristic of developmentally advanced primary xylem, are present in these traces. The occurrence of a well-developed vascular system throughout the root bud and between the parent root and bud provides evidence that retardation of growth of inhibited root buds in common milkweed is not caused by anatomical constraints.

Vascular differentiation in the wheat embryo

1971 ◽  
Vol 19 (1) ◽  
pp. 63 ◽  
Author(s):  
JG Swift ◽  
TP O'Brien
Keyword(s):  
Tracheary Element ◽  
Sieve Element ◽  
Serial Sections ◽  
Tracheary Elements ◽  
Vascular Differentiation ◽  
Tracheary Element Differentiation ◽  
Wheat Embryo ◽  
Sieve Elements ◽  
Foliage Leaf

The sequence of vascular differentiation in the scutellum, coleoptile, and firbt foliage leaf of the wheat embryo is traced by examining serial sections of these organs at selected intervals after the initial soaking of the grain. Mature sieve elements are found first in the scutellum 3-6 hr after soaking, in the midrib of the first leaf after 6 hr, and in the coleoptile after 18 hr. In all three organs xylem differentation lags behind that of the phloem; mature tracheary elements are present in the scutellum by 18 hr, in the midrib by 24 hr, and in the coleoptile by 30 hr. It is suggested that there are four loci of sieve element differentiation and two loci of tracheary element differentiation. These observations are discussed with reference to previous accounts of vascular differentiation.

Reassessing species boundaries in the Syagrus glaucescens complex (Arecaceae) using leaf anatomy

Botany ◽  
2021 ◽  
pp. 379-387
Author(s):  
D.H.T. Firmo ◽  
S.A. Santos ◽  
M.E.M.P. Perez ◽  
P. Soffiatti ◽  
B.F. Sant’Anna-Santos
Keyword(s):  
Species Identification ◽  
Leaf Anatomy ◽  
Vascular System ◽  
Identification Key ◽  
Species Boundaries ◽  
Vascular Bundles ◽  
Geographical Isolation ◽  
Species Occurrence ◽  
Species Diagnosis ◽  
High Degree

The Syagrus glaucescens complex comprises three species: Syagrus glaucescens Glaz. ex Becc., Syagrus duartei Glassman, and Syagrus evansiana Noblick. Recently, a new population of S. evansiana that possesses a high degree of endemism was reported in the Serra do Cabral mountain. Here we intend to study the leaf anatomy of the S. glaucescens complex and confirm whether this newly found population (from now on called Syagrus aff. evansiana) belongs to S. evansiana or not. Specimens were collected to investigate their leaf anatomy, which showed distinct differences between S. aff. evansiana and S. evansiana. The midrib anatomy revealed novelties for the S. glauscecens complex, proving useful for species diagnosis. Features such as accessory vascular bundles around the vascular system of the midrib and the number of collateral bundles are diagnostic for species identification. In addition, morphological and anatomical analyses indicated a correlation with the species occurrence. We found greater similarity between S. glaucescens and S. duartei, while S. evansiana and S. aff. evansiana are more alike. Here, we propose a new identification key based only on the leaf anatomy. Despite their morphological similarities, S. aff. evansiana and S. evansiana presented differences in leaf anatomy, which — when associated with their geographical isolation — suggests a fourth taxon in the complex.

scholarly journals Morphology and anatomy of leaf mine in Richterago riparia Roque (Asteraceae) in the campos rupestres of Serra do Cipó, Brazil

2002 ◽  
Vol 62 (1) ◽  
pp. 179-185 ◽  
Author(s):  
G. F. A. MELO DE PINNA ◽  
J. E. KRAUS ◽  
N. L. de MENEZES
Keyword(s):  
Host Plant ◽  
Vascular System ◽  
Glandular Trichomes ◽  
Protective Layer ◽  
Vascular Bundles ◽  
Campos Rupestres ◽  
Structural Alterations ◽  
Serra Do Cipó ◽  
Phenolic Substances

The leaf mine in Richterago riparia is caused by a lepidopteran larva (lepidopteronome). The leaves of R. riparia show campdodrome venation; the epidermis is unistratified, with stomata and glandular trichomes in adaxial and abaxial surfaces. The mesophyll is bilateral and the vascular system is collateral. During the formation of the mine, the larva consumes the chlorenchyma of the mesophyll and the smaller vascular bundles (veins of third and fourth orders). Structural alterations in the tissues of the host plant were not observed, except for the formation of a wound meristem and the presence of cells with phenolic substances next to the mine. Three cephalic exuviae of the miner were found in the mesophyll. This lepidopteronome is parenchymatic and the epidermis remains intact, but forms a protective layer for the mining insect.

scholarly journals Presence of Xylella fastidiosa in Sweet Orange Fruit and Seeds and Its Transmission to Seedlings

2003 ◽  
Vol 93 (8) ◽  
pp. 953-958 ◽  
Author(s):  
W.-B. Li ◽  
W. D. Pria ◽  
P. M. Lacava ◽  
X. Qin ◽  
J. S. Hartung
Keyword(s):  
Vascular System ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Germination Rate ◽  
Citrus Fruit ◽  
Vascular Bundles ◽  
Specific Amplification ◽  
Root Grafts ◽  
Citrus Seeds

Xylella fastidiosa, a xylem-limited bacterium, causes several economically important diseases in North, Central, and South America. These diseases are transmitted by sharpshooter insects, contaminated budwood, and natural root-grafts. X. fastidiosa extensively colonizes the xylem vessels of susceptible plants. Citrus fruit have a well-developed vascular system, which is continuous with the vascular system of the plant. Citrus seeds develop very prominent vascular bundles, which are attached through ovular and seed bundles to the xylem system of the fruit. Sweet orange (Citrus sinensis) fruit of cvs. Pera, Natal, and Valencia with characteristic symptoms of citrus variegated chlorosis disease were collected for analysis. X. fastidiosa was detected by polymerase chain reaction (PCR) in all main fruit vascular bundles, as well as in the seed and in dissected seed parts. No visual abnormalities were observed in seeds infected with the bacterium. However, the embryos of the infected seeds weighed 25% less than those of healthy seeds, and their germination rate was lower than uninfected seeds. There were about 2,500 cells of X. fastidiosa per infected seed of sweet orange, as quantified using real-time PCR techniques. The identification of X. fastidiosa in the infected seeds was confirmed by cloning and sequencing the specific amplification product, obtained by standard PCR with specific primers. X. fastidiosa was also detected in and recovered from seedlings by isolation in vitro. Our results show that X. fastidiosa can infect and colonize fruit tissues including the seed. We also have shown that X. fastidiosa can be transmitted from seeds to seedlings of sweet orange. To our knowledge, this is the first report of the presence of X. fastidiosa in seeds and its transmission to seedlings.

scholarly journals A crystalline inclusion in sieve element nuclei of Amsinckia. II. The inclusion in maturing cells

1979 ◽  
Vol 38 (1) ◽  
pp. 11-22
Author(s):  
K. Esau ◽  
A.C. Magyarosy
Keyword(s):  
Hydrostatic Pressure ◽  
Sieve Element ◽  
Crystalline Inclusion ◽  
Sieve Elements ◽  
P Protein ◽  
Sudden Release ◽  
Sieve Plates ◽  
Tubular Components

The compounds crystalloids formed in sieve element nuclei of Amsinckia douglasiana A. DC. (Boraginaceae) during differentiation of the cell become disaggregated during the nuclear breakdown characteristic of a maturing sieve element. The phenomenon occurs in both healthy and virus-infected plants. The crystalloid component termed cy, which is loosely aggregated, separates from the densely aggregated component termed cx and disperses. The cx component may become fragmented, or broken into large pieces, or remain intact after the cell matures. After their release from the nucleus both crystalloid components become spatially associated with the dispersed P-protein originating in the cytoplasm, but remain distinguishable from it. The component tubules of P-protein are hexagonal in transections and are somewhat wider than the 6-sided cy tubules. The cx tubules are much narrower than the P-protein or the cy tubules and have square transections. Both the P-protein and the products of disintegrated crystalloids accumulate at sieve plates in sieve elements subjected to sudden release of hydrostatic pressure by cutting the phloem. The question of categorizing the tubular components of the nuclear crystalloid of a sieve element with reference to the concept of P-protein is discussed.

Comparative chemotaxonomic investigations on amaranthus hybridus l. and Amaranthus spinosus L.

2021 ◽  
Vol 20 (1) ◽  
pp. 91-100
Author(s):  
C. Wahua ◽  
J. Nwikiri
Keyword(s):  
Niger Delta ◽  
Vascular System ◽  
Vascular Bundles ◽  
Stomatal Index ◽  
Amaranthus Hybridus ◽  
Anatomical Studies ◽  
Amaranthus Spinosus ◽  
The Family ◽  
Phytochemical Studies ◽  
Key Words Morphology

The present study is set to investigate the comparative chemotaxonomic investigations on Amaranthus hybridus L. and Amaranthus spinosus L. which belong to the family Amaranthaceae. They are dicots pre-dominantly found in the Niger Delta Tropics, Nigeria. The species are annual erect herbs with flower inflorescences as elongated spikes which are mostly paniculate occurring at ends of branches in globose fashion in axils of leaves.The nodes often have pair of axillary spines. Flowers are small, greenish with male ones at the top while the female ones below the clusters and stem is greenish but often reddish with one-seeded capsule as fruit in Amaranthus spinosus which attains up to 80 ± 20cm in height whereas A. hybridus differ in absence of a pair of axillary spines, the stems are greenish or slightly pinkish which grows up to 100 ± 10cm in height. A. hybridus is more of a vegetable and has alternate phyllotaxi and narrow cuneate base. Fruits from both species are circumscissile capsules and their inflorescences are terminal racemes positioned at their axils with female perianth segments of five. Epidermal studies revealed amphistomatic stomata which is anisocytic  type for both species. The stomatal index for A. spinosus adaxial foliar epidermis is 20% and the abaxial 20% whereas for A. hybridus adaxial is 20% and abaxial foliar stomatal index of 20%. Anatomical studies revealed open vascular system, collenchyma dominating the hypodermis while parenchyma occupied the general cortex and pith regions. A. hybridus has more vascular bundles and trichomes, and wider pith than A. spinosus. Phytochemical studies showed the presence of tannins, saponins, alkaloids, and flavonoids are present in A. spinosus while alkaloids were absent only in A. hybridus. This may be the reason why A. spinosus is used more in tradomedicine than A.hybridus which served more as vegetable. Key Words: Morphology, Anatomy, Phytochemistry, Amaranthus, Amaranthaceae

Vascular System of the Stem of the Wheat Plant. I. Mature State

1972 ◽  
Vol 20 (1) ◽  
pp. 49 ◽  
Author(s):  
JW Patrick
Keyword(s):  
Triticum Aestivum ◽  
Vascular System ◽  
Wheat Plant ◽  
Triticum Aestivum L ◽  
Vascular Bundles ◽  
Vascular Connections ◽  
Main Tiller

The courses of the various vascular bundles in the nodes of the main tiller of Triticum aestivum L. have been reconstructed from anatomical observations of con- secutive serial transverse sections. Of the bundles entering a node (n) from its attached leaf, the first-formed and largest, the median, passes directly through the node to the second node below (n-2), where it bifurcates and fuses with other strands. These continue to node n- 3 before fusing completely with the nodal plexus. The next six bundles to form (laterals) establish some links with bundles from higher leaves in the node of entry, much more extensive connections in node n- 1, and fuse completely with the nodal plexus in node n-2. The next four lateral bundles to differentiate are more extensively linked in node n and fuse completely with the nodal plexus in node n - I . The remaining 16-20 bundles from the leaf (intermediates) follow much the same course but develop more extensive connections with other bundles. The extensive plexus which develops in each node ensures vascular connections between most bundles. The significance of these in transport is briefly discussed.

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