scholarly journals Structural Integrity of Vascular System in Branching Units of Coniferous Shoot

2020 ◽  
Vol 89 (1) ◽  
Author(s):  
Alicja Banasiak ◽  
Beata Zagórska-Marek
Keyword(s):  
Biological System ◽  
Strong Correlation ◽  
Apical Meristem ◽  
Structural Integrity ◽  
Vascular System ◽  
Lateral Shoot ◽  
Developmental Processes ◽  
Phyllotactic Pattern ◽  
One Step ◽  
Resin Canals

In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of cortical resin canals, define the shoot anatomic diameter. This in turn reflects the size and vigor of the apical meristem. Both numbers belong to the mathematical series, associated with the shoot phyllotactic pattern. The number of canals is one step lower in a series than the number of sympodia. The first one, easier to determine, automatically defines the second. Using this protocol and screening the large number of branching shoots of selected conifers, we have discovered strong correlation between orientation of vascular sympodia in the lateral and supporting branches. There was no such correlation with regard to the chiral configurations of phyllotaxis. This finding reveals the presence of special phyllotactic compensation in the case of differences in anatomic diameter of the parental and lateral shoot under the imperative of maintaining the sympodia orientation within one branching unit. Phyllotaxis of the axillary apex is evidently not established at random but adapted to the condition of the subtending axis. The monopodial, regularly branching shoot of conifers is an attractive example of biological system, which is not a sum of independent, iteratively formed units. Rather, it appears to be an entity organized on hierarchically higher level, which emerges from coordination of developmental processes in a population of the units.

scholarly journals Related to phyllotaxis interlocked systems of vascular sympodia and cortical resin canals in Abies and Picea shoots

2014 ◽  
Vol 69 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Beata Zagórska-Marek ◽  
Alicja Banasiak
Keyword(s):  
Open System ◽  
Vascular System ◽  
Plant Morphogenesis ◽  
Phyllotactic Pattern ◽  
System A ◽  
One Step ◽  
Set Up ◽  
Resin Canals ◽  
Cut Surface ◽  
Internal Architecture

We report on some new aspects of the internal architecture of conifer shoot, proving that it is even more strongly related to phyllotaxis than was initially thought. The number of vascular sympodia in an open system of <em>Abies</em> and <em>Picea</em> shoots is correlated with the number of cortical resin canals. Both numbers are the consecutive members of the phyllotactic series, which defines the phyllotactic pattern of the shoot. This means that the concentric systems of alternately oriented vascular sympodia and resin canals are interlocked, following the course of superficial opposite parastichies. Such pattern of inner architecture most likely contributes to the mechanical strengthening of the shoot. It also provides a new example of heterogenetic induction in plant morphogenesis because the development of orderly spaced resin canals is dependent upon earlier differentiation of vascular system. A rapid method of assessing the number of vascular sympodia becomes available by means of counting the number of discrete cortical resin canals visible on the cut surface of the shoot sectioned transversely. Despite being set up on the smaller radius, the number of sympodia is always one step higher in a phyllotactic series than the number of canals.

Primary vascular patterns in root meristems of Pontederia cordata and their relevance to studies of root development

1980 ◽  
Vol 58 (12) ◽  
pp. 1351-1369 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Root Apex ◽  
Root Apical Meristem ◽  
Vascular Pattern ◽  
Quiescent Centre ◽  
Vascular Differentiation ◽  
Pontederia Cordata ◽  
Distribution Of Components ◽  
Root Apices

There are several files of metaxylem cells in root apices of Pontederia cordata L., each considered to consist of a series of prospective vessels with their ends in contact. Two longitudinally adjacent vessels may be in the same file of cells produced by the root apex or in adjacent files. As the root grows, successive prospective vessels are added to the apical ends of most of the files but not all files are continued. Addition of prospective vessels appears to take place within the "quiescent centre" of the root apical meristem. Where files are not continued there is no immediate readjustment of remaining files. The longitudinal and transverse distribution of components of the vascular system (including protophloem and protoxylem) is discussed in relation to the means by which the pattern of development may be controlled. Rates of production of vessels and the final lengths of the vessels are estimated. The observations and deductions are discussed in relation to other studies of root growth, vascular differentiation, and vascular pattern formation and maintenance.

scholarly journals Regeneration of Plants from Apical Meristem Tips and Nodal Segments of Arachis pintoi

2003 ◽  
Vol 30 (2) ◽  
pp. 75-79 ◽  
Author(s):  
H. Y. Rey ◽  
L. A. Mroginski
Keyword(s):  
Apical Meristem ◽  
In Vitro Regeneration ◽  
Nodal Segments ◽  
Naphthaleneacetic Acid ◽  
Ms Medium ◽  
Regeneration Potential ◽  
Arachis Pintoi ◽  
Solid Media ◽  
One Step

Abstract The in vitro regeneration potential of shoot apical tips (2 to 3 mm in length), meristems (0.3 to 0.5 mm in length), and nodal segments (4 to 7 mm long with an axillary bud) of diploid (2n = 2x = 20) and triploid (2n = 3x = 30) cytotypes of Arachis pintoi was evaluated. Explants were cultured on MS medium supplemented with different concentrations and combinations of naphthaleneacetic acid (NAA) and benzyladenine (BA). In one experiment the effect of gibberellic acid was tested. The cultures were done in liquid and solid media. Plant regeneration can be readily achieved from all explants in one step of 30 d culture on MS + 0.01 mg/L each of NAA and BA or two steps consisting of 1) shoots regeneration through culture of explants on MS + 0.01 mg/L each of NAA and BA, and 2) induction of rooting in regenerated shoots by reculture on MS + 0.01 mg/L NAA. The plantlets were successfully transferred to pots in a greenhouse.

scholarly journals Ontogenetic Changes in Auxin Biosynthesis and Distribution Determine the Organogenic Activity of the Shoot Apical Meristem in pin1 Mutants

2019 ◽  
Vol 20 (1) ◽  
pp. 180 ◽  
Author(s):  
Alicja Banasiak ◽  
Magdalena Biedroń ◽  
Alicja Dolzblasz ◽  
Mateusz Adam Berezowski
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Auxin Transport ◽  
Vascular System ◽  
Auxin Biosynthesis ◽  
Wild Type ◽  
Ontogenetic Changes ◽  
Auxin Distribution ◽  
Stem Development ◽  
Knockout Mutation

In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) regulates two crucial developmental processes: organogenesis and vascular system formation. However, the knockout mutation in the PIN1 gene does not fully inhibit these two processes. Therefore, we investigated a potential source of auxin for organogenesis and vascularization during inflorescence stem development. We analyzed auxin distribution in wild-type (WT) and pin1 mutant plants using a refined protocol of auxin immunolocalization; auxin activity, with the response reporter pDR5:GFP; and expression of auxin biosynthesis genes YUC1 and YUC4. Our results revealed that regardless of the functionality of PIN1-mediated PAT, auxin is present in the SAM and vascular strands. In WT plants, auxin always accumulates in all cells of the SAM, whereas in pin1 mutants, its localization within the SAM changes ontogenetically and is related to changes in the structure of the vascular system, organogenic activity of SAM, and expression levels of YUC1 and YUC4 genes. Our findings indicate that the presence of auxin in the meristem of pin1 mutants is an outcome of at least two PIN1-independent mechanisms: acropetal auxin transport from differentiated tissues with the use of vascular strands and auxin biosynthesis within the SAM.

scholarly journals Virtual phyllotaxis and real plant model cases

2008 ◽  
Vol 35 (10) ◽  
pp. 1025 ◽  
Author(s):  
Beata Zagórska-Marek ◽  
Marcin Szpak
Keyword(s):  
Apical Meristem ◽  
Geometric Model ◽  
Ontogenetic Changes ◽  
Plant Model ◽  
Phyllotactic Pattern ◽  
Random Manner ◽  
Simulation Results ◽  
Unknown Signal ◽  
Real Plant

Phyllotactic pattern results from genetic control of lateral primordia size (physiological or physical) relative to the size of organogenic lateral surface of shoot apical meristem (SAM). In order to understand the diversity of patterns and ontogenetic transitions of phyllotaxis we have developed a geometric model allowing changes of the above proportion in a computer simulation of SAM’s growth. The results of serial simulations confirmed that many phyllotactic patterns (including most esoteric ones) and ontogenetic transitions known from real plant model cases can be easily obtained in silico. Properties of virtual patterns often deviated from those of ideal mathematical lattices but closely resembled those of the natural ones. This proved the assumptions of the model, such as initiation in the first available space or ontogenetic changes in primordia size, to be quite realistic. Confrontation of simulation results with some sequences of real phyllotactic patterns (case study Verbena) questions the autonomy of SAM in its organogenic activity and suggests the involvement of unknown signal positioning primordia in a non-random manner in the first available space.

scholarly journals Toward a 3D model of phyllotaxis based on a biochemically plausible auxin-transport mechanism

2018 ◽  
Author(s):  
Félix P. Hartmann ◽  
Pierre Barbier de Reuille ◽  
Cris Kuhlemeier
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Auxin Transport ◽  
Vascular System ◽  
Three Dimensional ◽  
Integrative Approach ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Leaf Formation ◽  
Cell Layers

AbstractPolar auxin transport lies at the core of many self-organizing phenomena sustaining continuous plant organogenesis. In angiosperms, the shoot apical meristem is a potentially unique system in which the two main modes of auxin-driven patterning— convergence and canalization—co-occur in a coordinated manner and in a fully three-dimensional geometry. In the epidermal layer, convergence points form, from which auxin is canalized towards inner tissue. Each of these two patterning processes has been extensively investigated separately, but the integration of both in the shoot apical meristem remains poorly understood. We present here a first attempt of a three-dimensional model of auxin-driven patterning during phyllotaxis. We base our simulations on a biochemically plausible mechanism of auxin transport proposed by Cieslak et al. (2015) which generates both convergence and canalization patterns. We are able to reproduce most of the dynamics of PIN1 polarization in the meristem, and we explore how the epidermal and inner cell layers act in concert during phyllotaxis. In addition, we discuss the mechanism by which initiating veins connect to the already existing vascular system.Author summaryThe regularity of leaf arrangement around stems has long puzzled scientists. The key role played by the plant hormone auxin is now well established. On the surface of the tissue responsible for leaf formation, auxin accumulates at several points, from which new leaves eventually emerge. Auxin also guides the progression of new veins from the nascent leaves to the vascular system of the plant. Models of auxin transport have been developed to explain either auxin accumulation or auxin-driven venation. We propose the first three-dimensional model embracing both phenomena using a unifying mechanism of auxin transport. This integrative approach allows an assessment of our present knowledge on how auxin contributes to the early development of leaves. Our model reproduces many observations of auxin dynamics. It highlights how the inner and epidermal tissues act together to position new leaves. We also show that an additional, yet unknown, mechanism is required to attract new developing veins towards the main vasculature of the plant.

scholarly journals Vascular structure contributes to shoot sectoriality in Selaginella kraussiana

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Edyta M. Gola ◽  
Judith A. Jernstedt
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Vascular System ◽  
Shoot Development ◽  
Specific Structure ◽  
Developmental Changes ◽  
Vascular Structure ◽  
Vascular Connections

<em>Selaginella</em> species are characterized by regular anisotomous dichotomous divisions of the shoot apical meristem, giving rise to two new axes (branches) which differ in size. A vital process is the formation of vascular connections, which enables continuous communication and consequent functional and developmental integration of a plant during branching. Here, we present the sequence of developmental changes in the vascular system of <em>Selaginella kraussiana</em> related to dichotomous branching. Stem vasculature in <em>Selaginella kraussiana</em> consists of two meristeles which change in arrangement during shoot development. Using dye tracers, we documented developmental functional isolation of meristeles associated with the specific structure of the stelar system, which results in a spatiotemporal sectoriality of the shoot. We discuss sectoriality in terms of possible significance for shoot development.

scholarly journals Mural Cells: Potential Therapeutic Targets to Bridge Cardiovascular Disease and Neurodegeneration

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 593
Author(s):  
Alexander Lin ◽  
Niridu Jude Peiris ◽  
Harkirat Dhaliwal ◽  
Maria Hakim ◽  
Weizhen Li ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Neurodegenerative Diseases ◽  
Structural Integrity ◽  
Vascular System ◽  
Vascular Wall ◽  
Cell Plasticity ◽  
Mural Cell ◽  
Mural Cells ◽  
Heterogenous Population

Mural cells collectively refer to the smooth muscle cells and pericytes of the vasculature. This heterogenous population of cells play a crucial role in the regulation of blood pressure, distribution, and the structural integrity of the vascular wall. As such, dysfunction of mural cells can lead to the pathogenesis and progression of a number of diseases pertaining to the vascular system. Cardiovascular diseases, particularly atherosclerosis, are perhaps the most well-described mural cell-centric case. For instance, atherosclerotic plaques are most often described as being composed of a proliferative smooth muscle cap accompanied by a necrotic core. More recently, the role of dysfunctional mural cells in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, is being recognized. In this review, we begin with an exploration of the mechanisms underlying atherosclerosis and neurodegenerative diseases, such as mural cell plasticity. Next, we highlight a selection of signaling pathways (PDGF, Notch and inflammatory signaling) that are conserved across both diseases. We propose that conserved mural cell signaling mechanisms can be exploited for the identification or development of dual-pronged therapeutics that impart both cardio- and neuroprotective qualities.

scholarly journals Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Edyta M. Gola ◽  
Alicja Banasiak
Keyword(s):  
Pattern Formation ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Land Plants ◽  
Phyllotactic Pattern ◽  
Lateral Organs ◽  
Spatio Temporal

Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

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