scholarly journals МІКРОМОРФОЛОГІЯ ТА АНАТОМІЯ КВІТКИ LEUCOJUM AESTIVUM L. (AMARYLLIDACEAE J. ST.-HIL.)

2020 ◽  
Vol 80 (3-4) ◽  
pp. 26-33
Author(s):  
O. S. Fishchuk
Keyword(s):  
Ovary Wall ◽  
Structural Basis ◽  
Single Bundle ◽  
Vascular Bundles ◽  
Early Stages ◽  
Dorsal Vein ◽  
Leucojum Aestivum ◽  
Inner Circle

In the gynoecium of L. aestivum there are synascidiate, hemisynascidiate, symplicate, and asymplicate vertical zones. The longest zone is the fertile hemisynascidiate zone and the shortest is the synascidiate zone in the ovary. It was discovered that in L. aestivum the peduncle consists of 12 vascular bundles, which are reorganized into two circles of bundles, the outer with massive leading bundles, departing as dorsal bundles of perianth, traces of perianth tepals and septal bundles of carpels and inner circle of bundles over the nests are divided into three groups of ventral carpel bundles are lined up on four, which are located in the center of the ovary and providing nutrition to the ovules. Dorsal carpels bundles are double. Above the locule, ventral bundles of the carpel, as well as the double septal bundles, merge with the dorsal bundles and form a dorsal vein. The outer tepals of the simple perianth have nine vascular traces, and the inner tepals of the perianth have eight vascular traces. Traces of stamens are single-bundle, formed from traces of perianth tepals. The ovary has features of the early stages of fruit morphogenesis and adaptation to disclosure, such as differentiation of mesocarp and endocarp cells, double dorsal bundles of carpels. Structural flower features related to pollen proposal as reward pollinators. Since ovary is a structural basis of the fruit, histological ovary wall differentiation reflects the features of the subsequent morphogenesis of the fruit.

scholarly journals Three-dimensional analysis of synaptic organization in the hippocampal CA1 field in Alzheimer’s disease

Brain ◽  
2020 ◽  
Author(s):  
Marta Montero-Crespo ◽  
Marta Domínguez-Álvaro ◽  
Lidia Alonso-Nanclares ◽  
Javier DeFelipe ◽  
Lidia Blazquez-Llorca
Keyword(s):  
Electron Microscopy ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Cortical Atrophy ◽  
Structural Basis ◽  
Synaptic Organization ◽  
Synaptic Density ◽  
Early Stages ◽  
Late Stages

Abstract Alzheimer’s disease is the most common form of dementia, characterized by a persistent and progressive impairment of cognitive functions. Alzheimer’s disease is typically associated with extracellular deposits of amyloid-β peptide and accumulation of abnormally phosphorylated tau protein inside neurons (amyloid-β and neurofibrillary pathologies). It has been proposed that these pathologies cause neuronal degeneration and synaptic alterations, which are thought to constitute the major neurobiological basis of cognitive dysfunction in Alzheimer’s disease. The hippocampal formation is especially vulnerable in the early stages of Alzheimer’s disease. However, the vast majority of electron microscopy studies have been performed in animal models. In the present study, we performed an extensive 3D study of the neuropil to investigate the synaptic organization in the stratum pyramidale and radiatum in the CA1 field of Alzheimer’s disease cases with different stages of the disease, using focused ion beam/scanning electron microscopy (FIB/SEM). In cases with early stages of Alzheimer’s disease, the synapse morphology looks normal and we observed no significant differences between control and Alzheimer’s disease cases regarding the synaptic density, the ratio of excitatory and inhibitory synapses, or the spatial distribution of synapses. However, differences in the distribution of postsynaptic targets and synaptic shapes were found. Furthermore, a lower proportion of larger excitatory synapses in both strata were found in Alzheimer’s disease cases. Individuals in late stages of the disease suffered the most severe synaptic alterations, including a decrease in synaptic density and morphological alterations of the remaining synapses. Since Alzheimer’s disease cases show cortical atrophy, our data indicate a reduction in the total number (but not the density) of synapses at early stages of the disease, with this reduction being much more accentuated in subjects with late stages of Alzheimer’s disease. The observed synaptic alterations may represent a structural basis for the progressive learning and memory dysfunctions seen in Alzheimer’s disease cases.

Berry pericarp ontogenesis from fertilization to maturity of Vitis vinifera L. var Merlot

OENO One ◽  
1997 ◽  
Vol 31 (3) ◽  
pp. 109 ◽  
Author(s):  
Monique Fougère-Rifot ◽  
H.-S. Park ◽  
Jacques Bouard
Keyword(s):  
Cell Number ◽  
Grape Berry ◽  
Ovary Wall ◽  
Vascular Bundles ◽  
Berry Skin ◽  
Wall Thinning ◽  
Fruit Setting ◽  
Parenchyma Cells ◽  
Pulp Cells ◽  
The One

<p style="text-align: justify;">Grape-flower ovary transformations is followed from fertilized flower to berry came to maturity. Cell transformations are studied, especially vacuolar tannins, starch and cell wall thinning :</p><p style="text-align: justify;">- From fruit setting to veraison, cell number of carpellary wall located between outer epidennis and vascular bundles is multiplied by 2.</p><p style="text-align: justify;">- Cell size increase considerably but by different means according to tissues: hypodennis cells elongate tangentially while inner parenchyma cells round.</p><p style="text-align: justify;">- Vacuolar tannins content in internal parenchyma cells decrease as soon as ovary is fertilized. During growth and veraison tannic cell number decrease. At maturity, only the most external cells (superficial hypodennis) still have vacuolar tannins. All the other cells of ovary wall have no more tannins.</p><p style="text-align: justify;">- Wall thickness decrease begins as soon as growth starts and this phenomena is continuous to maturity. The wall thinning down begins near the locules of ovary and is propagated towards the ouside of pericarp.</p><p style="text-align: justify;">- Amyloplasts disappear progressively. At maturity, there is scarcely no more startch in grape-berry.</p><p style="text-align: justify;">In short, except cells of berry skin, all the cells of ovary wall enlarge, lost their vacuolar tannins and the cell walls become very thin ; they are pulp cells.</p><p style="text-align: justify;">ln the pericarp of mature berry, hypodennis is very thin (less than 50 μm in places and 2-5 layers of cells). Pulp or flesh takes up a great place.</p><p style="text-align: justify;">This work is consecutived to the one on ovary before fertilization (FOUGÈRE-RIFOT et al., 1995) that shown 20 development stages from ovary primordia to the fertilized egg. From fertilized ovary to mature berry the development of pericarp is divided into 5 stages (stages 21 to 25) :</p><p style="text-align: justify;">- Stage 21 : first appearance of ovary inflation. Ovary takes a round shape. The thickness of carpellary wall is about 300 μm.</p><p style="text-align: justify;">- Stage 22 : fruit setting. Vacuolar tannins of inner parenchym disappear.</p><p style="text-align: justify;">- Stage 23 : berry growth.</p><p style="text-align: justify;">- Stage 23A : transformation of inner parenchym into pulp.</p><p style="text-align: justify;">- Stage 238 : transformation of deep hypodennis into pulp</p><p style="text-align: justify;">- Stage 23C : pulp cell enlargement.</p><p style="text-align: justify;">- Stage 24 : veraison. The definitive size of the berry is about reached.</p><p style="text-align: justify;">- Stage 24A : beginning of veraison. The hypodermis has still some thick walls.</p><p style="text-align: justify;">- Stage 248 : end of veraison. The hypodennis cells near the outer pulp cells change into pulp cells</p><p style="text-align: justify;">- Stage 25: maturity. Pulp is became very developped.</p>

Some histochemical features of anther wall of Leucojum aestivum (Amaryllidaceae) during pollen development

Biologia ◽  
2012 ◽  
Vol 67 (5) ◽  
Author(s):  
Nuran Ekici ◽  
Feruzan Dane
Keyword(s):  
Cell Walls ◽  
Cell Activation ◽  
Developmental Stages ◽  
Middle Layer ◽  
Point Of View ◽  
Anther Wall ◽  
Vascular Bundles ◽  
Thin Sections ◽  
Leucojum Aestivum ◽  
Rna Content

AbstractIn this study, polysaccharide and RNA contents of anthers were investigated on different phases of sporogenesis by using light microscopy techniques from histological and cytological point of view in Leucojum aestivum. Paraffin and semi-thin sections of anthers were stained with toluidine blue and PAS. Anthers were tetrasporangiate. The wall of the anther consists of an epidermis, endothecium, middle layer and glandular tapetum. During one nucleated microspore and mature pollen phase microspores and tapetum cells began to degenerate and they were become very rich of RNA in L. aestivum. And also RNA content was increased in endothecium and middle layer cells except the epidermis cells of anther wall. An increase in RNA content indicates cell activation. Polysaccharides were not seen in young anther wall but they were seen in older ones. They were generally condensed in the cell walls and especially in the cell walls of vascular bundles of connective tissue. This could be thought that insoluble polysaccharides were used in metabolic events in early developmental stages. Appearance of polysaccharides in late phases was indicated that polysaccharides were used in the formation of cuticule and differentiation of endothelium cell walls.

scholarly journals Micromorphology and Anatomy of the Flowers in Clivia spp. and Scadoxus multiflorus (Haemantheae, Amaryllidaceae)

2021 ◽  
Vol 74 ◽  
Author(s):  
Oksana Fishchuk ◽  
Anastasiya Odintsova
Keyword(s):  
Light Microscopy ◽  
Lower Portion ◽  
Ovary Wall ◽  
Fleshy Fruit ◽  
Vascular Bundles ◽  
Common Pattern ◽  
General Morphology ◽  
Secretory Tissue ◽  
Clivia Miniata ◽  
Micromorphology And Anatomy

Abstract The general morphology, micromorphology, and anatomy of the flowers of Clivia miniata , Clivia nobilis , and Scadoxus multiflorus were studied using light microscopy. The studied species have large syntepalous and trimerous flowers, short floral tubes with adnate stamens, and inferior ovaries that develop baccate fruit. The gynoecium in the studied species consists of synascidiate, symplicate, and hemisymplicate zones. The style is composed of postgenitally fused carpels. The few ovules are located in a locule in the synascidiate and symplicate zones in C. miniata and C. nobilis , whereas in S. multiflorus , solitary ovules occupy the synascidiate zone in each locule. The septal nectaries are located in the hemisymplicate zone and occupy the uppermost 29% to 56% of the ovary height. Septal nectaries are of the nonlabyrinthine lilioid-type, covered with secretory tissue only in its lower portion. Nectary channels are apical or subapical and open near the style base. A common pattern of the venation of the floral parts was observed in all species: Tepal traces and stamen traces were fused in the ovary wall, the style was supplied by dorsal carpellary bundles, and ovules were supplied by ventral carpellary bundles entering the ovary from the bottom. The observed gynoecium inner structure provides adaptations for the development of fleshy fruit, with thickened parenchymous ovary wall, ovary base, and ovary roof, and numerous branched vascular bundles in the ovary wall around locules.

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.

Cambial Variant in the Stem of Serjania Corrugata (Sapindaceae)

IAWA Journal ◽  
2006 ◽  
Vol 27 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Gabriel U.C. Araújo ◽  
Cecilia G. Costa
Keyword(s):  
Cross Section ◽  
Vascular Bundle ◽  
Vascular Ring ◽  
Cambial Activity ◽  
Vascular Bundles ◽  
Stages Of Development ◽  
Early Stages ◽  
Meristematic Activity ◽  
Cambial Variant

The establishment of the cambial variant and the development of the stem of Serjania corrugata Radlk. (Sapindaceae) was analyzed. In the early stages of development, the stem is lobed, with five lobes and five furrows in cross section. Around the fourth internode, each lobe has a vascular arc with one or two more developed central vascular bundles, two lateral bundles and phloem in the interfascicular regions. Procambial strands are also found in perimedullary position, producing only phloem elements. At this stage, the beginning of the cambial activity can be seen in the central vascular bundle in each lobe. This activity then extends to the lateral vascular bundles and to the perimedullary phloem. Parenchymatic cells, located between the vascular ring of the lobe and the perimedullary phloem, dedifferentiate and initiate meristematic activity, uniting these two regions. The development of xylem masses (one in each lobe) that characterizes the adult stem results from this cambial activity. The development of the cambial variant in S. corrugata is quite similar to that previously described in S. elegans Cambess.

scholarly journals Comparative flower morphology of Agapanthus africanus and A. praecox (Amaryllidaceae)

2021 ◽  
Vol 12 (4) ◽  
pp. 620-627
Author(s):  
O. S. Fishchuk
Keyword(s):  
Vascular System ◽  
Vascular Anatomy ◽  
Flower Morphology ◽  
Single Bundle ◽  
Serial Sectioning ◽  
Cross Sectional ◽  
Standard Methods ◽  
Dorsal Vein ◽  
The Family ◽  
First Time

The structure of Agapanthus africanus and A. praecox flowers was studied on permanent cross-sectional and longitudinal sections using a light microscope. The genus Agapanthus belongs to the subfamily Agapanthoideae, the family Amaryllidaceae, which is characterized by the presence of the upper ovary, septal nectaries and fruit – fleshy capsule. Micromorphological studies of the flower are considered as a way for detection of unknown plant features, adjustment of plants to specialized ways of pollination and determining the first stages of morphogenesis of fruit, and further use these features in taxonomy. 10 flowers of A. africanus and A. praecox were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 micron thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. It was found that in the studied species the tepals have single-bundle traces. The vascular system of the superior ovary consists of a three bundle dorsal vein, of the ventral roots complex, which are reorganized into paired ventral bundles of the carpel, which form traces to ovules. For the first time, the following gynoecium zones were detected in A. africanus: a synascidiate structural zone with a height of about 560 μm and a fertile symplicate structural zone with a height of about 380 μm and a hemisymplicate zone of 2580 μm. In A. praecox gynoecium, there is a synascidiate structural zone with a height of 200 μm and a symplicate structural zone of 600 μm and a hemisymplicate zone of 620 μm. Septal nectaries appear in the hemisymplicate zone and open with nectar fissures at the base of the column, with a total septal nectar height of 2880 μm in A. africanus and 820 μm in A. praecox. The ovary roof is 300 µm in A. africanus and 200 µm in A. praecox. Triple dorsal bundles of carpels in A. africanus have been identified, which could be considered as adaptation of different stages of morphogenesis of fruit to dehiscence. The new data obtained by the vascular anatomy of the flower and the presence of different ovary zones significantly add to the information about anatomical and morphological features of the studied species, which can be further used in the taxonomy of the family Amaryllidaceae.

Anatomical features at the disarticulation zone in florets of fatuoid and nonfatuoid oat (Avena sativa L.)

2001 ◽  
Vol 79 (12) ◽  
pp. 1409-1416 ◽  
Author(s):  
G J Hoekstra ◽  
S J Darbyshire ◽  
D E Mather
Keyword(s):  
Avena Sativa ◽  
Small Cells ◽  
Vascular Bundles ◽  
Stages Of Development ◽  
Abscission Layer ◽  
Anatomical Features ◽  
Early Stages ◽  
Anatomical Basis

In oat (Avena sativa L.), the manner by which mature florets separate from the inflorescence depends on whether the plant is fatuoid or nonfatuoid and on whether it has naked or hulled grain. The anatomical basis for these differences is not well understood. Here, anatomical features were examined at the intersection of rachilla and lemma callus (disarticulation zone) in florets of fatuoid hulled-grain oat, which "shatter", and of nonfatuoid hulled-grain oat, fatuoid naked-grain oat, and nonfatuoid naked-grain oat, none of which shatter. A layer of one to several rows of small, thick-walled cells usually occurred at the disarticulation zone of fatuoid hulled-grain florets. This layer was less frequently observed at the disarticulation zone of nonfatuoid florets or fatuoid naked-grain florets. Visible at the early stages of development, these rows of small cells apparently form an abscission layer in mature florets of hulled-grain fatuoids. Disarticulation of florets is further assisted by the disintegration of medial parenchyma tissues of the lemma callus, resulting in the formation of lacunae around the vascular bundles. Although a layer of small cells in the disarticulation zone was often seen in mature fatuoid naked-grain florets, it did not function as an abscission layer.Key words: Avena, oat, fatuoid, disarticulation, abscission, shattering.

Pistil Structure of Banksia menziesii R.Br. (Proteaceae) in Relation to Fertility

1993 ◽  
Vol 41 (5) ◽  
pp. 481 ◽  
Author(s):  
SC Clifford ◽  
M Sedgley
Keyword(s):  
Distal Portion ◽  
Transfer Cells ◽  
Low Fertility ◽  
Structural Basis ◽  
Vascular Bundles ◽  
Transmitting Tract ◽  
Internal Morphology

The morphology and histochemistry of the pistil of Banksia menziesii were studied to determine whether the observed low fertility of the species has a structural basis. The distal portion of the style, the pollen presenter, was distinct in both external and internal morphology from the remainder of the style. It was an elongated structure with eight longitudinal ridges, a swollen base, and with pollen-receptive stigma cells enclosed within a groove located at its tip. The stigma was wet papillate, and was covered with a lipidic secretion overlying polysaccharide-rich mucilage. Below the groove, the solid transmitting tract comprised a few thick-walled cells surrounded by numerous transfer cells, and vascular bundles associated with sclerenchyma. The style immediately below the pollen presenter was constricted, and the transfer cells ended in this region. The upper stylar cortex consisted largely of sclerenchyma, and the transmitting tract narrowed towards the base, comprising only 10.9 ± 0.3 cells at the junction with the ovary. The ovary contained two ovules, both of which were functional at anthesis, although the upper ovule developed more quickly than the lower. The inflorescence consisted of over 700 flowers, of which 2.5 ± 0.2% had short styles and pollen presenters with exposed stigma papillae. Apart from this, there was no variation in pistil structure which would explain the observed low fertility.

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