Vascularisation de la fleur pistillée de Begonia handelii

1981 ◽  
Vol 59 (5) ◽  
pp. 819-825 ◽  
Author(s):  
Denis Barabé
Keyword(s):  
Pistillate Flower ◽  
Vascular Bundles ◽  
Vascular Pattern ◽  
Serial Sections ◽  
Inferior Ovary

The pistillate flower of Begonia handelii Irmscher has a tetramerous gynoecium. The analysis of serial sections shows that the anatomical pattern observed by Gauthier (1950) on trimerous gynoecia also occurs in tetramerous gynoecia. For each carpel there are theoretically seven vascular bundles which leave the stele. The vascular pattern of the pistillate flower of B. handelii leads us to adopt the appendicular theory of the inferior ovary. The position of vascular bundles, the presence of gaps, and the absence of recurrent bundles show that the ovary is formed by the union of appendicular organs. In this case, the inferior ovary results from the close union of carpels and perianth parts. In the pistillate flower of B. handelii, the perianth parts are disposed on two dimerous whorls: the first corresponds to a whorl of sepals, and the second to a whorl of petals.

scholarly journals Floral anatomy of Tristerix longebracteatus (Loranthaceae)

2020 ◽  
Vol 68 (1) ◽  
Author(s):  
Laura-Alejandra Lamilla ◽  
Camila-Andrea Robayo ◽  
Felipe Castaño ◽  
Xavier Marquínez-Casas ◽  
Lauren Raz
Keyword(s):  
New World ◽  
Floral Anatomy ◽  
Complex Pattern ◽  
Vascular Bundles ◽  
Serial Sections ◽  
Basic Fuchsin ◽  
Inferior Ovary ◽  
Information Gap ◽  
Fixation Techniques ◽  
Ovarian Cavity

Introduction: Most of the New World members of the Loranthaceae comprise a clade that corresponds to the tribe Psittacantheae. Previous studies on floral anatomy and development in this tribe have concentrated on the highly diversified subtribe Psittacanthinae, while the smaller subtribe Ligarineae has received less attention. A detailed anatomical description of Tristerix longebracteatus helps to fill this information gap. Objetive: The present research analyzes the anatomy of Tristerix longebracteatus flowers, detailing the structure of androecium and gynoecium, including megasporogenesis and microsporogenesis. Methodology: Anatomical serial sections of flowers at different stages of development were prepared, following processing with fixation techniques, incorporation in paraffin, microtome sectioning and staining with Astra-blue and basic fuchsin. Results: The large-sized flowers of Tristerix longebracteatus present a complex pattern of vascularization with 18-20 vascular bundles at the base of the inferior ovary. A group of three vascular bundles irrigate the 4-5 petals and associated stamens, and ten bundles continue through the gynoecium. The androecium is composed of four or five anthers with simultaneous microsporogenesis. The gynoecium as a single ovarian cavity with a central mamelon in which the archesporial tissue is oriented towards the style. The base of the style forms a nectary similar to that found in the sister genus Ligaria. Conclusions: The gynoecium with a single ovarian cavity and central mamelon is a condition shared by Tristerix (subtribe Ligarinae) and all the genera of the subtribe Psittacanthinae, except Tripodanthus. The base of the style forms a nectary similar to that found in the sister genus Ligaria. This type of stylar nectary is of taxonomic value for grouping species of the subtribe Ligarinae and difers from the annular nectary of subtribe Psittacanthinae.

Collenchyma in Panicum maximum (Poaceae): localisation and possible role

2003 ◽  
Vol 51 (1) ◽  
pp. 69 ◽  
Author(s):  
Elder A. S. Paiva ◽  
Sílvia R. Machado
Keyword(s):  
Electron Microscopy ◽  
Leaf Blade ◽  
Sudden Change ◽  
Panicum Maximum ◽  
Vascular Bundles ◽  
Serial Sections ◽  
Adaxial Side ◽  
Transition Area ◽  
Transmission Electron ◽  
Phases Of Development

This work relates the occurrence and distribution of collenchyma in Panicum maximum Jacq. P.�maximum leaves were collected at different phases of development and sampled from both the base of the sheath and from the sheath–leaf blade transition area. For the stems, the study was made by using hand-cut sections of the internodal base. In the leaves, analyses of serial sections showed, at the base and sheath–leaf blade transition area, a sudden change of tissue at vascular bundle. The vascular bundles are surrounded by sclerenchyma, both in the sheath and the leaf blade, as well as by fibrous threads that occur on the adaxial side of the central bundles. However, at the base of the sheath and at the sheath–leaf blade transition area, sclerenchyma was substituted for collenchyma. In the stem, the substitution of sclerenchyma associated with vascular bundles for collenchyma occurs at the base of the internode, in the pulvinus region. The analyses from transmission electron microscopy showed the presence of lamellated cell wall and active protoplast in collenchyma cells.

Organogénèse de la fleur pistillée du Begonia dregei et de l’Hillebrandia sandwicensis (Begoniaceae)

1989 ◽  
Vol 67 (12) ◽  
pp. 3625-3639 ◽  
Author(s):  
Anne Charpentier ◽  
Luc Brouillet ◽  
Denis Barabé
Keyword(s):  
Vascular Anatomy ◽  
Pistillate Flower ◽  
Ovary Wall ◽  
Gradual Transition ◽  
Evolutionary Status ◽  
Developmental Study ◽  
Intermediate Structure ◽  
Inferior Ovary ◽  
Floral Apex ◽  
Mixed Nature

The pistillate flower organogenesis of Begonia dregei Otto Dietr. (section Augustia) and Hillebrandia sandwicensis Oliver is described. Vascular anatomy and scanning electron microscopy show that the inferior ovary of B. dregei develops below the perianth, whereas the semi-inferior ovary of H. sandwicensis grows both above and below the insertion level of the perianth. A developmental study of both species showed that placental tissues have a mixed nature: parietal placentae develop from the ovary wall, whereas axile placentae are derived from the floral apex, with a gradual transition zone between the two tissues. Depending on the rate of growth of the two placental regions, the ovary becomes mostly axile or parietal, all intermediates being possible. Our study does not allow us to determine unambiguously which of the two types of placentation is the most primitive. Also, it is impossible to clearly ascertain the evolutionary status of the semi-inferior ovary of H. sandwicensis. However, ontogenetic results allowed us to shed new light on the nature of the ovary wall in Begonia. One may hypothesize that it is an intermediate structure between axial and appendicular organs, difficult to compare directly with a set of fused carpels and perianth parts, as postulated by the classical theory of the flower.

Observations relatives au trajet du bois primaire dans la tige de Lyginopteris oldhamia Binney (Pteridospermees)

1962 ◽  
Vol S7-IV (1) ◽  
pp. 83-86
Author(s):  
Christiane Louvel
Keyword(s):  
Vascular Bundles ◽  
Serial Sections ◽  
Du Bois ◽  
Coal Measures

Abstract The Coal Measures of Shore Littleborough, England, contain coal balls with well-preserved pteridosperm stems belonging to the genus Lyginopteris. Serial sections of the stem of L. oldhamia reveal the presence of the phenomenon of anastomosis between the vascular bundles of the primary wood.

Organogénèse de la fleur de Symplocarpus foetidus (Araceae)

1987 ◽  
Vol 65 (3) ◽  
pp. 446-455 ◽  
Author(s):  
Denis Barabé ◽  
Suzanne Forget ◽  
Louise Chrétien
Keyword(s):  
Cylindrical Shape ◽  
Serial Sections ◽  
Flower Primordia ◽  
Inferior Ovary ◽  
Inflorescence Axis ◽  
Ovarian Cavity

The flowering cycle of Symplocarpus foetidus in volves 2 years. During the 1st year, the different flower parts are formed. The spadix, spherical at the beginning, elongates gradually to an ovoid–cylindrical shape. The flower primordia take a quadrangular shape when the four perianth parts and stamens are beginning to differentiate. In the first stages of its growth, the developing ovary is in a superior position. At the end of its growth, as a result of the type of development of the flower of Symplocarpus, it becomes completely inferior. Generally, at the end of the 1st year of the flowering cycle, the gynoecium consists of a small protuberance at the top of the unilocular ovarian cavity. During the 2nd year, the ovary closes and penetrates into the axis, the style forms, and the unique suborthotropic ovule develops. Our study of the flower's organogenesis shows that the inferior position of the ovary does not result from an invagination of the aerenchyma of the inflorescence axis although the ovary is completely enclosed in the axis of the inflorescence at maturity. The analysis of serial sections shows that the tissue of the flower originates from an organogenic zone distinct from the aerenchyma of the inflorescence axis. Symplocarpus is the only Araceae to possess an inferior ovary. The authors consider this genus to be an advanced genus in this family.

scholarly journals Micromorphology and anatomy of the flowers of Galanthus nivalis and Leucojum vernum (Amaryllidaceae)

2020 ◽  
Vol 11 (3) ◽  
Author(s):  
O. S. Fishchuk ◽  
A. V. Odintsova
Keyword(s):  
Cross Sections ◽  
Vascular System ◽  
Fleshy Fruit ◽  
Vascular Bundles ◽  
Inferior Ovary ◽  
Dorsal Vein ◽  
Poorly Differentiated ◽  
Galanthus Nivalis ◽  
Significant Addition ◽  
First Time

We studied the structure of flowers of Galanthus nivalis and Leucojum vernum using cross-sections and longitudal sections of permanent preparations using a light microscope. Genera Galanthus and Leucojum belong to the Galantheae tribe characterized by a unique combination of features of the family Amaryllidaceae, i.e. absence of septal nectaries, poricidal anthers and fruit – fleshy capsule. Both species are represented in the flora of Ukraine and have the life form of bulb ephemeroid of decidous forests. Microscopic surveys of flowers are considered as an instrument for determining yet unknown structural adaptations of plants to specialized ways of pollination and determining the first stages of morphogenesis of fruit, because many features of the fruit appear already at the stage of flower. We determined that the tepals of both studied species have multi-bundle traces of 8–9 vascular bundles. Apical dehiscence of the anthers occurs due to short longitudinal sutures in the upper part of the anthers. The nectar disk on the roof of the inferior ovary is poorly differentiated, and has no vascular bundles. We associate the indicated peculiarities of the flower structure with the offer of pollen as the main reward of the pollinator during buzz-polination, which has not reported for the studied species. Placentation is axile in the lower part of the ovary and parietal in the upper one. We consider that the gynoecium of the studied species is eusyncarpous. The vascular system of the inferior ovary is composed of three dorsal and three septal veins, paired ventral bundles of carpels, which form the traces of ovules, and also small additional bundles in the wall of the ovary. For the first time, we have determined the presence of airy parenchyma in the ovules, ovary roof, the style and anthers’ connectives and have confirmed their presence in the tepals and the wall of the ovary at the stage of flowering. We found differentiation of the mesocarp into photosynthesizing and airy parenchyma, small sizes of cells of the endocardium in the area of the dorsal vein, bifurcate dorsal bundles of the carpels, which could be considered as adaptation of different stages of morphogenesis of fruit to dehiscence. Anatomical peculiarities of the ovaries of G. nivalis and L. vernum: numerous vascular bundles in the pericarp, thick parenchyma mesocarp with air-filled cavities, non-lignified endocarp at the stage of the flower we consider adaptations to the formation of fleshy fruit. The new data we obtained on the anatomical structure of the flowers is a significant addition of information about anthecological and carpological (post-anthetic) peculiarities of the surveyed species.

scholarly journals Primary and secondary thickening in the stem of Cordyline fruticosa (Agavaceae)

2010 ◽  
Vol 82 (3) ◽  
pp. 653-662 ◽  
Author(s):  
Marina B. Cattai ◽  
Nanuza L. de Menezes
Keyword(s):  
Vascular Bundles ◽  
Vascular Cylinder ◽  
Serial Sections ◽  
Outermost Layer ◽  
Secondary Thickening ◽  
Innermost Layer ◽  
Cordyline Fruticosa

The growth in thickness of monocotyledon stems can be either primary, or primary and secondary. Most of the authors consider this thickening as a result of the PTM (Primary Thickening Meristem) and the STM (Secondary Thickening Meristem) activity. There are differences in the interpretation of which meristem would be responsible for primary thickening. In Cordyline fruticosa the procambium forms two types of vascular bundles: collateral leaf traces (with proto and metaxylem and proto and metaphloem), and concentric cauline bundles (with metaxylem and metaphloem). The procambium also forms the pericycle, the outermost layer of the vascular cylinder consisting of smaller and less intensely colored cells that are divided irregularly to form new vascular bundles. The pericycle continues the procambial activity, but only produces concentric cauline bundles. It was possible to conclude that the pericycle is responsible for the primary thickening of this species. Further away from the apex, the pericyclic cells undergo periclinal divisions and produce a meristematic layer: the secondary thickening meristem. The analysis of serial sections shows that the pericycle and STM are continuous in this species, and it is clear that the STM originates in the pericycle.The endodermis is acknowledged only as the innermost layer of the cortex.

Floral ontogeny and an interpretation of the inferior ovary in Agave parryi

1969 ◽  
Vol 47 (1) ◽  
pp. 23-26 ◽  
Author(s):  
H. Lloyd Mogensen
Keyword(s):  
Three Dimensional ◽  
Serial Sections ◽  
Floral Ontogeny ◽  
Inferior Ovary ◽  
Floral Primordia ◽  
Floral Vasculature

A study of the histogenesis of the flower of Agave parryi was made using serial sections as well as three-dimensional views of dissected floral primordia. It is shown that floral ontogeny supports the appendicular interpretation of the inferior ovary of Agave parryi in that the flower parts do not arise from a smooth, ring-like meristem located at the tip of the pedicel but, rather, the flower parts arise as separate primordia. This study corroborates an investigation by Kaplan which shows that ontogeny can be used to support, rather than contradict, floral vasculature in interpreting the appendicular nature of the inferior ovary.

STUDIES IN THE FLORAL MORPHOLOGY OF THE MARANTACEAE: I. VASCULAR ANATOMY OF THE FLOWER OF SCHUMANNIANTHUS VIRGATUS ROLFE, WITH SPECIAL REFERENCE TO THE LABELLUM

1966 ◽  
Vol 44 (10) ◽  
pp. 1365-1370 ◽  
Author(s):  
V. D. Tilak ◽  
R. M. Pai
Keyword(s):  
Special Reference ◽  
Floral Morphology ◽  
Floral Anatomy ◽  
Vascular Anatomy ◽  
Vascular Bundles ◽  
Inferior Ovary ◽  
Anatomical Evidence ◽  
Floral Whorls

The floral anatomy of Schumannianthus virgatus Rolfe is described in detail. Anatomical observations indicate fusion of vascular bundles of various floral whorls commensurate with their adnation, and, in that sense, the inferior ovary is considered to be appendicular in nature. Anatomical evidence demonstrates reduction in part of the labellum and of the functional stamen. The anther is one-celled. The labellum is shown to be a unitary organ representing an anterolateral member of the inner androecial whorl.

Floral morphology of the Amaryllidaceae. I. Subfamily Amaryllidioideae

1972 ◽  
Vol 50 (7) ◽  
pp. 1555-1565 ◽  
Author(s):  
V. Singh
Keyword(s):  
Floral Morphology ◽  
Vascular System ◽  
Vascular Supply ◽  
Vascular Strand ◽  
Vascular Bundles ◽  
Inferior Ovary ◽  
Three Bundles ◽  
Perianth Tube ◽  
Peculiar Mode

The flowers of the subfamily Amaryllidioideae are similar to one another in that they are fragrant, showy, bisexual, and epigynous with two trimerous whorls of perianth and stamens each, and a compound gynoecium. A single vascular strand supplies the vascular system of both a perianth member and a stamen. It splits into three bundles, one median and two laterals. The former constitutes the vascular supply of a perianth member, while the latter, facing one another right and left, fuse to supply a stamen. This peculiar mode of branching of the vascular strand is considered to be associated with superposition of a stamen upon a perianth member. The corona of Narcissus which is supplied by inversely oriented vascular bundles, is regarded as an outgrowth from the perianth tube and those of Eucharis and Pancratium, which are non-vascular, to represent the stamen cup. Two series of vascular strands differentiate in all members investigated. While the inner series constitutes the placental supply, the strands of the outer series which vary in number in different genera, show various degrees of adnation among the traces occurring on the same radius. The nature of the inferior ovary has been discussed. The nectaries are considered to be of quite advanced type.

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