Heteroblastic seedlings of green ash. II. Early development of simple and compound leaves

1986 ◽  
Vol 64 (11) ◽  
pp. 2650-2661 ◽  
Author(s):  
E. K. Merrill
Keyword(s):  
Early Development ◽  
Leaf Primordia ◽  
The Other ◽  
Terminal Leaflet ◽  
Green Ash ◽  
Lateral Leaflet ◽  
Leaf Type ◽  
Simple Leaf ◽  
Compound Leaf

Simple and compound leaf primordia of green ash seedlings differ in shape from initiation. Simple leaf primordia are flattened until their lamina margins grow out at a primordial length of 150 μm. Compound leaf primordia are rounded and peglike at initiation and lateral leaflet buttresses appear when primordia are 150 μm long. Terminal leaflet margins appear when compound leaf primordia are 200 μm long. At initiation both types of leaf primordia are composed of densely cytoplasmic cells. Vacuolation proceeds so that densely cytoplasmic cells remain only in areas developing blades and leaflets and in procambium. Because simple and compound leaves of green ash differ from initiation, neither leaf type can be considered to result from a change in the ontogeny of the other.

Heteroblastic seedlings of green ash. I. Predictability of leaf form and primordial length

1986 ◽  
Vol 64 (11) ◽  
pp. 2645-2649 ◽  
Author(s):  
E. K. Merrill
Keyword(s):  
Leaf Development ◽  
Leaf Growth ◽  
Leaf Primordia ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Leaf Form ◽  
Compound Leaf ◽  
Controlled Conditions ◽  
Plastochron Index

Green ash (Fraxinus pennsylvanica var. subintegerrima) seedlings are heteroblastic; during development they produce two types of leaves, simple and compound. When grown under controlled conditions, the sequence of leaf types is predictable. Simple leaves are always at the first four nodes; compound leaves are always at node 8 and above. Nodes 5 through 7 have progressively fewer simple leaves and more compound leaves. Leaf growth on seedlings meets the preconditions of the plastochron index and leaf plastochron index. These indices, as well as the length of single expanding leaves, can be used to predict lengths of leaf primordia at nodes 4 and 8 so that early, simple and compound leaf development can be compared in further studies of green ash.

Rachis vascularization and leaflet venation in developing leaves of Fraxinus pennsylvanica

1985 ◽  
Vol 63 (12) ◽  
pp. 2383-2392 ◽  
Author(s):  
Philip R. Larson
Keyword(s):  
Leaf Development ◽  
Close Association ◽  
Terminal Leaflet ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Leaf Base ◽  
Lateral Leaflet ◽  
Curve Upward

Leaves of Fraxinus pennsylvanica are served by a double trace that exits the stem vasculature through a single gap. During embryonic leaf development, the leaf traces subdivide in the node to produce subsidiary bundles that differentiate acropetally in the leaf base and basipetally in the stem. The acropetal bundles converge distally in the node to form a rachis vasculature consisting of a semicircular arc joined by a ventral chord. Each lateral leaflet is vascularized by bundles contributed by both the semicircular arc and the ventral chord of the rachis. One rachis ridge bundle divides to form two leaflet ridge bundles and a new rachis ridge bundle diverges from the ventral chord. The leaflet ridge bundles diverge as basal veins and subsequent secondary veins diverge from the midvein in an approximate right–left sequence. Green ash has odd pinnate leaves; the terminal leaflet is vascularized by the rachis residual following departure of the last leaflet pair. Secondary veins extend to the lamina margins and then curve upward to initiate the marginal loops of the brochidodromous venation. Periclinal divisions occur in close association with secondary veins in the prospective plate meristem region. Anticlinal divisions occur in subepidermal layers of the internal ridge points in the prospective palisade mesophyll region.The latter divisions probably contribute both to lamina extension and to spreading of the conduplicately folded lamina wings.

scholarly journals Fetal erythropoiesis in steel mutant mice. III. Defect in differentiation from BFU-E to CFU-E during early development

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 539-547 ◽  
Author(s):  
DH Chui ◽  
SK Liao ◽  
K Walker
Keyword(s):  
Progenitor Cells ◽  
Early Development ◽  
The Other ◽  
Mutant Mice ◽  
Erythroid Progenitor ◽  
Erythroid Progenitor Cells ◽  
Other Hand ◽  
Colony Forming Units ◽  
Fetal Erythropoiesis

Abstract Erythroid progenitor cells in +/+ and Sl/Sld fetal livers manifested as burst-forming units-erythroid (BFU-E) and colony-forming units- erythroid (CFU-E) were assayed in vitro during early development. The proportion of BFU-E was higher as mutant than in normal fetal livers. On the other hand, the proportion of CFU-E was less in the mutant than in the normal. These results suggest that the defect in Sl/Sld fetal hepatic erythropoiesis is expressed at the steps of differentiation that effect the transition from BFU-E to CFU-E.

Micromere lineages in the glossiphoniid leechHelobdella

Development ◽  
2002 ◽  
Vol 129 (3) ◽  
pp. 719-732 ◽  
Author(s):  
Françoise Z. Huang ◽  
Dongmin Kang ◽  
Felipe-Andres Ramirez-Weber ◽  
Shirley T. Bissen ◽  
David A. Weisblat
Keyword(s):  
Early Development ◽  
Normal Development ◽  
The Other ◽  
Small Cells ◽  
Spiral Cleavage ◽  
Helobdella Robusta

In leech embryos, segmental mesoderm and ectoderm arise from teloblasts by lineages that are already relatively well characterized. Here, we present data concerning the early divisions and the definitive fate maps of the micromeres, a group of 25 small cells that arise during the modified spiral cleavage in leech (Helobdella robusta) and contribute to most of the nonsegmental tissues of the adult. Three noteworthy results of this work are as follows. (1) The c′′′ and dm′ clones (3d and 3c in traditional nomenclature) give rise to a hitherto undescribed network of fibers that run from one end of the embryo to the other. (2) The clones of micromeres b′′ and b′′′ (2b and 3b in traditional nomenclature) die in normal development; the b′′ clone can be rescued to assume the normal c′′ fate if micromere c′′ or its clone are ablated in early development. (3) Two qualitative differences in micromere fates are seen between H. robusta (Sacramento) and another Helobdella sp. (Galt). First, in Helobdella sp. (Galt), the clone of micromere b′′ does not normally die, and contributes a subset of the cells arising exclusively from c′′ in H. robusta (Sacramento). Second, in Helobdella sp. (Galt), micromere c′′′ makes no definitive contribution, whereas micromere dm′ gives rise to cells equivalent to those arising from c′′′ and dm′ in H. robusta (Sacramento).

scholarly journals Morphological characterization of domatium development in Callicarpa saccata

2019 ◽  
Vol 125 (3) ◽  
pp. 521-532
Author(s):  
Emma Sarath ◽  
Kazune Ezaki ◽  
Takenori Sasaki ◽  
Yu Maekawa ◽  
Yuji Sawada ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Morphological Characterization ◽  
Leaf Primordia ◽  
Normal Functioning ◽  
Simple Leaf ◽  
Mesophyll Tissue ◽  
Scanning Electron

Abstract Background and aims Domatia are plant structures within which organisms reside. Callicarpa saccata (Lamiaceae) is the sole myrmecophyte, or ‘ant plant’, that develops foliar (leaf-borne) myrmeco-domatia in this genus. In this work we examined domatium development in C. saccata to understand the developmental processes behind pouch-like domatia. Methods Scanning electron microscopy, sectioning and microcomputed tomography were carried out to compare the leaves of C. saccata with those of the closely related but domatia-less myrmecophyte Callicarpa subaequalis, both under cultivation without ants. Key results Callicarpa saccata domatia are formed as a result of excess cell proliferation at the blade/petiole junctions of leaf primordia. Blade/petiole junctions are important meristematic sites in simple leaf organogenesis. We also found that the mesophyll tissue of domatia does not clearly differentiate into palisade and spongy layers. Conclusions Rather than curling of the leaf margins, a perturbation of the normal functioning of the blade/petiole junction results in the formation of domatium tissue. Excess cell proliferation warps the shape of the blade and disturbs the development of the proximal–distal axis. This process leads to the generation of distinct structures that facilitate interaction between C. saccata and ants.

Propanidid, a useful anaesthetic for studying blood circulation in early development of fish

1987 ◽  
Vol 65 (5) ◽  
pp. 1286-1289
Author(s):  
Ronald S. Veenstra ◽  
Eugene K. Balon ◽  
Christine Flegler-Balon
Keyword(s):  
Blood Flow ◽  
Early Development ◽  
Blood Circulation ◽  
Salvelinus Fontinalis ◽  
Early Ontogeny ◽  
The Other ◽  
Brook Charr ◽  
Cocaine Hydrochloride ◽  
The Times ◽  
Blood Elements

The effectiveness of propanidid was tested by comparing it with cocaine hydrochloride, urethane, and traicaine methanesulfonate, anaesthetics already established for studies of early ontogeny in fishes. Free embryos of the brook charr, Salvelinus fontinalis, and 7-day-old amargosa pupfish, Cyprinodon nevadensis amargosae, were anaesthetized with dilute solutions of these drugs. The times taken until the blood elements ceased moving through the capillary loops of the developing caudal fin were compared. Propanidid was found to be superior to the other drugs tested in maintaining the longest duration of unaltered blood flow.

Dialium heterophyllum (Fabaceae: Dialioideae), a new tree species from the Amazon

Phytotaxa ◽  
2020 ◽  
Vol 477 (1) ◽  
pp. 47-59
Author(s):  
MARCUS JOSÉ DE AZEVEDO FALCÃO ◽  
VIDAL DE FREITAS MANSANO
Keyword(s):  
Risk Assessment ◽  
Amazon Basin ◽  
Floral Morphology ◽  
The Other ◽  
Terminal Leaflet ◽  
Tropical Africa ◽  
Distribution Maps ◽  
Neotropical Species ◽  
A New Species ◽  
Anthropic Pressure

In this work, we describe Dialium heterophyllum, a new species for the largest genus in the diverse and morphologically unique legume subfamily Dialioideae. Dialium, with 32 species, has its highest diversity in tropical Africa and Asia, with four species accepted until now in the Neotropics. The fifth species described here reinforces the idea that a large portion of the Neotropical diversity, notably in the Amazon, is still unknown. Dialium heterophyllum is restricted to the south of the Amazon Basin in Brazil and Bolivia, areas under intense anthropic pressure in recent years. Due to its floral morphology, the species appears to be closely related to the other Neotropical species of the genus, differing by its reduced leaf rachis with unifoliolate to trifoliolate leaves, generally opposed to sub-opposed leaflets, the terminal leaflet much longer than the lateral ones (when present) and than the leaf rachis. We provide illustrations, distribution maps, a conservation risk assessment and an identification key.

Heteroblastic seedlings of green ash. III. Cell division activity and marginal meristems

1986 ◽  
Vol 64 (11) ◽  
pp. 2662-2668 ◽  
Author(s):  
E. K. Merrill
Keyword(s):  
Cell Division ◽  
Leaf Blade ◽  
Developmental Stages ◽  
Leaf Primordia ◽  
Leaf Margin ◽  
Green Ash ◽  
Histological Differentiation ◽  
Cell Counts ◽  
Histological Criteria ◽  
Early Developmental

The early developmental stages of simple and compound leaves of green ash (50–400 μm long) were used to relate cell division activity (mitotic index) to developing leaf form and histological differentiation. Densely cytoplasmic cells within cross-sectioned leaf primordia have higher mitotic indices than protodermal cells and other internal cells that are more vacuolate. Among densely cytoplasmic cells mitotic indices decrease from the primordial leaf margin toward the procambium. Ground meristem cells within three to five cell widths of the primordial margin had the highest mitotic indices. Actual cell counts indicate that densely cytoplasmic cells increase in number in areas of leaf blade or leaflet initiation more than do vacuolate cells or protodermal cells. It is proposed that marginal meristems defined by spatial and histological criteria are important in producing new cells that are the basis for the generation of simple and compound leaf forms.

scholarly journals Demonstration of chromatinic structures in avian tubercle bacilli in the early stages of development

1947 ◽  
Vol 45 (4) ◽  
pp. 413-416 ◽  
Author(s):  
E. M. Brieger ◽  
C. F. Robinow
Keyword(s):  
Hydrochloric Acid ◽  
Early Development ◽  
The Other ◽  
Feulgen Reaction ◽  
Cytological Investigation ◽  
Stages Of Development ◽  
The Third ◽  
Early Stages ◽  
Other Hand ◽  
The Masses

In a cytological investigation of three branching and two non-branching strains grown on Loewenstein medium, it was found that avian tubercle bacilli contain chromatinic material which gives a positive Feulgen reaction and is readily stainable with Giemsa's solution after treatment of the fixed bacteria with hydrochloric acid.Growing filamentous forms of both ‘bacterial’ and ‘mycelial’ strains from 1 to 2 day old cultures contain variable numbers of irregularly spaced, more or less spherical chromatinic bodies which vary in staining in the same bacillus, some being red, others purple. During the third or fourth day the chromatinic material in the bacteria increases very much until most of it is fused into an almost homogeneous deeply stained column. In thenon-branchingstrains the filamentous forms with high chromatin content soon break up into small mono-or binucleate elements, and the same holds true for the ‘straight’ filamentous forms which are also present in cultures of branching strains. The ‘mycelial’ forms, on the other hand, disintegrate at this time (fourth or fifth day of cultivation), and it is uncertain whether they contribute (by partial fragmentation) to the masses of small mono- or binucleate forms which are the predominant element in old cultures of all the strains investigated.The chromatinic structures of avian tubercle bacilli have the same staining properties as those of ordinary non-acid-fast bacteria but differ from them in their behaviour during the early development of the bacilli.

Conflict in Unstructured Groups: An Explanation from Control-Theory

1982 ◽  
Vol 51 (1) ◽  
pp. 177-178
Author(s):  
David S. Abbey
Keyword(s):  
Control Theory ◽  
Early Development ◽  
Small Groups ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Feedback System ◽  
The Other ◽  
Two Systems ◽  
Group Members ◽  
Unstructured Groups

The early development of many small groups is marked by conflict and stress between two sub-groups. It is argued that each sub-group is governed by a different feedback system: one reduces deviations from plans (negative feedback system), whereas the other seeks novelty and spontaneity (positive feedback system). The two systems are incompatible and result in ‘storming’ or hostility among group members.

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