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.

The origin and development of root buds in Asclepias syriaca

1982 ◽  
Vol 60 (10) ◽  
pp. 2119-2125 ◽  
Author(s):  
Patricia L. Polowick ◽  
M. V. S. Raju
Keyword(s):  
Lateral Root ◽  
Early Stage ◽  
Lateral Roots ◽  
Cambial Activity ◽  
Root Anatomy ◽  
Main Root ◽  
Asclepias Syriaca ◽  
Bud Development ◽  
Vascular Connections ◽  
Root Buds

The persistence of Asclepias syriaca L. as a weed is related to its ability to propagate vegetatively by the development of adventitious buds on roots. These root buds arise on the main root and upper lateral roots within 25 days of the establishment of seedlings and are generally associated with the bases of lateral roots. A study of root anatomy shows that the origin of these buds is endogenous, in the pericycle and (or) its derivatives. No root buds are initiated until after lateral roots have developed and some cambial activity has begun. Vascular connections from the bud to the stele of the parent root, or an associated lateral root, are made at an early stage of bud development.

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.

Development of endodermal Casparian bands and xylem in lateral roots of broad bean

1990 ◽  
Vol 68 (12) ◽  
pp. 2729-2735 ◽  
Author(s):  
Carol A. Peterson ◽  
Barbara E. M. Lefcourt
Keyword(s):  
Broad Bean ◽  
Lateral Roots ◽  
Staining Procedure ◽  
Tracheary Elements ◽  
Main Root ◽  
Fluorochrome Staining ◽  
Primary Xylem ◽  
Casparian Bands ◽  
Casparian Band

A clearing and fluorochrome staining procedure for broad bean (Vicia faba L. cv. Windsor) roots with laterals was devised which allowed observation of their tracheary elements and Casparian bands in situ. The Casparian band of the main root overlying the primordium disappeared early in its development and the margins of the remaining band were displaced outward during subsequent growth of the lateral. The Casparian band matured centripetally in parenchyma across the base of the lateral as far as the endodermis of the lateral and then acropetally into the lateral itself. Casparian bands of the laterals were always connected to those of the main roots. In actively growing roots, the primordium may have emerged as far as 2.7 mm from the main root and still contain no differentiating xylem or Casparian band. Longer laterals contained differentiating xylem 3 mm from the tip and maturing Casparian bands 5 mm from the tip. In nongrowing roots, some primordia not yet emerged from the main root had mature xylem tracheary elements 0.4 mm from the tip and mature Casparian bands 0.25 mm from the tip. Key words: Casparian band, primary xylem, lateral roots, endodermis.

Chemical and Physical Effects of the Accumulation of Glyphosate in Common Milkweed (Asclepias syriaca) Root Buds

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Mark A. Waldecker ◽  
Donald L. Wyse
Keyword(s):  
Growth Chamber ◽  
Asclepias Syriaca ◽  
Partial Removal ◽  
Chemically Treated ◽  
Physical Effects ◽  
Common Milkweed Asclepias Syriaca ◽  
Bud Respiration ◽  
Root Buds

Distribution of14C-glyphosate [N-(phosphonomethyl)glycine] in chemically treated and physically manipulated common milkweed [Asclepias syriaca(L.) ♯ ASCSY] was studied in greenhouse and growth chamber experiments. Pretreatment with glyphosate at 0.6 and 1.1 kg ae/ha 3 days prior to14C-glyphosate application to leaves reduced the concentration of14C recovered from shoots and leaves above the14C-glyphosate-treated leaves but had no influence on the concentration of14C in proximal root buds. Partial removal of the shoot and root prior to the application of14C-glyphosate increased bud respiration and the concentration of14C in the proximal root buds. Proximal root buds treated with 1 mM of 6-benzyl-aminopurine (BAP) for 6 days (3 days prior to application of14C-glyphosate) contained seven times more14C/mg than root buds of BAP-untreated plants, suggesting that dormant buds could be chemically stimulated to accumulate higher concentrations of glyphosate. BAP-treated buds were killed by foliar applications of glyphosate at 1.1 kg/ha, indicating that proximal root buds can be stimulated to acquire lethal concentrations of glyphosate.

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 RESILIENCE OF FERNS: WITH REFERENCE TO DESICCATION AND REHYDRATION STRESS OFFER NEW INSIGHTS

2017 ◽  
Vol 4 (2) ◽  
pp. 89-94
Author(s):  
Kavitha C.H ◽  
Meenu Krishnan ◽  
Murugan K
Keyword(s):  
Vascular Plants ◽  
Stress Proteins ◽  
Secondary Xylem ◽  
Plant Water Relations ◽  
Vascular Bundles ◽  
Late Cenozoic ◽  
Primary Xylem ◽  
Hydraulic Failure ◽  
Pit Membrane ◽  
Selection For

Ferns are one of the oldest vascular plants in existence and they are the second most diverse group of vascular plants followed to angiosperms. To unravel fern success has focused on the eco-physiological power and stress tolerance of their sporophyte and the gametophyte generations. In this context, those insightsencompass plant water relations, as well as the tolerance to and recovery from drought or desiccation stresses in the fern life cycle are reviewed. Lack of secondary xylem in ferns is compensated by selection for efficient primary xylem composed of large, closely arranged tracheids with permeable pit membranes.Protection from drought-induced hydraulic failure appears to arise from a combination of pit membrane traits and the arrangement of vascular bundles. Features such as tracheid-based xylem and variously sized megaphylls are shared between ferns and more derived lineages, and offer an opportunity to compare convergent and divergent hydraulic strategies critical to the success of xylem-bearing plants. Similarly the synthesis and accumulation of sugar, proline and stress proteins along with the production of pool of polyphenols add strength to desiccation stress. Thus, it can possible to suggest that selection acted on the physiology in a synchronous manner that is consistent with selection for drought tolerance in the epiphytic niche, and the increasingly diverse habitats of the mid to late Cenozoic.

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

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