scholarly journals Anatomy of the floral, bract, and foliar nectaries of Triumfetta semitriloba (Tiliaceae)

2005 ◽  
Vol 83 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Carlos André Espolador Leitão ◽  
Renata Maria Strozi Alves Meira ◽  
Aristéa Alves Azevedo ◽  
João Marcos de Araújo ◽  
Kellen Lagares Ferreira Silva ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Type A ◽  
Structural Features ◽  
Floral Bract ◽  
Secretory Structures ◽  
Floral Nectary ◽  
Foliar Anatomy ◽  
Weedy Species ◽  
Floral Nectaries

Triumfetta semitriloba Jacq. (Tiliaceae) is a tropical weedy species with floral nectaries and glands located at the margins of the leaves. The objectives of this work were to describe the anatomy of these secretory structures and to analyze their exudates. Sucrose, glucose, and fructose were identified in the product released by these secretory structures, characterizing them as nectaries. The nectaries of T. semitriloba are of a specialized type; a secretory epidermis comprised of pluricellular and multiserial nectariferous trichomes covers a nectariferous parenchyma, vascularized by phloem and xylem. A mass of phenolic compounds occurs in the head cells of the nectariferous trichomes of the foliar and bract nectaries; however, it is absent in trichomes of the floral nectary. The leaf and bract nectaries differed from those from flowers in their length and diameter. Structural features of the nectaries of T. semitriloba are typical of other taxa of the Malvales.Key words: foliar anatomy, histochemistry, Malvales, nectaries, Tiliaceae, Triumfetta semitriloba.

scholarly journals SAT-006 A New Concept for the Endocrinology of Pre-Eclampsia: The Role of Spiral Steroids

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Fred I Chasalow ◽  
Ron Bochner
Keyword(s):  
Type A ◽  
Structural Features ◽  
Type B ◽  
Salt Diet ◽  
Breast Cyst ◽  
High K ◽  
Epithelial Na Channels ◽  
Low Salt

Abstract Background: In 1987, Graves observed that during the 3rd trimester, some patients with pre-eclampsia had high levels of unknown materials that could be detected with assays for digoxin (DLM). In 2018, we characterized a new candidate for the DLM, Ionotropin. It is a phosphocholine (PC) ester of a novel steroid with 23 carbon atoms. As Ionotropin shares structural features (a) with spironolactone (both have spiral lactones in the E-ring) and (b) with digoxin (E-ring lactone and 3α-5β configuration), we have proposed that Ionotropin may function as a potassium (K+) sparing diuretic. This suggestion is supported by the observations that [1] patients who cannot make Ionotropin (7-dehydrosterol reductase deficiency) are K+ wasting and [2] breast cyst fluids with high K+ levels also have high Ionotropin levels. Hypothesis: During the 3rd trimester, fetal requirements for K+ reach a maximum, fetal blood pressure increases and aldosterone signaling is blocked. This blockage leads to fetal sodium (Na+) wasting and is essential for formation of amniotic fluid. These events are consistent with a normal role for an unknown endogenous K+ sparing hormone and would be the basis for a modest elevation of maternal DLM during the 3rd trimester. Our hypothesis is that if any of the functions were inadequate, then the fetal-placental unit would synthesize excess PC-spiral steroids; the woman would exhibit symptoms of K+ sparing hormone excess (hypertension and proteinuria) and would be diagnosed with pre-eclampsia. Experimental Results: We have just reported a pilot study associating elevated PC esters of spiral steroids in women with pre-eclampsia. In brief, 12 of 19 women had elevated levels of at least one of the PC steroids (Z-score > 2) when compared to the levels in 20 pregnant women matched for gestational age and fetal sex. There are two basic mechanisms for this dichotomy: (a) there may be episodic secretion with of a DLM with a short half-life or (b) there may be two different underlying biochemical causes. In prior studies, there has been no indication of episodic secretion of DLM similar to that observed with glucocorticoids, Ionotropin or other PC spiral steroids. Discussion: There are two basic types of K+ sparing diuretics. Type A: Spironolactone functions by regulating the NaK-ATPase. Type B: Triamterene functions by blocking synthesis of epithelial Na+ channels. Thus, Type A would have high levels of spiral steroids and Type B would have low levels of spiral steroids. Type A patients would be expected to have higher risk of long-term consequences when compared to the Type B patients. Conclusion: The recognition of the division of pre-eclampsia into two separate diseases might be the key observation for developing Type-specific diagnosis and therapy. For example, a Type A patient might benefit from a low salt diet but that diet would not be expected to benefit a patient with Type B disease.

Structure of floral nectaries and comparison of reproductive and vestigial organs in the staminate and pistillate flowers of dioecious Silene latifolia (Caryophyllaceae)

Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 1-21
Author(s):  
Jay F. Anderson ◽  
Hema S.N. Duddu ◽  
Steven J. Shirtliffe ◽  
Arthur R. Davis
Keyword(s):  
Tip Growth ◽  
Silene Latifolia ◽  
Dioecious Species ◽  
Future Studies ◽  
Reproductive Structures ◽  
Floral Nectary ◽  
Floral Nectaries ◽  
Pollen Release ◽  
Stigmatic Papillae ◽  
Scanning Electron

Silene latifolia Poiret of Eurasia has established in North America, prompting this structural study of its mature unisexual buds and flowers. Floral nectaries, anther and stigma changes, and vestigial reproductive structures were studied using light and scanning electron microscopy. In staminate flowers, anthers dehisced before anthesis and >90% of their pollen was liberated within 36 h. Accumulated in the tubular calyx, nectar descended an anthophore from the stomatal-bearing nectary at the stamen bases. Nectary tissue surrounded the pistillode, a central filamentous organ lacking ovules but tipped by hairs resembling stigmatic papillae. In pistillate flowers, nectar flowed into an inflated calyx. The annular nectary had 10 regularly spaced, stomatal-lined craters and was continuous with the adaxial surfaces of the infertile antisepalous and epipetalous staminodes. Key elements of entomophilous pollination leading to successful sexual reproduction of this invasive species include secondary nectar presentation from disparate floral nectaries that, for pistillate flowers, also incorporate the staminodes; rapid pollen release from anthers; and elongation of papillae by tip growth that enhances each stigma’s receptive surface. Context is also provided for future studies of floral nectary development in this model dioecious species.

scholarly journals Structural Revisions in Natural Ellagitannins

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1901 ◽  
Author(s):  
Hidetoshi Yamada ◽  
Shinnosuke Wakamori ◽  
Tsukasa Hirokane ◽  
Kazutada Ikeuchi ◽  
Shintaro Matsumoto
Keyword(s):  
Phenolic Compounds ◽  
Biological Activities ◽  
Structural Diversity ◽  
Structural Features ◽  
Complex Structures ◽  
Structural Determination ◽  
Major Focus ◽  
Chebulagic Acid ◽  
Potential Applications

Ellagitannins are literally a class of tannins. Triggered by the oxidation of the phenolic parts on β-pentagalloyl-d-glucose, ellagitannins are generated through various structural conversions, such as the coupling of the phenolic parts, oxidation to highly complex structures, and the formation of dimer and lager analogs, which expand the structural diversity. To date, more than 1000 natural ellagitannins have been identified. Since these phenolic compounds exhibit a variety of biological activities, ellagitannins have potential applications in medicine and health enhancement. Within the context of identifying suitable applications, considerations need to be based on correct structural features. This review describes the structural revisions of 32 natural ellagitannins, namely alnusiin; alnusnin A and B; castalagin; castalin; casuarinin; cercidinin A and B; chebulagic acid; chebulinic acid; corilagin; geraniin; isoterchebin; nobotanin B, C, E, G, H, I, J, and K; punicalagin; punicalin; punigluconin; roxbin B; sanguiin H-2, H-3, and H-6; stachyurin; terchebin; vescalagin; and vescalin. The major focus is on the outline of the initial structural determination, on the processes to find the errors in the structure, and on the methods for the revision of the structure.

Vasculature and ultrastructure of the floral and stipular nectaries of Vicia faba (Leguminosae)

1988 ◽  
Vol 66 (7) ◽  
pp. 1435-1448 ◽  
Author(s):  
A. R. Davis ◽  
R. L. Peterson ◽  
R. W. Shuel
Keyword(s):  
Vicia Faba ◽  
Broad Bean ◽  
Field Bean ◽  
Extrafloral Nectary ◽  
Abaxial Surface ◽  
Floral Nectary ◽  
Ultrastructural Evidence ◽  
Companion Cells ◽  
Vicia Faba L ◽  
Floral Nectaries

The floral nectary of Vicia faba L. (faba bean, broad bean, or field bean) consists of a disk which bears a long, basal, tapered projection. Large, open stomata, located at the tip of the projection, probably serve as exits for nectar. Phloem is present in the floral nectary. The extrafloral nectary consists of numerous secretory and nonsecretory trichomes aggregated on the abaxial surface of each stipule. Both xylem and phloem are present in the stipule beneath the extrafloral nectary. In both nectary types, large companion cells accompany the phloem. Epidermal and parenchyma cells of the floral gland, as well as the companion cells, develop wall ingrowths and are therefore transfer cells. Ultrastructural evidence suggests a granulocrine mechanism of nectar secretion in the floral nectary, wherein both apoplastic and symplastic routes for prenectar movement and escape appear feasible. Floral and extrafloral nectar differ in sugar concentration and in the predominance of sucrose, both of which are higher in exudate from floral nectaries.

Depositional models for moraine formation in East Antarctic coastal oases

1997 ◽  
Vol 43 (144) ◽  
pp. 256-264 ◽  
Author(s):  
Sean J. Fitzsimons
Keyword(s):  
Type A ◽  
Structural Features ◽  
Type B ◽  
Debris Accumulation ◽  
Type D ◽  
Unconsolidated Sediment ◽  
History Of ◽  
Quaternary History ◽  
Type C ◽  
Depositional Models

AbstractThis paper examines the origin of moraine ridges in East Antarctic coastal oases and derives depositional models appropriate for the reconstruction of Quaternary history. On the basis of morphology, structure and sedimentology, four principal types of ridge may be identified: (1) type A moraines from when the basal debris zone crops out near an ice margin; (2) type B moraines form when large recumbent folds develop in the basal debris zone; (3) type C moraines are ice-contact screes and fans which form when debris accumulates at steep or cliffed ice margins; and (4) type D moraines are thrust-block moraines that form when unconsolidated sediment is entrained by freezing, shearing and thrusting of sediment blocks at the base of the glacier. Simple calculations of the rate of debris accumulation at ice margins suggest that type A, B and C moraines take thousands of years to form and record stable ice margins. Type D moraines are structural features that may form relatively quickly when ice margins override unconsolidated sediment. Constructing models to explain the origin of the moraines is an important part of reconstructing the Quaternary history of Antarctic coastal oases, because the models provide a basis for reconstructing the position and behaviour of the ice sheet during advance and retreat

Comparative Foliar Anatomy of South American Proteaceae

1998 ◽  
Vol 46 (4) ◽  
pp. 357 ◽  
Author(s):  
Fresia Torres
Keyword(s):  
South America ◽  
Structural Features ◽  
South American ◽  
Natural Group ◽  
Foliar Anatomy ◽  
Gevuina Avellana ◽  
The Family ◽  
Phylogenetic Origin ◽  
Individual Features

The family Proteaceae Knight is represented in South America by over 100 species that belong to eight genera, all Grevilleoideae. Nine species that represent all of the tribes established by Johnson and Briggs (1975) that occur in South America were studied: Embothrium coccineum, Lomatia dentata, L. ferruginea, L. hirsuta, Gevuina avellana, Roupala mollis, R. montana, Panopsis polystachia and Orites myrtoidea. We found anatomical and structural similarities between these species and the taxonomic scheme proposed by Johnson and Briggs (1975). In the Embothrieae, each species of Lomatiinae exhibits individual structural features, although in every case, there is at least one or more feature shared with the Embothriinae; suggesting a common phylogenetic origin, whereas E. coccineum preserves a larger number of ancestral features. Of the three subtribes of Macadamineae, the Roupalinae are a natural group with individual features, the Gevuininae share a few characters with the Lomatiinae and the Macadamiinae with the Oriteae. This last one is the most peculiar, although it shares a few characters with Embothrieae and Macadamieae.

scholarly journals Depositional models for moraine formation in East Antarctic coastal oases

1997 ◽  
Vol 43 (144) ◽  
pp. 256-264
Author(s):  
Sean J. Fitzsimons
Keyword(s):  
Type A ◽  
Structural Features ◽  
Type B ◽  
Debris Accumulation ◽  
Type D ◽  
Unconsolidated Sediment ◽  
History Of ◽  
Quaternary History ◽  
Type C ◽  
Depositional Models

AbstractThis paper examines the origin of moraine ridges in East Antarctic coastal oases and derives depositional models appropriate for the reconstruction of Quaternary history. On the basis of morphology, structure and sedimentology, four principal types of ridge may be identified: (1) type A moraines from when the basal debris zone crops out near an ice margin; (2) type B moraines form when large recumbent folds develop in the basal debris zone; (3) type C moraines are ice-contact screes and fans which form when debris accumulates at steep or cliffed ice margins; and (4) type D moraines are thrust-block moraines that form when unconsolidated sediment is entrained by freezing, shearing and thrusting of sediment blocks at the base of the glacier. Simple calculations of the rate of debris accumulation at ice margins suggest that type A, B and C moraines take thousands of years to form and record stable ice margins. Type D moraines are structural features that may form relatively quickly when ice margins override unconsolidated sediment. Constructing models to explain the origin of the moraines is an important part of reconstructing the Quaternary history of Antarctic coastal oases, because the models provide a basis for reconstructing the position and behaviour of the ice sheet during advance and retreat

scholarly journals Pollination and Floral Biology of a Rare Morning Glory Species Endemic to Thailand, Argyreia siamensis

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2402
Author(s):  
Awapa Jirabanjongjit ◽  
Paweena Traiperm ◽  
Tomoki Sando ◽  
Alyssa B. Stewart
Keyword(s):  
Mating System ◽  
Floral Biology ◽  
Morning Glory ◽  
Pollinator Attraction ◽  
Secretory Structures ◽  
Floral Nectary ◽  
Population Sizes ◽  
Nectariferous Tissue ◽  
Effective Pollinators ◽  
Two Populations

Argyreia siamensis is extremely rare, and very little is known about its reproduction. The species has colorful flowers that seem likely to attract pollinators, but population sizes are typically small (<30 individuals). To determine whether poor reproduction contributes to its rarity, we investigated its mating system and potential pollinators in two populations. We also examined the staminal trichomes and floral nectary to investigate their role in pollinator attraction. The mating system was assessed with a bagging experiment and pollinator visits were recorded with action cameras. Additionally, we tested the staminal trichomes and floral nectary for terpenes and flavonoids and examined floral nectary micromorphology via scanning electron microscope and compound light microscope. Our results reveal that A. siamensis is self-incompatible and dependent on pollinators; the western population was pollinated by bees (Meliponini and Amegilla), while the eastern population was mainly pollinated by skipper butterflies (Hesperiidae). Both staminal trichomes and the floral nectary appear to contribute to pollinator attraction through the presence of terpenes and flavonoids (in both secretory structures) and nectariferous tissue and nectarostomata (in the nectary). Our results indicate that A. siamensis has reliable and effective pollinators and that insufficient pollination is likely not a primary cause of its rarity.

Sign in / Sign up

Export Citation Format

Share Document