scholarly journals Floral development of Condylocarpon isthmicum (Apocynaceae)

Botany ◽  
2015 ◽  
Vol 93 (11) ◽  
pp. 769-781 ◽  
Author(s):  
Rosemeri Morokawa ◽  
Juliana Lischka Sampaio Mayer ◽  
André Olmos Simões ◽  
Luiza Sumiko Kinoshita

Apocynaceae is one of the largest families of angiosperms. Its representatives have flowers with relatively simple morphology, ranging from anthers free from the style head to more complex flowers in which the anthers are postgenitally united with the style head, forming a gynostegium, and those with a style head that is vertically differentiated into distinct functional regions. The aim of this study is to understand the morphology and secretory structures of Condylocarpon isthmicum (Vell.) A.DC. at different stages of development. This species, which is in the family Apocynaceae, has morphologically simple flowers. Flowers at four different stages of development were collected and processed for anatomical and histochemical analysis; floral anatomy was examined using light and scanning electron microscopy. The simplicity of the C. isthmicum flower morphology was contrasted with the complexity observed in the secretory structures at different stages of flower development. Four secretory structures were identified in this species: colleters, style head epidermal cells, nectariferous tissue, and an obturator. The colleters were observed in the bracts and bracteoles of the young inflorescences. The style head began the secretory phase in the pre-anthetic stage and remained in this phase until anthesis. The nectariferous tissue was secreted during anthesis, and the obturator was present only in post-anthetic flowers. We identified a nectary in the wall of the ovary, and we verified and described a new structure in the Apocynaceae, the obturator.

Botany ◽  
2016 ◽  
Vol 94 (5) ◽  
pp. 337-346 ◽  
Author(s):  
Ana Paula Stechhahn Lacchia ◽  
Elisabeth E.A. Dantas Tölke ◽  
Sandra M. Carmello-Guerreiro ◽  
Lia Ascensão ◽  
Diego Demarco

Colleters are secretory structures widely distributed in eudicots and with taxonomic value in many families. Although glandular trichomes have been described in some Anacardiaceae species, the chemical characterization of their secretions is scarce and to date there are no reports on colleters. Light microscopy and scanning electron microscopy were used to study the distribution and structure of colleters on the vegetative buds of Anacardium humile A.St.-Hil., Lithraea molleoides (Vell.) Engl., Spondias dulcis Parkinson, and Tapirira guianensis Aubl., and to characterize their secretory products histochemically. In all of these Anacardiaceae species, colleters are multicellular and multiseriate ovoid or club-shaped glandular trichomes of protodermic origin, present on both surfaces of leaf primordia. They reach the secretory phase at early stages of leaf development, after which they gradually degenerate, become brown, and fall off. Histochemical tests indicate that the secretion within the glandular cells and outside the trichomes is a complex mixture containing mucilage, fatty acids, and phenolic compounds, which are secretory products that can play an important role in the protection of meristems against desiccation and attack by pathogens. Therefore, the distribution of these glandular trichomes, their short-life, the chemical nature of their secretions and their presumed functions support their being classified as colleters.


2020 ◽  
pp. 151-164
Author(s):  
Марина Алексеевна Мазалова

Выявлена специфика организации и эволюционирования элитного семейного воспитания и домашнего образования, а также содержания государственной политики в сфере регулирования отношений воспитания в семье и определения на этой основе этапов развития данных процессов в России в XVIII – начале XX в. Организация исследований учитывает эволюцию семейной образовательной практики, которая позволяет проследить логику становления и развития элитного семейного воспитания и домашнего образования. Были определены критериальные признаки, характеризующие особенности содержания, организации и методики элитных педагогических процессов, протекавших в семье в изучаемый период. Периодизация осуществлялась на основе соотнесения с факторами элитизации личности в условиях семьи, среди важнейших названы содержание семейного воспитания и домашнего образования; совокупность средств, методов и педагогических приемов, требования к личности и профессиональным качествам домашних учителей и иностранных гувернеров и др. Выделено четыре исторических периода (этапа). На первом этапе (начало XVIII в. – 1750-е гг.) оформились базовые характеристики осуществления взаимодействия взрослых и детей с целью формирования элитной личности. Второй этап (1760-е гг. – начало XIX в.) характеризуется влиянием на лучшие практики семейного воспитания складывающейся системы государственного образования. Третий этап (начало XIX в. – 1840-е гг.) связан с возвращением к национальным ценностям в семейной воспитательной практике, ослаблением влияния иностранного гувернерства. Завершающий период – 1850-е гг. и до Революции 1917 г. – характеризуется тем, что все наиболее значимые элитивистские тенденции и традиции семейного воспитания и домашнего образования достигли высшей степени развития и выраженности. Предложенная нами периодизация позволяет определить временные этапы генезиса этих педагогических процессов, выделить основные тенденции их исторического эволюционирования, проследить особенности возникновения и проявления элитивистских образовательных тенденций в семьях дворянской и купеческой элиты, в императорской семье. The purpose of the article is to identify the characteristic features of the organization and logic of evolving the tendencies of elite family upbringing and home education as well as the content of the state policy in the sphere of regulating the relations of upbringing in the family and to define on that basis the stages of development of these processes in the period of the 18th – the early 20th centuries. The organization of the research takes into account the evolution of educational practice which allows us to track the logic of the formation and development of elite family upbringing and home education. We defined the criterial features characterizing the peculiarities of the content, organization and methodology of elite pedagogical processes going in the family in the period under study. Thechronological frames of the research are grounded. The periodization of the historical development of elite family upbringing was conducted on the basis of correlation with the factors of elitization of the personality under the conditions of the family. Among the most important are the content of family upbringing and home education, the sum total of the means, methods and pedagogical techniques, requirements for the personality and professional characteristics of home teachers and foreign family tutors and others. At the first stage (the early 18th – the 1750s) of the development of elite family upbringing and home education in Russia the basic characteristics of realizing an interaction of adults and children for the purpose of creating an elite personality are formed. The second stage (from the 1760s to the early 19the century) can be characterized by the influence of the forming system of state education on the best practices of family upbringing. The third stage of evolving elite family upbringing and home education (the early 19th – the 1840s) is connected with returning to national values in family upbringing practice, weakening the influence of foreign family tutorship on the formation of moral sphere of elite personality. The last period (the 1850s up to the revolution of 1917) can be characterized by the fact that all the most significant elitivist tendencies and traditions of family upbringing and home education reached the highest degree of their development and manifestation. The periodization of the development of elite family upbringing and home education in Russia in the 18th – the early 20th centuries suggested by us allows to identify the time stages of the genesis of these pedagogical processes, to single out the main tendencies of their historical evolving, to trace the peculiarities of emergence and manifestation of elitivist educational tendencies in families of the nobility and merchants belonging to the elite, in the family of the emperor.


1985 ◽  
Vol 63 (10) ◽  
pp. 1785-1788 ◽  
Author(s):  
Bruce K. Kirchoff ◽  
Helen Kennedy

Nonstructural, foliar nectaries have been found in two genera of the Marantaceae (Zingiberales). Two nectaries are located on each leaf, at the junction of the leaf sheath and petiole. Externally, they may be readily distinguished from the surrounding tissue by their lighter color and absence of hairs. Internally, they show no specifically differentiated nectariferous tissue. In most species, the location of the nectaries is correlated with the distribution of fiber bundles. In nonncctariferous regions these bundles lie directly beneath the epidermis, while in the region of the nectary they occur several cell layers beneath the epidermis. Nectar secretion takes place through stomates. The cells surrounding the substomatal cavity may play an important role in the process of secretion. The distribution of structural nectaries in the family is also discussed.


2020 ◽  
Vol 193 (1) ◽  
pp. 64-83 ◽  
Author(s):  
Flávia M Leme ◽  
Jürg Schönenberger ◽  
Yannick M Staedler ◽  
Simone P Teixeira

Abstract Species of Cannabaceae are wind pollinated, have inconspicuous and reduced flowers that are pistillate, staminate and apparently perfect on the same individual or on different individuals, with a single-whorled perianth and a pseudomonomerous gynoecium. Our objective is to understand the developmental processes that lead to such a reduced flower morphology and polygamy in Cannabis sativa, Celtis iguanaea and Trema micrantha. Floral buds and flowers were processed for surface, histological examinations and 3D reconstructions of vasculature. The single-whorled perianth is interpreted as a calyx because the organs are robust, have a broad base, an acute apex and quincuncial aestivation and are opposite the stamens. Petals are absent from inception. The dicliny is established at different development stages: stamens or carpels are absent from inception (Cannabis sativa), initiated and aborted during early (Trema micrantha, before sporo/gametogenesis) or late (Celtis iguanaea, after sporo/gametogenesis) development. Furthermore, in all species studied the carpels are congenitally united and the pseudomonomerous nature of the gynoecium is confirmed. Glandular trichomes are distributed on the bracts, sepals, anther connective and receptacle. Special floral features shared by species of Cannabaceae include precocious ovule development and sepals that are each vascularized by one bundle. The reduced flowers of Cannabaceae are the result of the absence from inception and/or abortion of organs and even of a whole whorl at different developmental stages, which were probably selected in response to pressures exerted by the similar pollination mechanism.


2019 ◽  
Author(s):  
Louis P. Ronse De Craene ◽  
Lai Wei

We investigated the floral anatomy and development of Macarthuria australis Hügel ex Endl., an unusual genus endemic to Australia, in the context of floral evolution of core Caryophyllales. Flower initiation is spiral, with sepals developing quincuncially. The first two petals continue the sequence of sepal initiation, but the remaining petals arise from common stamen–petal primordia. The androecium develops sequentially as three inner antesepalous and five outer antepetalous stamens. The globular ovary is trimerous with a short symplicate zone and two arillate ovules per locule. The rapid emergence of the androecium leads to a partial absorption of the petal primordia within the androecial tissue. The two first-formed petals have more room for development and precede the androecium, supporting the fact that petals are not staminodial in origin. This heterochronic shift correlates with an inversed developmental sequence of the antesepalous stamens. The constraint caused by the spatial occupation of sepals and carpels leads to the loss of two stamens, and the re-arrangement of stamens and petals along the flanks of the carpels. The floral development of Macarthuria anticipates a syndrome of stamen and petal development in other core Caryophyllales and culminating in the Caryophyllaceae.


1992 ◽  
Vol 70 (2) ◽  
pp. 258-271 ◽  
Author(s):  
Claudia Erbar

The early floral development of Stylidium adnatum and Stylidium graminifolium is characterized by an initial circular primordium whose areas in the transversal plane of the floral primordium show enhanced growth. The spiral inception of the five sepals starts before the differentiation of the initial circular primordium into two stamen primordia in transversal position (in relation to the floral diagram) and the corolla ring primordium below the stamen primordia. Then five petal primordia, which alternate with the sepals, arise on the corolla ring primordium (early sympetaly). Peculiar to the flowers of Stylidiaceae is the column that bears at its top both stigma and anthers. Probably this column should be interpreted as a receptacular tube. No distinct carpel primordia have been observed. The inferior ovary results from intercalary growth in the peripheral parts of the receptacle below the calyx, corolla, and stamen primordia. The residual floral apex gives rise to a transversal septum, by which the ovary becomes bilocular. None of the morphological, palynological, and embryological characters discussed contradicts a position of the Stylidiaceae near the Campanulales, and several of these characters support this position. Key words: Stylidiaceae, Campanulales, floral development, systematic position, floral biology.


2000 ◽  
Vol 8 (6) ◽  
pp. 34-35
Author(s):  
Willow B. Murphy ◽  
Walter A. Kelley ◽  
Richard C. Dujay

The genus Cryptantha Lehm ex G. Don section Oreocarya (E. Greene) Payson of the family Boraginaceae presents some problems to botanists, both professional and amateur, in the keying and identification of species. The genus contains approximately 150 species, the section about 60 perennial and biennial herbs located generally in western North America. Identification has presented some taxonomic difficulty due to the variability and lack of distinctive vegetative characters. Botanists have turned to the nutlet (fruit) and flower morphology to aid in identification for precise specific differentiation. In the past, 10X magnification and a decent botanical illustrator were required to provide the illustrations necessary to assist in this identification. We are in the process of collecting micrographs of nutlets (dorsal, sagital, and ventral views) and developing a webpage containing these micrographs along with descriptions of their morphological variations.


Zootaxa ◽  
2013 ◽  
Vol 3637 (5) ◽  
pp. 569 ◽  
Author(s):  
DAVID A. SÁNCHEZ

Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the Dendrobatoidea have similar disposition of digestive organs in early stages, but differentiate in late stages of development. Classifying the upper jaw sheath into the two recognized states is possible from very early stages of development, but gut disposition and nostril ornamentation cannot be determined until late in development, making classification and taxonomic assignment of tadpoles based on these morphological features challenging.


1999 ◽  
Vol 77 (4) ◽  
pp. 582-598 ◽  
Author(s):  
LP Ronse Decraene ◽  
E F Smets

Floral development and anatomy of Carica papaya L. have been investigated to shed light on (i) the morphology of the flower, (ii) the structural basis for the pollination mechanism, and (iii) the relationships of the Caricaceae. Carica is mostly dioecious with a strong dimorphism between staminate and pistillate flowers. The development of staminate flowers resembles that of pistillate flowers up to the initiation of the stamens. Further development leads to highly diverging morphologies. In staminate flowers a combination of contorted growth and the development of a common stamen-petal tube produces a long floral tube. The gynoecium grows into a central spearlike pistillode. The pistillate flowers have no traces of stamens and initiate five antesepalous carpel primordia. Common basal growth leads to the development of a large ovary with staglike stigmatic lobes and intruding placentae covered with numerous ascending ovules. Floral anatomy of staminate and pistillate flowers is described. The nature of the colleters is discussed. The morphological basis for reward production in C. papaya is clarified, and conflicting views on pollination are discussed. Nectaries of staminate flowers are located on the central rudimentary pistil and not at the base of the stamens, as previously reported. The anthers contain packages of calcium oxalate crystals. Pistillate flowers produce no nectar but have a stigmatic exudate. We compared the floral development and anatomy of Carica with that of Adenia (Passifloraceae) and Moringa (Moringaceae) in the view of a relationship with other glucosinolate-producing families. Although a derivation of the unisexual flowers from bisexual ancestors is probable, Storey's hypothetical derivation of pistillate flowers is not supported by the floral ontogeny and vasculature.Key words: Adenia, Caricaceae, Moringa anatomy, calcium oxalate packages, dioecy, floral structure, nectaries, ontogeny, pollination, systematic relationships.


1977 ◽  
Vol 55 (9) ◽  
pp. 1106-1120 ◽  
Author(s):  
V. Singh ◽  
R. Sattler

The primordia of the floral appendages are initiated in an acropetal succession. Members of the same whorl appear nearly simultaneously. The gynoecial whorl and the two staminal whorls are trimerous, whereas the perianth consists only of two anteriolateral tepals. However, the posterior (adaxial) tepal may be present as an extremely reduced buttress whose growth becomes arrested immediately after its inception. If this somewhat questionable tepal rudiment is included we have a perfectly trimerous and tetracyclic flower with alternation of successive whorls. Subtending bracts of the flowers are completely missing in all developmental stages. While the tepal primordia are dorsiventral from their inception, the stamen and pistil (carpel) primordia originate as hemispherical mounds which become dorsiventral in subsequent stages of development. Each pistil (carpel) primordium becomes horseshoe shaped. As the margins grow up and contact they fuse postgenitally. No cross zone is formed. Placentation is submarginal. In A. natans eight ovules are formed and in A. undulatus only two arise; all ovules are bitegmic. The floral apices have a two-layered tunica up to the stage of pistil formation. The inception of all floral appendages (including the ovules) occurs by periclinal cell division in the second tunica layer. The third layer (corpus) may contribute to the formation of the stamens and pistils. Each appendage primordium receives only one procambial strand which begins to differentiate after the inception of the primordium. The questionable rudimentary tepal buttress lacks a procambial strand. Apparently it does not reach the developmental stage at which procambial induction occurs. From the point of view of floral development, the two species of Aponogeton differ drastically from members of the Alismatales studied so far. Among the Helobiae, the Aponogetonaceae appear to be most closely related to the Scheuchzeriaceae and the Juncaginaceae (Triglochinaceae).


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