Pollen: The fertilizing element of plants that contains the male GAMETOPHYTES.Pollen Tube: A growth from a pollen grain down into the flower style which allows two sperm to pass, one to the ovum within the ovule, and the other to the central cell of the ovule to produce endosperm of SEEDS.Pollination: The transfer of POLLEN grains (male gametes) to the plant ovule (female gamete).Rhinitis, Allergic, Seasonal: Allergic rhinitis that occurs at the same time every year. It is characterized by acute CONJUNCTIVITIS with lacrimation and ITCHING, and regarded as an allergic condition triggered by specific ALLERGENS.Lilium: A plant genus in the family LILIACEAE generally growing in temperate areas. The word lily is also used in the common names of many plants of other genera that resemble true lilies. True lilies are erect perennial plants with leafy stems, scaly bulbs, usually narrow leaves, and solitary or clustered flowers.Betula: A plant genus of the family BETULACEAE. The tree has smooth, resinous, varicolored or white bark, marked by horizontal pores (lenticels), which usually peels horizontally in thin sheets.Allergens: Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Flowers: The reproductive organs of plants.Antigens, Plant: Substances found in PLANTS that have antigenic activity.Ambrosia: A plant genus of the family ASTERACEAE. The POLLEN is one cause of HAYFEVER.Cupressus: A plant genus of the family CUPRESSACEAE. Cypress ordinarily refers to this but also forms part of the name of plants in other genera.Cryptomeria: A plant genus of the family TAXODIACEAE. Its POLLEN is one of the major ALLERGENS.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Germination: The initial stages of the growth of SEEDS into a SEEDLINGS. The embryonic shoot (plumule) and embryonic PLANT ROOTS (radicle) emerge and grow upwards and downwards respectively. Food reserves for germination come from endosperm tissue within the seed and/or from the seed leaves (COTYLEDON). (Concise Dictionary of Biology, 1990)Ovule: The element in plants that contains the female GAMETOPHYTES.Plant Infertility: The failure of PLANTS to complete fertilization and obtain seed (SEEDS) as a result of defective POLLEN or ovules, or other aberrations. (Dict. of Plant Genet. and Mol. Biol., 1998)Self-Incompatibility in Flowering Plants: One of many different processes which occur in ANGIOSPERMS by which genetic diversity is maintained while INBREEDING is prevented.Alnus: A plant genus of the family BETULACEAE that is distinguished from birch (BETULA) by its usually stalked winter buds and by cones that remain on the branches after the small, winged nutlets are released.Olea: A plant genus of the family Oleaceae. The olive fruit is the source of olive oil.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Meteorological Concepts: The atmospheric properties, characteristics and other atmospheric phenomena especially pertaining to WEATHER or CLIMATE.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Poaceae: A large family of narrow-leaved herbaceous grasses of the order Cyperales, subclass Commelinidae, class Liliopsida (monocotyledons). Food grains (EDIBLE GRAIN) come from members of this family. RHINITIS, ALLERGIC, SEASONAL can be induced by POLLEN of many of the grasses.Cedrus: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. It is the source of cedarwood oil. Cedar ordinarily refers to this but also forms part of the name of plants in other genera.Reproduction: The total process by which organisms produce offspring. (Stedman, 25th ed)Papaver: A genus of Eurasian herbaceous plants, the poppies (family PAPAVERACEAE of the dicotyledon class Magnoliopsida), that yield OPIUM from the latex of the unripe seed pods.Angiosperms: Members of the group of vascular plants which bear flowers. They are differentiated from GYMNOSPERMS by their production of seeds within a closed chamber (OVARY, PLANT). The Angiosperms division is composed of two classes, the monocotyledons (Liliopsida) and dicotyledons (Magnoliopsida). Angiosperms represent approximately 80% of all known living plants.Bees: Insect members of the superfamily Apoidea, found almost everywhere, particularly on flowers. About 3500 species occur in North America. They differ from most WASPS in that their young are fed honey and pollen rather than animal food.Trees: Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.Gametogenesis, Plant: The process of germ cell development in plants, from the primordial PLANT GERM CELLS to the mature haploid PLANT GAMETES.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Immunoglobulin E: An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Betulaceae: A plant family of the order Fagales, subclass Hamamelidae, class Magnoliopsida. They have simple, serrate, alternate leaves. Male flowers are borne in long, pendulous catkins; the female in shorter, pendulous or erect catkins. The fruit is usually a small nut or a short-winged samara.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Cupressaceae: A plant family of the order Pinales, class Pinopsida, division Coniferophyta (conifers). They are mainly resinous, aromatic evergreen trees.Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Phleum: A plant genus of the family POACEAE that contains the Phl p 4 allergen.Self-Fertilization: The fusion of a male gamete with a female gamete from the same individual animal or plant.Germ Cells, Plant: The reproductive cells of plants.Hypersensitivity: Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.Genes, Plant: The functional hereditary units of PLANTS.Zea mays: A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.Skin Tests: Epicutaneous or intradermal application of a sensitizer for demonstration of either delayed or immediate hypersensitivity. Used in diagnosis of hypersensitivity or as a test for cellular immunity.Juniperus: A plant genus of the family CUPRESSACEAE. The species are slow growing coniferous evergreen trees or shrubs.Desensitization, Immunologic: Immunosuppression by the administration of increasing doses of antigen. Though the exact mechanism is not clear, the therapy results in an increase in serum levels of allergen-specific IMMUNOGLOBULIN G, suppression of specific IgE, and an increase in suppressor T-cell activity.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Honey: A sweet viscous liquid food, produced in the honey sacs of various bees from nectar collected from flowers. The nectar is ripened into honey by inversion of its sucrose sugar into fructose and glucose. It is somewhat acidic and has mild antiseptic properties, being sometimes used in the treatment of burns and lacerations.Wind: The motion of air relative to the earth's surface.Petunia: A plant genus of the family SOLANACEAE. Members contain steroidal glycosides.Fraxinus: A plant genus of the family OLEACEAE. Members contain secoiridoid glucosides.Brassica: A plant genus of the family Cruciferae. It contains many species and cultivars used as food including cabbage, cauliflower, broccoli, Brussel sprouts, kale, collard greens, MUSTARD PLANT; (B. alba, B. junica, and B. nigra), turnips (BRASSICA NAPUS) and rapeseed (BRASSICA RAPA).Artemisia: A plant genus of the family ASTERACEAE with strong-smelling foliage. It is a source of SANTONIN and other cytotoxic TERPENES.Lolium: Common member of the Gramineae family used as cattle FODDER. It harbors several fungi and other parasites toxic to livestock and people and produces allergenic compounds, especially in its pollen. The most commonly seen varieties are L. perenne, L. multiflorum, and L. rigidum.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Gametogenesis: The process of germ cell development from the primordial GERM CELLS to the mature haploid GAMETES: ova in the female (OOGENESIS) or sperm in the male (SPERMATOGENESIS).

Rational analyses of organelle trajectories in tobacco pollen tubes reveal characteristics of the actomyosin cytoskeleton. (1/2581)

To gain insight into the characteristics of organelle movement and the underlying actomyosin motility system in tobacco pollen tubes, we collected data points representing sequential organelle positions in control and cytochalasin-treated cells, and in a sample of extruded cytoplasm. These data were utilized to reconstruct approximately 900 tracks, representing individual organelle movements, and to produce a quantitative analysis of the movement properties, supported by statistical tests. Each reconstructed track appeared to be unique and to show irregularities in velocity and direction of movement. The regularity quotient was near 2 at the tip and above 3 elsewhere in the cell, indicating that movement is more vectorial in the tube area. Similarly, the progressiveness ratio showed that there were relatively more straight trajectories in the tube region than at the tip. Consistent with these data, arithmetical dissection revealed a high degree of randomlike movement in the apex, lanes with tip-directed movement along the flanks, and grain-directed movement in the center of the tube. Intercalated lanes with bidirectional movement had lower organelle velocity, suggesting that steric hindrance plays a role. The results from the movement analysis indicate that the axial arrangement of the actin filaments and performance of the actomyosin system increases from tip to base, and that the opposite polarity of the actin filaments in the peripheral (+-ends of acting filaments toward the tip) versus the central cytoplasm (+-ends of actin filaments toward to the grain) is installed within a few minutes in these tip-growing cells.  (+info)

Male gametic cell-specific gene expression in flowering plants. (2/2581)

The role of the male gamete-the sperm cell-in the process of fertilization is to recognize, adhere to, and fuse with the female gamete. These highly specialized functions are expected to be controlled by activation of a unique set of genes. However, male gametic cells traditionally have been regarded as transcriptionally quiescent because of highly condensed chromatin and a very reduced amount of cytoplasm. Here, we provide evidence for male gamete-specific gene expression in flowering plants. We identified and characterized a gene, LGC1, which was shown to be expressed exclusively in the male gametic cells. The gene product of LGC1 was localized at the surface of male gametic cells, suggesting a possible role in sperm-egg interactions. These findings represent an important step toward defining the molecular mechanisms of male gamete development and the cellular processes involved in fertilization of flowering plants.  (+info)

Exhaled and nasal NO levels in allergic rhinitis: relation to sensitization, pollen season and bronchial hyperresponsiveness. (3/2581)

Exhaled nitric oxide is a potential marker of lower airway inflammation. Allergic rhinitis is associated with asthma and bronchial hyperresponsiveness. To determine whether or not nasal and exhaled NO concentrations are increased in allergic rhinitis and to assess the relation between hyperresponsiveness and exhaled NO, 46 rhinitic and 12 control subjects, all nonasthmatic nonsmokers without upper respiratory tract infection, were randomly selected from a large-scale epidemiological survey in Central Norway. All were investigated with flow-volume spirometry, methacholine provocation test, allergy testing and measurement of nasal and exhaled NO concentration in the nonpollen season. Eighteen rhinitic subjects completed an identical follow-up investigation during the following pollen season. Exhaled NO was significantly elevated in allergic rhinitis in the nonpollen season, especially in perennially sensitized subjects, as compared with controls (p=0.01), and increased further in the pollen season (p=0.04), mainly due to a two-fold increase in those with seasonal sensitization. Nasal NO was not significantly different from controls in the nonpollen season and did not increase significantly in the pollen season. Exhaled NO was increased in hyperresponsive subjects, and decreased significantly after methacholine-induced bronchoconstriction, suggesting that NO production occurs in the peripheral airways. In allergic rhinitis, an increase in exhaled nitric oxide on allergen exposure, particularly in hyperresponsive subjects, may be suggestive of airway inflammation and an increased risk for developing asthma.  (+info)

LeProT1, a transporter for proline, glycine betaine, and gamma-amino butyric acid in tomato pollen. (4/2581)

During maturation, pollen undergoes a period of dehydration accompanied by the accumulation of compatible solutes. Solute import across the pollen plasma membrane, which occurs via proteinaceous transporters, is required to support pollen development and also for subsequent germination and pollen tube growth. Analysis of the free amino acid composition of various tissues in tomato revealed that the proline content in flowers was 60 times higher than in any other organ analyzed. Within the floral organs, proline was confined predominantly to pollen, where it represented >70% of total free amino acids. Uptake experiments demonstrated that mature as well as germinated pollen rapidly take up proline. To identify proline transporters in tomato pollen, we isolated genes homologous to Arabidopsis proline transporters. LeProT1 was specifically expressed both in mature and germinating pollen, as demonstrated by RNA in situ hybridization. Expression in a yeast mutant demonstrated that LeProT1 transports proline and gamma-amino butyric acid with low affinity and glycine betaine with high affinity. Direct uptake and competition studies demonstrate that LeProT1 constitutes a general transporter for compatible solutes.  (+info)

Process and current status of the epidemiologic studies on cedar pollinosis in Japan. (5/2581)

This paper reviews the present situation and future aspects of epidemiologic studies on Japanese cedar pollinosis. Increase of allergic rhinitis patients is observed in both the Patient Survey and the Reports on the Surveys of Social Medical Care Insurance Services, however, these surveys are conducted when cedar pollens do not pollute the air. Many have reported on the prevalence of pollinosis in limited areas but only a few nationwide epidemiologic surveys have been conducted. Most of the studies were conducted at special medical facilities such as university hospitals. There is a high possibility that patients who visit the specific facilities do not exactly represent the actual number of patients and epidemiologic pictures of pollinosis in Japan. The rapid advances in laboratory test methods may change the diagnostic criteria and increase the number of reported patients. Therefore, the prevalence of Japanese cedar pollinosis in Japan has not been determined yet. Determination of the prevalence of cedar pollinosis and description of the epidemiologic pictures constitute the essential steps toward the control of this clinical entity. Thus it is necessary to conduct an epidemiologic survey on Japanese representative samples with a standardized survey form with clear and concise diagnostic criteria.  (+info)

Pollen ultrastructure in anther cultures of Datura innoxia. I. Division of the presumptive vegetative cell. (6/2581)

Ultrastructural features of embryogenic pollen in Datura innoxia are described, just prior to, during, and after completion of the first division of the presumptive vegetative cell. In anther cultures initiated towards the end of the microspore phase and incubated at 28 degrees C in darkness, the spores divide within 24 h and show features consistent with those of dividing spores in vivo. Cytokinesis is also normal in most of the spores and the gametophytic cell-plate curves round the presumptive generative nucleus in the usual highly ordered way. Further differentiation of the 2 gametophytic cells does not take place and the pollen either switches to embryogenesis or degenerates. After 48-72 h, the remaining viable pollen shows the vegetative cell in division. The cell, which has a large vacuole and thin layer of parietal cytoplasm carried over from the microspore, divides consistently in a plane parallel to the microspore division. The dividing wall follows a less-ordered course than the gametophytic wall and usually traverses the vacuole, small portions of which are incorporated into the daughter cell adjacent to the generative cell. The only structural changes in the vegetative cell associated with the change in programme appear to be an increase in electron density of both plastids and mitochondria and deposition of an electron-dense material (possibly lipid) on the tonoplast. The generative cell is attached to the intine when the vegetative cell divides. Ribosomal density increases in the generative cell and exceeds that in the vegetative cell. A thin electron-dense layer also appears in the generative-cell wall. It is concluded that embryogenesis commences as soon as the 2 gametophytic cells are laid down. Gene activity associated with postmitotic synthesis of RNA and protein in the vegetative cell is switched off. The data are discussed in relation to the first division of the embryogenic vegetative cells in Nicotiana tabacum.  (+info)

Pollen ultrastructure in anther cultures of Datura innoxia. II. The generative-cell wall. (7/2581)

In young pollen grains of Datura innoxia, a wall of the usual hemispherical type separates the 2 gametophytic cells initially and, in the electron microscope, appears as an electron-translucent matrix which is contiguous with the intine. Before detachment of the generative cell from the intine, the matrix decreases in thickness and in places is dispersed altogether leaving the plasmalemmae on either side of it in close apposition. A particularly prominent zone, triangular in profile, is left where the wall joins with the intine. After detachment of the cell, remnants of the matrix can be seen distributed irregularly around the cell and it is supposed that these are partly derived from material in the triangular zone as the cell is drawn away from the intine. The wall residues persist throughout the maturation phase of the pollen and are considered to be either callose resulting from incomplete digestion of the initial wall, or some other polysaccharide material which is unevenly laid down along the wall and concentrated at the junction with the intine. In pollen induced into embryogenesis by anther culture, wall material is also distributed irregularly around the detached cell in a series of discrete zones, but these are more extensive than in vivo, closer together and in many instances highly dilated. The wall profiles thus have a beaded appearance, the 'beads' being connected together by short links of the 2 apposed plasmalemmae. The contents of the swollen zones have a similar electron density to that of the matrix in vivo but also show traces of a fibrillar component. It is postulated that this unusual swelling is a prelude to dispersal of the wall by disruption of the plasmalemmal links and to the establishment of cytoplasmic continuity between the 2 cells. The significance of such binucleate pollen grains in the formation of non-haploid embryos is discussed.  (+info)

Pollen ultrastructure in anther cultures of Datura innoxia. III. Incomplete microspore division. (8/2581)

During the microspore division in Datura innoxia, the mitotic spindle is oriented in planes both perpendicular (PE) and oblique (OB) to the spore wall against which the nucleus is situated. However, irrespective of polarity, the usual type of hemispherical wall is laid down at cytokinesis and isolates the generative cell from the rest of the pollen grain (type A). In PE spores the vegetative nucleus initially occupies a central position in the pollen grain, whereas in OB spores the vegetative nucleus lies at the periphery of the grain close to the generative cell. In anther cultures initiated just before the microspore division is due to take place, no marked change can be observed in either orientation or symmetry of the mitotic spindle when the spores divide. In some, however, cytokinesis is disrupted and deposition of the hemispherical wall arrested. In the absence of a complete wall, differentiation of the generative cell cannot take place and binucleate pollen grains are formed having 2 vegetative-type nuclei (type B). The 2 nuclei in the B pollens are always situated against the pollen-grain wall, suggesting that the disruption phenomenon is related to the OB spores. The incomplete wall always makes contact with the intine on the intine-side of the spindle. Wall material may be represented merely as short stubs projecting out from the intine into the cytoplasm, in which event the 2 nuclei lie close to each other and are separated by only a narrow zone of cytoplasm. In other grains the wall is partially developed between the nuclei and terminates at varying distances from the tonoplast; in these, the nuclei are separated by a wider zone of cytoplasm. The significance of these binucleate grains in pollen embryogenesis is discussed.  (+info)

  • Our investigation of pollen grains from across the plant kingdom further showed that microgel formation occurs with tested pollen species from eudicot plants. (nature.com)
  • Common features of pollen grains across various plant species include a microcapsule structure, function-driven shape, and ornamental architecture 12 . (nature.com)
  • In addition, each spore or pollen grain type is morphologically unique to its plant species. (tshaonline.org)
  • A few months later, other species of pollen-producing weeds and shrubs mature. (tshaonline.org)
  • In late summer and early fall, ragweeds and other species of grasses fill the Texas air with new types of pollen. (tshaonline.org)
  • In this study, we genetically dissected the organelle DNA decrease in pollen, a phenomenon that appears to be common in most angiosperm species. (le.ac.uk)
  • Filter bursting was directly compared with chopping in five species, yields were compared with published values for sonicated samples, and the method was applied by comparing genome size estimates for leaf and pollen nuclei in six species. (usda.gov)
  • In 41 % of species we met the most stringent criterion of screening 10 000 pollen grains per sample. (usda.gov)
  • Species Specificity in Pollen-Pistil Interactions" by Rob Swanson, Anna F. Edlund et al. (valpo.edu)
  • Although the pistil is a great facilitator of pollen function, it can also be viewed as an elaborate barrier that shields ovules from access from inappropriate pollen, such as pollen from other species. (valpo.edu)
  • In vitro pollen germination has been investigated at the genetic, physiological and biochemical levels in different plant species. (oeno-one.eu)
  • stated that gibberellins had an influence on pollen germination in seeded vine species. (oeno-one.eu)
  • Pollen grains germinate on the surface of the stigma in the flower by forming a pollen tube which usually emerges through one of the apertures in the pollen grain wall. (le.ac.uk)
  • 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. (biologists.org)
  • 1991 ) Differential effects of specific chromosomal deficiencies on the development of the maize pollen grain. (biologists.org)
  • In technical terms, pollen is the microscopic mature or immature multinucleate gametophyte generation of seed plants. (tshaonline.org)
  • Wind pollination is a successful strategy for many plants, and pollen can be transported over long distances. (springeropen.com)
  • However, it is important to distinguish between work carried out on gene flow (including cross pollination) and that carried out on pollen deposition itself. (springeropen.com)
  • For pollination to succeed, pollen must carry sperm through a variety of different floral tissues to access the ovules within the pistil. (valpo.edu)
  • Pollen is produced in compartments termed locules, which reside within the anther. (cpib.ac.uk)
  • Pollen release occurs as a result of an anther dehiscence process, during which the anther wall splits, exposing the pollen to the environment. (cpib.ac.uk)
  • Preliminary studies on pollen production and viability in wild relatives and cultivated cassava. (www.gov.uk)
  • However, little is known about the viability and other characteristics of pollen within wild and cultivated cassava germplasm. (www.gov.uk)
  • 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. (ishs.org)
  • 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. (ishs.org)
  • showed increasing and decreasing effect of 0.01 µM 24-epibrassinolide on pollen viability and germination. (oeno-one.eu)
  • Pollen is a remarkable natural material that plays a critical role in plant reproduction and transfers viable cellular material (i.e., male gametes or sperm cells) between different reproductive parts of plants 1 , 2 . (nature.com)
  • The two sperm cells are then transported within the pollen tube and delivered to the embryo sac inside the ovule to allow fertilisation to occur. (le.ac.uk)
  • Indeed, DPD1 has Mg²⁺-dependent exonuclease activity when expressed as a fusion protein and when assayed in vitro and is highly active in developing pollen. (le.ac.uk)
  • In this study, the effects of two brassinosteroid compounds, epibrassinolide and 22S,23S-homobrassinolide, and gibberellic acid (GA 3 ) on in vitro pollen germination of two table grape cultivars, 'Italia' and 'Cardinal' ( Vitis vinifera L.), were determined. (oeno-one.eu)
  • Pollen germination evaluated in vitro might validate germination in vivo ( Hormaza and Herrero, 1999 ). (oeno-one.eu)
  • Literature on in vitro pollen germination of horticultural crops is abundant with studies determining basic medium constituents including boric acid, mineral salts or plant growth regulators. (oeno-one.eu)
  • This study was conducted to determine the effects of two brassinosteroid compounds, epibrassinolide and 22S,23S-homobrassinolide, along with the other growth regulator group, gibberellins, on in vitro pollen germination and growth of grapevine cultivars. (oeno-one.eu)
  • Some of these plants produce pollen that causes very uncomfortable reactions in humans commonly refereed to as hay fever. (redferret.net)
  • Both pollen types possess a large vegetative cell containing within, a single generative cell (bicellular pollen) or sperm cell pair (tricellular pollen). (le.ac.uk)
  • 1953 ) The role of the vegetative nucleus in pollen tube growth and in the division of the generative nucleus in Tradescantia paludosa . (biologists.org)
  • One group ( n = 20) received mechanical PBL (PMBL-Ismigen ® , Lallemand Pharma AG, Switzerland) (group P) during the grass pollen season, sublingually for 10 consecutive days per month for 3 consecutive months (May, June and July 2017). (termedia.pl)
  • The pollen season in Lublin started on 19 May 2017 and ended on 12 August 2017. (termedia.pl)
  • Swedish flower pollen promotes healthy urine flow and helps maintain normal prostate cell function. (allstarhealth.com)
  • Woodland Scenics - Pollen 1oz Pack Yellow - Use this paper flower pollen to add. (craftonline.com.au)
  • Collectively, our experimental and computational results offer fundamental insights into how tuning pollen structure can cause dramatic alterations to material properties, and inspire future investigation into understanding how the material science of pollen might influence plant reproductive success. (nature.com)
  • 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 . (fanlore.org)
  • Dick is exposed to actual plant-based sex pollen and jumps Tim, because who wouldn't. (fanlore.org)
  • Pollen is the equivalent of sperm for a plant. (healthtap.com)
  • The reaction is usually from cross-sensitivity between a particular pollen and another plant. (healthtap.com)
  • Risk assessment for GMOs such as Bt maize requires detailed data concerning pollen deposition onto non-target host-plant leaves. (springeropen.com)
  • A field study of pollen on lepidopteran host-plant leaves was therefore undertaken in 2009-2012 in Germany. (springeropen.com)
  • The plant-specific pollen deposition data were supplemented with standardised measurements of pollen release rates and deposition obtained by volumetric pollen monitors and passive samplers. (springeropen.com)
  • Counting of the germinated pollens revealed that the effects of these plant hormones were cultivar- and substance-specific. (oeno-one.eu)
  • Pollens of the table grape cultivars 'Italia' and 'Cardinal' ( Vitis vinifera L.) were used as plant materials. (oeno-one.eu)
  • The vegetative cell which comprises the bulk of the pollen cytoplasm is responsible for the development of the pollen tube. (le.ac.uk)
  • The aperture gap in the exine layer is integral to pollen tube growth and is neighbored by pollen wall regions with distinct material properties. (nature.com)
  • The pistil provides everything the pollen requires for success in this endeavor including distinct guidance cues and essential nutrients that allow the pollen tube to traverse enormous distances along a complex path to the unfertilized ovule. (valpo.edu)
  • On the other hand, different bee colonies collect pollen from different plants and thus the reaction may not be universal. (healthtap.com)
  • The highest pollen deposition was within the field, but depositions of several thousand pollen grains per square meter were recorded over the kilometer range. (springeropen.com)
  • We analyzed data on maize pollen deposition at 216 sites in Germany, Switzerland, and Belgium from 2001 to 2010. (springeropen.com)
  • Maize pollen deposition was negatively correlated with distance from the nearest pollen source. (springeropen.com)
  • A power function model most accurately described the relationship between deposition and distance from the nearest pollen source, rather than the exponential model currently used in EU risk assessment and management, which underestimates exposure for distances greater than 10 m. (springeropen.com)
  • Because pollen grains are carried by wind into the surrounding landscape, quantitative data on pollen deposition are needed to estimate the exposure of non-target organisms that may consume the pollen deposited on their host plants. (springeropen.com)
  • Because variation and total aggregation of deposited pollen on leaves have been previously underestimated, lepidopteran larvae have actually been subjected to higher and more variable exposure. (springeropen.com)
  • 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. (springeropen.com)
  • Because exposure is the basis of any effect, the interpretation of maize pollen leaf deposition data is highly relevant to the above debate. (springeropen.com)
  • Background and Aims Flow cytometry has been used to measure nuclear DNA content in pollen, mostly to understand pollen development and detect unreduced gametes. (usda.gov)