Developmental anatomy of the shoot apex of leptosporangiate ferns. II. Leaf ontogeny of Adiantum capillus-veneris (Adiantaceae)

1988 ◽  
Vol 66 (9) ◽  
pp. 1729-1733 ◽  
Author(s):  
Ryoko Imaichi
Keyword(s):  
Leaf Development ◽  
Apical Cell ◽  
Leaf Primordium ◽  
Basal Part ◽  
Basal Cells ◽  
Superficial Cell ◽  
Leaf Ontogeny ◽  
Developmental Anatomy ◽  
Adiantum Capillus Veneris ◽  
Derivatives Of

Early leaf development of Adiantum capillus-veneris L. was examined with special reference to the origin of constituent cells of the leaf. At the earliest stage of leaf development, an enlarged superficial cell (leaf initial cell) occurs in the fourth or fifth cell packet derived from the shoot apical cell and divides to form a leaf apical cell. At the same time, cells surrounding the enlarged cell, which are not derivatives of it, also divide to form the basal part of a leaf primordium. Unlike the situation in leaves of other ferns, the leaf apical cell does not divide actively during early development, while the basal cells divide frequently from the beginning. The major part of a fairly developed leaf primordium therefore consists of derivatives of the basal cells. The leaf primordium is multicellular in origin in the sense that its distal part is derived from the enlarged superficial cell and its basal part from the cells surrounding the enlarged superficial cell.

The growth and development of the leaf in tomato (Lycopersicon esculentum). II. Leaf ontogeny

1976 ◽  
Vol 54 (23) ◽  
pp. 2704-2717 ◽  
Author(s):  
Warren K. Coleman ◽  
Richard I. Greyson
Keyword(s):  
Lycopersicon Esculentum ◽  
Mesophyll Cell ◽  
Leaf Primordium ◽  
Terminal Leaflet ◽  
Maturation Stage ◽  
Apical Region ◽  
Basal Region ◽  
Leaf Ontogeny ◽  
Spongy Mesophyll ◽  
Derivatives Of

Ontogenetic studies of compound leaves which develop their lateral appendages in basipetal sequence are rare. The histogenesis of the compound leaf in Lycopersicon esculentum cv. Farthest North was followed with emphasis placed on the differentiation of the major and minor venation in true leaf number 3, using whole, cleared leaflets and transverse and paradermal microtome sections. The primary vein procambium develops acropetally and continuously into the base of the 50-μ(micron)-long leaf primordium and is observed at the tip of 200-μ-long leaves. Correlated with this event, marginal meristem activity in the apical region of the peg-like leaf primordium begins to form the lamina of the terminal leaflet. External phloem is also observed in the basal region of the primordium at this stage. Slightly later, isolated stem and leaf loci of xylem initiation are observed. Secondary vein procambium is observed initially in the terminal leaflet when the leaf is 250 to 400 μ long. The subterminal lateral leaflets appear as small bulges on the differentiating rachis during this stage. A previously undescribed marginal vein differentiates basipetally from the leaflet tips and interconnects with derivatives of the secondary and minor veins. Discrete ontogenetic stages were recognized in minor veins as they developed from the upper spongy mesophyll layer in continuity with previously differentiated veins. Vein-ending formation was a random process and appeared to depend upon the maturation stage of the surrounding veins. Histological evidence was uncovered to support the concept of ‘morphological fields’ in terms of a close interplay between planes of mesophyll cell division and subsequent minor vein development.

scholarly journals The Diverse Roles of Auxin in Regulating Leaf Development

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 243 ◽  
Author(s):  
Yuanyuan Xiong ◽  
Yuling Jiao
Keyword(s):  
Leaf Development ◽  
Leaf Blade ◽  
Recent Progress ◽  
Auxin Transport ◽  
Leaf Primordium ◽  
Auxin Signaling ◽  
Plant Organs ◽  
Leaf Patterning ◽  
Flat Structures ◽  
Photosynthesis And Respiration

Leaves, the primary plant organs that function in photosynthesis and respiration, have highly organized, flat structures that vary within and among species. In recent years, it has become evident that auxin plays central roles in leaf development, including leaf initiation, blade formation, and compound leaf patterning. In this review, we discuss how auxin maxima form to define leaf primordium formation. We summarize recent progress in understanding of how spatial auxin signaling promotes leaf blade formation. Finally, we discuss how spatial auxin transport and signaling regulate the patterning of compound leaves and leaf serration.

Lineages, Lineage Stability and Pattern Formation in Leaves of Variegated Chimeras of Lophostemon confertus (R. Br.) Wilson & Waterhouse and Tristaniopis laurina (Smith) Wilson & Waterhouse (Myrtaceae)

1987 ◽  
Vol 35 (6) ◽  
pp. 701
Author(s):  
DV Beardsell ◽  
JA Considine
Keyword(s):  
Pattern Formation ◽  
Leaf Development ◽  
Cell Lineage ◽  
Leaf Ontogeny ◽  
Cell Lineages ◽  
Leaf Tissues ◽  
Colour Patterns ◽  
Lineage Stability ◽  
Light Green

Three variegated chimeras of L. confertus and T. laurina arise spontaneously in seedling populations: 1, white margin: green centre, 2, green margin: light green centre and 3, green margin: white centre. Types 1 and 2 are found in T. laurina and types 1 and 3 in L. confertus. We have determined chloroplast distribution in the leaf tissues by fluorescence microscopy to assess the basis for these colour patterns. In L. confertus, a layer of collenchyma underlies the adaxial epidermis, replaces the upper layer of palisade, and does not mask mutant inner tissues, concealed by the adaxial layer of palisade in type 2 leaves of T. laurina. The central colour patterns are explained on the basis of accepted paths of cell lineage in leaf development (protoderm green in all three types; hypodermal derivatives genetically green in 2 and 3; and subhypodermal cells chlorophyll-deficient in types 2 and 3). The cell lineages postulated are similar in both species and we show that the observations can be accounted for only by a shift in lineage path during leaf ontogeny. We conclude that some established concepts of leaf ontogeny require revision.

Morphogenesis of the compound leaf in three genotypes of the pea, Pisum sativum

1986 ◽  
Vol 64 (6) ◽  
pp. 1268-1276 ◽  
Author(s):  
K. S. Gould ◽  
Elizabeth G. Cutter ◽  
J. P. W. Young
Keyword(s):  
Pisum Sativum ◽  
Leaf Development ◽  
Culture System ◽  
Algebraic Model ◽  
Leaf Primordium ◽  
Axillary Shoots ◽  
Compound Leaf ◽  
Pisum Sativum L ◽  
Leaflet Anatomy

Leaf anatomy, ontogeny, and morphology were described and compared in a pea line (Pisum sativum L.) with conventional leaves and in isogenic lines carrying the mutations af (afila) or tl (tendril-less or acacia). The anatomy of stem, petiole, and rachis is not modified by these mutations. The tendrils, which in af replace leaflets, have normal tendril anatomy, and the terminal leaflets of the tl form have normal leaflet anatomy. The shoot apical dome has the same size and shape in the three genotypes, as does the leaf primordium up to the stage of initiation of the first laterals. The mature morphology of leaves varies with node of insertion. Some leaves, especially at nodes 3 and 4, have structures that are not typical of their genotype. An in vitro culture system is described for axillary shoots. Such shoots recapitulate most of the foliar features of seedling plants, but leaf morphology is on average more complex, and aberrant structures are more frequent. All these observations are discussed in relation to Young's algebraic model for compound leaf development.

scholarly journals Urothelial proliferation and regeneration after spinal cord injury

2017 ◽  
Vol 313 (1) ◽  
pp. F85-F102 ◽  
Author(s):  
F. Aura Kullmann ◽  
Dennis R. Clayton ◽  
Wily G. Ruiz ◽  
Amanda Wolf-Johnston ◽  
Christian Gauthier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cell Layer ◽  
Acute Injury ◽  
Intermediate Cell ◽  
Basal Cells ◽  
Superficial Cell ◽  
Chronic Injury ◽  
Cord Injury ◽  
Umbrella Cells

The basal, intermediate, and superficial cell layers of the urothelium undergo rapid and complete recovery following acute injury; however, the effects of chronic injury on urothelial regeneration have not been well defined. To address this discrepancy, we employed a mouse model to explore urothelial changes in response to spinal cord injury (SCI), a condition characterized by life-long bladder dysfunction. One day post SCI there was a focal loss of umbrella cells, which are large cells that populate the superficial cell layer and normally express uroplakins (UPKs) and KRT20, but not KRT5, KRT14, or TP63. In response to SCI, regions of urothelium devoid of umbrella cells were replaced with small superficial cells that lacked KRT20 expression and appeared to be derived in part from the underlying intermediate cell layer, including cells positive for KRT5 and TP63. We also observed KRT14-positive basal cells that extended thin cytoplasmic extensions, which terminated in the bladder lumen. Both KRT14-positive and KRT14-negative urothelial cells proliferated 1 day post SCI, and by 7 days, cells in the underlying lamina propria, detrusor, and adventitia were also dividing. At 28 days post SCI, the urothelium appeared morphologically patent, and the number of proliferative cells decreased to baseline levels; however, patches of small superficial cells were detected that coexpressed UPKs, KRT5, KRT14, and TP63, but failed to express KRT20. Thus, unlike the rapid and complete restoration of the urothelium that occurs in response to acute injuries, regions of incompletely differentiated urothelium were observed even 28 days post SCI.

scholarly journals Elevated CO2 concentrations alter nitrogen metabolism and accelerate senescence in sunflower (Helianthus annuus L.) plants  

2013 ◽  
Vol 59 (No. 7) ◽  
pp. 303-308 ◽  
Author(s):  
L. De la Mata ◽  
P. De la Haba ◽  
Alamillo JM ◽  
M. Pineda ◽  
E. Agüera
Keyword(s):  
Nitrate Reductase ◽  
Helianthus Annuus ◽  
Nitrogen Metabolism ◽  
Leaf Development ◽  
Nitrogen Assimilation ◽  
Nitrogen Availability ◽  
Leaf Ontogeny ◽  
Transcript Levels ◽  
Helianthus Annuus L ◽  
Accelerate Senescence

Elevated CO<sub>2</sub> concentrations were found to cause early senescence during leaf development in sunflower (Helianthus annuus L.) plants, probably by reducing nitrogen availability since key enzymes of nitrogen metabolism, including nitrate reductase (NR); glutamine synthetase (GS) and glutamate dehydrogenase (GDH), were affected. Elevated CO<sub>2</sub> concentrations significantly decreased the activity of nitrogen assimilation enzymes (NR and GS) and increased GDH deaminating activities. Moreover, they substantially rose the transcript levels of GS1 while lowering those of GS2. Increased atmospheric CO<sub>2</sub> concentrations doubled the CO<sub>2</sub> fixation and increased transpiration rates, although these parameters decreased during leaf ontogeny. It can be concluded that elevated atmospheric CO<sub>2</sub> concentrations alter enzymes involved in nitrogen metabolism at the transcriptional and post-transcriptional levels, thereby boosting mobilization of nitrogen in leaves and triggering early senescence in sunflower plants.

Lateral Congenital Anomalies of the Pharyngeal Apparatus: Part I. Normal Developmental Anatomy (Embryogenesis) for the Surgeon

2011 ◽  
Vol 77 (9) ◽  
pp. 1230-1242 ◽  
Author(s):  
Petros Mirilas
Keyword(s):  
Congenital Anomalies ◽  
Cranial Nerves ◽  
Pharyngeal Arches ◽  
Developmental Anatomy ◽  
Extensive Area ◽  
Spinal Nerves ◽  
Pharyngeal Apparatus ◽  
Aortic Arches ◽  
Apparatus Part ◽  
Derivatives Of

Knowledge of the embryogenesis of the pharyngeal apparatus is the only means of understanding the “architecture” of the neck. The embryonic pharynx (which includes future oral and nasal cavities) is a much more extensive area than the adult pharynx. The main feature of the developing pharynx is a series of arches, internal pouches, and external clefts, which together comprise the pharyngeal apparatus. This structure is associated with other developing splanchna of the neck, e.g., the thyroid and parathyroid glands, tonsils, and thymus. Within each of the pharyngeal arches are the developing aortic arches and, specific for each arch, cranial nerves. The complex relations of the mesenchymal derivatives of arches (muscles, cartilage, bones) with the neurovascular bundles within each arch are presented and explained. The pharyngeal apparatus undergoes dramatic transformations: pouches and clefts disappear without interruption (interruption would produce gills and support the misnomer “branchial apparatus”). In addition, in the lateroventral neck, somites migrate to produce other muscles such as sternocleidomastoid and trapezius innervated by spinal nerves. Lateral congenital anomalies largely rely on persistence of a cleft/and or pouch or communication between the two. Their tracts have a “crooked” course among other entities generated by alterations that take place during embryogenesis.

Growth and Development of the Wheat Tiller. I. Growth and Form of the Tiller Bud

1975 ◽  
Vol 23 (5) ◽  
pp. 715 ◽  
Author(s):  
RF Williams ◽  
BC Sharman ◽  
RHM Langer
Keyword(s):  
Growth Rates ◽  
Continuous System ◽  
Nitrogen Supply ◽  
Leaf Primordium ◽  
Developmental Morphology ◽  
Developmental Anatomy ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Axial Growth ◽  
Tiller Bud

The initiation and growth of the tiller bud is described in the context of the developing shoot in wheat. The experimental plants were subjected to two levels of nitrogen supply and to two light intensities so as to diversify the pattern of tiller growth. The descriptions cover properties of tiller bud placement within the shoot, the external developmental morphology, and some aspects of the developmental anatomy of the bud, and of the nodal plexus in relation to growth of the leaf primordium and tiller bud. The results have been integrated in terms of linear relative growth rates in both radial and axial directions. In spite of the mutual constraints imposed within the continuous system, severe gradients in axial growth rates were found to be consistent with the maintenance of the integrity of the system.

Ultrastructure of conidiogenesis and appendage ontogeny in the coelomycete Bartalinia robillardoides

2003 ◽  
Vol 81 (11) ◽  
pp. 1083-1090 ◽  
Author(s):  
M KM Wong ◽  
E BG Jones ◽  
M A Abdel-Wahab ◽  
D WT Au ◽  
L LP Vrijmoed
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Walls ◽  
Apical Cell ◽  
Conidiogenous Cell ◽  
Dense Layer ◽  
Basal Cells ◽  
Outer Electron ◽  
Transmission Electron ◽  
Scanning Electron

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 30–38 nm, and an inner less electron-dense layer, 100–125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.Key words: Annellidic, appendage ontogeny, coelomycetes, holoblastic.

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