Pollen Presenter Morphology and Anatomy in Banksia and Dryandra

1996 ◽  
Vol 44 (4) ◽  
pp. 447 ◽  
Author(s):  
PG Ladd ◽  
AJ Alkema ◽  
GJ Thomson
Keyword(s):  
Lower Proportion ◽  
Epidermal Cells ◽  
The Other ◽  
Transmitting Tissue ◽  
Pollination Success ◽  
Cell Layers ◽  
Thin Walled

Style shape, and pollen presenter morphology and anatomy, are similar in Banksia L.f, and Dryandra R.Br. There are four style shapes-straight, bowed, s-shaped and hooked. However, in Dryandra, s-shaped and hooked styles are uncommon. The stigma in all cases is contained within the pollen presenter, but there is variation in the location of the stigmatic groove on the presenter, from truly apical (terminal), obliquely terminal to rarely located at the base of the presenter as in B. ericifolia. There is also variation in whether the pollen is deposited over the stigmatic groove in bud or the slit is free of pollen at anthesis. In Banksia, 73% of species studied have the groove covered with pollen, while in Dryandra, a somewhat lower proportion of species (50%) has this configuration. Pollen cohesion on the presenter varies from sticky to loose but is mostly slightly sticky. Similar pollen presenter forms occur in both genera, but in Dryandra, the generally less elaborate shapes are more frequent than is the case in Banksia. Anatomically, the pollen presenters are quite complex, with several cell layers concentrically disposed around the central transmitting tissue. There is considerable variation in the epidermal cells of the presenters between species. In most, the cells are small and thick-walled, but in B. ilicifolia, they are very thin-walled and enlarged into elongated projections. Similar forms occur in other species. In B. tricuspis, the epidermal cells are enlarged, regularly rounded in shape and become smaller and thick-walled near the stigmatic groove. Underlying the epidermis, polyphenol-containing cells and sclerenchyma vary in proportion between species and also in their location within the presenter. The variation in wall characteristics of epidermal cells and the proportion of sclerenchyma in different species is likely to be related to maximising pollination success within an environment containing a variety of pollinator behaviours. Although vertebrates are important in pollinating many species, invertebrates are likely to be the primary pollinators of a significant number of the other species in both genera.

TELIOSPORE DEVELOPMENT IN THE PUCCINIASTREAE

1933 ◽  
Vol 9 (5) ◽  
pp. 458-485 ◽  
Author(s):  
S. M. Pady
Keyword(s):  
Epidermal Cells ◽  
The Other ◽  
General Situation ◽  
Thin Walled ◽  
Primordial Cell ◽  
Teliospore Development

The genera that constitute the Pucciniastreae display a wide variation in the type of teliospore produced, as well as in the time and place of production. From the standpoint of development, however, there is a general situation that is common. In all genera primordial cells are formed from enlarged hyphal cells of the mycelium. These give rise to teliospore initials which are in the epidermal cells in Calyptospora, Milesia, Hyalopsora and Thecopsora, and are subepidermal in the other genera. These initials divide to form the mature teliospores, which are thick or thin walled, and few to many-celled. In all cases the teliospore is the product of a single primordial cell.The teliospores of Calyptospora goeppertiana are formed from a perennial mycelium, which causes a witches' broom and hypertrophied stems on species of Vaccinium. The mycelium gives rise to primordial cells in the cortex just below the epidermis. Each primordial cell pierces the host wall above and the contents pass in to form the initial, which by growth and division becomes the teliospore. The mature teliospores are one- to four-celled, with a thickened, dark brown wall. Development is not simultaneous, but progressive, and the teliospores are first formed in the basal parts, moving slowly upward until every cell of the hypertrophied portion of the stem is completely filled. In four species of Milesia the method of development is similar. The spores, however, are thin walled, and are formed in the epidermal cells of the overwintered fronds of their fern hosts. Thecopsora vacciniorum is similar to Milesia in many respects. The teliospores are intra-epidermal, thin walled and multicellular. In Pucciniastrum the teliospores are subepidermal, and arise from primordial cells, as in Calyptospora, Milesia and Thecopsora. The teliospore initials are closely packed, and the mature spores may form extended crusts. The simplest type of development is found in Uredinopsis, which is generally considered to be the most primitive of the fern rusts. Primordial cells are formed in the same way as in the other genera. These round up to form the initials, and cross walls are laid down to give the mature spores.From these studies two possible lines of development are suggested, both beginning with Uredinopsis. One line would lead through the intra-epidermal forms, as Milesia, Calyptospora, etc., and the other through the subepidermal genera, as Pucciniastrum and Melampsoridium.

Penetration and growth of compatible and incompatible races of Phytophthora megasperma var. sojae in soybean hypocotyl tissues differing in age

1980 ◽  
Vol 58 (24) ◽  
pp. 2594-2601 ◽  
Author(s):  
P. Stössel ◽  
G. Lazarovits ◽  
E. W. B. Ward
Keyword(s):  
Glycine Max ◽  
Epidermal Cells ◽  
Mechanisms Of Resistance ◽  
Hypocotyl Growth ◽  
Phytophthora Megasperma ◽  
Cell Layers ◽  
Glycine Max L ◽  
Incompatible Reaction ◽  
Race 4 ◽  
Incompatible Interactions

Intact 6-day old soybean hypocotyls (Glycine max L., cv. Altona) were inoculated with zoospores of Phytophthora megasperma Drechs. var. sojae Hildeb. either at the top (susceptible to compatible races, resistant to incompatible races) or the bottom (resistant to both compatible and incompatible races) and, after a 22-h incubation, were examined by light microscopy. Penetration at the top and bottom by both compatible (race 6) and incompatible (race 4) P. megasperma var. sojae was predominantly between anticlinal walls of epidermal cells. Both races, but especially race 4, also penetrated directly into the outer walls of epidermal cells, but epidermal cells rarely were invaded. Both races grew mainly intercellularly, but race 6 produced haustoria more frequently than race 4. Race 6 haustoria at the top of the hypocotyl were usually encased, those of race 4 were not. Growth of both races was equally dense in the first few cell layers, but the numbers of race 4 hyphae decreased rapidly while those of race 6 became more abundant in the deeper layers. With race 4, but not with race 6, most cells in the infected tissue were necrotic. Differences between the compatible and the incompatible interactions were not absolute; there were many unsuccessful invasion attempts by race 6 and individual hyphae of race 4 spread deeply into the tissue. At the bottom of the hypocotyl, growth of both races was more restricted. Race 6 produced fewer haustoria than at the top, and similarities to the incompatible reaction with race 4 at the top suggest that similar mechanisms of resistance may be involved.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

Non-cell-autonomous function of the Antirrhinum floral homeotic proteins DEFICIENS and GLOBOSA is exerted by their polar cell-to-cell trafficking

Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3433-3441 ◽  
Author(s):  
M.C. Perbal ◽  
G. Haughn ◽  
H. Saedler ◽  
Z. Schwarz-Sommer
Keyword(s):  
Cell Layer ◽  
Epidermal Cells ◽  
Molecular Techniques ◽  
Cell Trafficking ◽  
Mads Box ◽  
Organ Identity ◽  
Cell Layers ◽  
Periclinal Chimeras ◽  
The Difference ◽  
Cell Autonomy

In Antirrhinum majus, petal and stamen organ identity is controlled by two MADS-box transcription factors, DEFICIENS and GLOBOSA. Mutations in either of these genes result in the replacement of petals by sepaloid organs and stamens by carpelloid organs. Somatically stable def and glo periclinal chimeras, generated by transposon excision events, were used to study the non-cell-autonomous functions of these two MADS-box proteins. Two morphologically distinct types of chimeras were analysed using genetic, morphological and molecular techniques. Restoration of DEF expression in the L1 cell layer results in the reestablishment of DEF and GLO functions in L1-derived cells only; inner layer cells retain their mutant sepaloid features. Nevertheless, this activity is sufficient to allow the expansion of petal lobes, highlighting the role of DEF in the stimulation of cell proliferation and/or cell shape and elongation when expressed in the L1 layer. Establishment of DEF or GLO expression in L2 and L3 cell layers is accompanied by the recovery of petaloid identity of the epidermal cells but it is insufficient to allow petal lobe expansion. We show by in situ immunolocalisation that the non-cell-autonomy is due to direct trafficking of DEF and GLO proteins from the inner layer to the epidermal cells. At least for DEF, this movement appears to be polar since DEF acts cell-autonomously when expressed in the L1 cell layer. Furthermore, the petaloid revertant sectors observed on second whorl mutant organs and the mutant margins of petals of L2L3 chimeras suggest that DEF and GLO intradermal movement is limited. This restriction may reflect the difference in the regulation of primary plasmodesmata connecting cells from the same layer and secondary plasmodesmata connecting cells from different layers. We propose that control of intradermal trafficking of DEF and GLO could play a role in maintaining of the boundaries of their expression domains.

scholarly journals Uptake and Metabolism of Tritiated 17ß-Oestradiol and Oestrone by Rabbit Uterine Tissue in vitro

1974 ◽  
Vol 27 (2) ◽  
pp. 137 ◽  
Author(s):  
RG Gabb ◽  
GM Stone
Keyword(s):  
Nuclear Receptor ◽  
Mode Of Action ◽  
Nuclear Extract ◽  
Lower Proportion ◽  
The Other ◽  
Uterine Tissue ◽  
Uptake And Metabolism

To determine whether the established capability of rabbit uterine tissue to interconvert 17 p-oestradiol and oestrone might have some effect on the mode of action of the oestrogens in this organ, the in vitro interconversion of [3H]-17p-oestradiol and [3H]oestrone by rabbit endometrial and myometrial tissue was investigated and the identity of radiometabolites in 'soluble, 'mitochondrial-microsomal' a'nd 'nuclear' preparations was studied. Both endometrial and myometrial tissue were found to be capable of oxidoreduction of the oestrogens, the equilibrium of the reaction favouring the reduction of oestrone. Irrespective of the tissue--steroid combination studied, the greater part of the radioactivity in all fractions was associated with 17p-oestradiol. The relative proportions of [3Hl-17p-oestradiol and [3H]oestrone varied between fractions, the nuclear preparation consistently showing a lower proportion of oestrone than the other fractions. Sephade<c fractionation of a 0'4M KCl 'nuclear extract' revealed that proportionately less oestrone than 17p-oestradiol was bound to the nuclear 'receptor'. These findings provide further evidence for 17p-oestradiol being the ovarian oestrogen which is active in the uterus, and suggest a role for uterine oxidoreduction of oestrogens in the control exercised over this organ by these steroids.

scholarly journals Trends in antiretroviral treatment use and treatment response in three Australian states in the first decade of combination antiretroviral treatment

Sexual Health ◽  
2008 ◽  
Vol 5 (2) ◽  
pp. 141 ◽  
Author(s):  
Kathleen Falster ◽  
Linda Gelgor ◽  
Ansari Shaik ◽  
Iryna Zablotska ◽  
Garrett Prestage ◽  
...  
Keyword(s):  
Viral Load ◽  
Antiretroviral Treatment ◽  
Undetectable Viral Load ◽  
Lower Proportion ◽  
The Other ◽  
Early Disease ◽  
Community Based ◽  
Disease Research ◽  
Sex With Men ◽  
Living With Hiv

Objectives: To determine if there were any differences in antiretroviral treatment (ART) use across the three eastern states of Australia, New South Wales (NSW), Victoria and Queensland, during the period 1997 to 2006. Methods: We used data from a clinic-based cohort, the Australian HIV Observational Database (AHOD), to determine the proportion of HIV-infected patients on ART in selected clinics in each state and the proportion of treated patients with an undetectable viral load. Data from the national Highly Specialised Drugs program and AHOD were used to estimate total numbers of individuals on ART and the proportion of individuals living with HIV on ART nationally and by state. Data from the HIV Futures Survey and the Gay Community Periodic Survey were used to determine the proportion of community-based men who have sex with men on ART. The proportion of patients with primary HIV infection (PHI) who commenced ART within 1 year of diagnosis was obtained from the Acute Infection and Early Disease Research Program (AIEDRP) CORE01 protocol and Primary HIV and Early Disease Research: Australian Cohort (PHAEDRA) cohorts. Results: We estimated that the numbers of individuals on ART increased from 3181 to 4553 in NSW, 1309 to 1926 in Victoria and 809 to 1615 in Queensland between 2000 and 2006. However, these numbers may reflect a lower proportion of individuals living with HIV on ART in NSW compared with the other states (37% compared with 49 and 55% in 2000). We found similar proportions of HIV-positive men who have sex with men participants were on ART in all three states over the study period in the clinic-based AHOD cohort (81–92%) and two large, community-based surveys in Australia (69–85% and 49–83%). Similar proportions of treated patients had an undetectable viral load across the three states, with a consistently increasing trend over time observed in all states. We found that more PHI patients commenced treatment in the first year following HIV diagnosis in NSW compared with Victoria; however, the sample size was very small. Conclusions: For the most part, patterns of ART use were similar across NSW, Victoria and Queensland using a range of available data from cohort studies, community surveys and national prescription databases in Australia. However, there may be a lower proportion of individuals living with HIV on ART in NSW compared with the other states, and there is some indication of a more aggressive treatment approach with PHI patients in NSW compared with Victoria.

Ultrastructural Characteristics of Capillaries Entering and Leaving the Stria Vascularis

1986 ◽  
Vol 95 (3) ◽  
pp. 309-312 ◽  
Author(s):  
Kensuke Watanabe
Keyword(s):  
Horseradish Peroxidase ◽  
Basal Cell ◽  
Stria Vascularis ◽  
The Other ◽  
Spiral Ligament ◽  
Perivascular Spaces ◽  
Basal Cells ◽  
Vascular Flow ◽  
Cell Layers ◽  
Ultrastructural Characteristics

Capillaries entering and leaving the stria vascularis were surrounded by layers of basal cells and fibrocytes. The entering capillaries were surrounded by one or two thin basal cells, while the leaving capillaries were surrounded by four or five thicker and interdigitated basal cell layers. Moreover, the layers surrounding the leaving capillaries persisted further into the spiral ligament. Two kinds of filaments were observed in the basal cells, one thin and the other thick. Capillaries were observed to leak horseradish peroxidase before they entered and after they left the stria vascularis. Although the reaction product of horseradish peroxidase was observed in all perivascular spaces of leaving capillaries, very little or no reaction product was observed around some entering capillaries. It is speculated that the layers of basal cells and fibrocytes around entering and leaving capillaries control the vascular flow out of the stria vascularis, although the layers around leaving capillaries may be more contractile than those around entering capillaries.

Distribution of Calcium and Phosphate in Cells of the Enamel Organ in the Rat Lower Incisor

1987 ◽  
Vol 1 (2) ◽  
pp. 236-244 ◽  
Author(s):  
T. Kawamoto ◽  
M. Shimizu
Keyword(s):  
The Other ◽  
Whole Body ◽  
Enamel Organ ◽  
Maturation Stage ◽  
Lower Incisor ◽  
X Ray ◽  
Other Hand ◽  
Freeze Dried ◽  
Significant Difference ◽  
Cell Layers

The distribution of calcium and phosphate in the cells of the enamel organ of the rat lower incisors was investigated by autoradiography and energy-dispersive x-ray spectrometry (EDS). Radioactive calcium or phosphate was injected i.p. into seven-day-old rats of the Wistar strain. The animals were frozen 0.5, 1, and 10 min after injection, and embedded in 5% carboxymethyl cellulose. Sagittal sections of 10 μm thickness were made in which the lower incisor was included as a part of the whole-body section. For autoradiography, the sections were freeze-dried and placed in contact with dry thin films prepared from autoradiographic emulsion. For EDS, sections were mounted on carbon stubs, freeze-dried, coated with carbon, and examined by EDS in a SEM. 45Ca and 32P autoradiograms showed that the radioactivity was located over the papillary layer cells adjacent to the secretory stage ameloblasts and was much higher here than in the ameloblastic layer. On the other hand, there was no significant difference between the amount of radioactivity of these two cell layers in the maturation stage, although higher radioactivity was detectable in the maturation stage enamel than in the secretory stage enamel. Pronounced Ka x-ray peaks were obtained for P, S, Cl, and K originating from the cells of the papillary and ameloblastic layers in the secretory stage, but only very low peaks were obtained for Ca. On the other hand, in addition to these elements, remarkably high Ca and Fe peaks could be detected in the ameloblastic layer of the maturation stage.

A new species and comparative morphology of Vesselowskya (Cunoniaceae)

2001 ◽  
Vol 14 (2) ◽  
pp. 175 ◽  
Author(s):  
Andrew C. Rozefelds ◽  
Richard W. Barnes ◽  
Belinda Pellow
Keyword(s):  
New Species ◽  
Cell Walls ◽  
New South ◽  
Comparative Morphology ◽  
Epidermal Cells ◽  
The Other ◽  
Abaxial Surface ◽  
South Wales ◽  
Central Column ◽  
A New Species

The vegetative and reproductive morphology of Vesselowskya Pampanini, southern marara, is described and illustrated in detail. The variation within V. rubifolia (F.Muell.) Pampanini sens. lat. is shown to be greater than has previously been recognised, with the differences identified supporting the recognition of a new segregate species, V. venusta Rozefelds, R.W.Barnes and Pellow sp. nov. Vesselowskya venusta occurs in the Barrington Tops Plateau of New South Wales and differs from V. rubifolia in possessing hairs on the abaxial surface of the sepals and lacking both a prominent distal connective protrusion on the anthers and colleters at the base of the stipules. The two Vesselowskya species are dioecious with a vestigial ovary in staminate flowers and reduced stamens in pistillate flowers. Dioecy is more pronounced in Vesselowskya, than in some Weinmannia species, and in both genera is expressed through reduction in the size of the ovaries in staminate flowers, and stamens in pistillate flowers. Vesselowskya shares with the other genera in the tribe Cunonieae (Pancheria, Weinmannia and Cunonia), a central column in the fruits, and Cunonia-type stipules, but differs from these genera in having valvate aestivation, digitate leaves, craspedodromous secondary venation with secondary veins terminating at a tooth, tuft domatia along the midrib, adaxial epidermal cells with strongly sinuous cell walls and the absence of hydathodes.

scholarly journals Sueria laxinervis, a new fossil species of Cycadales from the Upper Cretaceous Quiriquina Formation in Cocholgüe, Bíobío Region, Chile

Phytotaxa ◽  
2019 ◽  
Vol 402 (2) ◽  
pp. 126
Author(s):  
TOSHIHIRO YAMADA ◽  
TAKAE F. YAMADA ◽  
KAZUO TERADA ◽  
TAKESHI A. OHSAWA ◽  
ATSUSHI YABE ◽  
...  
Keyword(s):  
Upper Cretaceous ◽  
Epidermal Cells ◽  
The Other ◽  
Vascular Bundles ◽  
Fossil Species

A new fossil cycad species, Sueria laxinervis, is described from the Upper Cretaceous (Maastrichtian) Quiriquina Formation in Cocholgüe, Bíobío Region, Chile. The generic assignment is supported by the taeniopterid-type leaf with haplocheilic stomata and sinuate anticlinal walls of leaf epidermal cells, while S. laxinervis clearly differs from the other two described Sueria species in its sparse veins and large epidermal cells. The vascular bundles of the midrib are arranged in an inverted-omega shape, supporting the placement of Sueria in Cycadales.

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