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 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 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 Leaf and axillary shoot development from the shoot apical meristem

2003 ◽  
Vol 15 (1) ◽  
pp. 18-29
Author(s):  
Ken-ichiro Hibara ◽  
Masao Tasaka
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Shoot Development ◽  
Axillary Shoot

The shoot apical meristem and development of vascular architectureThis review is one of a selection of papers published on the Special Theme of Shoot Apical Meristems.

2006 ◽  
Vol 84 (11) ◽  
pp. 1660-1671 ◽  
Author(s):  
Nancy G. Dengler
Keyword(s):  
Arabidopsis Thaliana ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Leucine Zipper ◽  
Vascular Tissue ◽  
Vascular System ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Integrative Model ◽  
Class Iii

The shoot apical meristem (SAM) functions to generate external architecture and internal tissue pattern as well as to maintain a self-perpetuating population of stem-cell-like cells. The internal three-dimensional architecture of the vascular system corresponds closely to the external arrangement of lateral organs, or phyllotaxis. This paper reviews this correspondence for dicotyledonous plants in general and in Arabidopsis thaliana (L.) Heynh., specifically. Analysis is partly based on the expression patterns of the class III homeodomain-leucine zipper transcription factor ARABIDOPSIS THALIANA HOMEOBOX GENE 8 (ATHB8), a marker of the procambial and preprocambial stages of vascular development, and on the anatomical criteria for recognizing vascular tissue pattern. The close correspondence between phyllotaxis and vascular pattern present in mature tissues arises at early stages of development, at least by the first plastochron of leaf primordium outgrowth. Current literature provides an integrative model in which local variation in auxin concentration regulates both primordium formation on the SAM and the first indications of a procambial prepattern in the position of primordium leaf trace as well as in the elaboration of leaf vein pattern. The prospects for extending this model to the development of the complex three-dimensional vascular architecture of the shoot are promising.

Plant regeneration from stem callus of cassava

1979 ◽  
Vol 57 (16) ◽  
pp. 1761-1763 ◽  
Author(s):  
J. P. Tilquin
Keyword(s):  
Plant Regeneration ◽  
Gibberellic Acid ◽  
Shoot Apical Meristem ◽  
Manihot Esculenta ◽  
Apical Meristem ◽  
Callus Formation ◽  
Shoot Development ◽  
Meristem Culture ◽  
Manihot Esculenta Crantz ◽  
Leaf Differentiation

Callus formation and organogenesis have been induced on the internode culture of cassava (Manihot esculenta Crantz). Callusing was rapidly induced on the medium devised by Kartha, Gamborg, and Constabel for the shoot apical meristem culture of cassava. During culture, green protuberances appear on the callus followed by the differentiation of a leaf-like structure. The leaf-like structure degenerated after a month of differentiation. On the same medium, but lacking gibberellic acid (GA3), organogenesis is less frequent and precocious but the leaves which appear are typical of cassava; leaf differentiation is followed by shoot development.

scholarly journals Rolesof plant growth regulators on the shoot development from the shoot apical meristem of Eustoma grandiflorum (RAF.) shinners

2018 ◽  
Vol 1 (6) ◽  
pp. 58-67
Author(s):  
Huyen Thach Quynh Ngo ◽  
Huong Thanh Tran ◽  
Viet Trang Bui
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Adventitious Shoots ◽  
Shoot Development ◽  
Ms Medium ◽  
Eustoma Grandiflorum ◽  
Shoot Initiation

In this paper, plant growth regulators including 6-benzylaminopurine (BA), kinetin, indole-3-acetic acid (IAA), gibberellic acid (GA3) and ethrel, at different concentrations were used individually or in combination to induce adventitious shoots from the explants, which contain shoot apical meristem and young leaves. Histological and physiological changes during shoot development were analysed. The highest shoot initiation was achieved on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L BA and 1.0 mg/L GA3. Regenerated shoots were rooted on MS medium with 0.25 or 0.5 mg/L IAA. Shoot development from in vitro shoot explants initiated from the axil and cortex of stem. The shoot regeneration from shoot apical explants was effected by the meristem integrity or auxin from shoot apical meristem. Roles of plant growth regulators, especially polar auxin transport, and the ablation on the shoot initiation were discussed.

Shoot development – genetic interactions in the meristem

2005 ◽  
Vol 33 (6) ◽  
pp. 1499-1501 ◽  
Author(s):  
M.E. Byrne
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Shoot Development ◽  
Genetic Interactions ◽  
Leaf Patterning ◽  
Myb Domain ◽  
Homeodomain Transcription Factors

Development of the plant shoot is dependent on the shoot apical meristem. Interactions between KNOX homeodomain transcription factors and the myb domain transcription factor AS1 (ASYMMETRIC LEAVES1) regulate both meristem function as well as leaf patterning. This review summarizes these interactions.

Lasertechniques treatment of vascular malformations

Phlebologie ◽  
2010 ◽  
Vol 39 (03) ◽  
pp. 167-175
Author(s):  
M. Poetke ◽  
P. Urban ◽  
H.-P. Berlien
Keyword(s):  
Endothelial Cells ◽  
Spontaneous Regression ◽  
Vascular System ◽  
Vascular Malformations ◽  
Clinical Importance ◽  
Vascular Structure ◽  
Laser Application ◽  
Vascular Morphogenesis ◽  
Structural Abnormalities

SummaryVascular malformations are structural abnormalities, errors of vascular morphogenesis, which can be localized in all parts of the vascular system. All vascular malformations by definition, are present at birth and grow proportionately with the child; their volume can change. In contrast to the haemangiomas, which only proliferate from the endothelial cells the division in stages is of clinical importance. Vascular malformations are divided from the part of vascular system, which is affected.In principle the techniques of laser application in congenital vascular tumours like haemangiomas and in vascular malformations are similar, but the aim is different. In tumours the aim is to induce regression, in vascular malformations the aim is to destroy the pathologic vascular structure because there is no spontaneous regression. This means that the parameters for treatment of vascular malformations must be more aggressive than for vascular tumours.

Sign in / Sign up

Export Citation Format

Share Document