During pollen development each product of meiosis undergoes a stereotypical pattern of cell divisions to give rise to a three-celled gametophyte, the pollen grain. First an asymmetric mitosis generates a larger vegetative cell and a smaller generative cell, then the generative cell undergoes a second mitosis to give rise to two sperm cells. It is unknown how this pattern of cell divisions is controlled. We have identified an Arabidopsis gene, SIDECAR POLLEN, which is required for the normal cell division pattern during pollen development. In the genetic background of the NoO ecotype, sidecar pollen heterozygotes have about 45% wild-type pollen, 48% aborted pollen and 7% pollen with an extra cell. Homozygous sidecar pollen plants have about 20% wild-type pollen, 53% aborted pollen and 27% extra-celled pollen. Similar ratios of sidecar pollen phenotypes are seen in the Columbia ecotype but sidecar pollen is a gametophytic lethal in the Landsberg erecta ecotype. Thus this allele of sidecar pollen ...
The sporadic nature of inflorescence production and flower protogyny in caladium (Caladium ×hortulanum Birdsey) makes it desirable to store pollen and to rapidly assess its viability for cross-pollinations in breeding programs. This study was conducted to develop a procedure to determine caladium pollen viability and to use that procedure to evaluate the effect of short-term storage conditions on pollen viability. The sucrose level in the culture medium was found to have a significant impact on the in vitro germination of caladium pollen; a concentration of 6.8% was determined to be optimal for pollen germination. Caladium pollen lost viability within 1 day under room (24 °C) or freezing (-20 °C) temperatures, but could be stored at 4 °C for 2 to 4 days. Pollen stored at 4 °C produced successful pollinations. Data obtained from large-scale greenhouse pollinations supported use of this in vitro germination assay as a convenient way to evaluate caladium pollen viability (and fertility). ...
The classification of grass pollen is a classic problem in palynology. One approach to this problem is to image grass pollen using scanning electron microscopy (SEM) and to construct morphotypes on the basis of surface ornamentation patterns. In this paper, we construct a database of published SEM images of grass pollen surface ornamentation and use this database to review the status and utility of grass pollen morphotypes. Very little SEM data on grass pollen surface ornamentation have been collected. There are more SEM data on the pollen of species from larger subfamilies such as the Pooideae, but there are no SEM data on the pollen of relatively small subfamilies or the early-diverging APP clade of grasses. The available data support the following six morphotypes: the Hordeum-type, Triticum-type, Avena-type, Setaria-type, Pariana-type and Stipa-type. The phylogenetic distribution of these morphotypes cannot be assessed reliably with the available data, but the Pariana and Stipa types are ...
Physician reviewed timothy grass pollen allergen extract patient information - includes timothy grass pollen allergen extract description, dosage and directions.
Three years data of aerobiology of Islamabad (2005, 2006, and 2007) indicate that Islamabad is among the cities with highest pollen counts in the world. In our study of 3 years, highest pollen count was that of B. papyrifera on 10th March 2006 (34, 320 pollens/m3 air). The highest pollen count was seen in study of Domínguez[15] with data of last 25 years indicating that in Andalusia, South Spain, the higher pollen count belonged to Olea europaea. During only one day (May 22, 1991), 38, 393 olive pollen grains per cubic meter were detected in the air in Córdoba city [15].. For the first time, pollen and mold calendar of Islamabad was prepared from 3-year study (Tables 5, 4, 5). In spring (March to April), B. papyrifera pollens are the causes of severe allergic diseases like asthma, allergic rhinitis, and urticaria, whereas in fall (July to September), pollens of Cannabis are causing these allergic diseases. Grass pollens and molds are present throughout the year and are causing the above ...
... is a fine powder consisted of microspores (pollen grains), which are the male gametes of higher plants. Pollen is produced in the microsporangium (antherss of an angiosperm flower). Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species (see photomicrograph at right). Most, but certainly not all, are spherical. Pollen grains of pines, firs, and spruces are winged. The smallest pollen grain, that of the Forget-me-not plant (Myosotis sp.), is around 6 μm (0.006 mm) in diameter. The study of pollen is called Palynology and is highly useful in paleontology, archeology, and forensics.. The transfer of pollen grains to the female reproductive structure (carpel in angiosperms) is called pollination. Allergy to pollen is called hay fever. Generally pollens that cause allergies are those of anemophilous (literally wind-loving) plants, which produce very lightweight pollen grains in great quantities for wind dispersal, and subsequently contacting ...
Understanding the processes which underlie pollen release is key to efficient production of hybrid crops. Pollen is produced in compartments termed locules, which reside within the anther. Surrounding the locules are two cell layers: an outer epidermis and an inner endothecium. During pollen development, endothecial cells undergo secondary thickening - a process by which cell walls are lined by a helical arrangement of lignin fibres, strengthening the layer and providing a natural resistance to bending. Pollen release occurs as a result of an anther dehiscence process, during which the anther wall splits, exposing the pollen to the environment. A number of processes have been proposed to drive this process. In this report, we examine one such process: that in which anther dehiscence is driven by dehydration of the epidermis, which results in contraction of this layer and an associated change to the preferred curvature of the locule. We extend an existing bilayer model to incorporate expansion ...
Pollen is the haploid microgametophyte generation in seed plants and is considered the male partner in sexual reproduction. In flowering plants pollen comprises either two or three cells when shed from the flower. Both pollen types possess a large vegetative cell containing within, a single generative cell (bicellular pollen) or sperm cell pair (tricellular pollen). Pollen shows a wide variation in size, shape and surface patterning. Pollen grains vary in diameter from 5 µm in Myosotis (forget-me-not) to more than 200 µm in Curcurbita (ie melon) and round, ellipsoid and multifaceted pollen types occur ...
To fully understand the breeding potential of triploid herbaceous peony cultivars, and to promote the development of new peony cultivars and extend their culture in China, three triploid cultivars, Brightness, Roselette and Coral Sunset, were selected to investigate their pollen viability and fertility. In addition, fluorescence microscopy was used to observe pollen germination and pollen tube growth on the stigma of the domestic diploid cultivar Fen Yu Nu, which was used as the female parent of the three triploid cultivars. Our results show that pollen viability of the three triploid cultivars was very low, being highest (6.7%) in Brightness and lowest (2.2%) in Coral Sunset, and that the pollen grains of the three triploid cultivars had a very low germination rate on the maternal stigma, caused by very short pollen tubes that could not penetrate the stigma. Profuse callose was found in papillose cells of the stigma and pollen tubes and a large number of pollen grains detached from ...
Hay Fever sufferers can gain a great advantage in the management of their symptoms if they are made aware of the daily pollen count. This can enable them to plan ahead in their use of drugs and in their exposure to possible pollen sources.. The Councils Environmental Monitoring Team provides daily counts of the grass pollen levels measured in the Bath area. The grass pollen monitoring usually takes place from May or June to August.. This monitoring is carried out on behalf of the Met Office and the National Pollen and Aerobiology Research Unit (NPARU) and is part of a UK network of pollen monitoring sites.. Pollen is collected via a pollen trap located in as open an area as possible then analysed under the microscope to give the final count. More Information on the Pollen Forecast can be found on the Met Office Web site: http://www.metoffice.gov.uk/health/public/pollen-forecast. ...
POLLEN. Though palynology, which denotes the study of pollen and spores, is not a household word in Texas, the allergic effects of airborne pollen and spores are well known throughout the state. In technical terms, pollen is the microscopic mature or immature multinucleate gametophyte generation of seed plants. Its most important function is to carry the sperms needed for plant reproduction. A spore, on the other hand, is a cellular agent of asexual reproduction. Spores and pollen are similar in shape and size, in their ability to remain preserved in sediments for millions of years, and in their ability to be produced and dispersed by the millions. In addition, each spore or pollen grain type is morphologically unique to its plant species.. Each year thousands of Texans are immobilized by the crippling effects and allergic reactions caused by inhaling pollen and spores. It is estimated that the pollen count exceeds 500 pollen grains and spores per cubic meter of air during an average spring day ...
In this study, the response of pollens obtained from inflorescences of table grape cultivars Italia and Cardinal to different plant growth regulators added to the medium in Petri dishes was evaluated. Statistical analysis showed that pollen germination of cv. Italia was not influenced (p≥0.05) by the plant growth regulators (Table 1). Pollens not treated with any plant growth regulators (control) showed 26.08% germination, while the highest ratio was obtained from 0.001 mg L-1 EBR treatment (44.40%). The lowest percentage of germination was obtained from the application of 0.1 mg L-1 HBR (17.85%). Although no significant differences were observed, it was seen in the mean values of the applications that as the amount of GA3 in the combination treatments increased, the mean ratio of pollen germination slightly decreased. In addition, homobrassinolide yielded higher germination compared to epibrassinolide. Pollens of cv. Cardinal, on the other hand, responded significantly (p≤0.01) ...
Cypress pollen is another source of pollen coronae in Japan. However, the season of Japanese cypress pollen is almost same as that of our cedar pollen so that it is hard to distinguish its contribution from the cedar pollens contribution. (The amount of cypress pollen is less than cedar pollen ...
Wind pollination is a successful strategy for many plants, and pollen can be transported over long distances. Many agricultural or biological questions relate to gene flow mediated by pollen, and information on gene flow is crucial to understand introgression and seed purity. However, it is important to distinguish between work carried out on gene flow (including cross pollination) and that carried out on pollen deposition itself. This is also true for assessing genetically modified (GM) crops. With GM crops, gene flow may lead either to introgression into wild relatives [1]-[3] or to the presence of GM material in seeds, harvested materials, feed, or foodstuffs. Because there is a legal obligation for GM and GM-free agriculture to co-exist in Europe [4],[5], much research has been carried out to understand and manage gene flow from GM crops to other crops of the same or closely related species [6]-[13].. Pollen dispersal, independent of its ability to facilitate vertical gene flow, has been ...
These symptoms could be contributed to a pollen allergy, typically referred to as hay fever.. Weeds, grasses, trees, and some shrubs are the common culprits for pollen. Weeds have commonly been determined to be the most productive of pollen producers and are identified as the plant that causes the most allergies.. How does pollen cause my symptoms?. When pollen is inhaled through the nose and throat, the body experiences an immune response that results in hay fever, because it attaches to the cells and creates histamine. It is this releasing of histamine that causes the symptoms of pollen allergy.. How can I avoid pollen?. The most overlooked way to avoid pollen is a simple change of your home air filter. Air filters are proven to reduce many of the common airborne contaminants, such as pollen, from the air you breathe. In addition to changing your air filter on a regular basis, here are some other things you can do to avoid pollen this spring:. ...
Pollens practically-indestructible shell structure has long inspired the biomimetic design of organic materials. However, there is limited understanding of how the mechanical, chemical, and adhesion properties of pollen are biologically controlled and whether strategies can be devised to manipulate pollen beyond natural performance limits. Here, we report a facile approach to transform pollen grains into soft microgel by remodeling pollen shells. Marked alterations to the pollen substructures led to environmental stimuli responsiveness, which reveal how the interplay of substructure-specific material properties dictates microgel swelling behavior. Our investigation of pollen grains from across the plant kingdom further showed that microgel formation occurs with tested pollen species from eudicot plants. Collectively, our experimental and computational results offer fundamental insights into how tuning pollen structure can cause dramatic alterations to material properties, and inspire future
Green fluorescent protein (GFP) fused to the F-acton binding domain of mouse talin labels the actin cytoskeleton in the living generative and sperm cells of a third generation transgenic rice (Oryza sativa L.) plant, A005-G-T 1-2. Observations were made on pollen at four major developmental stages, viz. I. uni-nucleate microspore stage; II. early bi-cellular pollen stage; III. late bi-cellular pollen stage; and IV. tri-cellular pollen stage. At each of these developmental stages vegetative nucleus, generative nucleus/ cell, and sperm cells were seen undergoing continuous and coordinated motion and migration. These movements seemed to be influenced by associated microfilament networks existing in the pollen. Based on these observations we propose that it is the interaction between the microfilament networks (usually one existing in the central cytoplasm and another in the cortex) that controls the dynamic movement of the vegetative nucleus, generative nucleus/cell and sperm cells. Furthermore, we ...
PREMISE: The lack of ability to measure pollen performance traits in mixed pollinations has been a major hurdle in understanding the mechanisms of differential success of compatible pollen donors. In previous work, we demonstrated that nonrandom mating between two accessions of Arabidopsis thaliana, Columbia (Col) and Landsberg (Ler), is mediated by the male genotype. Despite these genetic insights, it was unclear at what stage of reproduction these genes were acting. Here, we used an experimental strategy that allowed us to differentiate different pollen populations in mixed pollinations to ask: (1) What pollen performance traits differed between Col and Ler accessions that direct nonrandom mating? (2) Is there evidence of interference competition? METHODS: We used genetically marked pollen that can be visualized colorimetrically to quantify pollen performance of single populations of pollen in mixed pollinations. We used this and other assays to measure pollen viability, germination, tube growth,
In higher plants, timely degradation of tapetal cells, the innermost sporophytic cells of the anther wall layer, is a prerequisite for the development of viable pollen grains. However, relatively little is known about the mechanism underlying programmed tapetal cell development and degradation. Here, we report a key regulator in monocot rice (Oryza sativa), PERSISTANT TAPETAL CELL1 (PTC1), which controls programmed tapetal development and functional pollen formation. The evolutionary significance of PTC1 was revealed by partial genetic complementation of the homologous mutation MALE STERILITY1 (MS1) in the dicot Arabidopsis (Arabidopsis thaliana). PTC1 encodes a PHD-finger (for plant homeodomain) protein, which is expressed specifically in tapetal cells and microspores during anther development in stages 8 and 9, when the wild-type tapetal cells initiate a typical apoptosis-like cell death. Even though ptc1 mutants show phenotypic similarity to ms1 in a lack of tapetal DNA fragmentation, delayed ...
Maize is wind pollinated and produces huge amounts of pollen. In consequence, the Cry toxins expressed in the pollen of Bt maize will be dispersed by wind in the surrounding vegetation leading to exposure of non-target organisms (NTO). NTO like lepidopteran larvae may be affected by the uptake of Bt-pollen deposited on their host plants. Although some information is available to estimate pollen deposition on host plants, recorded data are based on indirect measurements such as shaking or washing off pollen, or removing pollen with adhesive tapes. These methods often lack precision and they do not include the necessary information such as the spatial and temporal variation of pollen deposition on the leaves. Here, we present a new method for recording in situ the amount and the distribution of Bt-maize pollen deposited on host plant leaves. The method is based on the use of a mobile digital microscope (Dino-Lite Pro, including DinoCapture software), which can be used in combination with a notebook in the
Bee pollen allergic reaction symptoms - Are the health food store bee pollen meds just a gimmick for treating allergies? Yes. The pollens that cause allergies are very small, and carried by the wind. Flowers need bees to cross-pollinate, because the pollen is too big and heavy to be carried by the wind. Since theyre not airborne, people cant inhale them and react to them. Thus, the pollens found in bee pollen are not the pollens that cause your allergic symptoms.
In this study, immunologic interactive effects between timothy grass pollen grains and their PCGs were performed by an evaluation of allergy (humoral and cellular responses) and inflammatory parameters on Brown Norway rats, a good animal model of pollen allergy [17]. In parallel, allergic and inflammatory responses of these interactive effects were compared with those obtained on rats sensitized and challenged with only one aeroallergen, pollen grains or PCGs.. Our findings showed that combined effects between pollen and PCGs induce humoral responses. Previous studies showed that PCGs and pollen grains induced humoral responses on Brown Norway rats [9, 10, 16] when each aeroallergenic source was used for both sensitization and challenge. PCGs can also trigger IgE-mediated reactions in grass pollen-sensitive patients [4].. Humoral responses on allergic PG and GP groups were influenced mainly by PCGs. On these groups (PG and GP groups), the IgE and IgG1 levels were not different from those ...
Pollen is the natural food of bees and provides most of the nutrients bees require for growth and health. Honey provides very little nutrition, except carbohydrates which are essential for heat and movement. Pollen supplies all the rest, and bees cannot live long or raise brood for long without pollen.. Ingredients like properly selected brewers yeast and soy flours (but not all kinds) can come quite close to the bees needs for amino acids (protein), but adding natural pollen improves the diet considerably particularly when bees are not able to forage for pollen and also increases the rate of patty consumption. If the bees can get some natural pollen outside the hive, then supplements alone can be sufficient.. We make patties with various percentages of pollen, as well as straight supplement, and although most people request pollen, yeast, soy & sugar, we can make patties with any ingredients you request, including BeePro , MegaBee , FeedBee or other ingredients like egg or casein. (See ...
Nutritional Benefits of Pollen - Bee pollen is a nutrient rich food supplement easily added to your regular diet. There is a lot of myth and misinformation about the benefits of bee pollen. It contains 22 known essential nutritional elements which are beneficial to humans .. Bee pollen may be eaten by the teaspoonful as a food supplement. We recommend ½ a teaspoon twice daily. Stir it into yogurt, honey, or applesauce. Sprinkle it on your salad or cereal or take it straight with water or fruit juice. If you are a new pollen consumer, start off with small doses (4-6 pellets) to gauge how your bodys system will accept pollen. Doing so will help minimize a reaction to the natural substance. Like any food, there is a small chance of an allergic reaction to the pollen. Speak with your doctor if you have any concerns regarding bee pollen and allergies.. ...
TY - JOUR. T1 - Examination of climatological wind patterns and simulated pollen dispersion in a complex island environment. AU - Viner, Brian J.. AU - Arritt, Raymond W.. AU - Westgate, Mark E.. PY - 2017/8/1. Y1 - 2017/8/1. N2 - Complex terrain creates small-scale circulations which affect pollen dispersion but may be missed by meteorological observing networks and coarse-grid meteorological models. On volcanic islands, these circulations result from differing rates of surface heating between land and sea as well as rugged terrain. We simulated the transport of bentgrass, ryegrass, and maize pollen from 30 sources within the agricultural regions of the Hawaiian island Kauai during climatological conditions spanning season conditions and the La Niña, El Niño, and neutral phases of the El Niño-Southern Oscillation. Both pollen size and source location had major effects on predicted dispersion over and near the island. Three patterns of pollen dispersion were identified in response to ...
Bee Pollen Other name(s): pollen General description Pollen is found in flowering plants. Bees collect pollen while theyre searching for nectar. Pollen can be gathered from bees. It can also be harvested from plants by machines. Bee pollen contains the male reproductive cells (gametes) of flowers. It also contains digestive enzymes from bees. Pollen is rich in vitamins, minerals, trace elements, enzymes, and amino acids. Its also an excellent source of antioxidants. Its exact composition varies. This ...
We investigated whether the use of an intranasal corticosteroid can modify BHR during the grass pollen season in patients with mild asthma and seasonal allergic rhinitis. The effect of FP on BHR was studied in one season and the effect of equipotent doses of FP and BDP was studied in the next season. In the first season we found a significant and equal increase in BHR in patients in both the FP and placebo groups. In the next season we observed no increase in BHR in patients given placebo nor in those treated with BDP or FP. As expected, we found a decrease in nasal symptoms with intranasal corticosteroids. Rather unexpectedly, we found an improvement in % predicted FEV1 under low allergen exposure in the patients treated with BDP or FP. Thus, intranasal steroids were not able to prevent the increase in BHR which occurred in the first season nor to reduce BHR in the second season.. The increase in BHR during the grass pollen season is thought to be caused by a gradual cumulative effect of ...
Each spring, summer, and fall, tiny particles are released from trees, weeds, and grasses. These particles, known as pollen, hitch rides on currents of air. Although their mission is to fertilize parts of other plants, many never reach their targets. Instead, they enter human noses and throats, triggering a type of seasonal allergic rhinitis called pollen allergy, which many people know as hay fever or rose fever (depending on the season in which the symptoms occur). Of all the things that can cause an allergy, pollen is one of the most widespread. Many of the foods, drugs, or animals that cause allergies can be avoided to a great extent; even insects and household dust are escapable. Short of staying indoors when the pollen count is high--and even that may not help--there is no easy way to evade windborne pollen.. People with pollen allergies often develop sensitivities to other troublemakers that are present all year, such as dust mites. For these allergy sufferers, the "sneezin season" has ...
Ragweed (Ambrosia sp.) pollen grains (yellow) sticking to an anther, scanning electron micrograph (SEM). Pollen grains are reproductive structures produced by the male parts of flowering plants. Ragweed releases 1.6 million pollen grains per hour, which are highly allergic and a major contributor to hayfever. - Stock Image C002/6317
Turkish Journal of Fisheries and Aquatic Sciences 12: 851-859 (2012) www.trjfas.org ISSN 1303-2712 DOI: 10.4194/1303-2712-v12_4_13 Effects of Dietary Propolis and Pollen on Growth Performance, Fecundity and Some Hematological Parameters of Oreochromis niloticus Amany A. Abbass1,*, Amel M. El-Asely1, Mohamed M.M. Kandiel1 1 Benha University, Faculty of Veterinary Medicine, Deptartment of Fish Diseases and Management, Banha, Al Qalyubiyah, Egypt. * Corresponding Author: Tel.: +2013 2461 411; Fax: +2013 2461 411; E-mail: [email protected] Received 16 July 2012 Accepted 18 October 2012 Abstract This study aimed at identifying the effects of propolis and honeybee pollen (HBP) on growth performance, fecundity and some hematological indices of liver and kidney functions of Nile tilapia Oreochromis niloticus supplemented with 2.5% of propolis or HBP in diet for 21 days. The results showed that dietary propolis or HBP significantly (P,0.05) improved Specific Growth Rate (SGR), Average Daily Gain ...
Bee pollen1. Source: Multiflower, corn, rape, tea, etc.2. Specification:A. Bee pollen granuleB. Bee pollen powder 80-120meshC. Bee pollen tabletD....
Tenigenous marine and continental sediments constitute pollen reservoirs able to fulfil the lack of Pleistocene data extracted from autochtonous lacustrine sediments for palaeovegetation reconstructions. Nevertheless, it is essential to constrain the signification of the pollen signal in such still under-exploited sediments. This article introduces a study carried out on the shelf of the Gulf of Lions. It aims at (1) highlighting the transport of pollen grains and the signification of the record in that area as well as at (2) discussing the pollen transport in various sedimentary contexts. The present study was carried out on surface water of the Rhone River, sea water and surface sediments of the shelf of the Gulf of Lions. The pollen content of the Rhone River and of its plume is in agreement with the season of sampling. On the contrary, the other samples of sea water did not contain any pollen grain. The samples from the surface sediments of the shelf are very rich in pollen grains and ...
Pollen of anemophilous plants prevailed at all monitoring sites while pollen of entomophilous taxa occurred sporadically or in very low amounts. A similar pattern was reported in southeast Poland, however, with a different floral composition due to climatic differences. In Poland, pollen of the allergenic alder tree (Alnus sp.) accounts for most of the pollen count while in central Croatia the most allergenic weed, ragweed (Ambrosia sp.) does (Kasprzyk, 1999). Monthly pollen concentrations showed two peaks, in April and August, at all three sampling sites. These peaks coincided with the flowering of generally anemophilous tree and weed, especially ragweed. Similar results have also been reported from central Italy and south France (Clot, 2001; Emberlin et al., 1993; Spieksma and Frenguelli, 1991; J ger et al., 1991). Between-site differences were observed: monthly pollen concentrations measured in April at the Zagreb and Samobor sampling sites exceeded those recorded at the Ivani c Grad sampling ...
Sunflower pollen (Helianthus sp), coloured scanning electron micrograph (SEM). The outer wall (exine) has many small spiky projections. The pollen gets caught in the body hairs of insects visiting the flower. Cross pollination occurs when insects fly to another similar flower and pollen is left behind. Pollen contains the male reproductive cells of a plant. When the pollen grain, containing the male gametes, lands on the stigma of a flower, it germinates. A pollen tube grows out from the germinal pore, down through the stigma, to the ovary. The male nuclei pass down the tube, fertilize the ovules and seed is formed. Humans can also be allergic to daisy pollen. Magnification: x260 when shortest axis printed at 25 millimetres. - Stock Image C032/4451
I have been using a bee pollen supplements product for about two years now and I really do believe its been the main reason why Ive avoided colds and flu when the rest of my family have come down with them on a regular basis. I sometimes feel a cold coming on, but by the next morning symptoms disappeared. I dont suffer any allergic reactions or side effects to this amount of bee pollen. A lot of people take bee pollen, but what are the benefits of bee pollen, how much should you take and are there any health studies to back up the claims made by so many for "this miracle supplement"?. I personally take about 15 g of the pollen a day and find that to be effective, but the doses that other people recommend varying enormously. For example in Robert Risters book "Healing Without Medication", he suggests that bee pollen should not be taken for any more than two weeks of the time to prevent forming an allergy to the preparation. He also quotes typical doses as 1 - 1.5 grams per day which is well ...
BRAMBATTI, Adriana; BRAMMER, Sandra Patussi; WIETHOLTER, Paula e NASCIMENTO JUNIOR, Alfredo do. Genetic stability in triticale estimated by pollen viability. Arq. Inst. Biol. [online]. 2016, vol.83, e0802014. Epub 15-Dez-2016. ISSN 0020-3653. https://doi.org/10.1590/1808-1657000802014.. The study aimed to infer about the genetic stability from the pollen viability in hexaploid triticale genotypes used in block crossings breeding program from Brazilian Company of Agriculture Research (Embrapa Wheat). The experiments were conducted in a randomized design. For each genotype five repetitions were assessed. Each replication consisted of one plant and each replication consisted of one plant. Two hundred pollen grains were analyzed by optical microscopy and by the squash technique with 1% acetic carmine dye per slide, totalizing 1,000 pollen grains per genotype. The variables analyzed were: binucleate and trinucleate pollen grains, with little starch, empty, with more than one pore and with different ...
In plant cells, mitochondria and plastids contain their own genomes derived from the ancestral bacteria endosymbiont. Despite their limited genetic capacity, these multicopy organelle genomes account for a substantial fraction of total cellular DNA, raising the question of whether organelle DNA quantity is controlled spatially or temporally. In this study, we genetically dissected the organelle DNA decrease in pollen, a phenomenon that appears to be common in most angiosperm species. By staining mature pollen grains with fluorescent DNA dye, we screened Arabidopsis thaliana for mutants in which extrachromosomal DNAs had accumulated. Such a recessive mutant, termed defective in pollen organelle DNA degradation1 (dpd1), showing elevated levels of DNAs in both plastids and mitochondria, was isolated and characterized. DPD1 encodes a protein belonging to the exonuclease family, whose homologs appear to be found in angiosperms. Indeed, DPD1 has Mg²⁺-dependent exonuclease activity when expressed as ...
Abstract: The exocyst, a complex of eight proteins, contributes to the morphogenesis of polarized cells in a broad range of eukaryotes. In these organisms, the exocyst appears to facilitate vesicle docking at the plasma membrane during exocytosis. Although we had identified orthologs for each of the eight exocyst components in Arabidopsis (Arabidopsis thaliana), no function has been demonstrated for any of them in plants. The gene encoding one exocyst component ortholog, AtSEC8, is expressed in pollen and vegetative tissues of Arabidopsis. Genetic studies utilizing an allelic series of six independent T-DNA mutations reveal a role for SEC8 in male gametophyte function. Three T-DNA insertions in SEC8 cause an absolute, male-specific transmission defect that can be complemented by expression of SEC8 from the LAT52 pollen promoter. Microscopic analysis shows no obvious abnormalities in the microgametogenesis of the SEC8 mutants, and the mutant pollen grains appear to respond to the signals that ...
October 10, 2000. In August, Iowa State University scientists reported in the journal Oecologia that one kind of Bt-corn pollen naturally deposited on milkweeds in and near corn fields kills monarch butterfly caterpillars. This research confirms a laboratory study published in Nature last summer which showed that Bt-corn pollen is lethal to monarchs.. The Iowa scientists conducted three kinds of studies using two types of Bt corn marketed by Novartis Seeds: KnockOut, which contains a Bt gene named Event 176 and YieldGard with a Bt gene called Bt 11. KnockOut pollen typically contains more Bt toxin than YieldGard pollen. The three experiments were:. * To learn how much pollen caterpillars might be exposed to under field conditions, researchers counted pollen that fell on milkweeds, the favorite food of monarch caterpillars, within and near KnockOut, YieldGard and nonBt-corn plots.. * To assess mortality of caterpillars exposed to natural, field-deposited pollen, researchers placed caterpillars on ...
phdthesis{49014232-643e-4a99-964c-da745443d018, abstract = {Three sites, Torreberga in Skåne, Farslycke in Blekinge and Lake Bolmen in Småland, with Late Weichselian lake sediments were studied with respect to pollen analysis and palaeomagnetism. The chronologies are based on pollen stratigraphical correlations, radiocarbon dating and, for two of the sites, on a clay-varve chronology. The stratigraphies were correlated to the GRIP event stratigraphy and their ages are expressed in calendar years BP.,br/,,br, ,br/,,br, The pollen records compare well to the established Late Weichselian pollen stratigraphy for southern Sweden, and reflect the vegetation development from the deglaciation to the transition to the Holocene. The annual time-resolution of the varved clays has made it possible to calculate pollen accumulation rates based on actual sedimentation rates. The delayed onset of sedimentation in Torreberga implies that dead ice was present for at least 2000 years after the regional ...
Background: Grass pollen is one of the most important aeroallergens in Europe. It highly contributes to respiratory allergic diseases, mainly allergic rhinitis. In contact to water or airborne pollutants, pollen grains can release pollen cytoplasmic granules (PCGs) containing allergens. Because of their size (| 5 mu m), PCGs may penetrate deeper into the lungs to induce higher allergic responses, such as asthma. They have been associated with thunderstorm-related asthma. The aim of this study was to evaluate, with Brown Norway rats, the allergenic potential of isolated PCGs and to compare it with the allergenicity of whole timothy grass pollen. Methods: Rats were sensitized (day 0) and challenged (day 21), in controlled comparative conditions, with pollen grains (0.5 mg) or PCGs (4.5 x 10(7) and 0.5 mg). At day 25, blood samples, bronchoalveolar lavage fluid (BALF) and bronchial lymph node were collected. IgE and IgG1 levels in sera were assessed by ELISA. Alveolar cells, protein and cytokine
Grass pollens are known as very potent aeroallergens. The aim of the studywas to analyse the grass pollen season in Szczecin (western Poland) in the years 2000-2003 and to establisha relationship between the meteorological conditions and the pollen counts of Poaceae. The meteorologicalparameters...
Maize is wind-pollinated and releases prodigious quantities of pollen into the environment during anthesis [1]. In the case of genetically modified Bacillus thuringiensis (Bt) maize, this pollen also carries insecticidal Bt protein. Because non-target herbivores may feed on host plants dusted with Bt pollen-both within and around maize fields, this exposure and its subsequent effects must be evaluated to assess the risks associated with the cultivation of Bt maize.. Risks posed to non-target Lepidoptera by the cultivation of Bt maize plants resistant to lepidopteran species such as the European corn borer are widely acknowledged [2-5]. Scientific controversies exist, however, in regard to estimates of the potential magnitude of effects and measures such as isolation buffer distances applied for risk management [5-14].. Because exposure is the basis of any effect, the interpretation of maize pollen leaf deposition data is highly relevant to the above debate. For several reasons, successful ...
The function of pollen as a reward for foraging bees is little understood, though there is evidence to suggest that it can reinforce associations with visual and olfactory floral cues. Foraging bees do not feed on pollen, thus one could argue that it cannot serve as an appetitive reinforcer in the same way as sucrose. However, ingestion is not a critical parameter for sucrose reinforcement, since olfactory proboscis extension (PER) learning can be conditioned through antennal stimulation only. During pollen collection, the antennae and mouthparts come into contact with pollen, thus it is possible that pollen reinforces associative learning through similar gustatory pathways as sucrose. Here pollen was presented as the unconditioned stimulus (US), either in its natural state or in a 30% pollen-water solution, and was found to elicit proboscis extension following antennal stimulation. Control groups were exposed to either sucrose or a clean sponge as the US, or an unpaired presentation of the ...
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There are actually three hay fever seasons. Tree pollens appear first, usually between February and May, depending on the local climate. Then later in spring and summer there are both tree and grass pollens. Then in the fall is ragweed pollen season. Hay fever may be present at any or all of these times.. Although antihistamines are the most conventional treatment for hay fever, they can also cause drowsiness, depression and other undesirable side effects.. The best and safest way to control allergies is the natural way - by avoiding allergens, taking steps to normalize immune function and prevent or lessen the symptoms.. Ways to avoid allergens:. 1. Spend as little time outside as possible. Avoid the hours between 5:00 AM and 10:00 AM when pollen levels are at their highest. 2. Keep pets either inside or outside. Pets can pick up pollen on their fur and bring it indoors with them.. 3. Shower and change your clothes when you come indoors after spending time outside. Pollen can stick to your ...
Seasonal allergic rhinitis (SAR) is caused by various allergens, including wind-pollinated plants, and mainly by grass pollen allergens in Poland. The disease reduces the quality of life of patients and requires intensive treatment in the pollen season [1].. Polyvalent bacterial lysates (PBL) have been used for many years to prevent respiratory tract infections in children and adults [2]. Recent research also draws attention to the immunoregulatory potential of PBL, indicating the possibility of their future use in the prevention and treatment of atopic dermatitis, AR and asthma [3-7].. The aim of the study was to assess the impact of PBL on the clinical course of childhood SAR.. The study included 38 children aged 5-17 years (27 males; mean age: 9 ±3.2 years) with SAR caused by grass pollen, randomly selected from the group of children treated at the Outpatient Clinic of the University Childrens Hospital in Lublin. Main inclusion criteria were: SAR symptoms for at least two last grass pollen ...
Pollen is a fine powder produced by certain plants when they reproduce. During the spring, summer, and fall seasons, its released into the air and picked up by the wind, which brings it to other plants to fertilize them. Inside of these pollen grains are proteins that commonly cause allergic reactions (such as sneezing, runny nose, and itchy eyes) when breathed in. The pollen thats most often responsible for causing allergies comes from grasses, trees, and weeds. Many people with asthma are allergic to pollen. When they breathe it in, it can trigger their asthma symptoms.. ...
Sex Pollen is a common fanfiction trope used to bring two characters together in a sexual encounter. It involves one or several characters becoming infected with a pollen of some alien or magical plant, or they might be influenced in some other way (magic, alien technology, mind control, etc.) that causes them to lose inhibitions and/or revs up libido, usually resulting in non-con sex, which may lead to dramatic guilt and misunderstandings, or a resolution of UST. Sex pollen is related to, but distinct from Aliens Made Them Do It. Sex Pollen involves at least one character being under the influence of a substance or device, while the latter trope usually has both/all characters still in their right minds but compelled to have sex for external reasons. However, the division is not hard and fast. The essay Writing Sex Pollen Stories by Jen_in_Japan offers several classic uses for sex pollen, among them marital aid, getting a "wtf" couple together, breaking taboos, non-con, and "romantic ...
John Hungerford Pollen was the son of John Hungerford Pollen and Maria Margaret Pollen. The third of ten children, he was born in London in 1858. His father was professor of fine arts at the Catholic University in Dublin. Pollen junior was educated at The Oratory School in Birmingham, and then London University. Pollen entered the Society of Jesus in 1877 and was ordained in 1891.[2] In 1895 he was assigned the task of creating a history of the Society in England. Pollen became involved in historical research and archives. His research took him through England, France, and Italy. By 1920 he held the title of Keeper of the Archives.[3]. He was one of the group of Jesuit historians restoring the reputation of Robert Persons.[4] He was influential in the history of the term Counter-Reformation, accepting for the Catholic side the appellation for the period of Catholic reform centred on the Council of Trent, but at the same time offering an interpretation that made it less reactive, in relation to ...