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 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.

Ontogeny of floral organs and morphology of floral apex in Phellodendron amurense (Rutaceae)

2002 ◽  
Vol 50 (5) ◽  
pp. 633 ◽  
Author(s):  
Qingyuan Zhou ◽  
Yinzheng Wang ◽  
Xiaobai Jin
Keyword(s):  
Laser Scanning ◽  
Male Flower ◽  
Female Flower ◽  
Laser Scanning Confocal Microscopy ◽  
Morphological Evidence ◽  
Phellodendron Amurense ◽  
Flower Buds ◽  
Floral Organs ◽  
Floral Apex ◽  
Female Flowers

The ontogeny of floral organs and the morphology of floral apex in the dioecious Phellodendron amurense Rupr. were investigated by light microscopy (LM), scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Investigations indicated that P. amurense is hermaphroditic in its organisation and a common set of floral organs (sepals, petals, stamens and carpels) arise in all flowers during the early stages of development. Later, selective abortion of gynoecium and androecium occurs resulting in dimorphic unisexual flowers. The carpels in male flower buds become different from those in female flower buds soon after their initiation. The stamens of female flowers are not differentiated into anthers and filaments before abortion. The poorly differentiated carpel of male flowers never develops normal structures. Floral morphological evidence supports that Zanthoxylum, Tetradium and Phellodendron are related to one another in a linear sequence. LSCM revealed some interesting features on the apical meristem surface such as zonal differentiation, a triangular or sectorial cell, radiating cell files and linear rows of anticlinal cell walls fluorescing relatively brightly. The concept of carpel-enhancing meristem in the floral apex is tentatively proposed to account for the different fates of carpel development in male and female flowers in P. amurense.

Inception of the cupule of Quercus macrocarpa and Fagus grandifolia

1979 ◽  
Vol 57 (17) ◽  
pp. 1777-1782 ◽  
Author(s):  
Alastair D. Macdonald
Keyword(s):  
Female Flower ◽  
Fagus Grandifolia ◽  
Second Order ◽  
The Other ◽  
Third Order ◽  
Quercus Macrocarpa ◽  
First Order ◽  
Female Inflorescence ◽  
Inflorescence Axis ◽  
Morphological Nature

The female inflorescence of Fagus grandifolia comprises two flowers; one flower terminates the first-order inflorescence axis, the other flower terminates the second-order inflorescence axis. Each flower is flanked by two cupular valves each of which arise in the axil of a bract. The two valves flanking the flower terminating the first-order inflorescence axis represent second-order inflorescence axes and the two valves flanking the flower terminating the second-order inflorescence axis represent third-order inflorescence axes. The four valves remain discrete. Each female flower of Quercus macrocarpa terminates a second-order inflorescence axis and is surrounded by a continuous cupule. The cupule first forms as two primordia in the axils of each of the two transversal second-order bracts. These cupular primordia represent third-order inflorescence branches. The cupule primordia become continuous about the pedicel by meristem extension. The cupules of Fagus and Quercus are homologous to the extent that they are modified axes of the inflorescence. This serves as a model to interpret the morphological nature of the fagaceous cupule.

Development of the female flower and gynecandrous partial inflorescence of Myrica californica

1979 ◽  
Vol 57 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Alastair D. Macdonald
Keyword(s):  
Fourth Order ◽  
Female Flower ◽  
Second Order ◽  
Third Order ◽  
First Order ◽  
Unique Structure ◽  
Inflorescence Axis ◽  
Definition Of ◽  
Fifth Order ◽  
Partial Inflorescence

Organogenesis of the female flower and gynecandrous partial inflorescence is described. Approximately 25 first-order inflorescence bracts are formed in an acropetal sequence. A second-order inflorescence axis, the partial inflorescence, develops in the axil of each bract. Third-, fourth-, and fifth-order axes arise in the axils of second-, third-, and fourth-order bracts. A gynoecium terminates a second-order axis and sometimes a distal third-order axis. A gynoecium consists of two stigmas and one basal, unitegmic, orthotropous ovule. The wall enclosing the ovule, the circumlocular wall, is comprised distally of gynoecial tissue and proximally of tissue of the inflorescence axis and its appendages. The latter portion of the wall is formed by zonal growth. Androecial members, formed proximal to the gynoecium on the partial inflorescence, are carried onto the circumlocular wall by zonal growth. A stamen may develop from the last-formed primordium before gynoecial inception or from a potentially stigmatic primordium. The papillae of the flower and fruit arise as emergences and from potentially bracteate, axial, and staminate primorida during the development of the circumlocular wall. The term circumlocular wall is used in a neutral sense to describe this unique structure. Since the gynoecium is composed of gynoecial appendages and inflorescence axis and appendages, a functional definition of gynoecium must be expanded to include any tissue, including an inflorescence, that surrounds the ovule(s) and forms the fruit(s).

Development of the inflorescence and flower of Sagittaria cuneata

1977 ◽  
Vol 55 (9) ◽  
pp. 1087-1105 ◽  
Author(s):  
V. Singh ◽  
R. Sattler
Keyword(s):  
Male Flower ◽  
Female Flower ◽  
Point Of View ◽  
Stamen Primordia ◽  
Tunica Layer ◽  
Mature Flower ◽  
Floral Apex ◽  
Developmental Point ◽  
Floral Bud ◽  
Developmental Modification

The reproductive region of Sagittaria cuneata is basically trimerous. This trimery is exhibited in the arrangement of the bracts, sepals, petals, pairs of stamens in the male flower, and pairs of staminodia in the female flower. In the male flower after the inception of three sepal primordia, each of the three petal primordia arises with one pair of stamen primordia on an alternisepalous bulge of the floral apex, i.e., a petal–stamen (CA) primordium. Subsequent stamen primordia are formed in alternation with the six first-formed primordia. If, for convenience sake, the first six primordia are referred to as the first whorl of stamens up to four additional whorls may be produced. Depending on the size of the floral bud, the third and fourth whorls (if present) consist of two to six stamen primordia, whereas the fifth whorl (if present) contains one to five stamen primordia. Finally, primordia of pistillodes are formed in varying numbers. In the female flower the presence of CA primordia could not be as clearly established as in the male flower. However, again each petal primordium is definitely associated with a pair of antepetalous primordia. The latter primordia develop into staminodia. In alternation with the first six staminodia six additional staminodia are formed and then again in alternation many whorls of pistils (carpels). Even in the mature flower the basic trimery is reflected in the triangular shape of the globose and massive gynoecium. From a developmental point of view, the male and female flowers are primarily trimerous. The polyandric androecium and the large pleiomerous gynoecium are superimposed on the primary trimery. It appears quite possible that this developmental modification also reflects a phylogenetic derivation. This means that the pleiomerous gynoecium and androecium are not primitive but rather advanced. There is no indication of a spiral arrangement of stamens and carpels.Whereas the foliage leaves, bracts, and sepals are initiated as dorsiventral primordia, the petals, stamens, staminodia, pistils, and pistillodes arise as more or less hemispherical mounds and become dorsiventral thereafter. The vegetative apices, inflorescence apices and the floral apices have a two-layered tunica over a massive corpus. Foliage leaves, bracts, sepals, petals, stamens, staminodia, carpels, and pistillodes are initiated by periclinal divisions in the second tunica layer. In the case of the stamens and staminodia the corpus may also contribute. Ovules are initiated by periclinal divisions of the second layer of the carpel primordium.

Bulk Contributions Modulate the Sum-Frequency Generation Spectra of Interfacial Water on Model Sea-Spray Aerosols

2018 ◽  
Author(s):  
Sandeep K. Reddy ◽  
Raphael Thiraux ◽  
Bethany A. Wellen Rudd ◽  
Lu Lin ◽  
Tehseen Adel ◽  
...  
Keyword(s):  
Single Layer ◽  
Sum Frequency Generation ◽  
Second Order ◽  
Interfacial Structure ◽  
Sea Spray ◽  
Third Order ◽  
Systematic Analysis ◽  
Sum Frequency ◽  
Structure Of Water ◽  
Frequency Generation

Vibrational sum-frequency generation (vSFG) spectroscopy is used to determine the molecular structure of water at the interface of palmitic acid monolayers. Both measured and calculated spectra display speci c features due to third-order contributions to the vSFG response which are associated with nite interfacial electric potentials. We demonstrate that theoretical modeling enables to separate the third-order contributions, thus allowing for a systematic analysis of the strictly surface-sensitive, second-order component of the vSFG response. This study provides fundamental, molecular-level insights into the interfacial structure of water in a neutral surfactant system with relevance to single layer bio-membranes and environmentally relevant sea-spray aerosols. These results emphasize the key role that computer simulations can play in interpreting vSFG spectra and revealing microscopic details of water at complex interfaces, which can be difficult to extract from experiments due to the mixing of second-order, surface-sensitive and third-order, bulk-dependent contributions to the vSFG response.

Evidence for general base catalysis by protic solvents in a kinetic study of alcoholyses and hydrolyses of 1-(phenoxycarbonyl)pyridinium ions under both solvolytic and non-solvolytic conditions

2009 ◽  
Vol 74 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Dennis N. Kevill ◽  
Byoung-Chun Park ◽  
Jin Burm Kyong
Keyword(s):  
Second Order ◽  
Base Catalysis ◽  
Substitution Reactions ◽  
Third Order ◽  
Methoxy Derivative ◽  
First Order ◽  
General Base ◽  
Protic Solvents ◽  
Kinetics Of ◽  
Pyridinium Ions

The kinetics of nucleophilic substitution reactions of 1-(phenoxycarbonyl)pyridinium ions, prepared with the essentially non-nucleophilic/non-basic fluoroborate as the counterion, have been studied using up to 1.60 M methanol in acetonitrile as solvent and under solvolytic conditions in 2,2,2-trifluoroethan-1-ol (TFE) and its mixtures with water. Under the non- solvolytic conditions, the parent and three pyridine-ring-substituted derivatives were studied. Both second-order (first-order in methanol) and third-order (second-order in methanol) kinetic contributions were observed. In the solvolysis studies, since solvent ionizing power values were almost constant over the range of aqueous TFE studied, a Grunwald–Winstein equation treatment of the specific rates of solvolysis for the parent and the 4-methoxy derivative could be carried out in terms of variations in solvent nucleophilicity, and an appreciable sensitivity to changes in solvent nucleophilicity was found.

scholarly journals Evaluation of Damage Process of a Coating by Using Nonlinear Ultrasonic Method

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 440
Author(s):  
Chunguang Xu ◽  
Lei He ◽  
Shiyuan Zhou ◽  
Dingguo Xiao ◽  
Pengzhi Ma
Keyword(s):  
Tensile Stress ◽  
Order Parameter ◽  
Evaluation Method ◽  
Early Stage ◽  
Ultrasonic Method ◽  
Nonlinear Coefficient ◽  
Damage Index ◽  
Second Order ◽  
External Loading ◽  
Nonlinear Ultrasonic

During the service or external loading of the surface coating, the damage accumulation may develop in the coating or at the interface between the substrate and the coating, but it is difficult to measure directly in the early stage, so the acoustic nonlinear parameters are used as the early damage index of the coating. In this paper, the nonlinear wave motion equation is solved by the perturbation method and the new relationship between the relative ratio of second-order parameter and third-order parameter was derived. The nonlinear ultrasonic testing system is used to detect received signals during tensile testing of for the specimen with Al2O3 coatings. It is found that when the stress is less than 260 MPa, the appearance of the coating has no obvious change, but the nonlinear coefficients measured by the experiment increase with the increase of the tensile stress. By comparing the curves of nonlinear coefficients and stress respectively, the fluctuation of curves the second-order nonlinear coefficient A2 and the relative nonlinear coefficient β′ to stress is relatively small, and close to the linear relationship with the tensile stress, which indicates that the two parameters of the specimen with Al2O3 coatings are more sensitive to the bonding conditions, and can be used as an evaluation method to track the coating damage.

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