Microscopic Examination Of Vascular Differentiation And Pattern Formation In The Inflorescence Stems Of Arabidopsis

1999 ◽  
Vol 5 (S2) ◽  
pp. 1284-1285
Author(s):  
G. Freshour ◽  
M. Hahn ◽  
Z-H Ye
Keyword(s):  
Pattern Formation ◽  
Vascular Plants ◽  
Vascular System ◽  
The Body ◽  
Vascular Bundles ◽  
Vascular Differentiation ◽  
Evolutionary Mechanisms ◽  
Vascular Tissues ◽  
Inflorescence Stems ◽  
Food Transport

Plant vascular system is the principal means to carry water and food throughout the plant body. It is composed of two types of conducting vascular tissues, xylem and phloem. Xylem carries water and minerals from the root to the shoot, whereas phloem transports photosynthates from leaves to other parts of the body. The evolution of vascular system which solved the problem of water and food transport was considered to be one of the key events for the successful emergence of vascular plants on the land from aquatic environments. Although vascular tissues in almost all vascular plants consist of xylem and phloem, diverse arrangements of vascular tissues within the bundles and of vascular bundles in the stele were evolved (1). The occurrence of diverse vascular patterns in vascular plants offers an excellent opportunity to study the evolutionary mechanisms controlling pattern formation. In this report, we present our studies on the vascular differentiation and pattern formation in the inflorescence stems of Arabidopsis thaliana.

scholarly journals Molecular Changes Concomitant with Vascular System Development in Mature Galls Induced by Root-Knot Nematodes in the Model Tree Host Populus tremula × P. alba

2020 ◽  
Vol 21 (2) ◽  
pp. 406 ◽  
Author(s):  
Fabien Baldacci-Cresp ◽  
Marc Behr ◽  
Annegret Kohler ◽  
Nelly Badalato ◽  
Kris Morreel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
De Novo ◽  
Vascular System ◽  
System Development ◽  
Primary Cell Wall ◽  
Root Knot Nematode ◽  
Vascular Differentiation ◽  
Vascular Tissues ◽  
Model Tree

One of the most striking features occurring in the root-knot nematode Meloidogyne incognita induced galls is the reorganization of the vascular tissues. During the interaction of the model tree species Populus and M. incognita, a pronounced xylem proliferation was previously described in mature galls. To better characterise changes in expression of genes possibly involved in the induction and the formation of the de novo developed vascular tissues occurring in poplar galls, a comparative transcript profiling of 21-day-old galls versus uninfected root of poplar was performed. Genes coding for transcription factors associated with procambium maintenance and vascular differentiation were shown to be differentially regulated, together with genes partaking in phytohormones biosynthesis and signalling. Specific signatures of transcripts associated to primary cell wall biosynthesis and remodelling, as well as secondary cell wall formation (cellulose, xylan and lignin) were revealed in the galls. Ultimately, we show that molecules derived from the monolignol and salicylic acid pathways and related to secondary cell wall deposition accumulate in mature galls.

scholarly journals BdERECTA controls vasculature patterning and phloem-xylem organization in Brachypodium distachyon

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kaori Sakai ◽  
Sylvie Citerne ◽  
Sébastien Antelme ◽  
Philippe Le Bris ◽  
Sylviane Daniel ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Vascular Tissue ◽  
Vascular System ◽  
Brachypodium Distachyon ◽  
Premature Stop Codon ◽  
Vascular Network ◽  
Vascular Bundles ◽  
Large Set ◽  
Vascular Tissues ◽  
Tissue Organization

Abstract Background The vascular system of plants consists of two main tissue types, xylem and phloem. These tissues are organized into vascular bundles that are arranged into a complex network running through the plant that is essential for the viability of land plants. Despite their obvious importance, the genes involved in the organization of vascular tissues remain poorly understood in grasses. Results We studied in detail the vascular network in stems from the model grass Brachypodium distachyon (Brachypodium) and identified a large set of genes differentially expressed in vascular bundles versus parenchyma tissues. To decipher the underlying molecular mechanisms of vascularization in grasses, we conducted a forward genetic screen for abnormal vasculature. We identified a mutation that severely affected the organization of vascular tissues. This mutant displayed defects in anastomosis of the vascular network and uncommon amphivasal vascular bundles. The causal mutation is a premature stop codon in ERECTA, a LRR receptor-like serine/threonine-protein kinase. Mutations in this gene are pleiotropic indicating that it serves multiple roles during plant development. This mutant also displayed changes in cell wall composition, gene expression and hormone homeostasis. Conclusion In summary, ERECTA has a pleiotropic role in Brachypodium. We propose a major role of ERECTA in vasculature anastomosis and vascular tissue organization in Brachypodium.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

scholarly journals Petiole-Lamina Transition Zone: A Functionally Crucial but Often Overlooked Leaf Trait

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 774
Author(s):  
Max Langer ◽  
Thomas Speck ◽  
Olga Speck
Keyword(s):  
Transition Zone ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Body Plan ◽  
The Body ◽  
Vascular Bundles ◽  
Cross Sectional ◽  
Thin Sections ◽  
Transition Zones ◽  
The Cross

Although both the petiole and lamina of foliage leaves have been thoroughly studied, the transition zone between them has often been overlooked. We aimed to identify objectively measurable morphological and anatomical criteria for a generally valid definition of the petiole–lamina transition zone by comparing foliage leaves with various body plans (monocotyledons vs. dicotyledons) and spatial arrangements of petiole and lamina (two-dimensional vs. three-dimensional configurations). Cross-sectional geometry and tissue arrangement of petioles and transition zones were investigated via serial thin-sections and µCT. The changes in the cross-sectional geometries from the petiole to the transition zone and the course of the vascular bundles in the transition zone apparently depend on the spatial arrangement, while the arrangement of the vascular bundles in the petioles depends on the body plan. We found an exponential acropetal increase in the cross-sectional area and axial and polar second moments of area to be the defining characteristic of all transition zones studied, regardless of body plan or spatial arrangement. In conclusion, a variety of terms is used in the literature for describing the region between petiole and lamina. We prefer the term “petiole–lamina transition zone” to underline its three-dimensional nature and the integration of multiple gradients of geometry, shape, and size.

Symmetrical vascularization patterns in normal and retinoic acid treated limb regenerates of the axolotl, Ambystoma mexicanum

1998 ◽  
Vol 76 (9) ◽  
pp. 1795-1796 ◽  
Author(s):  
Steven R Scadding ◽  
Andrew Burns
Keyword(s):  
Retinoic Acid ◽  
Pattern Formation ◽  
Vascular System ◽  
Limb Regeneration ◽  
Ambystoma Mexicanum ◽  
Limb Pattern ◽  
Regeneration Blastema

The purpose of this investigation was to determine whether there were any asymmetries in the vascularization of the limb-regeneration blastema in the axolotl, Ambystoma mexicanum, that might be related to pattern formation, and to determine if retinoic acid could modify the vascular patterns of the blastema. We used acrylic casts of the vascular system of the limbs to assess the pattern of vascularization. We observed a very regular symmetrical arrangement of capillaries in the limb-regeneration blastema that did not appear to be modified by doses of retinoic acid sufficient to modify the limb pattern.

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.

Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. 1. Production and translocation of a necrosis-inducing toxin

1969 ◽  
Vol 47 (7) ◽  
pp. 1147-1151 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston
Keyword(s):  
Activated Carbon ◽  
Root System ◽  
Vascular System ◽  
Early Symptom ◽  
Vascular Tissues ◽  
Detached Leaves ◽  
Necrotic Spots ◽  
Whole Plants ◽  
Necrotic Spotting

Necrotic spotting of leaves is an early symptom of attack by Sclerotium bataticola on sunflowers. Spots appear after invasion of vascular tissues by the pathogen, which does not spread appreciably from the point of inoculation.Inoculation of one stem of plants split apically to give twin stems on one root system resulted in necrotic spotting of leaves first on the inoculated, and later on the uninoculated stem. Introducing cell-free filtrates of cultures of S. bataticola into sunflower plants or detached leaves resulted in production of the same type of necrotic spots. Introduction of eosin dye, which is translocated in the vascular system, into whole plants and detached leaves produced patterns of coloration similar to the patterns of necrotic spotting. The necrosis may be attributed to a translocatable toxin produced by the fungus.It is indicated that the toxin is neither an enzyme nor a protein. It has not been eluted after adsorption by activated carbon.

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.

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