Floral development of Myrica gale and the controversy over floral concepts

1973 ◽  
Vol 51 (10) ◽  
pp. 1965-1975 ◽  
Author(s):  
Alastair D. Macdonald ◽  
Rolf Sattler
Keyword(s):  
Floral Development ◽  
Vascular Tissue ◽  
A Priori ◽  
Median Plane ◽  
Layer Growth ◽  
Myrica Gale ◽  
The Third ◽  
Cell Divisions ◽  
Floral Apex ◽  
Upward Growth

Two bracteoles form by divisions in the second layer of cells on the transversal flanks of the floral apex. Four stamens form in the male by cell divisions in the third layer of cells; one develops opposite each bracteole and two form in the median plane on either side of the floral apex. In the female bud a girdling gynoecial primordium forms by periclinal divisions in the second layer. Growth becomes localized in two or three zones in the gynoecial primordium; upward growth results in the formation of two or three stigmas. The gynoecial wall forms by intercalary growth above and below the region of bracteole attachment. The ovule develops by the resumption of growth of the floral apex. A single vascularized integument, formed at first by periclinal divisions in the protoderm, encloses the nucellus. The development and pattern of the vascular tissue is described. Four conceptual frameworks regarding the morphological nature of the flower are outlined and the data derived from this study are analyzed in relation to each framework. The interpretations are conflicting and it is considered that this is due, in part, to an a priori establishment of mutually exclusive categories.

Floral development of Comptonia peregrina (Myricaceae)

1974 ◽  
Vol 52 (10) ◽  
pp. 2165-2169 ◽  
Author(s):  
Alastair D. Macdonald
Keyword(s):  
Floral Development ◽  
Early Stage ◽  
Male Flower ◽  
Female Flower ◽  
Median Plane ◽  
Distal Portion ◽  
Second Order ◽  
Third Order ◽  
Floral Apex ◽  
Growth Activity

Early stages of development of the male and female flower are similar; two second-order bracts arise in the transversal plane on either side of the floral apex before the apex flattens and becomes somewhat concave because of growth activity at the flank of the apex. In the female flower, the gynoecium develops as an extension of the girdling gynoecial primordium and the two primordial stigmas each result from more rapid growth in the median plane at the distal portion of the gynoecial wall. The floral apex resumes growth to form the unitegmic ovule. Third-order lanceolate-shaped bracts develop from a meristem situated in the axil of each second-order bract. In the male flower, staminate primordia arise at three or four loci on the ridge surrounding the apex. The apex briefly resumes growth. Growth of the second-order bracts terminates at an early stage. The floral construction is compared to other myricaceous species. It is concluded that the axillary scale-like bracts of the female flower are third-order bracts; the gynoecium does not overtop the second-order axis and the female flower is not a reduced cyme; the male flower is more floral- than inflorescence-like compared to some other myricaceous species.

Floral development of Alisma triviale

1972 ◽  
Vol 50 (3) ◽  
pp. 619-627 ◽  
Author(s):  
V. Singh ◽  
R. Sattler
Keyword(s):  
Floral Development ◽  
Vascular Tissue ◽  
Radial Symmetry ◽  
Early Growth ◽  
Stages Of Development ◽  
The Third ◽  
Lack Of Fusion ◽  
Stamen Primordia ◽  
Procambial Strand ◽  
The Many

The primordia of the floral appendages are initiated in acropetal order. They develop in the same order in which they appear but for the petals, which are retarded in their early growth and mature rapidly shortly before anthesis. While the sepal primordia are dorsiventral from their inception, the primordia of other appendages are of nearly radial symmetry and become more or less dorsiventral in their later stages of development. Each petal primordium together with the primordia of a stamen pair arise on one common petal–stamen (CA) primordium. The many pistil primordia arise on three antesepalous gynoecial bulges and the area between them. Thus, in its development the flower exhibits primarily a tricyclic trimerous plan. The floral apices have a two-layered tunica up to the stage of pistil inception. The initiation of all floral appendages occurs by periclinal divisions in the second layer. The third layer (corpus) may contribute, especially in the case of the petal–stamen primordia and the gynoecial bulges. The development of procambium is acropetal. Each primordium receives a single procambial strand shortly after its initiation. Thus, procambial differentiation occurs as a response to primordial inception and not according to the principle of the conservatism of vascular tissue. Additional procambial strands may differentiate as a response to increase in size. The relationships of Alisma to some ranalian families are discussed. Since the floral pattern of Alisma may be considered as a secondary derivation from a trimerous pattern, it does not appear primitive at all. Other primitive features such as apocarpy and lack of fusion of pistil margins are however retained. Thus, Alisma is a good example for heterobathmy.

Effect of the Stages of Floral Development and Postharvest Temperatures to Flowering of Eremurus in Israel

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 536d-536
Author(s):  
Rina Kamenetsky
Keyword(s):  
Morphological Analysis ◽  
Developmental Disorder ◽  
Floral Development ◽  
The Third ◽  
Initial Stage ◽  
Floral Differentiation ◽  
Soil Temperatures ◽  
Very High ◽  
Development Application ◽  
Flowering Process

The influence of postharvest temperature on the flowering response of Eremurus was studied. The plants were harvested at four different stages of development and were separated into three groups. The first group was immediately exposed to 2 °C, the second group to 20 °C followed by 2 °C, and the third group to 20 °C followed by 32 °C and, subsequently, 2 °C. Scanning electron microscopy (SEM) was used for concurrent morphological analysis of floral development. Application of 2 °C to the plants in the initial stage of floral development caused plant destruction and death, while the same treatment applied at the stage of full differentiation promoted normal flowering. Temperatures of 20 °C and, especially, 32 °C, significantly improved flowering of the plants harvested in the early stages of florogenesis, whereas the same treatment applied to the plants harvested at the end of flower differentiation did not affect the flowering process. A developmental disorder, which we term “Interrupted Floral Development” (IFD), was observed only in the plants harvested when the racemes were fully differentiated. This was probably caused by the very high air and soil temperatures that prevail in Israel during the summer. The extent of floral differentiation has a determinant role in subsequent scape elongation and flowering.

scholarly journals Ethylene and 1-methylcyclopropene action over senescence of nasturtium flowers

2015 ◽  
Vol 33 (4) ◽  
pp. 453-458 ◽  
Author(s):  
Tania P Silva ◽  
Fernando L Finger
Keyword(s):  
Floral Development ◽  
Development Stage ◽  
Flower Senescence ◽  
Premature Senescence ◽  
Flower Opening ◽  
Development Stages ◽  
Post Harvest ◽  
The Third ◽  
Exogenous Ethylene ◽  
Floral Bud

ABSTRACT: This work describes ethylene and 1-methylcyclopropene (1-MCP) action on post-harvest shelf life of four development stages of nasturtium flowers. To reach this goal, we carried out three experiments. In the first and second experiments, we studied five ethylene (0; 0.1; 1; 10; 100 and 1000 μL/L) and three 1-MCP concentrations (0.25; 0.5 and 0.75 μL/L), respectively. In the third experiment, 1-MCP was followed by combined with ethylene (only 1-MCP; only ethylene; and 24 hours of exposure to 0.75 μL/L 1-MCP followed by 24 hours of exposure to 100 μL/L ethylene). All experiments had two control treatments, one keeping non-exposed flowers inside and another outside exposure chambers. Experiments were set in factorial design, in complete blocks at random, with four 10-flower replications each. Flower senescence was determined by a pre-established visual scale and by observing floral bud development. Ethylene dose above 10 μL/L induced flower wilting and premature senescence from the second floral development stage. Furthermore, higher concentrations of exogenous ethylene promoted irregular flower opening and/or morphological abnormalities in opened flowers. 1-MCP effectively extended post-harvest longevity of nasturtium flowers, independent of the concentration and even in the presence of exogenous ethylene.

Über Gewissen und Gewissheit

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Dina Emundts
Keyword(s):  
Immanuel Kant ◽  
A Priori ◽  
Categorical Imperative ◽  
Moral Principles ◽  
The Third ◽  
The Status

AbstractThis paper suggests an understanding of the concept of “Gewissen” (conscience) according to which Gewissen is best understood as a receptivity to moral principles that corresponds to certain moral feelings. In the first part of the paper this suggestion is spelled out and alternatives to it are discussed. As is shown in the second part, this suggestion goes back to the thought of Immanuel Kant, but it can be developed even if one does not follow Kant in his understanding of the categorical imperative as an a priori principle. However, if one does not follow Kant with respect to the status of the categorical imperative, there are some interesting consequences for our understanding of conscience and especially for our understanding of its relation to knowledge and certainty. These consequences are discussed in the third part of this paper.

Floral development of Potamogeton densus

1973 ◽  
Vol 51 (3) ◽  
pp. 647-656 ◽  
Author(s):  
U. Posluszny ◽  
R. Sattler
Keyword(s):  
Floral Development ◽  
The Other ◽  
Floral Meristem ◽  
Developmental Sequence ◽  
Initial Activity ◽  
The Third ◽  
Stamen Primordia ◽  
Procambial Strand ◽  
Inflorescence Axis ◽  
Rates Of Growth

The floral appendages of Potamogeton densus are initiated in an acropetal sequence. The first primordia to be seen externally are those of the lateral tepals, though sectioning young floral buds (longitudinally, parallel to the inflorescence axis) reveals initial activity in the region of the lower median (abaxial) tepal and stamen at a time when the floral meristem is not yet clearly demarcated. The lateral (transversal) stamens are initiated simultaneously and unlike the median stamens each arises as two separate primordia. The upper median (adaxial) tepal and stamen develop late in relation to the other floral appendages, and in some specimens are completely absent. Rates of growth of the primordia vary greatly. Though the lower median tepal and stamen are initiated first, they grow slowly up to gynoecial inception, while the upper median tepal appears late in the developmental sequence but grows rapidly, soon overtaking the other tepal primordia. The four gynoecial primordia arise almost simultaneously, although variation in their sequence of inception occurs. The two-layered tunica of the floral apices gives rise to all floral appendages through periclinal divisions in the second layer. The third layer (corpus) is involved as well in the initiation of the stamen primordia. Procambial strands develop acropetally, lagging behind primordial initiation. The lateral stamens though initiating as two primordia each form a single, central procambial strand, which differentiates after growth between the two primordia of the thecae has occurred. A great amount of deviation from the normal tetramerous flower is found, including completely trimerous flowers, trimerous gynoecia with tetramerous perianth and androecium, and organs differentiating partially as tepals and partially as stamens.

A mathematical model for the third-body concept

2017 ◽  
Vol 23 (3) ◽  
pp. 420-432 ◽  
Author(s):  
Pavel Krejčí ◽  
Adrien Petrov
Keyword(s):  
Mathematical Model ◽  
A Priori Estimates ◽  
A Priori ◽  
Dynamical Problem ◽  
Sobolev Embedding ◽  
Third Body ◽  
Embedding Theory ◽  
The Third ◽  
Galerkin Approximations ◽  
Body Concept

The third-body concept is a pragmatic tool used to understand the friction and wear of sliding materials. The wear particles play a crucial role in this approach and constitute the main part of the third-body. This paper aims to introduce a mathematical model for the motion of a third-body interface separating two surfaces in contact. This model is written in accordance with the formalism of hysteresis operators as solution operators of the underlying variational inequalities. The existence result for this dynamical problem is obtained by using a priori estimates established for Faedo–Galerkin approximations, and some more specific techniques such as anisotropic Sobolev embedding theory.

scholarly journals SlGT11 Controls Floral Organ Patterning and Floral Determinacy in Tomato

2020 ◽  
Author(s):  
Liling Yang ◽  
Shilian Qi ◽  
Arfa touqeer ◽  
Haiyang Li ◽  
Xiaolan Zhang ◽  
...  
Keyword(s):  
Floral Development ◽  
Bulked Segregant Analysis ◽  
Floral Organ ◽  
Fruit Production ◽  
Floral Meristem ◽  
Rnai Silencing ◽  
The Third ◽  
Spatiotemporal Expression ◽  
Higher Temperature ◽  
Floral Determinacy

Abstract Background: Flower development directly affects fruit production in tomato. Despite the framework mediated by ABC genes have been established in Arabidopsis, the spatiotemporal precision of floral development in tomato has not been well examined.Results: Here, we analyzed a novel tomato stamenless like flower (slf) mutant in which the development of stamens and carpels is disturbed, with carpelloid structure formed in the third whorl and ectopic formation of floral and shoot apical meristem in the fourth whorl. Using bulked segregant analysis (BSA), we assigned the causal mutation to the gene Solanum lycopersicum GT11 (SlGT11) that encodes a transcription factor belonging to Trihelix gene family. SlGT11 is expressed in the early stages of the flower and the expression becomes more specific to the primordium position corresponding to stamens and carpels in later stages of the floral development. Further RNAi silencing of SlGT11 verifies the defective phenotypes of the slf mutant. The carpelloid stamen in slf mutant indicates that SlGT11 is required for B-function activity in the third whorl. The failed termination of floral meristem and the occurrence of floral reversion in slf indicate that part of the C-function requires SlGT11 activity in the fourth whorl. Furthermore, we find that at higher temperature, the defects of slf mutant are substantially enhanced, with petals transformed into sepals, all stamens disappeared, and the frequency of ectopic shoot/floral meristem in fourth whorl increased, indicating that SlGT11 functions in the development of the three inner floral whorls. Consistent with the observed phenotypes, it was found that B, C and an E-type MADS-box genes were in part down regulated in slf mutants.Conclusions: Together with the spatiotemporal expression pattern, we suggest that SlGT11 functions in floral organ patterning and maintenance of floral determinacy in tomato.

Il buono, il brutto e il cattivo. Disambiguare il naturalismo di Quine

2009 ◽  
pp. 75-97
Author(s):  
Susan Haack
Keyword(s):  
Empirical Study ◽  
A Priori ◽  
Scientific Investigation ◽  
The Third ◽  
Epistemological Naturalism

- Quine's ‘epistemology naturalised' has been profoundly influential, but it is also highly ambiguous. Quine seems at times to claim only that epistemology is not a purely a priori enterprise but an empirical study, continuous with the sciences of cognition; at others, that epistemological questions can be turned over to the sciences to resolve; and on other occasions, that epistemological questions are misconceived and should be replaced by scientific investigation into cognition. What is argued here is that the first and most modest version of Quine's epistemological naturalism is potentially fruitful, the second and more ambitious indefensible, and the third and most ambitious not only false but disastrous.

The Impact of the Court of Justice of the European Union on Neighbouring Countries

2020 ◽  
pp. 349-396
Author(s):  
Arie Reich ◽  
Hans-W. Micklitz
Keyword(s):  
European Union ◽  
A Priori ◽  
Policy Recommendations ◽  
Eu Law ◽  
The European Union ◽  
The Third ◽  
Court Of Justice ◽  
The Many ◽  
The Impact ◽  
Legal Integration

The concluding chapter sums up the overall findings of the project through three different strands of analysis: the first breaks down the eleven jurisdictions into three groups based on the relative quantity and impact of Court of Justice of the European Union (CJEU) citations found in these jurisdictions. By drawing conclusions from all the country reports through a comparative and macro-perspective, the goal is to distil the insights of the entire project and formulate policy recommendations in the light of EU external policy and legal integration objectives vis-à-vis its neighbourhood; the second examines the many factors that a priori could have an impact on whether judges are likely to cite the CJEU in their judgments, and then discusses what the research has found in relation to the actual role played by these factors; the third tries to place the current project into the context of overall research on the global reach of EU law, which can be ‘exported’ to non-members of the EU through various mechanisms, such as mutual and formal agreement or through more unilateral and spontaneous forms. They include modes of extraterritorial application of EU law, territorial extension, and the so-called ‘Brussels Effect’. The chapter concludes with some general observations and thoughts and formulates possible policy recommendations.

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