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Sample records for progamic pollen tube

  1. Sporophytic control of pollen tube growth and guidance in maize

    Science.gov (United States)

    Lausser, Andreas; Kliwer, Irina; Srilunchang, Kanok-orn; Dresselhaus, Thomas

    2010-01-01

    Pollen tube germination, growth, and guidance (progamic phase) culminating in sperm discharge is a multi-stage process including complex interactions between the male gametophyte as well as sporophytic tissues and the female gametophyte (embryo sac), respectively. Inter- and intra-specific crossing barriers in maize and Tripsacum have been studied and a precise description of progamic pollen tube development in maize is reported here. It was found that pollen germination and initial tube growth are rather unspecific, but an early, first crossing barrier was detected before arrival at the transmitting tract. Pollination of maize silks with Tripsacum pollen and incompatible pollination of Ga1s/Ga1s-maize silks with ga1-maize pollen revealed another two incompatibility barriers, namely transmitting tract mistargeting and insufficient growth support. Attraction and growth support by the transmitting tract seem to play key roles for progamic pollen tube growth. After leaving transmitting tracts, pollen tubes have to navigate across the ovule in the ovular cavity. Pollination of an embryo sac-less maize RNAi-line allowed the role of the female gametophyte for pollen tube guidance to be determined in maize. It was found that female gametophyte controlled guidance is restricted to a small region around the micropyle, approximately 50–100 μm in diameter. This area is comparable to the area of influence of previously described ZmEA1-based short-range female gametophyte signalling. In conclusion, the progamic phase is almost completely under sporophytic control in maize. PMID:19926683

  2. Transport logistics in pollen tubes.

    Science.gov (United States)

    Chebli, Youssef; Kroeger, Jens; Geitmann, Anja

    2013-07-01

    Cellular organelles move within the cellular volume and the effect of the resulting drag forces on the liquid causes bulk movement in the cytosol. The movement of both organelles and cytosol leads to an overall motion pattern called cytoplasmic streaming or cyclosis. This streaming enables the active and passive transport of molecules and organelles between cellular compartments. Furthermore, the fusion and budding of vesicles with and from the plasma membrane (exo/endocytosis) allow for transport of material between the inside and the outside of the cell. In the pollen tube, cytoplasmic streaming and exo/endocytosis are very active and fulfill several different functions. In this review, we focus on the logistics of intracellular motion and transport processes as well as their biophysical underpinnings. We discuss various modeling attempts that have been performed to understand both long-distance shuttling and short-distance targeting of organelles. We show how the combination of mechanical and mathematical modeling with cell biological approaches has contributed to our understanding of intracellular transport logistics.

  3. Effect of gamma rays doses on pollen germination, polysiphony and pollen tube elongation in Pinus patula Schiede et Deppe

    International Nuclear Information System (INIS)

    Katiyar, S.R.; Chauhan, Y.S.

    1987-01-01

    The present study aimed to study the effects of gamma radiation ( 60 Co) on pollen germination and pollen tube elongation in Pinus patula. Pollen germination and pollen tube elongation are stimulated by low doses of radiation. Although higher doses of radiation inhibit the germination of pollen, pollen tube elongation remains unaffected. Thus in Pinus patula pollen tube elongation is less radiosensitive than pollen germination. Compared to control pollen, irradiated pollen produced more number of long pollen tubes. Therefore pollen tube size can be improved using low doses of radiation. (author). 15 refs., 5 figs., 2 tables

  4. Gibberellin regulates pollen viability and pollen tube growth in rice.

    Science.gov (United States)

    Chhun, Tory; Aya, Koichiro; Asano, Kenji; Yamamoto, Eiji; Morinaka, Yoichi; Watanabe, Masao; Kitano, Hidemi; Ashikari, Motoyuki; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

    2007-12-01

    Gibberellins (GAs) play many biological roles in higher plants. We collected and performed genetic analysis on rice (Oryza sativa) GA-related mutants, including GA-deficient and GA-insensitive mutants. Genetic analysis of the mutants revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. To understand these differences in transmission, we examined the effect of GA on microsporogenesis and pollen tube elongation in rice using new GA-deficient and GA-insensitive mutants that produce semifertile flowers. Phenotypic analysis revealed that the GA-deficient mutant reduced pollen elongation1 is defective in pollen tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semidominant mutant Slr1-d3 is mainly defective in viable pollen production. Quantitative RT-PCR revealed that GA biosynthesis genes tested whose mutations are transmitted to the next generation at a lower frequency are preferentially expressed after meiosis during pollen development, but expression is absent or very low before the meiosis stage, whereas GA signal-related genes are actively expressed before meiosis. Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

  5. Cotton transformation via pollen tube pathway.

    Science.gov (United States)

    Wang, Min; Zhang, Baohong; Wang, Qinglian

    2013-01-01

    Although many gene transfer methods have been employed for successfully obtaining transgenic cotton, the major constraint in cotton improvement is the limitation of genotype because the majority of transgenic methods require plant regeneration from a single transformed cell which is limited by cotton tissue culture. Comparing with other plant species, it is difficult to induce plant regeneration from cotton; currently, only a limited number of cotton cultivars can be cultured for obtaining regenerated plants. Thus, development of a simple and genotype-independent genetic transformation method is particularly important for cotton community. In this chapter, we present a simple, cost-efficient, and genotype-independent cotton transformation method-pollen tube pathway-mediated transformation. This method uses pollen tube pathway to deliver transgene into cotton embryo sacs and then insert foreign genes into cotton genome. There are three major steps for pollen tube pathway-mediated genetic transformation, which include injection of -foreign genes into pollen tube, integration of foreign genes into plant genome, and selection of transgenic plants.

  6. Effects of fluorides and sulphur dioxide on pollen germination and growth of the pollen tube

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    Leon Mejnartowicz

    2014-01-01

    Full Text Available The action of fluorides and sulphur dioxides from emissions from a phosphate fertilizer factory significantly reduced the germination of Scots pine pollen grains. The pollen tube length indicated that its growth is uninhibited even though the pollen was collected under conditions of air-pollution. There are statistically significant differences showing longer tubes in the sensitive trees pollen grains. l he ageing of pollen from the sensitive trees occurs probably more rapidly than in the tolerant trees.

  7. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

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    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  8. A pollen-specific RALF from tomato that regulates pollen tube elongation.

    Science.gov (United States)

    Covey, Paul A; Subbaiah, Chalivendra C; Parsons, Ronald L; Pearce, Gregory; Lay, Fung T; Anderson, Marilyn A; Ryan, Clarence A; Bedinger, Patricia A

    2010-06-01

    Rapid Alkalinization Factors (RALFs) are plant peptides that rapidly increase the pH of plant suspension cell culture medium and inhibit root growth. A pollen-specific tomato (Solanum lycopersicum) RALF (SlPRALF) has been identified. The SlPRALF gene encodes a preproprotein that appears to be processed and released from the pollen tube as an active peptide. A synthetic SlPRALF peptide based on the putative active peptide did not affect pollen hydration or viability but inhibited the elongation of normal pollen tubes in an in vitro growth system. Inhibitory effects of SlPRALF were detectable at concentrations as low as 10 nm, and complete inhibition was observed at 1 mum peptide. At least 10-fold higher levels of alkSlPRALF, which lacks disulfide bonds, were required to see similar effects. A greater effect of peptide was observed in low-pH-buffered medium. Inhibition of pollen tube elongation was reversible if peptide was removed within 15 min of exposure. Addition of 100 nm SlPRALF to actively growing pollen tubes inhibited further elongation until tubes were 40 to 60 mum in length, after which pollen tubes became resistant to the peptide. The onset of resistance correlated with the timing of the exit of the male germ unit from the pollen grain into the tube. Thus, exogenous SlPRALF acts as a negative regulator of pollen tube elongation within a specific developmental window.

  9. De novo post-pollen mitosis II tobacco pollen tube transcriptome

    Czech Academy of Sciences Publication Activity Database

    Hafidh, Said; Breznenová, Katarína; Honys, David

    2012-01-01

    Roč. 7, č. 8 (2012), s. 918-921 ISSN 1559-2316 R&D Projects: GA ČR GPP501/11/P321; GA ČR GA522/09/0858 Institutional research plan: CEZ:AV0Z50380511 Keywords : de novo pollen tube transcriptome * male gametophyte development * pollen tube growth Subject RIV: ED - Physiology

  10. Ion Implantation Hampers Pollen Tube Growth and Disrupts Actin Cytoskeleton Organization in Pollen Tubes of Pinus thunbergii

    International Nuclear Information System (INIS)

    Li Guoping; Yang Lusheng; Huang Qunce; Qin Guangyong

    2008-01-01

    Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.

  11. Pollen tube germination in maize does not require transcriptomic changes

    Science.gov (United States)

    One objective for our group is to better understand the molecular and genetic basis of pollen and pollen tube function, given its critical role in seed production and its importance as a means of gene flow between plant populations. We compared gene expression levels in seedlings...

  12. Ultrastructural features of Mimulus aurantiacus (Scrophulariaceae) pollen tubes in vivo

    OpenAIRE

    Ekici,Nuran; Dane,Feruzan; Olgun,Göksel

    2009-01-01

    The aim of this study is to give information on ultrastructure of in vivo pollen tubes of Mimulus aurantiacus which were collected from the Botanical Garden of the University of California at Berkeley. Materials were prepared according to electron microscopy methods and examined under Zeiss electron microscope. Four zones were examined in the pollen tubes of Mimulus aurantiacus. APICAL ZONE: Mitochondria, smooth endoplasmic reticulum, rough endoplasmic reticulum, dictyosomes and secretory ves...

  13. Molecular cloning and transcriptional activity of a new Petunia calreticulin gene involved in pistil transmitting tract maturation, progamic phase, and double fertilization.

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    Lenartowski, Robert; Suwińska, Anna; Prusińska, Justyna; Gumowski, Krzysztof; Lenartowska, Marta

    2014-02-01

    Calreticulin (CRT) is a highly conserved and ubiquitously expressed Ca²⁺-binding protein in multicellular eukaryotes. As an endoplasmic reticulum-resident protein, CRT plays a key role in many cellular processes including Ca²⁺ storage and release, protein synthesis, and molecular chaperoning in both animals and plants. CRT has long been suggested to play a role in plant sexual reproduction. To begin to address this possibility, we cloned and characterized the full-length cDNA of a new CRT gene (PhCRT) from Petunia. The deduced amino acid sequence of PhCRT shares homology with other known plant CRTs, and phylogenetic analysis indicates that the PhCRT cDNA clone belongs to the CRT1/CRT2 subclass. Northern blot analysis and fluorescent in situ hybridization were used to assess PhCRT gene expression in different parts of the pistil before pollination, during subsequent stages of the progamic phase, and at fertilization. The highest level of PhCRT mRNA was detected in the stigma-style part of the unpollinated pistil 1 day before anthesis and during the early stage of the progamic phase, when pollen is germinated and tubes outgrow on the stigma. In the ovary, PhCRT mRNA was most abundant after pollination and reached maximum at the late stage of the progamic phase, when pollen tubes grow into the ovules and fertilization occurs. PhCRT mRNA transcripts were seen to accumulate predominantly in transmitting tract cells of maturing and receptive stigma, in germinated pollen/growing tubes, and at the micropylar region of the ovule, where the female gametophyte is located. From these results, we suggest that PhCRT gene expression is up-regulated during secretory activity of the pistil transmitting tract cells, pollen germination and outgrowth of the tubes, and then during gamete fusion and early embryogenesis.

  14. Control of Cell Wall Extensibility during Pollen Tube Growth

    OpenAIRE

    Hepler, Peter K.; Rounds, Caleb M.; Winship, Lawrence J.

    2013-01-01

    Tip-growing pollen tubes achieve rapid elongation while maintaining cell wall integrity by balancing local expansion, controlled by local changes in wall viscosity, against exocytosis, influenced by the activity of the actin cytoskeleton, cellular energetics, and calcium and proton physiology.

  15. Antinuclear human autoantibodies as markers in Nicotiana tabacum pollen tubes

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    C. Poggialini

    2014-01-01

    Full Text Available In the present paper we report on the use of antinuclear human autoantibodies as specific markers in Nicotiana tabacum pollen tubes. The antibodies have been tested by fluorescence techniques using a confocal laser scanning microscope. All the antibodies showed specifc labelling pattern and the results, although preliminary in nature, could open new perspectives of research.

  16. Peptide signalling during the pollen tube journey and double fertilization.

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    Qu, Li-Jia; Li, Ling; Lan, Zijun; Dresselhaus, Thomas

    2015-08-01

    Flowering seed plants (angiosperms) have evolved unique ways to protect their gametes from pathogen attack and from drying out. The female gametes (egg and central cell) are deeply embedded in the maternal tissues of the ovule inside the ovary, while the male gametes (sperm cells) are enclosed in the vegetative pollen tube cell. After germination of the pollen tube at the surface of papilla cells of the stigma the two immobile sperm cells are transported deep inside the sporophytic maternal tissues to be released inside the ovule for double fertilization. Angiosperms have evolved a number of hurdles along the pollen tube journey to prevent inbreeding and fertilization by alien sperm cells, and to maximize reproductive success. These pre-zygotic hybridization barriers require intensive communication between the male and female reproductive cells and the necessity to distinguish self from non-self interaction partners. General molecules such as nitric oxide (NO) or gamma-aminobutyric acid (GABA) therefore appear to play only a minor role in these species-specific communication events. The past 20 years have shown that highly polymorphic peptides play a leading role in all communication steps along the pollen tube pathway and fertilization. Here we review our current understanding of the role of peptides during reproduction with a focus on peptide signalling during self-incompatibility, pollen tube growth and guidance as well as sperm reception and gamete activation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. [The development of pollen grains and formation of pollen tubes in higher plants : I. Quantitative measurements of the DNA-content of generative and vegetative nuclei in the pollen grain and pollen tube of Petunia hybrida mutants].

    Science.gov (United States)

    Hesemann, C U

    1971-01-01

    The DNA-content of generative and vegetative nuclei in mature pollen grains of four Petunia hybrida mutants was determined by cytophotometry. In addition the DNA-content of generative and vegetative nuclei in the pollen tube of two of these four mutants (virescens-2 n and ustulata-2 n) was cytophotometrically measured.The DNA-values found in the generative nuclei indicate that the DNA-replication continues in the mature pollen grain and comes to an end only after the migration of the nuclei into the pollen tube. These data are in disagreement with the results of DNA-measurements described for a limited number of other species which all show completion of DNA-synthesis during the maturation stage of the pollen grains.The vegetative nuclei of the four Petunia mutants studied show significant differences in the onset of the degenerative phase. Extreme variation is manifested in the ustulata-2 n mutant in which the degeneration of nuclei may reach the final stage in the maturing pollen grain. However in this mutant vegetative nuclei with an unaltered DNA-content may also be demonstrated in the pollen tube. Some of the vegetative nuclei in the pollen tube of ustulata-2 n exhibit an increased amount of DNA which could be the result of differential DNA-replication in the vegetative nuclei. The decrease of the DNA-content in a certain fraction of the vegetative nuclei in the maturing pollen grain does not agree with observations made in other species by several authors who report DNA constancy until the pollen grain is fully mature.The data obtained from the analysis of the four Petunia hybrida mutants point to an important role of the vegetative nucleus in the development of the pollen tube. The Petunia hybrida mutants may be regarded as especially favourable material for investigations concerning the function of the vegetative cell in the development of the pollen grain and pollen tube.

  18. Using maize as a model to study pollen tube growth and guidance, cross-incompatibility and sperm delivery in grasses.

    Science.gov (United States)

    Dresselhaus, Thomas; Lausser, Andreas; Márton, Mihaela L

    2011-09-01

    In contrast to animals and lower plants such as mosses and ferns, sperm cells of flowering plants (angiosperms) are immobile and require transportation to the female gametes via the vegetative pollen tube cell to achieve double fertilization. The path of the pollen tube towards the female gametophyte (embryo sac) has been intensively studied in many intra- and interspecific crossing experiments with the aim of increasing the gene pool of crop plants for greater yield, improved biotic and abiotic stress resistance, and for introducing new agronomic traits. Many attempts to hybridize different species or genotypes failed due to the difficulty for the pollen tubes in reaching the female gametophyte. Detailed studies showed that these processes are controlled by various self-incompatible (intraspecific) and cross-incompatible (interspecific) hybridization mechanisms. Understanding the molecular mechanisms of crossing barriers is therefore of great interest in plant reproduction, evolution and breeding research. In particular, pre-zygotic hybridization barriers related to pollen tube germination, growth, guidance and sperm delivery, which are considered the major hybridization controls in nature and thus also contribute to species isolation and speciation, have been intensively investigated. Despite this general interest, surprisingly little is known about these processes in the most important agronomic plant family, the Gramineae, Poaceae or grasses. Small polymorphic proteins and their receptors, degradation of sterility locus proteins and general compounds such as calcium, γ-aminobutyric acid or nitric oxide have been shown to be involved in progamic pollen germination, adhesion, tube growth and guidance, as well as sperm release. Most advances have been made in the Brassicaceae, Papaveraceae, Linderniaceae and Solanaceae families including their well-understood self-incompatibility (SI) systems. Grass species evolved similar mechanisms to control the penetration

  19. Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast.

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    Yaning Cui

    Full Text Available Histone deacetylase (HDAC is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA and sodium butyrate (NaB to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components.

  20. Pollen tube branching in the ovary of five species of Oenothera

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    Renata Śnieżko

    2014-01-01

    Full Text Available Flowers of Oenothera hookeri Torr. et Gray, Oe. brevistylis and Oe. lamarkiana de Vries were pollinated after anthesis by insects. Oe. biennis L., Oe. suaveolens Desf and sulfurea were selfpollinated in the buds. Pollen morphology was slightly different: Oe. hookeri have regular, triporated pollen, often germinating through two pores; in Oe. suaveolens many pollen grains had callose patches on the intine; in Oe. brevistylis tetraporated pollen were more often than in other species; in Oe. lamarckiana many pollen grains were empty; in Oe. biennis and Oe. suaveolens pollen grain size and viability varied. The pollen tube growth and fertilization were similar in 5 species and can be considered as typical for Oenothera. In the ovary pollen tubes branched and changed their growth direction. Near micropyle they formed short branches to the inner integument. In the nucellus the pollen tube became swollen.

  1. Silencing of the pollen-specific gene NTP303 and its family members in tobacco affects in vivo pollen tube growth and results in male sterile plants

    NARCIS (Netherlands)

    Groot, de P.; Weterings, K.; Been, de M.; Wittink, F.; Hulzink, R.; Custers, J.B.M.; Herpen, van T.W.J.M.; Wullems, G.

    2004-01-01

    In seed plants, successful fertilization requires correct regulation of pollen tube growth. At germination and during growth, the pollen tube interacts with tissues from the pistil while the pollen tube extends via tip growth. Despite the fact that much research has been devoted to the mechanisms

  2. Unusual behavior of growing pollen tubes in the ovary of plum culture (Prunus domestica L.

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    Đorđević Milena

    2010-01-01

    Full Text Available Unusual behavior of growing pollen tubes in different combinations of pollination was observed in the ovary of the plum (Prunus domestica L. cv 'Čačanska Lepotica'. It primarily refers to several issues, i.e. the curling up of pollen tubes within the micropyle, the growth of two pollen tubes into the nucellus of an ovule, the occurrence of a bundle above the nucellar cap and fluorescence of the part of the embryo sac containing the egg apparatus. Upon the growth of pollen tubes into the nucellus of the ovule, subsequently penetrating pollen tubes form a bundle either above the micropyle entrance or above the nucellus. Branching and bending of pollen tubes by 180o upon their growth into the micropyle was also observed.

  3. Overexpression of the tomato pollen receptor kinase LePRK1 rewires pollen tube growth to a blebbling mode

    Science.gov (United States)

    The tubular growth of a pollen tube cell is crucial for the sexual reproduction of flowering plants. LePRK1 is a pollen-specific and plasma membrane–localized receptor-like kinase from tomato (Solanum lycopersicum). LePRK1 interacts with another receptor, LePRK2, and with KINASE PARTNER PROTEIN (KPP...

  4. Effect of smoke derivatives on in vitro pollen germination and pollen tube elongation of species from different plant families

    Czech Academy of Sciences Publication Activity Database

    Kumari, A.; Papenfus, H. B.; Kulkarni, M. G.; Pošta, Martin; van Staden, J.

    2015-01-01

    Roč. 17, č. 4 (2015), s. 825-830 ISSN 1435-8603 Institutional support: RVO:61388963 Keywords : karrikinolide * pollen germination * pollen tube growth * smoke-water * trimethylbutenolide Subject RIV: CC - Organic Chemistry Impact factor: 2.216, year: 2015

  5. Ultrastructural features of Mimulus aurantiacus (Scrophulariaceae) pollen tubes in vivo.

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    Ekici, Nuran; Dane, Feruzan; Olgun, Göksel

    2009-03-01

    The aim of this study is to give information on ultrastructure of in vivo pollen tubes of Mimulus aurantiacus which were collected from the Botanical Garden of the University of California at Berkeley. Materials were prepared according to electron microscopy methods and examined under Zeiss electron microscope. Four zones were examined in the pollen tubes of Mimulus aurantiacus. Apical zone: Mitochondria, smooth endoplasmic reticulum, rough endoplasmic reticulum, dictyosomes and secretory vesicles were observed. Subapical zone: This area contained abundant rough endoplasmic reticulum and occasionally some smooth endoplasmic reticulum. The polysomes, mitochondria, proplastids that contain starch, small vacuoles and a few lipid bodies were detected. Nuclear zone: Both generative and vegetative cell nuclei lie in this zone. The vegetative cell nucleus was large and long. Rough endoplasmic reticulum, mitochondria, ribosomes, dictyosomes, and amyloplasts that are rich of starch were observed. Vacuolation and plug formation zone: Cytoplasm of the tubes was full of large vacuoles. Few organelles such as mitochondria, dictyosome and rough endoplasmic reticulum were detected along their periphery.

  6. Effects on cuytoskeleton system in pollen tube of pinus thunbergii induced by ion beam implantation

    International Nuclear Information System (INIS)

    Huang Qunce; Liang Qiuxia; Li Guopin

    2008-01-01

    The damage of the cytoskeleton system in the pollen and the pollen tube of Pinus thunbergii induced by ion beam implantation were researched. The results showed that the disorganization of the micro-tubules in the pollen tube was produced by N + implantation. The abnormal states of the pollen tube in morphology were very correlative with the abnormality of the cytoskeleton system. N + implantation was responsible for morphological abnormalities in the pollen tubes. There was a distinct correlation between the damage effects and the ion implantation dose. The add of dose caused more obvious damage effects. Furthermore, the state of the cytoskeleton system in the pollen tube was influenced by the ion implantation. The impact grade depended also on the ion implantation dose. (authors)

  7. Arabidopsis COBRA-LIKE 10, a GPI-anchored protein, mediates directional growth of pollen tubes

    NARCIS (Netherlands)

    Li, S.; Ge, F.R.; Xu, M.; Zhao, X.Y.; Huang, G.Q.; Zhou, L.Z.; Wang, J.G.; Kombrink, A.; McCormick, S.; Zhang, X.S.; Zhang, Y.

    2013-01-01

    Successful reproduction of flowering plants requires constant communication between female tissues and growing pollen tubes. Female cells secrete molecules and peptides as nutrients or guidance cues for fast and directional tube growth, which is executed by dynamic changes of intracellular

  8. Quantitative proteomics of the tobacco pollen tube secretome identifies novel pollen tube guidance proteins important for fertilization

    Czech Academy of Sciences Publication Activity Database

    Hafidh, Said; Potěšil, D.; Fíla, Jan; Čapková, Věra; Zdráhal, Z.; Honys, David

    2016-01-01

    Roč. 17, MAY 3 (2016), č. článku 81. ISSN 1465-6906 R&D Projects: GA ČR GA15-22720S; GA ČR(CZ) GA14-32292S; GA ČR(CZ) GA15-16050S; GA MŠk(CZ) LD14109; GA MŠk(CZ) LM2015043; GA MŠk(CZ) ED1.1.00/02.0068; GA MŠk(CZ) LQ1601 Institutional support: RVO:61389030 Keywords : Protein secretion * Pollen tube guidance * Cell-cell signaling Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 11.313, year: 2015

  9. Calreticulin is required for calcium homeostasis and proper pollen tube tip growth in Petunia

    OpenAIRE

    Suwi?ska, Anna; Was?g, Piotr; Zakrzewski, Przemys?aw; Lenartowska, Marta; Lenartowski, Robert

    2017-01-01

    Main conclusion Calreticulin is involved in stabilization of the tip-focused Ca 2+ gradient and the actin cytoskeleton arrangement and function that is required for several key processes driving Petunia pollen tube tip growth. Although the precise mechanism is unclear, stabilization of a tip-focused calcium (Ca2+) gradient seems to be critical for pollen germination and pollen tube growth. We hypothesize that calreticulin (CRT), a Ca2+-binding/buffering chaperone typically residing in the lum...

  10. Plant Reproduction and the Pollen Tube Journey--How the Females Lure the Males

    Science.gov (United States)

    Lorbiecke, Rene

    2012-01-01

    The growth of pollen tubes is one of the most characteristic events in angiosperm reproduction. This article describes an activity for visualizing the journey and guidance of pollen tubes in the reproductive structures of a flowering plant. The activity uses a semi-in vivo system with rapid-cycling "Brassica rapa," also known as Fast Plants.…

  11. [Does a lateral gradient of membrane potential on the plasma membrane of growing pollen tube of germinating pollen grain exist?].

    Science.gov (United States)

    Andreev, I M

    2011-01-01

    The data presented in the article by Breigina et al. (2009) "Changes in the membrane potential during pollen grain germination and pollen tube growth" (Tsitologiya. 51 (10): 815-823) and concerning the measurement of electric membrane potential (Delta Psi) on the plasma membrane of growing pollen tube of germinating pollen grain with the use of fluorescent potential-sensitive dye, di-4-ANEPPS, were critically analyzed in order to clarify whether a lateral gradient of Delta Psi on this membrane indeed exists. This analysis showed that the main conclusion of the authors of the above article on the existence of polar distribution of Delta Psi along the pollen tube plasma membrane is not in accordance with a number of known peculiarities of di-4-ANEPPS behavior in biological membranes and requires a significant revision. The findings in question reported by the authors, in my opinion, might be interpreted as evidence for the presence on the plasma membrane of growing pollen tube not only the membrane potential Delta Psi but also lateral gradient of so called intra-membrane dipole potential. Based on the comments made, another interpretation of the experimental results described by Breigina et al. has been offered. In addition, some drawbacks in the methodology used by the authors for measurement of Delta Psi with other fluorescent potential-sensitive dye, DiBAC3(3), are also shortly considered.

  12. External application of gametophyte-specific ZmPMEI1 induces pollen tube burst in maize.

    Science.gov (United States)

    Woriedh, Mayada; Wolf, Sebastian; Márton, Mihaela L; Hinze, Axel; Gahrtz, Manfred; Becker, Dirk; Dresselhaus, Thomas

    2013-09-01

    Regulated demethylesterification of homogalacturonan, a major component of plant cell walls, by the activity of pectin methylesterases (PMEs), plays a critical role for cell wall stability and integrity. Especially fast growing plant cells such as pollen tubes secrete large amounts of PMEs toward their apoplasmic space. PME activity itself is tightly regulated by its inhibitor named as PME inhibitor and is thought to be required especially at the very pollen tube tip. We report here the identification and functional characterization of PMEI1 from maize (ZmPMEI1). We could show that the protein acts as an inhibitor of PME but not of invertases and found that its gene is strongly expressed in both gametophytes (pollen grain and embryo sac). Promoter reporter studies showed gene activity also during pollen tube growth toward and inside the transmitting tract. All embryo sac cells except the central cell displayed strong expression. Weaker signals were visible at sporophytic cells of the micropylar region. ZmPMEI1-EGFP fusion protein is transported within granules inside the tube and accumulates at the pollen tube tip as well as at sites where pollen tubes bend and/or change growth directions. The female gametophyte putatively influences pollen tube growth behavior by exposing it to ZmPMEI1. We therefore simulated this effect by applying recombinant protein at different concentrations on growing pollen tubes. ZmPMEI1 did not arrest growth, but destabilized the cell wall inducing burst. Compared with female gametophyte secreted defensin-like ZmES4, which induces burst at the very pollen tube tip, ZmPMEI1-induced burst occurs at the subapical region. These findings indicate that ZmPMEI1 secreted by the embryo sac likely destabilizes the pollen tube wall during perception and together with other proteins such as ZmES4 leads to burst and thus sperm release.

  13. Calreticulin is required for calcium homeostasis and proper pollen tube tip growth in Petunia.

    Science.gov (United States)

    Suwińska, Anna; Wasąg, Piotr; Zakrzewski, Przemysław; Lenartowska, Marta; Lenartowski, Robert

    2017-05-01

    Calreticulin is involved in stabilization of the tip-focused Ca 2+ gradient and the actin cytoskeleton arrangement and function that is required for several key processes driving Petunia pollen tube tip growth. Although the precise mechanism is unclear, stabilization of a tip-focused calcium (Ca 2+ ) gradient seems to be critical for pollen germination and pollen tube growth. We hypothesize that calreticulin (CRT), a Ca 2+ -binding/buffering chaperone typically residing in the lumen of the endoplasmic reticulum (ER) of eukaryotic cells, is an excellent candidate to fulfill this role. We previously showed that in Petunia pollen tubes growing in vitro, CRT is translated on ER membrane-bound ribosomes that are abundant in the subapical zone of the tube, where CRT's Ca 2+ -buffering and chaperone activities might be particularly required. Here, we sought to determine the function of CRT using small interfering RNA (siRNA) to, for the first time in pollen tubes growing in vitro, knockdown expression of a gene. We demonstrate that siRNA-mediated post-transcriptional silencing of Petunia hybrida CRT gene (PhCRT) expression strongly impairs pollen tube growth, cytoplasmic zonation, actin cytoskeleton organization, and the tip-focused Ca 2+ gradient. Moreover, reduction of CRT alters the localization and disturbs the structure of the ER in abnormally elongating pollen tubes. Finally, cytoplasmic streaming is inhibited, and most of the pollen tubes rupture. Our data clearly show an interplay between CRT, Ca 2+ gradient, actin-dependent cytoplasmic streaming, organelle positioning, and vesicle trafficking during pollen tube elongation. Thus, we suggest that CRT functions in Petunia pollen tube growth by stabilizing Ca 2+ homeostasis and acting as a chaperone to assure quality control of glycoproteins passing through the ER.

  14. Effects of X-rays on seed setting and pollen tube growth in self-incompatible petunia

    International Nuclear Information System (INIS)

    Gilissen, L.J.W.

    1978-01-01

    The high sensitivity of seed setting and the relative insensitivity of pollen tube growth in the style to X-irradiation of pollen of Petunia hybrida L. indicated that pollen tube growth is independent of activities of the pollen genome. The S-specificity of the pollen grain in relation to incompatibility must, therefore, have built up during maturation of the pollen grain. X-irradiation of styles caused changes in some enzymes essential for basic metabolism, without affecting the pattern of compatible or incompatible pollen tube growth. Compatible and incompatible pollen tube growth in the style appeared to be independent of the metabolic state of the stylar cells and their simultaneous gene-activity. It is suggested that the S-specificity of the style, which is responsible for pollen tube growth regulation, is expressed at a very young stage of flower development. (Auth.)

  15. Boron toxicity causes multiple effects on Malus domestica pollen tube growth

    Directory of Open Access Journals (Sweden)

    Kefeng eFang

    2016-02-01

    Full Text Available Boron is an essential micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this stress is not known. This study aimed to evaluate the effect of boron stress on Malus domestica pollen tube growth and its possible regulatory pathway. Our results show that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron stress could decrease [Ca2+]c and induce the disappearance of the [Ca2+]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron stress. Immuno-localization and fluorescence labeling, together with Fourier-transform infrared analysis (FTIR, suggested that boron stress influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca2+]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth.

  16. Boron Toxicity Causes Multiple Effects on Malus domestica Pollen Tube Growth.

    Science.gov (United States)

    Fang, Kefeng; Zhang, Weiwei; Xing, Yu; Zhang, Qing; Yang, Liu; Cao, Qingqin; Qin, Ling

    2016-01-01

    Boron is an important micronutrient for plants. However, boron is also toxic to cells at high concentrations, although the mechanism of this toxicity is not known. This study aimed to evaluate the effect of boron toxicity on Malus domestica pollen tube growth and its possible regulatory pathway. Our results showed that a high concentration of boron inhibited pollen germination and tube growth and led to the morphological abnormality of pollen tubes. Fluorescent labeling coupled with a scanning ion-selective electrode technique detected that boron toxicity could decrease [Ca(2+)]c and induce the disappearance of the [Ca(2+)]c gradient, which are critical for pollen tube polar growth. Actin filaments were therefore altered by boron toxicity. Immuno-localization and fluorescence labeling, together with fourier-transform infrared analysis, suggested that boron toxicity influenced the accumulation and distribution of callose, de-esterified pectins, esterified pectins, and arabinogalactan proteins in pollen tubes. All of the above results provide new insights into the regulatory role of boron in pollen tube development. In summary, boron likely plays a structural and regulatory role in relation to [Ca(2+)]c, actin cytoskeleton and cell wall components and thus regulates Malus domestica pollen germination and tube polar growth.

  17. The effect of intracellular calcium level regulators on the synthesis of pollen tube callose in Oenothera biennis L.

    Directory of Open Access Journals (Sweden)

    Elżbieta Bednarska

    2014-01-01

    Full Text Available It is shown that callose synthesis in the Oenothera biennis pollen tube is regulated by the endogenous Ca2+ level. Calcium antagonists reduced the amount of callose in the wall above the tip of the pollen tube (Verapamil - calcium channels blocker and at the tube tip after stopping tube growth (La3+ - a Ca2+ substitute. Ruthenium red and ionophore A 23187, which raise the Ca 21 level in the cytoplasm, induced callose synthesis at the tip of pollen tube.

  18. FIMBRIN1 is involved in lily pollen tube growth by stabilizing the actin fringe.

    Science.gov (United States)

    Su, Hui; Zhu, Jinsheng; Cai, Chao; Pei, Weike; Wang, Jiaojiao; Dong, Huaijian; Ren, Haiyun

    2012-11-01

    An actin fringe structure in the subapex plays an important role in pollen tube tip growth. However, the precise mechanism by which the actin fringe is generated and maintained remains largely unknown. Here, we cloned a 2606-bp full-length cDNA encoding a deduced 77-kD fimbrin-like protein from lily (Lilium longiflorum), named FIMBRIN1 (FIM1). Ll-FIM1 was preferentially expressed in pollen and concentrated at actin fringe in the subapical region, as well as in longitudinal actin-filament bundles in the shank of pollen tubes. Microinjection of Ll-FIM1 antibody into lily pollen tubes inhibited tip growth and disrupted the actin fringe. Furthermore, we verified the function of Ll-FIM1 in the fim5 mutant of its closest relative, Arabidopsis thaliana. Pollen tubes of fim5 mutants grew with a larger diameter in early stages but could recover into normal forms in later stages, despite significantly slower growth rates. The actin fringe of the fim5 mutants, however, was impaired during both early and late stages. Impressively, stable expression of fim5pro:GFP:Ll-FIM1 rescued the actin fringe and the growth rate of Arabidopsis fim5 pollen tubes. In vitro biochemical analysis showed that Ll-FIM1 could bundle actin filaments. Thus, our study has identified a fimbrin that may stabilize the actin fringe by cross-linking actin filaments into bundles, which is important for proper tip growth of lily pollen tubes.

  19. The C-terminal hypervariable domain targets Aradopsis ROP9 to the invaginated pollen tube plasma membrane

    Science.gov (United States)

    Rop9 is a small GTPase of the Type II class, whereas the often studied type I Rops play roles during pollen tube growth. In pollen, Rop9 is located at the invaginated plasma membrane that surrounds the sperm cells, whereas type I Rops are located at the apical membrane of the pollen tube. The C-ter...

  20. Silencing of the pollen-specific gene NTP303 and its family members in tobacco affects in vivo pollen tube growth and results in male sterile plants.

    Science.gov (United States)

    de Groot, Peter; Weterings, Koen; de Been, Mark; Wittink, Floyd; Hulzink, Raymond; Custers, Jan; van Herpen, Marinus; Wullems, George

    2004-07-01

    In seed plants, successful fertilization requires correct regulation of pollen tube growth. At germination and during growth, the pollen tube interacts with tissues from the pistil while the pollen tube extends via tip growth. Despite the fact that much research has been devoted to the mechanisms regulating pollen tube growth, many aspects are currently unknown. Previously, we have isolated a pollen-specific gene from tobacco--NTP303--that probably functions during pollen tube growth. NTP303 is part of a family of five members. Its expression is regulated both at the transcriptional and at the translational level. While NTP303 transcripts accumulate to high levels between early bi-cellular and mature pollen stages, NTP303 protein is hardly detectable until germination and pollen tube growth. In order to elucidate the role and function of NTP303 in the pollen tube, we studied the effect of NTP303 gene silencing on pollen function. Therefore, we have transformed tobacco plants with NTP303 co-suppression and anti-sense gene constructs. In these plants, the kanamycin resistance trait--which was linked to the NTP303-silencing gene--was not transmitted through the male gametophyte. This indicated that lowering the transcript level of NTP303 and/or its family members interferes with pollen function. Because we could not find a readily distinguishable phenotype in pollen from the hemizygous anti-sense and co-suppression plants, we rescued the defective pollen to produce doubled haploid plants that were homozygous for the NTP303 anti-sense gene. We found that in pollen from these plants the transcript levels of all NTP303 family members were reduced. Although pollen and pollen tubes from these plants appeared completely normal in vitro, the pollen tubes showed slower growth rates in vivo and arrested in the style before they reached the ovary, so that fertilization failed. These data demonstrate that NTP303 and its family members are essential for normal pollen tube growth

  1. Transcriptional evidence for inferred pattern of pollen tube-stigma metabolic coupling during pollination.

    Directory of Open Access Journals (Sweden)

    Xun Yue

    Full Text Available It is difficult to derive all qualitative proteomic and metabolomic experimental data in male (pollen tube and female (pistil reproductive tissues during pollination because of the limited sensitivity of current technology. In this study, genome-scale enzyme correlation network models for plants (Arabidopsis/maize were constructed by analyzing the enzymes and metabolic routes from a global perspective. Then, we developed a data-driven computational pipeline using the "guilt by association" principle to analyze the transcriptional coexpression profiles of enzymatic genes in the consecutive steps for metabolic routes in the fast-growing pollen tube and stigma during pollination. The analysis identified an inferred pattern of pollen tube-stigma ethanol coupling. When the pollen tube elongates in the transmitting tissue (TT of the pistil, this elongation triggers the mobilization of energy from glycolysis in the TT cells of the pistil. Energy-rich metabolites (ethanol are secreted that can be taken up by the pollen tube, where these metabolites are incorporated into the pollen tube's tricarboxylic acid (TCA cycle, which leads to enhanced ATP production for facilitating pollen tube growth. In addition, our analysis also provided evidence for the cooperation of kaempferol, dTDP-alpha-L-rhamnose and cell-wall-related proteins; phosphatidic-acid-mediated Ca2+ oscillations and cytoskeleton; and glutamate degradation IV for γ-aminobutyric acid (GABA signaling activation in Arabidopsis and maize stigmas to provide the signals and materials required for pollen tube tip growth. In particular, the "guilt by association" computational pipeline and the genome-scale enzyme correlation network models (GECN developed in this study was initiated with experimental "omics" data, followed by data analysis and data integration to determine correlations, and could provide a new platform to assist inachieving a deeper understanding of the co-regulation and inter

  2. Post-pollination mechanisms in Nicotiana longiflora and N. plumbaginifolia: pollen tube growth rate, offspring paternity and hybridization.

    Science.gov (United States)

    Figueroa-Castro, Dulce M; Holtsford, Timothy P

    2009-09-01

    In natural populations where interfertile species coexist, conspecific and heterospecific pollen can be delivered to the stigmas. Post-pollination mechanisms might determine the seed siring success of different pollen donors within species as well as the chances for hybridization between species. Nicotiana longiflora and N. plumbaginifolia occur in sympatry in Northwest Argentina, where they have overlapping flowering seasons and share floral visitors. We explored (1) pollen tube growth rates for outcross versus self pollen in single-donor pollinations; (2) siring success of self versus outcross pollen donors in competitive pollinations, and (3) possibilities for hybridization by performing two- (outcross conspecific vs. heterospecific) and three-pollen donor (self vs. outcross vs. heterospecific) crosses. In N. longiflora, both pollen tube growth rate and siring success favored outcross pollen over self pollen and strong rejection of heterospecific pollen. In N. plumbaginifolia, pollen tube growth rate was similar for self and outcross pollen, self pollen sired similar numbers of offspring than outcross pollen and heterospecific pollen sired roughly the same number of progeny than self pollen. Results suggest that in natural sympatric populations, interspecific crosses would likely lead to unidirectional hybridization with N. plumbaginifolia as the seed parent.

  3. Anther response to high-temperature stress during development and pollen thermotolerance heterosis as revealed by pollen tube growth and in vitro pollen vigor analysis in upland cotton.

    Science.gov (United States)

    Song, Guicheng; Wang, Miaomiao; Zeng, Bin; Zhang, Jing; Jiang, Chenliang; Hu, Qirui; Geng, Guangtao; Tang, Canming

    2015-05-01

    Pollen tube growth in styles was strongly inhibited by temperature above 35 °C, and the yield of cotton decreased because of the adverse effect of high temperatures during square development. High-temperature stress during flowering influences the square development of upland cotton (Gossypium hirsutum L.) and cotton yield. Although it is well known that square development is sensitive to high temperature, high-temperature sensitive stages of square development and the effects of high temperature on pollen tube growth in the styles are unknown. The effect of high temperature on anther development corresponding to pollen vigor is unknown during anther development. The objectives of this study were to identify the stages of square development that are sensitive to high temperatures (37/30 and 40/34 °C), to determine whether the abnormal development of squares influenced by high temperature is responsible for the variation in the in vitro germination percent of pollen grains at anthesis, to identify the effect of high temperature on pollen germination in the styles, and to determine pollen thermotolerance heterosis. Our results show that the stages from the sporogenous cell to tetrad stage (square length styles was strongly inhibited by temperature above 35 °C, and the yield of cotton decreased because of the effect of high temperature during square development. The thermotolerance of hybrid F1 pollen showed heterosis, and pollen viability could be used as a criterion for screening for high-temperature tolerance cultivars. These results can be used in breeding to develop new cotton cultivars that can withstand high-temperature conditions, particularly in a future warmer climate.

  4. Messenger RNas : their utilization and degradation during pollen germination and tube growth

    Directory of Open Access Journals (Sweden)

    Joseph P. Mascarenhas

    2014-01-01

    Full Text Available During pollen germination and tube growth at least 230 new proteins are synthesized, as determined by 35S-methionime labeling and two dimensional gel electrophoretic analysis of the labeled proteins. The same number and pattern of protein spots is seen whether or not actinomycin D is included in the, medium, indicating that the mRNAs present in the unger-minated pollen grain and those newly synthesized code for the same proteins. The genetic program during at least the latter part of pollen maturation prior to anthesis and that during pollen germination and tube growth thus appears to be similar if not identical. During the first hour of pollen tube growth about 500/0 of the protein synthesis that occurs utilizes previously synthesized mRNAs. The remaining 50% occurs on newly made mRNAs. The ungerminated mature pollen grain contains 196 pg of RNA and approximately 6 X 106 molecules of poly(A+ RNA, i.e. mRNAs. The rate of protein synthesis corrected for internal pool changes in the labeled amino acid used (3H-leucine is highest during the first 15 min of pollen tube growth. The rate decreases rapidly thereafter for the next 45 min. Concurrent with the reduction in rate of protein synthesis there is a reduction in the poly(A content of the pollen RNA and in the amount of poly(A per pollen, grain. The total RNA per pollen grain, however, appears not to change during this period.

  5. Molecular evidence that rough endoplasmic reticulum is the site of calreticulin translation in Petunia pollen tubes growing in vitro.

    Science.gov (United States)

    Suwińska, Anna; Lenartowski, Robert; Smoliński, Dariusz Jan; Lenartowska, Marta

    2015-07-01

    In germinating pollen grains and growing pollen tubes, CRT is translated on ER membrane-bound ribosomes in the regions where its activity is required for stabilization of tip-focused Ca (2+) gradient. Pollen tube growth requires coordination of signaling, exocytosis, and actin cytoskeletal organization. Many of these processes are thought to be controlled by finely tuned regulation of cytoplasmic Ca(2+) in discrete regions of the tube cytoplasm. Most notably, a mechanism must function to maintain a steep gradient of Ca(2+) that exists at the tip of growing pollen tube. Several pieces of evidence point to calreticulin (CRT) as a key Ca(2+)-binding/-buffering protein involved in pollen germination and pollen tube growth. We previously hypothesized that in germinating pollen and growing tubes, CRT is translated on the ribosomes associated with endoplasmic reticulum (ER) in the regions where its activity might be required. In this report, we have addressed this idea by identifying the sites where CRT mRNA, CRT protein, 18S rRNA, and rough ER are localized in Petunia pollen tubes. We observed all four components in the germinal aperture of pollen grains and in subapical regions of elongating tubes. These results seem to support our idea that CRT is translated on ER membrane-bound ribosomes during pollen germination and pollen tube growth. In elongated pollen tubes, we found CRT mainly localized in the subapical zone, where ER and Golgi stacks are abundant. In eukaryotic cells, these organelles serve as mobile intracellular stores of easily releasable Ca(2+), which can be buffered by proteins such as CRT. Therefore, we postulate that subapical-localized CRT is involved in pollen tube growth by maintaining the stable tip-focused Ca(2+) gradient and thus modulating local Ca(2+) concentration within the tube cytoplasm.

  6. A microfluidic platform for the investigation of elongation growth in pollen tubes

    International Nuclear Information System (INIS)

    Agudelo, C G; Sanati, A; Ghanbari, M; Packirisamy, M; Geitmann, A

    2012-01-01

    Pollen tubes are an excellent model for the investigation of plant cell growth: they elongate at very high rates and are easily cultured in vitro. One major constraint in the study of pollen tube growth has been the difficulty in providing an in vitro testing environment that physically resembles the in vivo conditions. This work presents the development of a microfluidic platform for the study and manipulation of individual pollen tubes. The platform is fabricated from polydimethylsiloxane using a Silicon/SU-8 mold and makes use of microfluidics to distribute pollen grains to serially arranged microchannels into which the tubes grow to allow for individual testing. A 2D finite element fluid analysis is done to assist optimization of the architectural design. Validation of the device is carried out by growing Camellia japonica pollen. Results show that pollen tube germination and growth rate within the microfluidic network are similar to those obtained in conventional plate or batch assays. The microfluidic network allows for specific testing of a variety of structural features as demonstrated with a simple collision test, and it permits the straightforward integration of further single-cell test assays. (paper)

  7. Pyruvate decarboxylase provides growing pollen tubes with a competitive advantage in petunia.

    Science.gov (United States)

    Gass, Nathalie; Glagotskaia, Tatiana; Mellema, Stefan; Stuurman, Jeroen; Barone, Mario; Mandel, Therese; Roessner-Tunali, Ute; Kuhlemeier, Cris

    2005-08-01

    Rapid pollen tube growth places unique demands on energy production and biosynthetic capacity. The aim of this work is to understand how primary metabolism meets the demands of such rapid growth. Aerobically grown pollen produce ethanol in large quantities. The ethanolic fermentation pathway consists of two committed enzymes: pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH). Because adh mutations do not affect male gametophyte function, the obvious question is why pollen synthesize an abundant enzyme if they could do just as well without. Using transposon tagging in Petunia hybrida, we isolated a null mutant in pollen-specific Pdc2. Growth of the mutant pollen tubes through the style is reduced, and the mutant allele shows reduced transmission through the male, when in competition with wild-type pollen. We propose that not ADH but rather PDC is the critical enzyme in a novel, pollen-specific pathway. This pathway serves to bypass pyruvate dehydrogenase enzymes and thereby maintain biosynthetic capacity and energy production under the unique conditions prevailing during pollen-pistil interaction.

  8. An osmotic model of the growing pollen tube.

    Directory of Open Access Journals (Sweden)

    Adrian E Hill

    Full Text Available Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip.

  9. An Osmotic Model of the Growing Pollen Tube

    Science.gov (United States)

    Hill, Adrian E.; Shachar-Hill, Bruria; Skepper, Jeremy N.; Powell, Janet; Shachar-Hill, Yair

    2012-01-01

    Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip. PMID:22615784

  10. Propidium iodide competes with Ca(2+) to label pectin in pollen tubes and Arabidopsis root hairs.

    Science.gov (United States)

    Rounds, Caleb M; Lubeck, Eric; Hepler, Peter K; Winship, Lawrence J

    2011-09-01

    We have used propidium iodide (PI) to investigate the dynamic properties of the primary cell wall at the apex of Arabidopsis (Arabidopsis thaliana) root hairs and pollen tubes and in lily (Lilium formosanum) pollen tubes. Our results show that in root hairs, as in pollen tubes, oscillatory peaks in PI fluorescence precede growth rate oscillations. Pectin forms the primary component of the cell wall at the tip of both root hairs and pollen tubes. Given the electronic structure of PI, we investigated whether PI binds to pectins in a manner analogous to Ca(2+) binding. We first show that Ca(2+) is able to abrogate PI growth inhibition in a dose-dependent manner. PI fluorescence itself also relies directly on the amount of Ca(2+) in the growth solution. Exogenous pectin methyl esterase treatment of pollen tubes, which demethoxylates pectins, freeing more Ca(2+)-binding sites, leads to a dramatic increase in PI fluorescence. Treatment with pectinase leads to a corresponding decrease in fluorescence. These results are consistent with the hypothesis that PI binds to demethoxylated pectins. Unlike other pectin stains, PI at low yet useful concentration is vital and specifically does not alter the tip-focused Ca(2+) gradient or growth oscillations. These data suggest that pectin secretion at the apex of tip-growing plant cells plays a critical role in regulating growth, and PI represents an excellent tool for examining the role of pectin and of Ca(2+) in tip growth.

  11. Characterisation of detergent-insoluble membranes in pollen tubes of Nicotiana tabacum (L.

    Directory of Open Access Journals (Sweden)

    Alessandra Moscatelli

    2015-02-01

    Full Text Available Pollen tubes are the vehicle for sperm cell delivery to the embryo sac during fertilisation of Angiosperms. They provide an intriguing model for unravelling mechanisms of growing to extremes. The asymmetric distribution of lipids and proteins in the pollen tube plasma membrane modulates ion fluxes and actin dynamics and is maintained by a delicate equilibrium between exocytosis and endocytosis. The structural constraints regulating polarised secretion and asymmetric protein distribution on the plasma membrane are mostly unknown. To address this problem, we investigated whether ordered membrane microdomains, namely membrane rafts, might contribute to sperm cell delivery. Detergent insoluble membranes, rich in sterols and sphingolipids, were isolated from tobacco pollen tubes. MALDI TOF/MS analysis revealed that actin, prohibitins and proteins involved in methylation reactions and in phosphoinositide pattern regulation are specifically present in pollen tube detergent insoluble membranes. Tubulins, voltage-dependent anion channels and proteins involved in membrane trafficking and signalling were also present. This paper reports the first evidence of membrane rafts in Angiosperm pollen tubes, opening new perspectives on the coordination of signal transduction, cytoskeleton dynamics and polarised secretion.

  12. Incompatible pollen tubes in the plum style and their impact on fertilization success

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    Đorđević Milena

    2014-01-01

    Full Text Available The pistils of plum (Prunus domestica L. cv. ‘Čačanska Lepotica’ were self- and cross-pollinated in order to investigate occurrence of incompatible pollen tubes in the style, and their impact on fertilization success. The investigation also included open pollination variant. The highest percentage of these stopped the growth in the upper third of the style. Under cross-pollination variant, 15.4% and 12.1% of pollen tubes observed in the upper part of the style in the first and the second years of study, respectively, were found incompatible. In view of the above parameters, in the self- pollination variant, 15.0% and 17.0% of pollen tubes were found incompatible by years. As for the open pollination, percentages of incompatible pollen tubes in the upper part of the style by years were 14.0% and 14.4%, respectively. The occurrence of incompatible pollen tubes did not influence the fertilization success in these pollination variants. [Projekat Ministarstva nauke Republike Srbije, br. TR31064-Development and preservation of genetic potential of temperate zone fruits

  13. Pollen

    Science.gov (United States)

    ... that pollen can also be transported indoors on people and pets. Dry your clothes in an automatic dryer rather ... that pollen can also be transported indoors on people and pets. Dry your clothes in an automatic dryer rather ...

  14. Gene expression profile indicates involvement of NO in Camellia sinensis pollen tube growth at low temperature.

    Science.gov (United States)

    Pan, Junting; Wang, Weidong; Li, Dongqin; Shu, Zaifa; Ye, Xiaoli; Chang, Pinpin; Wang, Yuhua

    2016-10-18

    Nitric oxide (NO) functions as a critical signaling molecule in the low-temperature stress responses in plants, including polarized pollen tube growth in Camellia sinensis. Despite this, the potential mechanisms underlying the participation of NO in pollen tube responses to low temperature remain unclear. Here, we investigate alterations to gene expression in C. sinensis pollen tubes exposed to low-temperature stress and NO using RNA-Seq technology, in order to find the potential candidate genes related to the regulation of pollen tube elongation by NO under low-temperature stress. Three libraries were generated from C. sinensis cv. 'Longjingchangye' pollen tubes cultured at 25 °C (CsPT-CK) and 4 °C (CsPT-LT) or with 25 μM DEA NONOate (CsPT-NO). The number of unigenes found for the three biological replications were 39,726, 40,440 and 41,626 for CsPT-CK; 36,993, 39,070 and 39,439 for CsPT-LT; and 39,514, 38,298 and 39,061 for CsPT-NO. A total of 36,097 unique assembled and annotated sequences from C. sinensis pollen tube reads were found in a BLAST search of the following databases: NCBI non-redundant nucleotide, Swiss-prot protein, Kyoto Encyclopedia of Genes and Genomes, Cluster of Orthologous Groups of proteins, and Gene Ontology. The absolute values of log 2 Ratio > 1 and probability > 0.7 were used as the thresholds for significantly differential gene expression, and 766, 497 and 929 differentially expressed genes (DEGs) were found from the comparison analyses of the CK-VS-LT, CK-VS-NO and LT-VS-NO libraries, respectively. Genes related to metabolism and signaling pathways of plant hormones, transcription factors (TFs), vesicle polarized trafficking, cell wall biosynthesis, the ubiquitination machinery of the ubiquitin system and species-specific secondary metabolite pathways were mainly observed in the CK-VS-LT and CK-VS-NO libraries. Differentially expressed unigenes related to the inhibition of C. sinensis pollen tube growth under low

  15. Pollen tube growth test (PTGT) in environmental biomonitoring and predictive radiation biology studies: problem and prospect

    International Nuclear Information System (INIS)

    Pandey, Devi D.

    2012-01-01

    In Environmental and Human Bio monitoring studies of Hazardous xenobiotics over living system particularly at cell level, it is desirable to have easy and sensitive test system like Cell Viability assay, MNT, Cell Culture photo toxicity Test, PTGT etc. Out of these the PTGT quite better than other because the in vitro culture of pollen grain can provides a sensitive indication of toxicity at cellular level, since germination and growth of pollen tube will inhibited in presence of toxic substance like DDT, Heavy metal, even Radionuclide's. This test system is easy, economical and widely accepted through out world. In PTGT pollen tube never containing Chloroplast or other plastids so pollen tube resembles animals more than a plant organ and is therefore also a suitable as model for Genotoxicity Assessment of compounds harmful to animal and humans. Lack of plastids in PT, PTGT will not identify the toxic effect of compounds that targets Non cyclic and cyclic photoposphorylation of photosynthesis. This test system valid in International Toxicity Testing Protocol. But this method is time consuming and problem in measurement of pollen tube growing in a culture medium became usually bent and make measurement difficult. Other disadvantage of this method is requirement of DMSO to dissolve test substance of low water suitability in culture medium. DMSO shown to have no effect on PTG at Concentration not more than 1% but some extent interfere with results. Values of PTG are quantified in ED50/IC50 that is the concentration of test compounds that reduces pollen tube growth to 50% of control. So PTGT could be very sensitive and easy to assess in common lab in International way. (author)

  16. In vitro pollen germination, pollen tube growth and longevity in some ...

    African Journals Online (AJOL)

    Jane

    2011-08-03

    Aug 3, 2011 ... Loquat (Eriobotrya japonica Lindl.) is one of the most perspective trees with tasty fruits suitable for commercial production in Iran. However, self-incompatibility of most loquat cultivars makes it necessary to select good pollinizers in breeding and orchard establishment programs. Therefore, studies on pollen ...

  17. Male-female crosstalk during pollen germination, tube growth and guidance, and double fertilization.

    Science.gov (United States)

    Dresselhaus, Thomas; Franklin-Tong, Noni

    2013-07-01

    Sperm cells of flowering plants are non-motile and thus require transportation to the egg apparatus via the pollen tube to execute double fertilization. During its journey, the pollen tube interacts with various sporophytic cell types that support its growth and guide it towards the surface of the ovule. The final steps of tube guidance and sperm delivery are controlled by the cells of the female gametophyte. During fertilization, cell-cell communication events take place to achieve and maximize reproductive success. Additional layers of crosstalk exist, including self-recognition and specialized processes to prevent self-fertilization and consequent inbreeding. In this review, we focus on intercellular communication between the pollen grain/pollen tube including the sperm cells with the various sporophytic maternal tissues and the cells of the female gametophyte. Polymorphic-secreted peptides and small proteins, especially those belonging to various subclasses of small cysteine-rich proteins (CRPs), reactive oxygen species (ROS)/NO signaling, and the second messenger Ca(2+), play center stage in most of these processes.

  18. Identification of a Nicotiana plumbaginifolia plasma membrane H(+)-ATPase gene expressed in the pollen tube.

    Science.gov (United States)

    Lefebvre, Benoit; Arango, Miguel; Oufattole, Mohammed; Crouzet, Jérôme; Purnelle, Bénédicte; Boutry, Marc

    2005-08-01

    In Nicotiana plumbaginifolia, plasma membrane H(+)-ATPases (PMAs) are encoded by a gene family of nine members. Here, we report on the characterization of a new isogene, NpPMA5 (belonging to subfamily IV), and the determination of its expression pattern using the beta-glucuronidase (gusA) reporter gene. pNpPMA5-gusA was expressed in cotyledons, in vascular tissues of the stem (mainly in nodal zones), and in the flower and fruit. In the flower, high expression was found in the pollen tube after in vitro or in vivo germination. Northern blotting analysis confirmed that NpPMA5 was expressed in the pollen tube contrary to NpPMA2 (subfamily I) or NpPMA4 (subfamily II), two genes highly expressed in other tissues. The subcellular localization of PM H(+)-ATPase in the pollen tube was analyzed by immunocytodecoration. As expected, this enzyme was localized to the plasma membrane. However, neither the tip nor the base of the pollen tube was labeled, showing an asymmetrical distribution of this enzyme. This observation supports the hypothesis that the PM H(+)-ATPase is involved in creating the pH gradient that is observed along the pollen tube and is implicated in cell elongation. Compared to other plant PM H(+)-ATPases, the C-terminal region of NpPMA5 is shorter by 26 amino acid residues and is modified in the last 6 residues, due to a sequence rearrangement, which was also found in the orthologous gene of Nicotiana glutinosa, a Nicotiana species distant from N. plumbaginifolia and Petunia hybrida and Lycopersicon esculentum, other Solanacae species. This modification alters part of the PM H(+)-ATPase regulatory domain and raises the question whether this isoform is still regulated.

  19. Pectin and the role of the physical properties of the cell wall in pollen tube growth of Solanum chacoense.

    Science.gov (United States)

    Parre, Elodie; Geitmann, Anja

    2005-02-01

    The cell wall is one of the structural key players regulating pollen tube growth, since plant cell expansion depends on an interplay between intracellular driving forces and the controlled yielding of the cell wall. Pectin is the main cell wall component at the growing pollen tube apex. We therefore assessed its role in pollen tube growth and cytomechanics using the enzymes pectinase and pectin methyl esterase (PME). Pectinase activity was able to stimulate pollen germination and tube growth at moderate concentrations whereas higher concentrations caused apical swelling or bursting in Solanum chacoense Bitt. pollen tubes. This is consistent with a modification of the physical properties of the cell wall affecting its extensibility and thus the growth rate, as well as its capacity to withstand turgor. To prove that the enzyme-induced effects were due to the altered cell wall mechanics, we subjected pollen tubes to micro-indentation experiments. We observed that cellular stiffness was reduced and visco-elasticity increased in the presence of pectinase. These are the first mechanical data that confirm the influence of the amount of pectins in the pollen tube cell wall on the physical parameters characterizing overall cellular architecture. Cytomechanical data were also obtained to analyze the role of the degree of pectin methyl-esterification, which is known to exhibit a gradient along the pollen tube axis. This feature has frequently been suggested to result in a gradient of the physical properties characterizing the cell wall and our data provide, for the first time, mechanical support for this concept. The gradient in cell wall composition from apical esterified to distal de-esterified pectins seems to be correlated with an increase in the degree of cell wall rigidity and a decrease of visco-elasticity. Our mechanical approach provides new insights concerning the mechanics of pollen tube growth and the architecture of living plant cells.

  20. FIMBRIN1 Is Involved in Lily Pollen Tube Growth by Stabilizing the Actin Fringe[C][W][OA

    Science.gov (United States)

    Su, Hui; Zhu, Jinsheng; Cai, Chao; Pei, Weike; Wang, Jiaojiao; Dong, Huaijian; Ren, Haiyun

    2012-01-01

    An actin fringe structure in the subapex plays an important role in pollen tube tip growth. However, the precise mechanism by which the actin fringe is generated and maintained remains largely unknown. Here, we cloned a 2606-bp full-length cDNA encoding a deduced 77-kD fimbrin-like protein from lily (Lilium longiflorum), named FIMBRIN1 (FIM1). Ll-FIM1 was preferentially expressed in pollen and concentrated at actin fringe in the subapical region, as well as in longitudinal actin-filament bundles in the shank of pollen tubes. Microinjection of Ll-FIM1 antibody into lily pollen tubes inhibited tip growth and disrupted the actin fringe. Furthermore, we verified the function of Ll-FIM1 in the fim5 mutant of its closest relative, Arabidopsis thaliana. Pollen tubes of fim5 mutants grew with a larger diameter in early stages but could recover into normal forms in later stages, despite significantly slower growth rates. The actin fringe of the fim5 mutants, however, was impaired during both early and late stages. Impressively, stable expression of fim5pro:GFP:Ll-FIM1 rescued the actin fringe and the growth rate of Arabidopsis fim5 pollen tubes. In vitro biochemical analysis showed that Ll-FIM1 could bundle actin filaments. Thus, our study has identified a fimbrin that may stabilize the actin fringe by cross-linking actin filaments into bundles, which is important for proper tip growth of lily pollen tubes. PMID:23150633

  1. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes.

    Science.gov (United States)

    Winship, Lawrence J; Rounds, Caleb; Hepler, Peter K

    2016-12-30

    Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily ( Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.

  2. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes

    Directory of Open Access Journals (Sweden)

    Lawrence J. Winship

    2016-12-01

    Full Text Available Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.

  3. Pollen

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past vegetation and climate derived from pollen found in lake and ocean sediments. Parameter keywords describe what was measured in this data set....

  4. A plant plasma membrane Ca2+ pump is required for normal pollen tube growth and fertilization

    DEFF Research Database (Denmark)

    Schiøtt, Morten; Romanowsky, Shawn M; Bækgaard, Lone

    2004-01-01

    Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome...... and a high frequency of aborted fertilization, resulting in a >80% reduction in seed set. These findings identify a plasma membrane Ca(2+) transporter as a key regulator of pollen development and fertilization in flowering plants.......Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome......-inducing) plasmid that is transferred to plant cells] gene disruptions of ACA9 were found to result in partial male sterility. Complementation was observed by using a ACA9-yellow fluorescence protein (YFP) fusion that displayed plasma membrane localization. Mutant aca9 pollen displayed a reduced growth potential...

  5. Exogenous γ-aminobutyric acid (GABA) affects pollen tube growth via modulating putative Ca2+-permeable membrane channels and is coupled to negative regulation on glutamate decarboxylase

    Science.gov (United States)

    Yu, Guang-Hui; Zou, Jie; Feng, Jing; Peng, Xiong-Bo; Wu, Ju-You; Wu, Ying-Liang; Palanivelu, Ravishankar; Sun, Meng-Xiang

    2014-01-01

    γ-Aminobutyric acid (GABA) is implicated in pollen tube growth, but the molecular and cellular mechanisms that it mediates are largely unknown. Here, it is shown that exogenous GABA modulates putative Ca2+-permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and non-invasive micromeasurement technology (NMT) revealed that the influx of Ca2+ increases in pollen tubes in response to exogenous GABA. It is also demonstrated that glutamate decarboxylase (GAD), the rate-limiting enzyme of GABA biosynthesis, is involved in feedback controls of Ca2+-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca2+-permeable channels relays an extracellular GABA signal and integrates multiple signal pathways to modulate tobacco pollen tube growth. Thus, the data explain how GABA mediates the communication between the style and the growing pollen tubes. PMID:24799560

  6. Influence of Electric Fields and Conductivity on Pollen Tube Growth assessed via Electrical Lab-on-Chip

    Science.gov (United States)

    Agudelo, Carlos; Packirisamy, Muthukumaran; Geitmann, Anja

    2016-01-01

    Pollen tubes are polarly growing plant cells that are able to rapidly respond to a combination of chemical, mechanical, and electrical cues. This behavioural feature allows them to invade the flower pistil and deliver the sperm cells in highly targeted manner to receptive ovules in order to accomplish fertilization. How signals are perceived and processed in the pollen tube is still poorly understood. Evidence for electrical guidance in particular is vague and highly contradictory. To generate reproducible experimental conditions for the investigation of the effect of electric fields on pollen tube growth we developed an Electrical Lab-on-Chip (ELoC). Pollen from the species Camellia displayed differential sensitivity to electric fields depending on whether the entire cell or only its growing tip was exposed. The response to DC fields was dramatically higher than that to AC fields of the same strength. However, AC fields were found to restore and even promote pollen growth. Surprisingly, the pollen tube response correlated with the conductivity of the growth medium under different AC frequencies—consistent with the notion that the effect of the field on pollen tube growth may be mediated via its effect on the motion of ions. PMID:26804186

  7. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Directory of Open Access Journals (Sweden)

    Abercrombie Jason M

    2011-07-01

    Full Text Available Abstract Background A number of innovations underlie the origin of rapid reproductive cycles in angiosperms. A critical early step involved the modification of an ancestrally short and slow-growing pollen tube for faster and longer distance transport of sperm to egg. Associated with this shift are the predominantly callose (1,3-β-glucan walls and septae (callose plugs of angiosperm pollen tubes. Callose synthesis is mediated by callose synthase (CalS. Of 12 CalS gene family members in Arabidopsis, only one (CalS5 has been directly linked to pollen tube callose. CalS5 orthologues are present in several monocot and eudicot genomes, but little is known about the evolutionary origin of CalS5 or what its ancestral function may have been. Results We investigated expression of CalS in pollen and pollen tubes of selected non-flowering seed plants (gymnosperms and angiosperms within lineages that diverged below the monocot/eudicot node. First, we determined the nearly full length coding sequence of a CalS5 orthologue from Cabomba caroliniana (CcCalS5 (Nymphaeales. Semi-quantitative RT-PCR demonstrated low CcCalS5 expression within several vegetative tissues, but strong expression in mature pollen. CalS transcripts were detected in pollen tubes of several species within Nymphaeales and Austrobaileyales, and comparative analyses with a phylogenetically diverse group of sequenced genomes indicated homology to CalS5. We also report in silico evidence of a putative CalS5 orthologue from Amborella. Among gymnosperms, CalS5 transcripts were recovered from germinating pollen of Gnetum and Ginkgo, but a novel CalS paralog was instead amplified from germinating pollen of Pinus taeda. Conclusion The finding that CalS5 is the predominant callose synthase in pollen tubes of both early-diverging and model system angiosperms is an indicator of the homology of their novel callosic pollen tube walls and callose plugs. The data suggest that CalS5 had transient expression

  8. Maize EMBRYO SAC family peptides interact differentially with pollen tubes and fungal cells.

    Science.gov (United States)

    Woriedh, Mayada; Merkl, Rainer; Dresselhaus, Thomas

    2015-08-01

    EMBRYO SAC1-4 (ES1-4) peptides belong to the defensin subgroup of cysteine-rich peptides known to mediate pollen tube burst in Zea mays (maize). ES1-4 are reported here to also be capable of inhibiting germination and growth of the maize fungal pathogens Fusarium graminearum and Ustilago maydis at higher concentrations. Dividing the peptides into smaller pieces showed that a 15-amino-acid peptide located in a highly variable loop region lacking similarity to other defensins or defensin-like peptides binds to maize pollen tube surfaces, causing swelling prior to burst. This peptide fragment and a second conserved neighbouring fragment showed suppression of fungal germination and growth. The two peptides caused swelling of fungal cells, production of reactive oxygen species, and finally the formation of big vacuoles prior to burst at high peptide concentration. Furthermore, peptide fragments were found to bind differently to fungal cells. In necrotrophic F. graminearum, a peptide fragment named ES-d bound only at cell surfaces whereas the peptide ES-c bound at cell surfaces and also accumulated inside cells. Conversely, in biotrophic U. maydis, both peptide fragments accumulated inside cells, but, if applied at higher concentration, ES-c but not ES-d accumulated mainly in vacuoles. Mapping of peptide interaction sites identified amino acids differing in pollen tube burst and fungal response reactions. In summary, these findings indicate that residues targeting pollen tube burst in maize are specific to the ES family, while residues targeting fungal growth are conserved within defensins and defensin-like peptides. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  9. Distribution of exogenous DNA in upland cotton by pollen tube pathway

    International Nuclear Information System (INIS)

    Yang Shuhua; Ge Cailin; Zhu Jing; Wang Zegang; Luo Shishi; Ni Wanchao

    2007-01-01

    The distribution of exogenous DNA in upland cotton by pollen tube pathway was studied. The results showed that the exogenous DNA could be transported into ovules by dripping and injection. The optimum time for treatment is at 33 h after pollination. The radioactivity in ovules by dripping exogenous DNA was lower than that by injecting. In autoradiogram, the number of sliver grains in the treated ovules was more than that in the controls. (authors)

  10. Emerging roles for microtubules in angiosperm pollen tube growth highlight new research cues

    Directory of Open Access Journals (Sweden)

    Alessandra eMoscatelli

    2015-02-01

    Full Text Available In plants, actin filaments have an important role in organelle movement and cytoplasmic streaming. Otherwise microtubules have a role in restricting organelles to specific areas of the cell and in maintaining organelle morphology. In somatic plant cells, microtubules also participate in cell division and morphogenesis, allowing cells to take their definitive shape in order to perform specific functions. In the latter case, microtubules influence assembly of the cell wall, controlling the delivery of enzymes involved in cellulose synthesis and of wall modulation material to the proper sites.In angiosperm pollen tubes, organelle movement is generally attributed to the acto-myosin system, the main role of which is in distributing organelles in the cytoplasm and in carrying secretory vesicles to the apex for polarized growth. Recent data on membrane trafficking suggests a role of microtubules in fine delivery and repositioning of vesicles to sustain pollen tube growth. This review examines the role of microtubules in secretion and endocytosis, highlighting new research cues regarding cell wall construction and pollen tube-pistil crosstalk, that help unravel the role of microtubules in polarized growth.

  11. Segmentation of Pollen Tube Growth Videos Using Dynamic Bi-Modal Fusion and Seam Carving.

    Science.gov (United States)

    Tambo, Asongu L; Bhanu, Bir

    2016-05-01

    The growth of pollen tubes is of significant interest in plant cell biology, as it provides an understanding of internal cell dynamics that affect observable structural characteristics such as cell diameter, length, and growth rate. However, these parameters can only be measured in experimental videos if the complete shape of the cell is known. The challenge is to accurately obtain the cell boundary in noisy video images. Usually, these measurements are performed by a scientist who manually draws regions-of-interest on the images displayed on a computer screen. In this paper, a new automated technique is presented for boundary detection by fusing fluorescence and brightfield images, and a new efficient method of obtaining the final cell boundary through the process of Seam Carving is proposed. This approach takes advantage of the nature of the fusion process and also the shape of the pollen tube to efficiently search for the optimal cell boundary. In video segmentation, the first two frames are used to initialize the segmentation process by creating a search space based on a parametric model of the cell shape. Updates to the search space are performed based on the location of past segmentations and a prediction of the next segmentation.Experimental results show comparable accuracy to a previous method, but significant decrease in processing time. This has the potential for real time applications in pollen tube microscopy.

  12. The diversity of the pollen tube pathway in plants: towards an increasing control by the sporophyte

    Directory of Open Access Journals (Sweden)

    Jorge eLora

    2016-02-01

    Full Text Available Plants, unlike animals, alternate multicellular diploid and haploid generations in their life cycle. While this is widespread all along the plant kingdom, the size and autonomy of the diploid sporophyte and the haploid gametophyte generations vary along evolution. Vascular plants show an evolutionary trend towards a reduction of the gametophyte, reflected both in size and lifespan, together with an increasing dependence from the sporophyte. This has resulted in an overlooking of the importance of the gametophytic phase in the evolution of higher plants. This reliance on the sporophyte is most notorious along the pollen tube journey, where the male gametophytes have to travel a long way inside the sporophyte to reach the female gametophyte. Along evolution, there is a change in the scenery of the pollen tube pathway that favors pollen competition and selection. This trend, towards apparently making complicated what could be simple, appears to be related to an increasing control of the sporophyte over the gametophyte with implications for understanding plant evolution.

  13. Dissecting the regulation of pollen tube growth by modelling the interplay of hydrodynamics, cell wall and ion dynamics

    Directory of Open Access Journals (Sweden)

    Junli eLiu

    2014-08-01

    Full Text Available Hydrodynamics, cell wall and ion dynamics are all important properties that regulate pollen tube growth. Currently, the two main pollen tube growth models, the cell wall model and the hydrodynamic model do not appear to be reconcilable. Here we develop an integrative model for pollen tube growth and show that our model reproduces key experimental observations: 1 that the hypertonic condition leads to a much longer oscillatory period and that the hypotonic condition halves the oscillatory period; 2 that oscillations in turgor are experimentally undetectable; 3 that increasing the extracellular calcium concentration or decreasing the pH decreases the growth oscillatory amplitude; 4 that knockout of Raba4d, a member of the Rab family of small GTPase proteins, decreases pollen tube length after germination for 24 hours. Using the model generated here, we reveal that 1 when cell wall extensibility is large, pollen tube may sustain growth at different volume changes and maintain relatively stable turgor; 2 turgor increases if cell wall extensibility decreases; 3 increasing turgor due to decrease in osmolarity in the media, although very small, increases volume change . However, increasing turgor due to decrease in cell wall extensibility decreases volume change. In this way regulation of pollen tube growth by turgor is context dependent. By changing the osmolarity in the media, the main regulatory points are extracellular osmolarity for water flow and turgor for the volume encompassed by the cell wall. However, if the viscosity of cell wall changes, the main regulatory points are turgor for water flow and wall extensibility for the volume encompassed by the cell wall. The novel methodology developed here reveals the underlying context-dependent regulatory principle of pollen tube growth.

  14. The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube.

    Science.gov (United States)

    Rounds, Caleb M; Hepler, Peter K; Winship, Lawrence J

    2014-09-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. © 2014 American Society of Plant Biologists. All Rights Reserved.

  15. Effect of gamma-radiation of pollen tube growth and seed set in barley-rye crosses

    International Nuclear Information System (INIS)

    Rohilla, J.S.; Khanna, V.K.

    1993-01-01

    One variety of barley and one variety of rye were taken to study the effect of gamma-radiation on pollen germination, pollen tube growth and seed set in barley-rye crosses. There was an increase in pollen germination and pollen tube growth over control at 1 kR dose but it was reduced at higher doses. Seed set was maximum at 1 kR and it was more than control from 1-5 kR. Only seeds of the cross Karan - 4 (1 kR)*MRSP-992 were able to germinate. In these germinated seeds the root growth was arrested after the fourth day of germination and they turned brown. The shoot growth was also very poor and it stopped after a week. (author) 11 refs.; 2 tabs

  16. De Novo Transcriptome Sequencing of Olea europaea L. to Identify Genes Involved in the Development of the Pollen Tube.

    Science.gov (United States)

    Iaria, Domenico; Chiappetta, Adriana; Muzzalupo, Innocenzo

    2016-01-01

    In olive (Olea europaea L.), the processes controlling self-incompatibility are still unclear and the molecular basis underlying this process are still not fully characterized. In order to determine compatibility relationships, using next-generation sequencing techniques and a de novo transcriptome assembly strategy, we show that pollen tubes from different olive plants, grown in vitro in a medium containing its own pistil and in combination pollen/pistil from self-sterile and self-fertile cultivars, have a distinct gene expression profile and many of the differentially expressed sequences between the samples fall within gene families involved in the development of the pollen tube, such as lipase, carboxylesterase, pectinesterase, pectin methylesterase, and callose synthase. Moreover, different genes involved in signal transduction, transcription, and growth are overrepresented. The analysis also allowed us to identify members in actin and actin depolymerization factor and fibrin gene family and member of the Ca(2+) binding gene family related to the development and polarization of pollen apical tip. The whole transcriptomic analysis, through the identification of the differentially expressed transcripts set and an extended functional annotation analysis, will lead to a better understanding of the mechanisms of pollen germination and pollen tube growth in the olive.

  17. Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

    Science.gov (United States)

    Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

    2011-01-01

    Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487

  18. UV dosimetry in pollen of Pinus silvestris and stimulation studies of pollen tube growth after irradiation with UV and ionizing radiations

    International Nuclear Information System (INIS)

    Seibold, H.W.

    1976-01-01

    Pollen tube growth after exposure to UV- and ionizing radiation was investigated in Pinus silvestris as a function of different parameters. The preconditions for this are an exact UV dosimetry and the conversion of the UV dose of [erg] into [rad]. In spite of the fact that the calculation methods are theoretically already well known, the experimental determination of the absorbed energy dose, in particular the absorption factors, was complicated by the morphological structure of the pollen. The total-irradiation experiments showed that the stimulation and inhibition of pollen tube growth is highly dependent on the dose/dose rate region chosen. Stimulation is highly dependent on the dose rate after UV irradiation as well as after exposure to ionizing radiation. When the dose rates are very small, the values are practically the same as in non-irradiated controls; with increasing doses rate, stimulation increases, whereas at very high dose rates only growth inhibition is observed. After exposure to ionizing radiation, the quantum energy or wavelength of the radiation has no effect on tube growth; after UV irradiation, on the other hand, there is hardly any stimulation at short wavelengths. As these observations were not sufficient for drawing conclusions on the site of the stimulatory action, partial UV exposure with separate irradiation of the two nuclei and the cytoplasm was also carried out. Stimulation was found in each of the three irradiation sites; although nuclei and cytoplasma react differently and also differ in the initial reaction stages, there is always an anhancement of pollen tube growth. These findings are compared with some of the current hypotheses for an explanation of the stimulatory effect. (orig.) [de

  19. Loss of the Arabidopsis thaliana P4-ATPases ALA6 and ALA7 Impairs Pollen Fitness and Alters the Pollen Tube Plasma Membrane

    Directory of Open Access Journals (Sweden)

    Stephen C McDowell

    2015-04-01

    Full Text Available Members of the P4 subfamily of P-type ATPases are thought to create and maintain lipid asymmetry in biological membranes by flipping specific lipids between membrane leaflets. In Arabidopsis, 7 of the 12 Aminophospholipid ATPase (ALA family members are expressed in pollen. Here we show that double knockout of ALA6 and ALA7 (ala6/7 results in siliques with a ~2-fold reduction in seed set with a high frequency of empty seed positions near the bottom. Seed set was reduced to near zero when plants were grown under a hot/cold temperature stress. Reciprocal crosses indicate that the ala6/7 reproductive deficiencies are due to a defect related to pollen transmission. In-vitro growth assays provide evidence that that ala6/7 pollen tubes are short and slow, with ~2-fold reductions in both maximal growth rate and overall length relative to wild-type. Outcrosses show that when ala6/7 pollen are in competition with wild-type pollen, they have a near 0% success rate in fertilizing ovules near the bottom of the pistil, consistent with ala6/7 pollen having short and slow growth defects. The ala6/7 phenotypes were rescued by the expression of either an ALA6-YFP or GFP-ALA6 fusion protein, which showed localization to both the plasma membrane and highly-mobile endomembrane structures. A mass spectrometry analysis of mature pollen grains revealed significant differences between ala6/7 and wild-type, both in the relative abundance of lipid classes and in the average number of double bonds present in acyl side chains. A change in the properties of the ala6/7 plasma membrane was also indicated by a ~10-fold reduction of labeling by lipophilic FM-dyes relative to wild-type. Together, these results indicate that ALA6 and ALA7 provide redundant activities that function to directly or indirectly change the distribution and abundance lipids in pollen, and support a model in which ALA6 and ALA7 are critical for pollen fitness under normal and temperature-stress conditions.

  20. Overexpression of Arabidopsis thaliana PTEN caused accumulation of autophagic bodies in pollen tubes by disrupting phosphatidylinositol 3-phosphate dynamics

    Science.gov (United States)

    Autophagy is a pathway in eukaryotes by which nutrient remobilization occurs through bulk protein and organelle turnover. Autophagy not only aides cells in coping with harsh environments but also plays a key role in many physiological processes that include pollen germination and tube growth. Most a...

  1. NADPH oxidase activity in pollen tubes is affected by calcium ions, signaling phospholipids and Rac/Rop GTPases

    Czech Academy of Sciences Publication Activity Database

    Potocký, Martin; Pejchar, Přemysl; Gutkowska, Malgorzata; Jiménez-Quesada, M. J.; Potocká, Andrea; Alché, J.; Kost, B.; Žárský, Viktor

    2012-01-01

    Roč. 169, č. 16 (2012), s. 1654-1663 ISSN 0176-1617 R&D Projects: GA ČR GP522/09/P299 Institutional research plan: CEZ:AV0Z50380511 Keywords : Pollen tube * Tip growth * NADPH oxidase Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.699, year: 2012

  2. Turnover of phosphatidic acid through distinct signaling pathways affects multiple aspects of pollen tube growth in tobacco

    Czech Academy of Sciences Publication Activity Database

    Pleskot, Roman; Pejchar, Přemysl; Bezvoda, R.; Lichtscheidl, I.K.; Wolters-Arts, M.; Marc, J.; Žárský, Viktor; Potocký, Martin

    2012-01-01

    Roč. 3, č. 54 (2012) ISSN 1664-462X R&D Projects: GA AV ČR IAA601110916; GA MŠk(CZ) LC06034 Institutional research plan: CEZ:AV0Z50380511 Keywords : phosphatidic acid * pollen tube * phospholipase D Subject RIV: EB - Genetics ; Molecular Biology

  3. Combination of U.V.-B and ozone reduces pollen tube growth more than either stress alone

    International Nuclear Information System (INIS)

    Feder, W.A.; Shrier, R.

    1990-01-01

    The rate of in vitro Nicotiana tabacum L. “Bel-W3” pollen tube growth was reduced 62 and 44%, respectively, when pollen tubes were exposed to 120 ppb ozone (O 3 ) for 3 hr or 300 μW/cm 2 ultraviolet-B (u.v.-B) radiation for 30 min. Petunia hybrida Vilm. “White Cascade” pollen tube growth was reduced 34 and 59%, respectively, upon exposure to O 3 or u.v.-B at the above doses. The combination of u.v.-B at 300 μW/cm 2 for 30 min, followed by O 3 at 120 ppb for 3 hr, reduced pollen tube growth by 79% for “Bel-W3” and 75% for “White Cascade”. The effect appeared to be additive, implying that different target areas may be affected by the two stressors. In the Northeast, plants are exposed to both u.v.-B and O 3 during the normal growing season. This may result in an unexpectedly higher stress on the reproductive system than had been previously suspected based on these two stressors acting individually. (author)

  4. Nitric oxide participates in cold-inhibited Camellia sinensis pollen germination and tube growth partly via cGMP in vitro.

    Directory of Open Access Journals (Sweden)

    Yu-Hua Wang

    Full Text Available Nitric oxide (NO plays essential roles in many biotic and abiotic stresses in plant development procedures, including pollen tube growth. Here, effects of NO on cold stress inhibited pollen germination and tube growth in Camellia sinensis were investigated in vitro. The NO production, NO synthase (NOS-like activity, cGMP content and proline (Pro accumulation upon treatment with NO scavenger cPTIO, NOS inhibitor L-NNA, NO donor DEA NONOate, guanylate cyclase (GC inhibitor ODQ or phosphodiesterase (PDE inhibitor Viagra at 25°C (control or 4°C were analyzed. Exposure to 4°C for 2 h reduced pollen germination and tube growth along with increase of NOS-like activity, NO production and cGMP content in pollen tubes. DEA NONOate treatment inhibited pollen germination and tube growth in a dose-dependent manner under control and reinforced the inhibition under cold stress, during which NO production and cGMP content promoted in pollen tubes. L-NNA and cPTIO markedly reduced the generation of NO induced by cold or NO donor along with partly reverse of cold- or NO donor-inhibited pollen germination and tube growth. Furthermore, ODQ reduced the cGMP content under cold stress and NO donor treatment in pollen tubes. Meanwhile, ODQ disrupted the reinforcement of NO donor on the inhibition of pollen germination and tube growth under cold condition. Additionally, Pro accumulation of pollen tubes was reduced by ODQ compared with that receiving NO donor under cold or control condition. Effects of cPTIO and L-NNA in improving cold-treated pollen germination and pollen tube growth could be lowered by Viagra. Moreover, the inhibitory effects of cPTIO and L-NNA on Pro accumulation were partly reversed by Viagra. These data suggest that NO production from NOS-like enzyme reaction decreased the cold-responsive pollen germination, inhibited tube growth and reduced Pro accumulation, partly via cGMP signaling pathway in C. sinensis.

  5. Expression of an isoflavone reductase-like gene enhanced by pollen tube growth in pistils of Solanum tuberosum.

    Science.gov (United States)

    van Eldik, G J; Ruiter, R K; Colla, P H; van Herpen, M M; Schrauwen, J A; Wullems, G J

    1997-03-01

    Successful sexual reproduction relies on gene products delivered by the pistil to create an environment suitable for pollen tube growth. These compounds are either produced before pollination or formed during the interactions between pistil and pollen tubes. Here we describe the pollination-enhanced expression of the cp100 gene in pistils of Solanum tuberosum. Temporal analysis of gene expression revealed an enhanced expression already one hour after pollination and lasts more than 72 h. Increase in expression also occurred after touching the stigma and was not restricted to the site of touch but spread into the style. The predicted CP100 protein shows similarity to leguminous isoflavone reductases (IFRs), but belongs to a family of IFR-like NAD(P)H-dependent oxidoreductases present in various plant species.

  6. Arabinogalactan proteins as interactors along the crosstalk between the pollen tube and the female tissues

    Directory of Open Access Journals (Sweden)

    Ana Marta Pereira

    2016-12-01

    Full Text Available Arabinogalactan Proteins (AGPs have long been considered to be implicated in several steps of the reproductive process of flowering plants. Pollen tube growth along the pistil tissues requires a multiplicity of signalling pathways to be activated and turned off precisely, at crucial timepoints, to guarantee successful fertilization and seed production. In the recent years, an outstanding effort has been made by the plant reproduction scientific community in order to better understand this process. This resulted in the discovery of a fairly substantial number of new players essential for reproduction, as well as their modes of action and interactions. Besides all the indications of AGPs involvement in reproduction, there were no convincing evidences about it. Recently, several studies came out to prove what had long been suggested about this complex family of glycoproteins. AGPs consist of a large family of hydroxyproline-rich proteins, predicted to be anchored to the plasma membrane and extremely rich in sugars. These two last characteristics always made them perfect candidates to be involved in signalling mechanisms, in several plant developmental processes. New findings finally relate AGPs to concrete functions in plant reproduction. In this review, it is intended not only to describe how different molecules and signalling pathways are functioning to achieve fertilization, but also to integrate the recent discoveries about AGPs along this process.

  7. The Apical Actin Fringe Contributes to Localized Cell Wall Deposition and Polarized Growth in the Lily Pollen Tube1[W][OPEN

    Science.gov (United States)

    Rounds, Caleb M.; Hepler, Peter K.; Winship, Lawrence J.

    2014-01-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. PMID:25037212

  8. Effect of dose rate and exposure time on the stimulation effect of tube growth of Pinus sylvestris pollen

    International Nuclear Information System (INIS)

    Zelles, L.; Fendrik, I.; Technische Univ. Hannover

    1975-01-01

    The stimulating effect of ionizing radiation in respect to dose rate and exposure time was studied using the tube growth of Pinus silvestris pollen. Stimulation was registered with a small dose (50 rad) supplied at low dose rates (0.5; 1.0; 3.0 and 5.0 rad/sec) and with higher doses (300; 800 and 1,400 rad) supplied at higher dose rates (10; 40 and 50 rad/sec). This suggests that only the exposure time is of importance for radiation-induced stimulation provided that the exposure time does not exceed 100 sec. (orig.) [de

  9. Comparative proteomic analysis reveals a dynamic pollen plasma membrane protein map and the membrane landscape of receptor-like kinases and transporters important for pollen tube growth and interaction with pistils in rice.

    Science.gov (United States)

    Yang, Ning; Wang, Tai

    2017-01-05

    The coordination of pollen tube (PT) growth, guidance and timely growth arrest and rupture mediated by PT-pistil interaction is crucial for the PT to transport sperm cells into ovules for double fertilization. The plasma membrane (PM) represents an important interface for cell-cell interaction, and PM proteins of PTs are pioneers for mediating PT integrity and interaction with pistils. Thus, understanding the mechanisms underlying these events is important for proteomics. Using the efficient aqueous polymer two-phase system and alkali buffer treatment, we prepared high-purity PM from mature and germinated pollen of rice. We used iTRAQ quantitative proteomic methods and identified 1,121 PM-related proteins (PMrPs) (matched to 899 loci); 192 showed differential expression in the two pollen cell types, 119 increased and 73 decreased in abundance during germination. The PMrP and differentially expressed PMrP sets all showed a functional skew toward signal transduction, transporters, wall remodeling/metabolism and membrane trafficking. Their genomic loci had strong chromosome bias. We found 37 receptor-like kinases (RLKs) from 8 kinase subfamilies and 209 transporters involved in flux of diversified ions and metabolites. In combination with the rice pollen transcriptome data, we revealed that in general, the protein expression of these PMrPs disagreed with their mRNA expression, with inconsistent mRNA expression for 74% of differentially expressed PMrPs. This study identified genome-wide pollen PMrPs, and provided insights into the membrane profile of receptor-like kinases and transporters important for pollen tube growth and interaction with pistils. These pollen PMrPs and their mRNAs showed discordant expression. This work provides resource and knowledge to further dissect mechanisms by which pollen or the PT controls PMrP abundance and monitors interactions and ion and metabolite exchanges with female cells in rice.

  10. Dynamic 1-aminocyclopropane-1-carboxylate-synthase and -oxidase transcript accumulation patterns during pollen tube growth in tobacco styles.

    Science.gov (United States)

    Weterings, Koen; Pezzotti, Mario; Cornelissen, Marc; Mariani, Celestina

    2002-11-01

    In flowering plants, pollination of the stigma sets off a cascade of responses in the distal flower organs. Ethylene and its biosynthetic precursor 1-aminocyclopropane-1-carboxylate (ACC) play an important role in regulating these responses. Because exogenous application of ethylene or ACC does not invoke the full postpollination syndrome, the pollination signal probably consists of a more complex set of stimuli. We set out to study how and when the pollination signal moves through the style of tobacco (Nicotiana tabacum) by analyzing the expression patterns of pistil-expressed ACC-synthase and -oxidase genes. Results from this analysis showed that pollination induces high ACC-oxidase transcript levels in all cells of the transmitting tissue. ACC-synthase mRNA accumulated only in a subset of transmitting tract cells and to lower levels as compared with ACC-oxidase. More significantly, we found that although ACC-oxidase transcripts accumulate to uniform high levels, the ACC-synthase transcripts accumulate in a wave-like pattern in which the peak coincides with the front of the ingrowing pollen tube tips. This wave of ACC-synthase expression can also be induced by incongruous pollination and (partially) by wounding. This indicates that wounding-like features of pollen tube invasion might be part of the stimuli evoking the postpollination response and that these stimuli are interpreted differently by the regulatory mechanisms of the ACC-synthase and -oxidase genes.

  11. Radiation-induced pollen germination, tube growth, its localized cytochemical constituents, fruit set and fruit size in alkaloid yielding species Solanum torvum L

    International Nuclear Information System (INIS)

    Chauhan, Y.S.; Katiyar, S.R.

    1990-01-01

    The volume of pollen, total number of pollen/flower, the percent of pollen germination and tube growth of long-styled flower were higher than the short-styled flowers in S. torvum. In addition, the pollination studies were conducted among the four selected sets for optimum fruit set investigation. Fruit set was not seen in both the first and second sets (female shorts-short male and female short-long male). However, the maximum fruit set was obtained in the fourth set (female long-male long). Pollen grains of long-styled flowers irradiated with 1-800 krad were germinated in the basal medium. The percent of pollen germination and the tube growth was stimulated over the control with 1 and 50 krad dose exposures, but increasing dose rates inhibited both the above processes. Utilization of insoluble polysaccharides, and the synthesis of RNA and protein were enhanced over the control with the effect of 50 krad. The higher (800 krad) dose exposures inhibited all the above cytochemical constituents. Various dose-treated pollens were used to pollinate the stigma surface of the long-styled flowers. The fruit set, fruit volume, fresh and dry weight of fruits, and the number of seed set/fruit, were enhanced over the control by 1 and 50 krad, while the higher doses caused inhibitory effect. Interestingly, the fruit set was not caused by radiation doses 400 krad and above. (author)

  12. Defensin-like ZmES4 mediates pollen tube burst in maize via opening of the potassium channel KZM1.

    Directory of Open Access Journals (Sweden)

    Suseno Amien

    2010-06-01

    Full Text Available In contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. Upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. The first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. In contrast the physiological mechanisms leading to pollen tube burst and thus sperm discharge remained elusive. Here, we describe the role of polymorphic defensin-like cysteine-rich proteins ZmES1-4 (Zea mays embryo sac from maize, leading to pollen tube growth arrest, burst, and explosive sperm release. ZmES1-4 genes are exclusively expressed in the cells of the female gametophyte. ZmES4-GFP fusion proteins accumulate in vesicles at the secretory zone of mature synergid cells and are released during the fertilization process. Using RNAi knock-down and synthetic ZmES4 proteins, we found that ZmES4 induces pollen tube burst in a species-preferential manner. Pollen tube plasma membrane depolarization, which occurs immediately after ZmES4 application, as well as channel blocker experiments point to a role of K(+-influx in the pollen tube rupture mechanism. Finally, we discovered the intrinsic rectifying K(+ channel KZM1 as a direct target of ZmES4. Following ZmES4 application, KZM1 opens at physiological membrane potentials and closes after wash-out. In conclusion, we suggest that vesicles containing ZmES4 are released from the synergid cells upon male-female gametophyte signaling. Subsequent interaction between ZmES4 and KZM1 results in channel opening and K(+ influx. We further suggest that K(+ influx leads to water uptake and culminates in osmotic tube burst. The species-preferential activity of polymorphic ZmES4 indicates that the mechanism described represents a pre-zygotic hybridization

  13. Defensin-Like ZmES4 Mediates Pollen Tube Burst in Maize via Opening of the Potassium Channel KZM1

    Science.gov (United States)

    Márton, Mihaela L.; Debener, Thomas; Geiger, Dietmar; Becker, Dirk; Dresselhaus, Thomas

    2010-01-01

    In contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. Upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. The first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. In contrast the physiological mechanisms leading to pollen tube burst and thus sperm discharge remained elusive. Here, we describe the role of polymorphic defensin-like cysteine-rich proteins ZmES1-4 (Zea mays embryo sac) from maize, leading to pollen tube growth arrest, burst, and explosive sperm release. ZmES1-4 genes are exclusively expressed in the cells of the female gametophyte. ZmES4-GFP fusion proteins accumulate in vesicles at the secretory zone of mature synergid cells and are released during the fertilization process. Using RNAi knock-down and synthetic ZmES4 proteins, we found that ZmES4 induces pollen tube burst in a species-preferential manner. Pollen tube plasma membrane depolarization, which occurs immediately after ZmES4 application, as well as channel blocker experiments point to a role of K+-influx in the pollen tube rupture mechanism. Finally, we discovered the intrinsic rectifying K+ channel KZM1 as a direct target of ZmES4. Following ZmES4 application, KZM1 opens at physiological membrane potentials and closes after wash-out. In conclusion, we suggest that vesicles containing ZmES4 are released from the synergid cells upon male-female gametophyte signaling. Subsequent interaction between ZmES4 and KZM1 results in channel opening and K+ influx. We further suggest that K+ influx leads to water uptake and culminates in osmotic tube burst. The species-preferential activity of polymorphic ZmES4 indicates that the mechanism described represents a pre-zygotic hybridization barrier and may be a

  14. The Juxtamembrane and carboxy-terminal domains of Arabidopsis PRK2 are critical for ROP-induced growth in pollen tubes

    Science.gov (United States)

    Polarized growth of pollen tubes is a critical step for successful reproduction in angiosperms and is controlled by ROP GTPases. Spatiotemporal activation of ROP (Rho GTPases of plants) necessitates a complex and sophisticated regulatory system, in which guanine nucleotide exchange factors (RopGEFs)...

  15. Overcoming hybridization barriers by the secretion of the maize pollen tube attractant ZmEA1 from Arabidopsis ovules.

    Science.gov (United States)

    Márton, Mihaela L; Fastner, Astrid; Uebler, Susanne; Dresselhaus, Thomas

    2012-07-10

    A major goal of plant reproduction research is to understand and overcome hybridization barriers so that the gene pool of crop plants can be increased and improved upon. After successful pollen germination on a receptive stigma, the nonmotile sperm cells of flowering plants are transported via the pollen tube (PT) to the egg apparatus for the achievement of double fertilization. The PT path is controlled by various hybridization mechanisms probably involving a larger number of species-specific molecular interactions. The egg-apparatus-secreted polymorphic peptides ZmEA1 in maize and LURE1 and LURE2 in Torenia fournieri as well as TcCRP1 in T. concolor were shown to be required for micropylar PT guidance, the last step of the PT journey. We report here that ZmEA1 attracts maize PTs in vitro and arrests their growth at higher concentrations. Furthermore, it binds to the subapical region of maize PT tips in a species-preferential manner. To overcome hybridization barriers at the level of gametophytic PT guidance, we expressed ZmEA1 in Arabidopsis synergid cells. Secreted ZmEA1 enabled Arabidopsis ovules to guide maize PT in vitro in a species-preferential manner to the micropylar opening of the ovule. These results demonstrate that the egg-apparatus-controlled reproductive-isolation barrier of PT guidance can be overcome even between unrelated plant families. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. NaStEP: a proteinase inhibitor essential to self-incompatibility and a positive regulator of HT-B stability in Nicotiana alata pollen tubes.

    Science.gov (United States)

    Jiménez-Durán, Karina; McClure, Bruce; García-Campusano, Florencia; Rodríguez-Sotres, Rogelio; Cisneros, Jesús; Busot, Grethel; Cruz-García, Felipe

    2013-01-01

    In Solanaceae, the self-incompatibility S-RNase and S-locus F-box interactions define self-pollen recognition and rejection in an S-specific manner. This interaction triggers a cascade of events involving other gene products unlinked to the S-locus that are crucial to the self-incompatibility response. To date, two essential pistil-modifier genes, 120K and High Top-Band (HT-B), have been identified in Nicotiana species. However, biochemistry and genetics indicate that additional modifier genes are required. We recently reported a Kunitz-type proteinase inhibitor, named NaStEP (for Nicotiana alata Stigma-Expressed Protein), that is highly expressed in the stigmas of self-incompatible Nicotiana species. Here, we report the proteinase inhibitor activity of NaStEP. NaStEP is taken up by both compatible and incompatible pollen tubes, but its suppression in Nicotiana spp. transgenic plants disrupts S-specific pollen rejection; therefore, NaStEP is a novel pistil-modifier gene. Furthermore, HT-B levels within the pollen tubes are reduced when NaStEP-suppressed pistils are pollinated with either compatible or incompatible pollen. In wild-type self-incompatible N. alata, in contrast, HT-B degradation occurs preferentially in compatible pollinations. Taken together, these data show that the presence of NaStEP is required for the stability of HT-B inside pollen tubes during the rejection response, but the underlying mechanism is currently unknown.

  17. Evaluation of the effect of clinostat rotation on pollen germination and tube development as a tool for selection of plants in Space

    Science.gov (United States)

    De Micco, Veronica; Scala, Michele; Aronne, Giovanna

    2006-05-01

    The choice of species and cultivar on which rely to sustain Close Loop Environmental Systems is generally approached by analysing the behaviour of plants in presence of stress (sporophytic selection). In this paper, we investigated the possibility to conduct the selection among genotypes in Space through the male gametophytic selection. Thus, we studied the effect of simulated microgravity on pollen germination and tube development of both woody and herbaceous crop species: Prunus armeniaca (apricot), P. dulcis (almond), Malus domestica (apple) and Vicia faba (broad bean). Pollen collected from just bloomed flowers was assessed for viability and incubated on the optimal growing medium in petri dishes both on a uni-axial clinostat and stationary in 1g. Then, pollen was observed under a light microscope to detect percent germination and growth direction. Histochemical analyses were performed to verify the presence and distribution of storage substances. Moreover, specific stainings and epifluorescent microscopy were applied to count nuclei, follow the migration of sperm cells and investigate the presence, size and morphology of callose plugs. Results showed that simulated microgravity affected pollen tube development. The different response showed by the various species indicates that male-gametophytic selection could be useful for the selection of plants in microgravity.

  18. Power spectrum, growth velocities and cross-correlations of longitudinal and transverse oscillations of individual Nicotiana tabacum pollen tube.

    Science.gov (United States)

    Haduch-Sendecka, Aleksandra; Pietruszka, Mariusz; Zajdel, Paweł

    2014-08-01

    We report on our results concerning growth rate and oscillation modes of the individual pollen tube apex. The observed volumetric growth and growth rate periodicity in the longitudinal (axial) direction are accompanied by transverse oscillations with similar frequencies but higher energies than the axial modes. Examination of the time-domain coherence between oscillations in mutually perpendicular directions revealed minimal energy dissipation in the unperturbed (isotonic) case, opposite to the two remaining cases (hypertonic, hypotonic) with notable correlations. We conjecture that the minimal energy loss is therefore optimal in the natural growth conditions. The longitudinal growth velocity is also found to be the fastest in the unperturbed case. As a result, the isolated system (pollen tube tip) is conserving energy by transforming it from elastic potential energy of extending apical wall to the kinetic energy of periodical motion. The energy dissipation is found to be about 20 % smaller in axial direction than in lateral one, indicating that the main energy consumption is dedicated to the elongation. We further observe that the hypertonic spectrum is shifted towards lower and the hypotonic towards higher frequencies with respect to the isotonic spectrum. In consequence, the turgor pressure inside the growing cell influences monotonically the frequency of both modes of oscillations. The calculated power spectrum seen as a measure of the overall energy efficiency of tip growth under hypertonic, hypotonic and isotonic conditions implies that the biochemistry has been fine tuned to be optimal under normal growth conditions, which is the developmental implication of this work. A simple theoretical extension of the Ortega equation is derived and analysed with respect to its contribution to power spectrum. We show that the plastic term, related to the effective turgor pressure, with maximum contribution at frequency f = 0 is responsible for the steady growth. In turn

  19. Asymmetric localization of Arabidopsis SYP124 syntaxin at the pollen tube apical and sub-apical zones is involved in tip growth

    Directory of Open Access Journals (Sweden)

    Silva Pedro

    2010-08-01

    Full Text Available Abstract Background The continuous polarized vesicle secretion in pollen tubes is essential for tip growth but the location of endo- and exocytic sub-domains remains however controversial. In this report we aimed to show that Arabidopsis thaliana syntaxins are involved in this process and contribute to spatially define exocytosis and membrane recycling. Results Using GFP-fusion constructs, we imaged the distribution of pollen-specific (AtSYP124 and non-pollen syntaxins (AtSYP121 and AtSYP122 in transiently transformed Nicotiana tabacum pollen tubes. All three proteins associate with the plasma membrane and with apical vesicles indicating a conserved action mechanism for all SYPs. However, the GFP tagged SYP124 showed a specific distribution with a higher labelling at the plasma membrane flanks, 10-25 μm behind the apex. This distribution is affected by Ca2+ fluxes as revealed by treatment with Gd3+ (an inhibitor of extracellular Ca2+ influx and TMB-8 (an inhibitor of intracellular Ca2+ release. Both inhibitors decreased growth rate but the distribution of SYP124 at the plasma membrane was more strongly affected by Gd3+. Competition with a related dominant negative mutant affected the specific distribution of SYP124 but not tip growth. In contrast, co-expression of the phosphatidylinositol-4-monophosphate 5-kinase 4 (PIP5K4 or of the small GTPase Rab11 perturbed polarity and the normal distribution of GFP-SYP but did not inhibit the accumulation in vesicles or at the plasma membrane. Conclusions The results presented suggest that in normal growing pollen tubes, a net exocytic flow occurs in the flanks of the tube apex mediated by SYP124. The specific distribution of SYP124 at the plasma membrane is affected by changes in Ca2+ levels in agreement with the importance of this ion for exocytosis. Apical growth and the specific localization of SYP124 were affected by regulators of membrane secretion (Ca2+, PIP5K4 and Rab11 but competition with a

  20. Knockin' on pollen's door: live cell imaging of early polarization events in germinating Arabidopsis pollen

    Science.gov (United States)

    Vogler, Frank; Konrad, Sebastian S. A.; Sprunck, Stefanie

    2015-01-01

    Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane. PMID:25954283

  1. Viabilidade do pólen e desenvolvimento do tubo polínico em macieira (Malus spp. Germination of pollen and the development of pollen tubes in apple (Malus spp.

    Directory of Open Access Journals (Sweden)

    Adriana Cibele de Mesquita Dantas

    2005-12-01

    Full Text Available No presente trabalho, estudaram-se características associadas à germinação in vitro e ao desenvolvimento in vivo do tubo polínico em seis variedades-copa e de porta-enxertos de macieira como subsídios para o estabelecimento de programas de melhoramento genético. Utilizou-se de pólen de seis cultivares de macieira inoculado em meio de cultura com ágar (10 g.L-1 em água destilada, combinados com concentrações de sacarose (0; 10; 20; 30; 40 e 50% e ácido bórico (0 e 40 mg.L-1. Para o estudo do desenvolvimento do tubo polínico, realizou-se coleta das flores em quatro períodos (6; 12; 24 e 48 horas após as polinizações em M9 x Marubakaido e a autofecundação em M9, sendo os tubos polínicos analisados em coloração de azul de anilina acidificada/carmim acético e em fluorescência. A sacarose, em concentrações entre 15% a 25%, pode ser empregada com sucesso para a germinação in vitro de grãos de pólen da macieira. O ácido bórico não teve efeito positivo para esta característica. Na ausência do ácido bórico e na presença de 15% de sacarose, observaram-se os maiores percentuais de germinação: Fuji (51,1%, Imperatriz (31,7%, M.9 (20,8%, Catarina (19,2%, Gala (13,7% e Marubakaido (6,1%. Quanto ao desenvolvimento do tubo polínico, com 12 horas da polinização, iniciou-se a germinação no pólen, no estigma, no cruzamento M.9 x Marubakaido, e após 24 horas da polinização observou-se 83% de germinação. As técnicas de coloração com azul de anilina acidificada com carmim acético e de visualização em fluorescência foram eficientes na visualização e coloração dos grãos de pólen e do desenvolvimento dos tubos polínicos.In the present work it was studied features associated to the germination of pollen and the development of pollen tubes in six apple varieties as subsidies for the establishment of genetic improvement programs. Pollen grains were inoculated in culture medium with distilled water, agar (10

  2. The effect of UV irradiated vegetative and generative nuclei as well as cytoplasm on pollen tube growth of Pinus Silvestris

    International Nuclear Information System (INIS)

    Zelles, L.; Seibold, H.W.; Ernst, D.E.W.; Technische Univ. Hannover

    1976-01-01

    Pollen grains of Pinus Silvestris were irradiated with UV-rays, and the stimulation, or restraint of gemination was studied. Gemination of the pollen was retarded by irradiation of the nucleus. This book place proportionally to the increasing doses: The conditions of irradiation and the effects of the stimulation and retardation are described in detail. Different dose rates with different effects on nucleus and cytoplasma are observed. (AJ) [de

  3. NaStEP: A Proteinase Inhibitor Essential to Self-Incompatibility and a Positive Regulator of HT-B Stability in Nicotiana alata Pollen Tubes1[W][OA

    Science.gov (United States)

    Jiménez-Durán, Karina; McClure, Bruce; García-Campusano, Florencia; Rodríguez-Sotres, Rogelio; Cisneros, Jesús; Busot, Grethel; Cruz-García, Felipe

    2013-01-01

    In Solanaceae, the self-incompatibility S-RNase and S-locus F-box interactions define self-pollen recognition and rejection in an S-specific manner. This interaction triggers a cascade of events involving other gene products unlinked to the S-locus that are crucial to the self-incompatibility response. To date, two essential pistil-modifier genes, 120K and High Top-Band (HT-B), have been identified in Nicotiana species. However, biochemistry and genetics indicate that additional modifier genes are required. We recently reported a Kunitz-type proteinase inhibitor, named NaStEP (for Nicotiana alata Stigma-Expressed Protein), that is highly expressed in the stigmas of self-incompatible Nicotiana species. Here, we report the proteinase inhibitor activity of NaStEP. NaStEP is taken up by both compatible and incompatible pollen tubes, but its suppression in Nicotiana spp. transgenic plants disrupts S-specific pollen rejection; therefore, NaStEP is a novel pistil-modifier gene. Furthermore, HT-B levels within the pollen tubes are reduced when NaStEP-suppressed pistils are pollinated with either compatible or incompatible pollen. In wild-type self-incompatible N. alata, in contrast, HT-B degradation occurs preferentially in compatible pollinations. Taken together, these data show that the presence of NaStEP is required for the stability of HT-B inside pollen tubes during the rejection response, but the underlying mechanism is currently unknown. PMID:23150644

  4. Pollen characteristics and in vitro pollen germination of Cedrus ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... This study aims to determine the germination characteristics, pollen tube developments, effects of germination media and temperature and incubation durations of the pollens obtained from the four clones (11342, 11344, 11345 and 11351) of Cedrus libani A. Rich. (Lebanon Cedrus) obtained from clonal.

  5. Two-peaked dose curves for irradiated pollen growth

    International Nuclear Information System (INIS)

    Andrejchenko, S.V.; Grodzinskij, D.M.

    1992-01-01

    The effect of γ-radiation on growth activity of bicellular pollen of hybrid petunia has been investigated. Irradiation of pollen with doses of 5 to 70 Gy increases the pollen tube growth in an artificial culture medium. As the radiation dose increases the germination ability of pollen gradually decreases and the mean pollen tube length shortens, which is accompanied by the suppression of the generative cell division into spermia and inhibition of the unscheduled incorporation of labelled thymidine into DNA. With radiation doses of 1200 to 1700 Gy some pollen tubes grow intensively. It is suggested that the phenomenon observed lays the basis for the gametic transformation

  6. Bee Pollen

    Science.gov (United States)

    ... for nutrition; as an appetite stimulant; to improve stamina and athletic performance; and for premature aging, premenstrual ... use bee pollen as a general tonic, to increase urine flow, and for alcohol intoxication. Bee pollen ...

  7. ELECTRONIC SPORT: HOW PRO-GAMING NEGOTIATES TERRITORIAL BELONGING AND GENDER

    Directory of Open Access Journals (Sweden)

    Janina Maric

    2011-11-01

    Full Text Available The article explores the phenomenon of electronic sport (e-sport, which refers to organised and competitive video gaming. It is approached as a 'social world' and a specific culture of gaming, which produces organised groups, events and broadcasting. Located at the intersection of gaming and sports, e-sport adopts elements from both areas. From a grounded theory perspective, the article discusses the contexts, meanings and practices of pro-gaming within e-sport as researched in a study consisting of semi-structured interviews with e-sport fans, gamers, journalists and team managers and observation of e-sport events and clubhouses. The results point out that territorial belonging and gender remain relevant for pro-gaming. Both can inspire belonging and result in exclusions or inclusions. But while territorial belonging is adopted as a flexible practice, gender is structuring gaming within e-sport.

  8. ELECTRONIC SPORT: HOW PRO-GAMING NEGOTIATES TERRITORIAL BELONGING AND GENDER

    OpenAIRE

    Janina Maric

    2011-01-01

    The article explores the phenomenon of electronic sport (e-sport), which refers to organised and competitive video gaming. It is approached as a 'social world' and a specific culture of gaming, which produces organised groups, events and broadcasting. Located at the intersection of gaming and sports, e-sport adopts elements from both areas. From a grounded theory perspective, the article discusses the contexts, meanings and practices of pro-gaming within e-sport as researched in a study consi...

  9. The PTI1-like kinase ZmPti1a from maize (Zea mays L.) co-localizes with callose at the plasma membrane of pollen and facilitates a competitive advantage to the male gametophyte.

    Science.gov (United States)

    Herrmann, Markus M; Pinto, Sheena; Kluth, Jantjeline; Wienand, Udo; Lorbiecke, René

    2006-10-06

    The tomato kinase Pto confers resistance to bacterial speck disease caused by Pseudomonas syringae pv. tomato in a gene for gene manner. Upon recognition of specific avirulence factors the Pto kinase activates multiple signal transduction pathways culminating in induction of pathogen defense. The soluble cytoplasmic serine/threonine kinase Pti1 is one target of Pto phosphorylation and is involved in the hypersensitive response (HR) reaction. However, a clear role of Pti1 in plant pathogen resistance is uncertain. So far, no Pti1 homologues from monocotyledonous species have been studied. Here we report the identification and molecular analysis of four Pti1-like kinases from maize (ZmPti1a, -b, -c, -d). These kinase genes showed tissue-specific expression and their corresponding proteins were targeted to different cellular compartments. Sequence similarity, expression pattern and cellular localization of ZmPti1b suggested that this gene is a putative orthologue of Pti1 from tomato. In contrast, ZmPti1a was specifically expressed in pollen and sequestered to the plasma membrane, evidently owing to N-terminal modification by myristoylation and/or S-acylation. The ZmPti1a:GFP fusion protein was not evenly distributed at the pollen plasma membrane but accumulated as an annulus-like structure which co-localized with callose (1,3-beta-glucan) deposition. In addition, co-localization of ZmPti1a and callose was observed during stages of pollen mitosis I and pollen tube germination. Maize plants in which ZmPti1a expression was silenced by RNA interference (RNAi) produced pollen with decreased competitive ability. Hence, our data provide evidence that ZmPti1a plays an important part in a signalling pathway that accelerates pollen performance and male fitness. ZmPti1a from maize is involved in pollen-specific processes during the progamic phase of reproduction, probably in crucial signalling processes associated with regions of callose deposition. Pollen

  10. The PTI1-like kinase ZmPti1a from maize (Zea mays L. co-localizes with callose at the plasma membrane of pollen and facilitates a competitive advantage to the male gametophyte

    Directory of Open Access Journals (Sweden)

    Wienand Udo

    2006-10-01

    Full Text Available Abstract Background The tomato kinase Pto confers resistance to bacterial speck disease caused by Pseudomonas syringae pv. tomato in a gene for gene manner. Upon recognition of specific avirulence factors the Pto kinase activates multiple signal transduction pathways culminating in induction of pathogen defense. The soluble cytoplasmic serine/threonine kinase Pti1 is one target of Pto phosphorylation and is involved in the hypersensitive response (HR reaction. However, a clear role of Pti1 in plant pathogen resistance is uncertain. So far, no Pti1 homologues from monocotyledonous species have been studied. Results Here we report the identification and molecular analysis of four Pti1-like kinases from maize (ZmPti1a, -b, -c, -d. These kinase genes showed tissue-specific expression and their corresponding proteins were targeted to different cellular compartments. Sequence similarity, expression pattern and cellular localization of ZmPti1b suggested that this gene is a putative orthologue of Pti1 from tomato. In contrast, ZmPti1a was specifically expressed in pollen and sequestered to the plasma membrane, evidently owing to N-terminal modification by myristoylation and/or S-acylation. The ZmPti1a:GFP fusion protein was not evenly distributed at the pollen plasma membrane but accumulated as an annulus-like structure which co-localized with callose (1,3-β-glucan deposition. In addition, co-localization of ZmPti1a and callose was observed during stages of pollen mitosis I and pollen tube germination. Maize plants in which ZmPti1a expression was silenced by RNA interference (RNAi produced pollen with decreased competitive ability. Hence, our data provide evidence that ZmPti1a plays an important part in a signalling pathway that accelerates pollen performance and male fitness. Conclusion ZmPti1a from maize is involved in pollen-specific processes during the progamic phase of reproduction, probably in crucial signalling processes associated with regions

  11. Does stronger pollen competition improve offspring fitness when pollen load does not vary?

    Science.gov (United States)

    Pélabon, Christophe; Hennet, Lauriane; Bolstad, Geir H; Albertsen, Elena; Opedal, Øystein H; Ekrem, Runa K; Armbruster, W Scott

    2016-03-01

    Competition among pollen grains from a single donor is expected to increase the quality of the offspring produced because of the recessive deleterious alleles expressed during pollen-tube growth. However, evidence for such an effect is inconclusive; a large number of studies suffer from confounding variation in pollen competition with variation in pollen load. In this study, we tested the effect of pollen competition on offspring performance independently of pollen-load variation. We compared seed mass and early seedling performance in Dalechampia scandens (Euphorbiaceae) between crosses in which variation in pollen competition was achieved, without variation in pollen load, by manipulating the dispersion of pollen grains on the stigmas. Despite a large sample size (211 crosses on 20 maternal plants), we failed to find an effect of pollen competition on seed characteristics or early seedling performance. Paternal effects were always limited, and pollen competition never reduced the within-father (residual) variance. These results suggest that limited within-donor variation in genetic quality of pollen grains reduces the potential benefits of pollen competition in the study population. The lack of paternal effects on early sporophyte performance further suggests that benefits of pollen competition among pollen from multiple donors should be limited as well, and it raises questions about the significance of pollen competition as a mechanism of sexual selection. © 2016 Botanical Society of America.

  12. Coconut (Cocos nucifera l.) pollen cryopreservation.

    Science.gov (United States)

    Karun, A; Sjini, K K; Niral, V; Amarnth, C H; Remya, P; Rajesh, M K; Samsudeen, K; Jerard, B A; Engelmann, F

    2014-01-01

    Coconut genetic resources are threatened by pests and pathogens, natural hazards and human activities. Cryopreservation is the only method allowing the safe and cost-effective long-term conservation of recalcitrant seed species such as coconut. The objective of this work was to test the effect of cryopreservation and of cryostorage duration on coconut pollen germination and fertility. Pollen of two coconut varieties (West Coast Tall WWCTW and Chowghat Orange Dwarf CODC) was collected in March-May over three successive years, desiccated to 7.5 % moisture content (FW) and cryopreserved by direct immersion in liquid nitrogen. Germination and pollen tube length (PTL) of desiccated and cryopreserved pollen were not significantly different for both WCT and COD over the three harvest months of the three consecutive years of study. Pollen germination ranged from 24 to 32 % in desiccated pollen whereas it was between 26 and 29 % in cryopreserved COD pollen. In the case of WCT, germination ranged from 30 to 31 % in desiccated pollen, while it was between 28 and 32 % in cryopreserved pollen. PTL of cryopreserved pollen ranged between 224-390 nm and 226-396 mm for COD and WCT, respectively. Germination of COD pollen varied between 29.0 and 44.1 % after 4 years and 1.0/1.5 years cryostorage, respectively. Germination of WCT pollen did not change significantly between 0 and 6 years cryostorage, being comprised between 32 (24 h) and 40 % (1.5 years). Germination and vigour of cryopreserved pollen were generally higher compared to that of pollen dried in oven and non-cryopreserved. Normal seed set was observed in COD and WCT palms using pollen cryostored for 6 months and 4 years. Cryopreserved pollen of five Tall and five Dwarf accessions displayed 24-31 % and 25-49 % germination, respectively. These results show that it is now possible to establish pollen cryobanks to contribute to coconut germplasm long-term conservation.

  13. Pollen Biology of Ornamental Ginger (Hedychium spp. J. Koenig)

    Science.gov (United States)

    An improved in vitro pollen germination assay was developed to assess the viability of stored Hedychium pollen. The effect of polyethylene glycol (PEG) (10, 15, and 20% w/v) on pollen germination and tube growth was evaluated for H. longicornutum and two commercial Hedychium cultivars, ‘Orange Brush...

  14. Knockin’ on pollen’s door: live cell imaging of early polarization events in germinating Arabidopsis pollen

    Directory of Open Access Journals (Sweden)

    Frank eVogler

    2015-04-01

    Full Text Available Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane.

  15. Allergies, asthma, and pollen

    Science.gov (United States)

    Reactive airway - pollen; Bronchial asthma - pollen; Triggers - pollen; Allergic rhinitis - pollen ... Things that make allergies or asthma worse are called triggers. It is important to know your triggers because avoiding them is your first step toward feeling better. ...

  16. Flowering and the Pollen Fertility in Iranian Garlic Clones

    Directory of Open Access Journals (Sweden)

    A. R. Abbasifar

    2015-06-01

    Full Text Available Garlic (Allium sativum L. cannot produce seed because it is a sterile plant. For studying bolting and determination of pollen fertility, 68 Iranian garlic clones were gathered from different parts of Iran and evaluated in Research Field of Horticultural Department, Faculty of Agriculture, Bu-Ali Sina University in 2010-2011 and 2011-2012. For determining the pollen fertility, some tests including specific RAPD marker, pollen germination, pollen viability detection using acetocarmine and in vitro culture of ovules and fruits were used. Results showed that 37 of Iranian garlic clones could produce scape and inflorescence. The percentage range of pollen stained with acetocarmine was from 0.5 up to 20 percent showing infertility of pollens. Lack of two markers (OPJ121300 and OPJ121700 and pollen tube growth proved the infertility of garlic clones pollen. Fruits and embryo sac were alive for more than two months, showing their potential for producing seeds following pollination with fertile pollens.

  17. Evidence for DNA repair after ultraviolet irradiation of Petunia hybrida pollen

    International Nuclear Information System (INIS)

    Jackson, J.F.; Linskens, H.F.; Katholieke Universiteit Nijmegen; Katholike Universiteit Nijmegen

    1978-01-01

    Ultraviolet irradiation of Petunia hybrida pollen led to an unscheduled labelling of pollen DNA by 3 H-thymidine during the early stages of germination. Hydroxyurea increased this DNA labelling, while added boron, required absolutely for pollen germination, tube elongation and tube generative cell mitosis, was not needed for this repair-like DNA synthesis. (orig.) [de

  18. Prunus necrotic ringspot virus Early Invasion and Its Effects on Apricot Pollen Grain Performance.

    Science.gov (United States)

    Amari, Khalid; Burgos, Lorenzo; Pallas, Vicente; Sanchez-Pina, María Amelia

    2007-08-01

    ABSTRACT The route of infection and the pattern of distribution of Prunus necrotic ringspot virus (PNRSV) in apricot pollen were studied. PNRSV was detected both within and on the surface of infected pollen grains. The virus invaded pollen during its early developmental stages, being detected in pollen mother cells. It was distributed uniformly within the cytoplasm of uni- and bicellular pollen grains and infected the generative cell. In mature pollen grains, characterized by their triangular shape, the virus was located mainly at the apertures, suggesting that PNRSV distribution follows the same pattern as the cellular components required for pollen tube germination and cell wall tube synthesis. PNRSV also was localized inside pollen tubes, especially in the growth zone. In vitro experiments demonstrated that infection with PNRSV decreases the germination percentage of pollen grains by more than half and delays the growth of pollen tubes by approximately 24 h. However, although PNRSV infection affected apricot pollen grain performance during germination, the presence of the virus did not completely prevent fertilization, because the infected apricot pollen tubes, once germinated, were able to reach the apricot embryo sacs, which, in the climatic conditions of southeastern Spain, mature later than in other climates. Thus, infected pollen still could play an important role in the vertical transmission of PNRSV in apricot.

  19. PCP-B class pollen coat proteins are key regulators of the hydration checkpoint in Arabidopsis thaliana pollen-stigma interactions.

    Science.gov (United States)

    Wang, Ludi; Clarke, Lisa A; Eason, Russell J; Parker, Christopher C; Qi, Baoxiu; Scott, Rod J; Doughty, James

    2017-01-01

    The establishment of pollen-pistil compatibility is strictly regulated by factors derived from both male and female reproductive structures. Highly diverse small cysteine-rich proteins (CRPs) have been found to play multiple roles in plant reproduction, including the earliest stages of the pollen-stigma interaction. Secreted CRPs found in the pollen coat of members of the Brassicaceae, the pollen coat proteins (PCPs), are emerging as important signalling molecules that regulate the pollen-stigma interaction. Using a combination of protein characterization, expression and phylogenetic analyses we identified a novel class of Arabidopsis thaliana pollen-borne CRPs, the PCP-Bs (for pollen coat protein B-class) that are related to embryo surrounding factor (ESF1) developmental regulators. Single and multiple PCP-B mutant lines were utilized in bioassays to assess effects on pollen hydration, adhesion and pollen tube growth. Our results revealed that pollen hydration is severely impaired when multiple PCP-Bs are lost from the pollen coat. The hydration defect also resulted in reduced pollen adhesion and delayed pollen tube growth in all mutants studied. These results demonstrate that AtPCP-Bs are key regulators of the hydration 'checkpoint' in establishment of pollen-stigma compatibility. In addition, we propose that interspecies diversity of PCP-Bs may contribute to reproductive barriers in the Brassicaceae. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  20. Pollen lipidomics: lipid profiling exposes a notable diversity in 22 allergenic pollen and potential biomarkers of the allergic immune response.

    Directory of Open Access Journals (Sweden)

    Mohamed Elfatih H Bashir

    Full Text Available BACKGROUND/AIM: Pollen grains are the male gametophytes that deliver sperm cells to female gametophytes during sexual reproduction of higher plants. Pollen is a major source of aeroallergens and environmental antigens. The pollen coat harbors a plethora of lipids that are required for pollen hydration, germination, and penetration of the stigma by pollen tubes. In addition to proteins, pollen displays a wide array of lipids that interact with the human immune system. Prior searches for pollen allergens have focused on the identification of intracellular allergenic proteins, but have largely overlooked much of the extracellular pollen matrix, a region where the majority of lipid molecules reside. Lipid antigens have attracted attention for their potent immunoregulatory effects. By being in close proximity to allergenic proteins on the pollen surface when they interact with host cells, lipids could modify the antigenic properties of proteins. METHODOLOGY/PRINCIPAL FINDINGS: We performed a comparative pollen lipid profiling of 22 commonly allergenic plant species by the use of gas chromatography-mass spectroscopy, followed by detailed data mining and statistical analysis. Three experiments compared pollen lipid profiles. We built a database library of the pollen lipids by matching acquired pollen-lipid mass spectra and retention times with the NIST/EPA/NIH mass-spectral library. We detected, identified, and relatively quantified more than 106 lipid molecular species including fatty acids, n-alkanes, fatty alcohols, and sterols. Pollen-derived lipids stimulation up-regulate cytokines expression of dendritic and natural killer T cells co-culture. CONCLUSIONS/SIGNIFICANCE: Here we report on a lipidomic analysis of pollen lipids that can serve as a database for identifying potential lipid antigens and/or novel candidate molecules involved in allergy. The database provides a resource that facilitates studies on the role of lipids in the

  1. Kanamycin resistance during in vitro development of pollen from transgenic tomato plants

    NARCIS (Netherlands)

    Bino, R.J.; Hille, J.; Franken, J.

    1987-01-01

    Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes.

  2. Effects of Alternaria alternata f.sp. lycopersici toxins on pollen

    NARCIS (Netherlands)

    Bino, R.J.; Franken, J.; Witsenboer, H.M.A.; Hille, J.; Dons, J.J.M.

    1988-01-01

    Effects of the phytotoxic compounds (AAL-toxins) isolated from cell-free culture filtrates of Alternaria alternata f.sp. lycopersici on in vitro pollen development were studied. AAL-toxins inhibited both germination and tube growth of pollen from several Lycopersicon genotypes. Pollen from

  3. In Vitro Pollen Germination of Eichhornia crassipes (Mart. Solms: An Insight into its Preferred Mode of Clonal Reproduction

    Directory of Open Access Journals (Sweden)

    Somnath BHOWMIK

    2012-05-01

    Full Text Available Eichhornia crassipes (Mart. Solms is an aquatic invasive weed throughout the tropical and subtropical regions of the world. The plant rarely produces any fruit under natural condition In order to understand the causes of failure of seed set in this plant various aspect of pollen biology were studied. Pollen fertility and pollen viability was assessed using Muntzing� s mixture and in acetic orcein and TTZ, while pollen germination was assessed with different concentrations of sucrose supplemented with boric acid and Ca and Mg salts. The aim of present study was to find out the cause of sexual incompatibility of Eichhornia crassipes (Mart. Solms. In spite of high pollen fertility, pollen viability and pollen germination the species show hardly any fruit set under natural condition. The abnormal pollen germination like curling of pollen tubes, shrinkage of pollen tube tips and bending of pollen tube might be reasons of sexual incompatibility of this species. It is observed that the taxa required comparatively low sucrose concentration (5% for their optimal in vitro pollen germination (54.08%. Boric acid to certain extent also influences the in vitro pollen germination (56.2%. In the present investigation the nature of substrate in association with the effect of Boric acid, CaCO3, MgSO4 on the in vitro pollen germination of Eichhornia crassipes is also worked out. However the tested salts show no significant effect on pollen germination in the present study.

  4. Profiling and functional classification of esterases in olive (Olea europaea) pollen during germination.

    Science.gov (United States)

    Rejón, Juan D; Zienkiewicz, Agnieszka; Rodríguez-García, María Isabel; Castro, Antonio J

    2012-10-01

    A pollen grain contains a number of esterases, many of which are released upon contact with the stigma surface. However, the identity and function of most of these esterases remain unknown. In this work, esterases from olive pollen during its germination were identifided and functionally characterized. The esterolytic capacity of olive (Olea europaea) pollen was examined using in vitro and in-gel enzymatic assays with different enzyme substrates. The functional analysis of pollen esterases was achieved by inhibition assays by using specific inhibitors. The cellular localization of esterase activities was performed using histochemical methods. Olive pollen showed high levels of non-specific esterase activity, which remained steady after hydration and germination. Up to 20 esterolytic bands were identified on polyacrylamide gels. All the inhibitors decreased pollen germinability, but only diisopropyl fluorophosphate (DIFP) hampered pollen tube growth. Non-specific esterase activity is localized on the surface of oil bodies (OBs) and small vesicles, in the pollen intine and in the callose layer of the pollen tube wall. Acetylcholinesterase (AChE) activity was mostly observed in the apertures, exine and pollen coat, and attached to the pollen tube wall surface and to small cytoplasmic vesicles. In this work, for the first time a systematic functional characterization of esterase enzymes in pollen from a plant species with wet stigma has been carried out. Olive pollen esterases belong to four different functional groups: carboxylesterases, acetylesterases, AChEs and lipases. The cellular localization of esterase activity indicates that the intine is a putative storage site for esterolytic enzymes in olive pollen. Based on inhibition assays and cellular localization of enzymatic activities, it can be concluded that these enzymes are likely to be involved in pollen germination, and pollen tube growth and penetration of the stigma.

  5. Calreticulin expression in relation to exchangeable Ca(2+) level that changes dynamically during anthesis, progamic phase, and double fertilization in Petunia.

    Science.gov (United States)

    Lenartowski, Robert; Suwińska, Anna; Lenartowska, Marta

    2015-01-01

    Calcium (Ca(2+)) plays essential roles in plant sexual reproduction, but the sites and the mechanism of Ca(2+) mobile storage during pollen-pistil interactions have not been fully defined. Because the Ca(2+)-buffering protein calreticulin (CRT) is able to bind and sequester Ca(2+), it can serve as a mobile intracellular store of easily releasable Ca(2+) and control its local concentration within the cytoplasm. Our previous studies showed an enhanced expression of Petunia hybrida CRT gene (PhCRT) during pistil transmitting tract maturation, pollen germination and tube outgrowth on the stigma, gamete fusion, and early embryogenesis. Here, we demonstrate that elevated expression of CRT results in the accumulation of this protein in response to anthesis, pollination, sperm cells deposition within the receptive synergid and fertilization, when the level of exchangeable Ca(2+) changes dynamically. CRT localizes mainly to the endoplasmic reticulum and Golgi compartments in the pistil transmitting tract cells, germinated pollen/tubes, and sporophytic/gametophytic cells of the ovule and corresponds with loosely bound Ca(2+). Additionally, the immunogold research shows, for the first time, highly selective CRT distribution in specific nuclear sub-domains. On the basis of our results, we discuss the possible functions of CRT with respect to the critical role of Ca(2+) homeostasis during key events of the multi-step process of generative reproduction in angiosperms.

  6. Receptividade do estigma e desenvolvimento do tubo polínico em flores de pessegueiro submetidas à temperatura elevada Stigma receptivity and pollen tube development in peach flowers submitted to high temperature

    Directory of Open Access Journals (Sweden)

    Ilisandra Zanandrea

    2011-12-01

    Full Text Available Dentre os diversos fatores que afetam a produtividade do pessegueiro em regiões subtropicais, está a ocorrência de temperaturas elevadas no início da floração. Tais temperaturas podem causar danos ao estigma e à germinação do grão de pólen, ocasionando decréscimo na fecundação e na fixação dos frutos. O presente trabalho teve por objetivo detectar diferenças entre genótipos quanto à tolerância à temperatura elevada (29±2ºC, bem como verificar se tais diferenças poderiam ser detectadas por um processo simples, utilizando ramos destacados. Para isso, foram realizados dois experimentos, sendo um com ramos destacados e outro com plantas inteiras em vasos, obtidas por enxertia, no outono. As estimativas de graus de receptividade do estigma e de comprimento do tubo polínico nos ramos destacados sugerem que as seleções Conserva 1566 e Conserva 693 e a cv. 'Maciel' não sofrem negativamente influência da temperatura de 29°C. A receptividade do estigma, mesmo em ramos destacados, pode discriminar os genótipos quanto à tolerância da parte feminina a temperaturas próximas a 29°C.Several factors can cause an erratic production of peaches under subtropical conditions. The occurrence of high temperatures on the beginning of blooming is one of them. Such temperatures can damage the stigma and the pollen germination, causing a decrease on fecundation and fruit set. The present work had the objective of looking for differences in tolerance to 29±2ºC among peach genotypes, as well as checking if a simple method using detached twigs would be suitable to detect differences. Two experiments were conducted using whole plants in vase, on one and detached twigs on the other. Estimates of pollen tube growth on the pistil and stigma receptivity suggested that selections Conserva 1566 and Conserva 693 and cv. 'Maciel' were tolerant to temperatures around 29°C at begining of blooming. Stigma receptivity, even in detached twigs, showed

  7. Pollen reference collection digitization

    NARCIS (Netherlands)

    Ercan, F.E.Z.; Donders, T.H.; Bijl, P.K.; Wagner, F.

    2016-01-01

    The extensive Utrecht University pollen reference collection holds thousands of pollen samples of many species and genera from all over the world and has been a basis for the widely-used North West European Pollen Flora. These samples are fixed on glass slides for microscopy use, but the aging

  8. Simple methods for in vitro pollen germination and pollen preservation of selected species of the genus Agave

    Directory of Open Access Journals (Sweden)

    Sigifredo López Díaz

    2008-01-01

    Full Text Available Simple methods to evaluate the viability and to preserve Agave tequilana Weber var. azul and A. angustifolia Haw pollen were established. Pollen viability was assessed by improving a growing media and evaluating three common pollen germination media components: sucrose, boric acid, and calcium ion. Optimal germination of pollen was obtained at 0.300 M sucrose, 0.324 mM boric acid, and 1.219 mM calcium nitrate and incubated at a temperature of 25°C. Agave pollen was preserved in olive oil and organic solvents. Olive oil, which is immiscible with water, provides an anhydrous environment and limits available oxygen, conditions similar to those provided by some organic solvents. Fresh pollen was put into eppendorf tubes containing n-butanol, n-propanol, isopropanol, extra virgin olive oil and preserved at -20, 4, and 25°C. The germination of the preserved pollen was scored at different time periods during preservation employing the optimal germination medium. The viability of pollen grains preserved at -20°C in olive oil, proved olive oil as an efficient medium for agave pollen preservation for at least 6 months.

  9. Among-species differences in pollen quality and quantity limitation: implications for endemics in biodiverse hotspots.

    Science.gov (United States)

    Alonso, Conchita; Navarro-Fernández, Carmen M; Arceo-Gómez, Gerardo; Meindl, George A; Parra-Tabla, Víctor; Ashman, Tia-Lynn

    2013-11-01

    Insufficient pollination is a function of quantity and quality of pollen receipt, and the relative contribution of each to pollen limitation may vary with intrinsic plant traits and extrinsic ecological properties. Community-level studies are essential to evaluate variation across species in quality limitation under common ecological conditions. This study examined whether endemic species are more limited by pollen quantity or quality than non-endemic co-flowering species in three endemic-rich plant communities located in biodiversity hotspots of different continents (Andalusia, California and Yucatan). Natural variations in pollen receipt and pollen tube formation were analysed for 20 insect-pollinated plants. Endemic and non-endemic species that co-flowered were paired in order to estimate and compare the quantity and quality components of pre-zygotic pollination success, obtained through piecewise regression analysis of the relationship between pollen grains and pollen tubes of naturally pollinated wilted flowers. Pollen tubes did not frequently exceed the number of ovules per flower. Only the combination of abundant and good quality pollen and a low number of ovules per flower conferred relief from pre-zygotic pollen limitation in the three stochastic pollination environments studied. Quality of pollen receipt was found to be as variable as quantity among study species. The relative pollination success of endemic and non-endemic species, and its quantity and quality components, was community dependent. Assessing both quality and quantity of pollen receipt is key to determining the ovule fertilization potential of both endemic and widespread plants in biodiverse hotspot regions. Large natural variation among flowers of the same species in the two components and pollen tube formation deserves further analysis in order to estimate the environmental, phenotypic and intraindividual sources of variation that may affect how plants evolve to overcome this limitation in

  10. Storage of strawberry pollen

    Directory of Open Access Journals (Sweden)

    Rafet Aslantaş

    2013-12-01

    Full Text Available This study was carried out to determine storage ability of strawberry pollen at different temperatures for three different strawberry cultivars 'Aliso', 'Brio', and 'Cruz'. Strawberry pollen was stored at room temperature (22 ±2°C, +4°C, -4°C and -18°C in stabile humidity conditions. Strawberry poIlen was germinated using the hanging drop method in a 20% sucrose solution. Pollen germination rate increased because of low temperature storage. Pollen stored at room temperature and +4°C, -4°C, and -18°C was kept for 8 months, about one year, and 20 months, respectively. Pollen germination rates decreased as the length of storage period increased. The reaction of all cultivars tested on the duration and temperature of storage was similar.

  11. Molecular and cellular characterization of the tomato pollen profilin, LePro1.

    Directory of Open Access Journals (Sweden)

    Long-Xi Yu

    Full Text Available Profilin is an actin-binding protein involved in the dynamic turnover and restructuring of the actin cytoskeleton in all eukaryotic cells. We previously cloned a profilin gene, designated as LePro1 from tomato pollen. To understand its biological role, in the present study, we investigated the temporal and spatial expression of LePro1 during pollen development and found that the transcript was only detected at late stages during microsporogenesis and pollen maturation. Using antisense RNA, we successfully knocked down the expression of LePro1 in tomato plants using stable transformation, and obtained two antisense lines, A2 and A3 showing significant down-regulation of LePro1 in pollen resulting in poor pollen germination and abnormal pollen tube growth. A disorganized F-actin distribution was observed in the antisense pollen. Down-regulation of LePro1 also appeared to affect hydration of pollen deposited on the stigma and arrested pollen tube elongation in the style, thereby affecting fertilization. Our results suggest that LePro1 in conjunction with perhaps other cytoskeletal proteins, plays a regulatory role in the proper organization of F-actin in tomato pollen tubes through promoting actin assembly. Down-regulation of LePro1 leads to interruption of actin assembly and disorganization of the actin cytoskeleton thus arresting pollen tube growth. Based on the present and previous studies, it is likely that a single transcript of profilin gives rise to multiple forms displaying multifunctionality in tomato pollen.

  12. PENINGKATAN KETERAMPILAN MENULIS CERITA NARASI MELALUI PENERAPAN PROGAM LITERASI BERBANTUAN MEDIA BUKU CERITA ANAK PADA SISWA SD

    Directory of Open Access Journals (Sweden)

    Randy Widi Prayoga

    2017-11-01

    Full Text Available This study aims to describe the application of literacy programs with the help of children's story books to improve the skills of writing narrative stories of students. This research uses qualitative approach with research type of PTK. The learning process is implemented in 3 stages namely pramenulis, writing, and pascamesnulis. The study was conducted in 3 cycles. The results show that learning has been well implemented by teachers and students. The value of narrative story writing has increased from cycle I of 69.8 to 80 in cycle II and increased again to 85 in cycle III.Penelitian ini bertujuan untuk mendeskripsikan penerapan progam literasi dengan berbantuan buku cerita anak untuk meningkatkan keterampilan menulis cerita narasi siswa. Penelitian ini menggunakan pendekatan kualitatif dengan jenis penelitian PTK. Proses pembelajaran dilaksanakan dalam tiga tahap, yakni pramenulis, menulis, dan pascamesnulis. Penelitian dilaksanakan dalam tiga siklus. Hasil penelitian menunjukkan bahwa pembelajaran telah dilaksanakan dengan baik oleh guru dan siswa. Nilai menulis cerita narasi mengalami peningkatan dari siklus I sebesar 69,8 menjadi 80 pada siklus II dan meningkat lagi menjadi 85 pada siklus III.

  13. EXO70C2 is a key regulatory factor for optimal tip growth of pollen

    KAUST Repository

    Synek, Lukas

    2017-03-30

    The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.

  14. Post-X-irradiation effects on petunia pollen germinating in vitro and in vivo

    International Nuclear Information System (INIS)

    Gilissen, L.J.W.

    1978-01-01

    The germination of Petunia hybrida L. pollen grains in germination medium, containing 10% sucrose and 0.01 % H 3 BO 3 , was linearly related to relative humidity (RH): being minimal at 0 % RH and maximal at 100 % RH. The low germination at 0 % RH was completely restored after transfer to 100 % RH. Germination in medium decreased with increasing X-ray exposures between O and 400 kR. This decrease was caused by pollen rupture. No in vitro germination occurred at exposures of 400 kR and more. The radiosensitivity of pollen in vitro was minimal at 80 % RH. Transfer of pollen to the stigma post-X-irradiation resulted in resistance to much higher exposures of irradiation (<750 kR). The differences in radiosensitivity of the pollen germinated in vitro and in vivo are due possibly to the differences in composition of the germination medium and the stigmatic exudate. Pollen tube growth of irradiated pollen after compatible or incompatible pollination at first showed retarded then normal tube growth. A conclusion is that X-irradiation of pollen cannot influence the characteristics of pollen tube growth after compatible or incompatible pollination. (author)

  15. How honey bees carry pollen

    Science.gov (United States)

    Matherne, Marguerite E.; Anyanwu, Gabriel; Leavey, Jennifer K.; Hu, David L.

    2017-11-01

    Honey bees are the tanker of the skies, carrying thirty percent of their weight in pollen per foraging trip using specialized orifices on their body. How do they manage to hang onto those pesky pollen grains? In this experimental study, we investigate the adhesion force of pollen to the honeybee. To affix pollen to themselves, honey bees form a suspension of pollen in nectar, creating a putty-like pollen basket that is skewered by leg hairs. We use tensile tests to show that the viscous force of the pollen basket is more than ten times the honeybee's flight force. This work may provide inspiration for the design of robotic flying pollinators.

  16. Pollen-pistil interactions in North American and Chinese Cypripedium L. (Orchidaceae)

    Science.gov (United States)

    Retha Edens-Meier; Nan Vance; Yi-Bo Luo; Peng Li; Eric Westhus; Peter. Bernhardt

    2010-01-01

    Fluorescence microscopy is used to compare frequencies of pollen tube penetration in in situ populations of Cypripedium bardolphianumW.W. Smith et Farrer, Cypripedium flavum W.W. Smith, Cypripedium montanum Dougl. ex Lindl., Cypripedium parviflorum Salisbury var. pubescens...

  17. Radioprotective effect of the pollen

    International Nuclear Information System (INIS)

    Jiang Ying; Zhu Gengbo; Huang Meiying; Yin Zhiwei; Fang Jixi; Fan Xiudi

    1990-10-01

    The radioprotective injury effect of pollen in animals was studied. Research came to the conclusion that: (1) the acute death rate of animals is decreased by the pollen; (2) the peripheral leukocytes and spleen-B-lymph cells of animals are increased by the pollen; (3) the activity of superoxide dimutase (SOD) in the erythrocytes of animals is increased by the pollen; (4) the pollen has the function of protecting the structure of the organs of thymus and testes and so on; (5) the plasma hydroxyproline of animals is remarkably decreased by the pollen

  18. Floral phenology, secondary pollen presentation and pollination mechanism in Inula racemosa (Angiosperms: Asteraceae

    Directory of Open Access Journals (Sweden)

    P.A. Shabir

    2013-06-01

    Full Text Available Inula racemosa Hook. f. is protandrous, discharges pollen grains inside the anther tube and presents pollen secondarily onto the sweeping hairs of the style. The style and stigmatic branches present the yellow clumped pollen grains for pollination. This study describes floral functional morphology and phenology, anther dehiscence and pollen presentation, growth and behaviour of style during anthesis and pollination mechanism of I. racemosa. The species is entomophilous and is characterized by a highly asynchronous sexual phase. A large degree of asynchrony from floret to floret in a capitulum, and capitulum to capitulum in a plant, keeps the pollen dispersed for a longer duration. Two insect families were represented in the pollinator survey: Hymenoptera and Diptera. A significant correlation was observed between the number of capitula visited per bout and foraging time. We discuss morphological features of the ?owers which may enhance the pollen removal rate per bee visit and consequently cause a high visitation and pollination rate.

  19. Germination and storage of pollen

    NARCIS (Netherlands)

    Visser, T.

    1955-01-01

    Germination of pear pollen markedly improved when boric acid was added to the medium. The pollen was more sensitive to boron in water than in 10 % sugar solution. Supplying weak solutions of boron to pear branches before flowering resulted in a good germination of the pollen in sugar solution

  20. Hybridizing pines with diluted pollen

    Science.gov (United States)

    Robert Z. Callaham

    1967-01-01

    Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

  1. Methods to isolate a large amount of generative cells, sperm cells and vegetative nuclei from tomato pollen for omics analysis

    Directory of Open Access Journals (Sweden)

    Yunlong eLu

    2015-06-01

    Full Text Available The development of sperm cells from microspores involves a set of finely regulated molecular and cellular events and the coordination of these events. The mechanisms underlying these events and their interconnections remain a major challenge. Systems analysis of genome-wide molecular networks and functional modules with high-throughput omics approaches is crucial for understanding the mechanisms; however, this study is hindered because of the difficulty in isolating a large amount of cells of different types, especially generative cells (GCs, from the pollen. Here, we optimized the conditions of tomato pollen germination and pollen tube growth to allow for long-term growth of pollen tubes in vitro with sperm cells (SCs generated in the tube. Using this culture system, we developed methods for isolating GCs, SCs and vegetative-cell nuclei (VN from just-germinated tomato pollen grains and growing pollen tubes and their purification by Percoll density gradient centrifugation. The purity and viability of isolated GCs and SCs were confirmed by microscopy examination and fluorescein diacetate staining, respectively, and the integrity of VN was confirmed by propidium iodide staining. We could obtain about 1.5 million GCs and 2.0 million SCs each from 180 mg initiated pollen grains, and 10 million VN from 270 mg initiated pollen grains germinated in vitro in each experiment. These methods provide the necessary preconditions for systematic biology studies of SC development and differentiation in higher plants.

  2. Methods to isolate a large amount of generative cells, sperm cells and vegetative nuclei from tomato pollen for "omics" analysis.

    Science.gov (United States)

    Lu, Yunlong; Wei, Liqin; Wang, Tai

    2015-01-01

    The development of sperm cells (SCs) from microspores involves a set of finely regulated molecular and cellular events and the coordination of these events. The mechanisms underlying these events and their interconnections remain a major challenge. Systems analysis of genome-wide molecular networks and functional modules with high-throughput "omics" approaches is crucial for understanding the mechanisms; however, this study is hindered because of the difficulty in isolating a large amount of cells of different types, especially generative cells (GCs), from the pollen. Here, we optimized the conditions of tomato pollen germination and pollen tube growth to allow for long-term growth of pollen tubes in vitro with SCs generated in the tube. Using this culture system, we developed methods for isolating GCs, SCs and vegetative cell nuclei (VN) from just-germinated tomato pollen grains and growing pollen tubes and their purification by Percoll density gradient centrifugation. The purity and viability of isolated GCs and SCs were confirmed by microscopy examination and fluorescein diacetate staining, respectively, and the integrity of VN was confirmed by propidium iodide staining. We could obtain about 1.5 million GCs and 2.0 million SCs each from 180 mg initiated pollen grains, and 10 million VN from 270 mg initiated pollen grains germinated in vitro in each experiment. These methods provide the necessary preconditions for systematic biology studies of SC development and differentiation in higher plants.

  3. Pd-nanoparticles cause increased toxicity to kiwifruit pollen compared to soluble Pd(II)

    International Nuclear Information System (INIS)

    Speranza, Anna; Leopold, Kerstin; Maier, Marina; Taddei, Anna Rita; Scoccianti, Valeria

    2010-01-01

    In the present study, endpoints including in vitro pollen performance (i.e., germination and tube growth) and lethality were used as assessments of nanotoxicity. Pollen was treated with 5-10 nm-sized Pd particles, similar to those released into the environment by catalytic car exhaust converters. Results showed Pd-nanoparticles altered kiwifruit pollen morphology and entered the grains more rapidly and to a greater extent than soluble Pd(II). At particulate Pd concentrations well below those of soluble Pd(II), pollen grains experienced rapid losses in endogenous calcium and pollen plasma membrane damage was induced. This resulted in severe inhibition and subsequent cessation of pollen tube emergence and elongation at particulate Pd concentrations as low as 0.4 mg L -1 . Particulate Pd emissions related to automobile traffic have been increasing and are accumulating in the environment. This could seriously jeopardize in vivo pollen function, with impacts at an ecosystem level. - Nanoparticulate Pd - which resembles emissions from automobile catalysts - affects pollen to a higher extent than soluble Pd.

  4. Pd-nanoparticles cause increased toxicity to kiwifruit pollen compared to soluble Pd(II)

    Energy Technology Data Exchange (ETDEWEB)

    Speranza, Anna, E-mail: anna.speranza@unibo.i [Dipartimento di Biologia, Universita di Bologna, via Irnerio 42, 40126 Bologna (Italy); Leopold, Kerstin, E-mail: kerstin.leopold@lrz.tu-muenchen.d [Arbeitsgruppe fuer Analytische Chemie, Technische Universitaet Muenchen, Garching (Germany); Maier, Marina, E-mail: marina.maier@ch.tum.d [Arbeitsgruppe fuer Analytische Chemie, Technische Universitaet Muenchen, Garching (Germany); Taddei, Anna Rita, E-mail: artaddei@unitus.i [CIME, Universita della Tuscia, Viterbo (Italy); Scoccianti, Valeria, E-mail: valeria.scoccianti@uniurb.i [Dipartimento di Scienze dell' Uomo, dell' Ambiente e della Natura, Universita di Urbino ' Carlo Bo' , Urbino (Italy)

    2010-03-15

    In the present study, endpoints including in vitro pollen performance (i.e., germination and tube growth) and lethality were used as assessments of nanotoxicity. Pollen was treated with 5-10 nm-sized Pd particles, similar to those released into the environment by catalytic car exhaust converters. Results showed Pd-nanoparticles altered kiwifruit pollen morphology and entered the grains more rapidly and to a greater extent than soluble Pd(II). At particulate Pd concentrations well below those of soluble Pd(II), pollen grains experienced rapid losses in endogenous calcium and pollen plasma membrane damage was induced. This resulted in severe inhibition and subsequent cessation of pollen tube emergence and elongation at particulate Pd concentrations as low as 0.4 mg L{sup -1}. Particulate Pd emissions related to automobile traffic have been increasing and are accumulating in the environment. This could seriously jeopardize in vivo pollen function, with impacts at an ecosystem level. - Nanoparticulate Pd - which resembles emissions from automobile catalysts - affects pollen to a higher extent than soluble Pd.

  5. Multiple BiP genes of Arabidopsis thaliana are required for male gametogenesis and pollen competitiveness.

    Science.gov (United States)

    Maruyama, Daisuke; Sugiyama, Tomoyuki; Endo, Toshiya; Nishikawa, Shuh-Ichi

    2014-04-01

    Immunoglobulin-binding protein (BiP) is a molecular chaperone of the heat shock protein 70 (Hsp70) family. BiP is localized in the endoplasmic reticulum (ER) and plays key roles in protein translocation, protein folding and quality control in the ER. The genomes of flowering plants contain multiple BiP genes. Arabidopsis thaliana has three BiP genes. BIP1 and BIP2 are ubiquitously expressed. BIP3 encodes a less well conserved BiP paralog, and it is expressed only under ER stress conditions in the majority of organs. Here, we report that all BiP genes are expressed and functional in pollen and pollen tubes. Although the bip1 bip2 double mutation does not affect pollen viability, the bip1 bip2 bip3 triple mutation is lethal in pollen. This result indicates that lethality of the bip1 bip2 double mutation is rescued by BiP3 expression. A decrease in the copy number of the ubiquitously expressed BiP genes correlates well with a decrease in pollen tube growth, which leads to reduced fitness of mutant pollen during fertilization. Because an increased protein secretion activity is expected to increase the protein folding demand in the ER, the multiple BiP genes probably cooperate with each other to ensure ER homeostasis in cells with active secretion such as rapidly growing pollen tubes.

  6. Calcium in pollen-pistil interaction in 'Petunia hybrida Hat'. Pt. 3. Localization of Ca2+ ions and Ca2+-ATPase in pollinated pistil

    International Nuclear Information System (INIS)

    Bednarska, E.; Butowt, R.

    1995-01-01

    Studies were carried out of Ca 2+ and Ca 2+ -ATPase localization in pollinated (6 and 48 h after pollination) pistils of 'Petunia hybrida'. The results were confronted with Ca 2+ localization in mature pollen grain and in unpollinated pistil. It has been found that after pollination the number of Ca 2+ sequestered in the stigmal exudate and in the sporoderm of the pollen grain gets lower. That phenomenon was associated with the appearance of a large number of Sb/Ca precipitates in the submembrane cytoplasm of the germinating pollen. In the vacuolized pollen grain, i.e. grown into a pollen tube, there were only a few precipitates. In the pollen tube, Ca 2+ were found in the organelles of the tip cytoplasm and in the external pectin cell wall. Studies with the use of 45 Ca 2+ have revealed that the source of calcium ions incorporated into the pollen tube tip and its pectin wall is the transmitting tract of the style. In the transmitting tract overgrown with pollen tubes, Ca 2+ were localized in the intercellular matrix and in the transmitting cell. Sb/Ca precipitates occurred in the nuclei, around the secretary vesicles and on the plasmalemma in the transverse walls region. Elevated Ca 2+ level was found in degenerating cells (inhibited pollen tubes, transmitting cells, nucellar cells). The progressing degeneration process of the cells of the transmitting tract of the pollinated pistil was associated with a decrease in the activity of plasmalemma Ca 2+ -ATPase. (author). 30 refs, 19 figs

  7. Pollen Performance in Clarkia Taxa with Contrasting Mating Systems: Implications for Male Gametophytic Evolution in Selfers and Outcrossers

    Directory of Open Access Journals (Sweden)

    Alisa A. Hove

    2013-04-01

    Full Text Available We tested three predictions regarding the joint evolution of pollen performance and mating system. First, due to the potential for intense intrasexual competition in outcrossing populations, we predicted that outcrossers would produce faster-growing pollen than their selfing relatives. Second, if elevated competition promotes stronger selection on traits that improve pollen performance, then, among-plant variation in pollen performance would be lower in outcrossers than in selfers. Third, given successive generations of adaptation to the same maternal genotype in selfers, we predicted that, in selfing populations (but not in outcrossing ones, pollen would perform better following self- than cross-pollinations. We tested these predictions in field populations of two pairs of Clarkia (Onagraceae sister taxa. Consistent with our predictions, one outcrosser (C. unguiculata exhibited faster pollen germination and less variation in pollen tube growth rate (PTGR among pollen donors than its selfing sister species, C. exilis. Contrary to our predictions, the selfing C. xantiana ssp. parviflora exhibited faster PTGR than the outcrossing ssp. xantiana, and these taxa showed similar levels of variation in this trait. Pollen performance following self- vs. cross-pollinations did not differ within either selfing or outcrossing taxa. While these findings suggest that mating system and pollen performance may jointly evolve in Clarkia, other factors clearly contribute to pollen performance in natural populations.

  8. Pollen morphology of the Alangiaceae

    NARCIS (Netherlands)

    Reitsma, Tj.

    1970-01-01

    This paper presents a pollen-morphological study of Alangium, a genus mainly restricted to the tropics of the Old World, of which 18 of the 19 known species were studied. The pollen grains, studied with the use of a light microscope, a transmission electron microscope and a scanning electron

  9. Allergenic pollen pollinosis in Madrid.

    Science.gov (United States)

    Subiza, J; Jerez, M; Jiménez, J A; Narganes, M J; Cabrera, M; Varela, S; Subiza, E

    1995-07-01

    A 15-year pollen count was performed in the atmosphere of Madrid, Spain, to determine the months in which the highest concentrations of allergenic pollens occur. Pollen counts were done with a Burkard spore trap (Burkard Manufacturing, Rickmansworth, Herst., U.K.). The results were subsequently compared with results of skin tests in patients with pollinosis born and living in and around Madrid. The highest airborne presence (percent of total yearly pollen counts, mean of counts from 1979 to 1993) was for Quercus spp. (17%); followed by Platanus spp. (15%), Poaceae (15%), Cupressaceae (11%), Olea spp. (9%), Pinus spp. (7%), Populus spp. (4%), and Plantago spp. (4%). The most predominant pollens from January to April are tree pollens (Cupressaceae, Alnus, Fraxinus, Ulmus, Populus, Platanus, and Morus), although these are also abudant in May and June (Quercus, Olea, and Pinus spp.). The grass pollination period shows a double curve: the first peak occurs from February to April (8% of yearly grasses), and the second peak occurs from May to July (90% of yearly grasses). Among allergenically significant weeds, the most notable is Plantago; in contrast, Rumex, Urticaceae, Cheno-Amaranthaceae, and Artemisia spp. have very low concentrations (arizonica (20%). The population of Madrid is exposed to high concentrations of allergenic pollen from February to July, although the most intense period is from May to June. Grass pollens are the most important cause of pollinosis in this area.

  10. Biochemical and ultrastructural changes in pollen of Zea mays L. grown under enhanced UV-B radiation

    International Nuclear Information System (INIS)

    Santos, A.; Almeida, J.M.; Santos, I.; Salema, R.

    1998-01-01

    The influence of ultraviolet-B (UV-B) radiation on the development of the male gametophyte was studied in Zea mays L. cv. LG12 grown in a growth chamber under PAR light supplemented with UV-B radiation and compared with a second set of plants grown under PAR light. Pollen samples collected from both groups of plants were cultured on germination medium and it was found that UV-B had no effect on pollen germination. Total pollen protein content was not affected but UV-B absorbing pigments increased. Some ultrastructural alterations were observed in pollen and pollen tubes, in particular large amounts of electron dense deposits were seen throughout the cytoplasm and in association with the pollen wall. In mature spikes of UV-B treated plants, anthers retained numerous pollen grains in their loculi while anthers of control plants were almost empty. UV-B treatment delayed flowering by 2±3 d. These results show that UV-B treatment of maize plants interferes with flowering, pollen ultrastructure and anther maturation even though pollen germination is unaffected. The significant increase of UV-B absorbing pigments in pollen grains could represent a defence mechanism that enables plants to complete their reproductive cycle. (author)

  11. Pollen viability of Salix myrtilloides L. – an endangered species in Poland

    Directory of Open Access Journals (Sweden)

    Magdalena Pogorzelec

    2016-12-01

    Full Text Available Salix myrtilloides L. (swamp willow is the most endangered species among the boreal Salix species in Poland. The number and size of its population have been decreasing constantly since the 1990s. The main aim of the study was to determine the viability of collected S. myrtilloides pollen and optimal conditions for its in vitro germination. The pollen of S. myrtilloides was collected from 25 male individuals from a population growing in the mid-forest peat bog Dekowina (Sobibór Landscape Park in May 2014. Two methods were applied to estimate the viability of fresh and stored pollen: staining pollen with 2% acetocarmine solution and in vitro germinability. Various temperature (11°C, 23°C and light conditions as well as different concentrations of glucose (1%, 2.5%, 5%, or 7.5% were tested for the optimization of in vitro germination. We documented relatively high S. myrtilloides pollen viability. Pollen tube growth was found to be largely affected by both glucose content in the medium and thermal conditions during germination. Fresh pollen germinated most effectively on the medium with 2.5% glucose (stored pollen – in 5% glucose, at 23°C and in the presence of light. We conclude that pollen viability of S. myrtilloides does not seem to be a limiting factor for reproductive success. Moreover, the pollen is not sterile even after storage for 12 months. The S. myrtilloides individuals from the Dekowina peat bog produce viable pollen grains that are able to germinate and therefore it can be used to pollinate other populations present in the Polesie Lubelskie region for gene pool enrichment.

  12. PECTATE LYASE-LIKE10 is associated with pollen wall development in Brassica campestris.

    Science.gov (United States)

    Jiang, Jingjing; Yao, Lina; Yu, Youjian; Lv, Meiling; Miao, Ying; Cao, Jiashu

    2014-11-01

    PECTATE LYASE-LIKE10 (PLL10) was previously identified as one of the differentially expressed genes both in microspores during the late pollen developmental stages and in pistils during the fertilization process in Chinese cabbage (Brassica campestris ssp. chinensis). Here, antisense-RNA was used to study the functions of BcPLL10 in Chinese cabbage. Abnormal pollen was identified in the transgenic lines (bcpll10-4, -5, and -6). In fertilization experiments, fewer seeds were harvested when the antisense-RNA lines were used as pollen donor. In vivo and in vitro pollen germination assays less germinated pollen tubes were observed in bcpll10 lines. Scanning electron microscopy observation verified that the tryphine materials were over accumulated around the pollen surface and sticked them together in bcpll10. Moreover, transmission electron microscopy observation revealed that the internal endintine was overdeveloped and predominantly occupied the intine, and disturbed the normal proportional distribution of the two layers in the non-germinal furrow region; and no obvious demarcation existed between them in the germinal furrow region in the bcpll10 pollen. Collectively, this study presented a novel PLL gene that played an important role during the pollen wall development in B. campestris, which may also possess potential importance for male sterility usage in agriculture. © 2014 Institute of Botany, Chinese Academy of Sciences.

  13. Pollen rain and pollen representation across a forest-páramo ecotone in northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.; Duivenvoorden, J.F.; Hooghiemstra, H.

    2009-01-01

    Modern pollen spectra were studied in forest and páramo vegetation from the Guandera area, northern Ecuador. Pollen representation was estimated by comparing the presence of plant taxa from a recent vegetation survey with the pollen spectra in moss polsters and pollen traps. In total, 73 pollen taxa

  14. CHARACTERIZATION OF THE MAIZE POLLEN TRANSCRIPTOME

    Science.gov (United States)

    Pollen is a primary vehicle for transgene flow from engineered plants to their non-transgenic, native or weedy relatives. Hence, gene flow will be affected by pollen fitness (e.g., how well a particular pollen grain can outcompete other pollen present on the stigma and complete ...

  15. Sulfinylated Azadecalins act as functional mimics of a pollen germination stimulant in Arabidopsis pistils

    Science.gov (United States)

    Qin, Yuan; Wysocki, Ronald J; Somogyi, Arpad; Feinstein, Yelena; Franco, Jessica Y; Tsukamoto, Tatsuya; Dunatunga, Damayanthi; Levy, Clara; Smith, Steven; Simpson, Robert; Gang, David; Johnson, Mark A; Palanivelu, Ravishankar

    2011-01-01

    SUMMARY Polarized cell elongation is triggered by small molecule cues during development of diverse organisms. During plant reproduction, pollen interactions with the stigma result in the polar outgrowth of a pollen tube, which delivers sperm cells to the female gametophyte to effect double fertilization. In many plants, pistils stimulate pollen germination. However, in Arabidopsis, the effect of pistils on pollen germination and the pistil factors that stimulate pollen germination remain poorly characterized. Here, we demonstrate that stigma, style, and ovules in Arabidopsis pistils stimulate pollen germination. We isolated an Arabidopsis pistil extract fraction that stimulates Arabidopsis pollen germination, and employed ultrahigh resolution ESI FT-ICR and MS/MS techniques to accurately determine the mass (202.126 daltons) of a compound that is specifically present in this pistil extract fraction. Using the molecular formula (C10H19NOS) and tandem mass spectral fragmentation patterns of the m/z (mass to charge ratio) 202.126 ion, we postulated chemical structures, devised protocols, synthesized N-Methanesulfinyl 1- and 2-azadecalins that are close structural mimics of the m/z 202.126 ion, and showed that they are sufficient to stimulate Arabidopsis pollen germination in vitro (30 µM stimulated ~50% germination) and elicit accession-specific response. Although N-Methanesulfinyl 2-azadecalin stimulated pollen germination in three species of Lineage I of Brassicaceae, it did not induce a germination response in Sisymbrium irio (Lineage II of Brassicaceae) and tobacco, indicating that activity of the compound is not random. Our results show that Arabidopsis pistils promote germination by producing azadecalin-like molecules to ensure rapid fertilization by the appropriate pollen. PMID:21801250

  16. Characterization of a pollen-specific cDNA clone from Nicotiana tabacum expressed during microgametogenesis and germination.

    Science.gov (United States)

    Weterings, K; Reijnen, W; van Aarssen, R; Kortstee, A; Spijkers, J; van Herpen, M; Schrauwen, J; Wullems, G

    1992-04-01

    This report describes the isolation and characterization of a cDNA clone representing a gene specifically expressed in pollen. A cDNA library was constructed against mRNA from mature pollen of Nicotiana tabacum. It was screened differentially against cDNA from mRNA of leaf and of pollen. One clone, NTPc303, was further characterized. On northern blot this clone hybridizes to a transcript 2100 nucleotides in length. NTPc303 is abundant in pollen. Expression of the corresponding gene is restricted to pollen, because no other generative or vegetative tissue contains transcripts hybridizing to NTPc303. Expression of NTP303 is evolutionarily conserved: homologous transcripts are present in pollen from various plant species. The first NTP303 transcripts are detectable on northern blot at the early bi-nucleate stage and accumulate until the pollen has reached maturity. During germination and pollen tube growth in vitro new NTP303 transcripts appear. This transcription has been proved by northern blots as well as by pulse labelling experiments. Nucleotide sequence analysis revealed that NTPc303 has an open reading frame coding for a predicted protein of 62 kDa. This protein shares homology to ascorbate oxidase and other members of the blue copper oxidase family. A possible function for this clone during pollen germination is discussed.

  17. The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins.

    Science.gov (United States)

    Chao, Qing; Gao, Zhi-Fang; Wang, Yue-Feng; Li, Zhe; Huang, Xia-He; Wang, Ying-Chun; Mei, Ying-Chang; Zhao, Biligen-Gaowa; Li, Liang; Jiang, Yu-Bo; Wang, Bai-Chen

    2016-06-01

    Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.

  18. Use of γ-irradiated pollen for the gene transfer in Petunia

    International Nuclear Information System (INIS)

    Andrejchenko, S.V.; Grodzinskij, D.M.

    1986-01-01

    Possibility of using gamma-irradiated pollen for the gene transfer in Petunia is shown. Occurrence of gametic transformation provided not only the gene integration and expression but also their transfer to the daughter generations. The described methodical approach to construction of the plant eucariotic cell genome is based not only on its simplicity but also on the fact that gamma-radiation doses of 1000 Gy and higher have no desorganizing effect on the chromatine structure in such a degree that its transcription activity is completely lost. Besides, selective inactivation of the locus radiation in the pollen genome is much assisted by their different radioresistance. Though the gene transfer by gametic transformation is mostly irregular but its probability may be increased by the correct selection of the pollen irradiation dose in a range in which the growth of pollen tube before ovary is conserved and reparation of one-strand and two-strand DNA breaks preventing chromatine fragmentation is suppressed

  19. Pollen Forecast and Dispersion Modelling

    Science.gov (United States)

    Costantini, Monica; Di Giuseppe, Fabio; Medaglia, Carlo Maria; Travaglini, Alessandro; Tocci, Raffaella; Brighetti, M. Antonia; Petitta, Marcello

    2014-05-01

    The aim of this study is monitoring, mapping and forecast of pollen distribution for the city of Rome using in-situ measurements of 10 species of common allergenic pollens and measurements of PM10. The production of daily concentration maps, associated to a mobile phone app, are innovative compared to existing dedicated services to people who suffer from respiratory allergies. The dispersal pollen is one of the most well-known causes of allergic disease that is manifested by disorders of the respiratory functions. Allergies are the third leading cause of chronic disease and it is estimated that tens millions of people in Italy suffer from it. Recent works reveal that during the last few years there was a progressive increase of affected subjects, especially in urban areas. This situation may depend: on the ability to transport of pollutants, on the ability to react between pollutants and pollen and from a combination of other irritants, existing in densely populated and polluted urban areas. The methodology used to produce maps is based on in-situ measurements time series relative to 2012, obtained from networks of air quality and pollen stations in the metropolitan area of Rome. The monitoring station aerobiological of University of Rome "Tor Vergata" is located at the Department of Biology. The instrument used to pollen monitoring is a volumetric sampler type Hirst (Hirst 1952), Model 2000 VPPS Lanzoni; the data acquisition is carried out as reported in Standard UNI 11008:2004 - "Qualità dell'aria - Metodo di campionamento e conteggio dei granuli pollinici e delle spore fungine aerodisperse" - the protocol that describes the procedure for measuring of the concentration of pollen grains and fungal spores dispersed into the atmosphere, and reported in the "Manuale di gestione e qualità della R.I.M.A" (Travaglini et. al. 2009). All 10 allergenic pollen are monitored since 1996. At Tor Vergata university is also operating a meteorological station (SP2000, CAE

  20. Tube plug

    International Nuclear Information System (INIS)

    Zafred, P. R.

    1985-01-01

    The tube plug comprises a one piece mechanical plug having one open end and one closed end which is capable of being inserted in a heat exchange tube and internally expanded into contact with the inside surface of the heat exchange tube for preventing flow of a coolant through the heat exchange tube. The tube plug also comprises a groove extending around the outside circumference thereof which has an elastomeric material disposed in the groove for enhancing the seal between the tube plug and the tube

  1. Nitric Oxide Binds to and Modulates the Activity of a Pollen Specific Arabidopsis Diacylglycerol Kinase

    KAUST Repository

    Wong, Aloysius Tze

    2014-01-01

    Nitric oxide (NO) is an important signaling molecule in plants. In the pollen of Arabidopsis thaliana, NO causes re-orientation of the growing tube and this response is mediated by 3′,5′-cyclic guanosine monophosphate (cGMP). However, in plants, NO

  2. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... any of these problems: a dislodged tube a blocked or clogged tube any signs of infection (including redness, swelling, or warmth at the tube site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site severe abdominal pain lasting ...

  3. The effects of pesticides on morphology, viability, and germination of Blackberry (Rubus glaucus Benth.) and Tree tomato (Solanum betaceum Cav.) pollen grains.

    Science.gov (United States)

    Padilla, Flavio; Soria, Norman; Oleas, Abrahan; Rueda, Darwin; Manjunatha, Bangeppagari; Kundapur, Rajesh R; Maddela, Naga Raju; Rajeswari, Bugude

    2017-07-01

    The objective of this study was to determine the effect of application of pesticides on morphology, viability, and germination of pollen grains of Blackberry (Rubus glaucus Benth.) and Tree tomato (Solanum betaceum Cav.). The study was performed at Patate, Tungurahua province, Ecuador and was divided into two phases. Phase one dedicated to the study of morphology, viability, and identification of nutrient solution for better germination of pollen grains and phase two for the analysis of the effect of conventional, organic, and biological pesticides on pollen grain germination and pollen tube length. To study pollen morphology, pollens were extracted by hand pressure and was analyzed by optical and electron microscopy. The viable pollen grains were identified by staining with 1% acetocarmine. Even though Tree tomato and Blackberry pollen grains are morphologically similar, their exine shapes differ. We observed four times increase in pollen germination rate when suspended in nutrient solution (Sucrose with Boric acid) than control (water). Pollen grains under nutrient solution were subjected to different groups of pesticides for the period of 2, 4, and 6 h. With respect to pesticide affect, the Blackberry pollen grain germination followed the following order: Lecaniceb > Beauveb > Metazeb => Myceb > Control. However, the effect on Tree tomato pollen grains was as follows: Lecaniceb > Myceb > Cantus > Bacillus thuringiensis > Kripton > Control. As per as pollen grain germination is concerned, we observed that the chemical pesticides are more harmful than other pesticides. So, it is necessary to perform screening test for different pesticides and their effect on pollen grain germination before applying to the fields.

  4. National Allergy Bureau Pollen and Mold Report

    Science.gov (United States)

    ... Search AAAAI National Allergy Bureau Pollen and Mold Report Date: May 19, 2018 Location: San Antonio (2), ... 18/2018 ( click here to view ). Our Allergen Report Email Service can automatically email you daily pollen ...

  5. Calcium in pollen-pistil interaction in `Petunia hybrida Hat`. Pt. 3. Localization of Ca{sup 2+} ions and Ca{sup 2+}-ATPase in pollinated pistil

    Energy Technology Data Exchange (ETDEWEB)

    Bednarska, E.; Butowt, R. [Uniwersytet Mikolaja Kopernika, Torun (Poland)

    1995-12-31

    Studies were carried out of Ca{sup 2+} and Ca{sup 2+}-ATPase localization in pollinated (6 and 48 h after pollination) pistils of `Petunia hybrida`. The results were confronted with Ca{sup 2+} localization in mature pollen grain and in unpollinated pistil. It has been found that after pollination the number of Ca{sup 2+} sequestered in the stigmal exudate and in the sporoderm of the pollen grain gets lower. That phenomenon was associated with the appearance of a large number of Sb/Ca precipitates in the submembrane cytoplasm of the germinating pollen. In the vacuolized pollen grain, i.e. grown into a pollen tube, there were only a few precipitates. In the pollen tube, Ca{sup 2+} were found in the organelles of the tip cytoplasm and in the external pectin cell wall. Studies with the use of {sup 45}Ca{sup 2+} have revealed that the source of calcium ions incorporated into the pollen tube tip and its pectin wall is the transmitting tract of the style. In the transmitting tract overgrown with pollen tubes, Ca{sup 2+} were localized in the intercellular matrix and in the transmitting cell. Sb/Ca precipitates occurred in the nuclei, around the secretary vesicles and on the plasmalemma in the transverse walls region. Elevated Ca{sup 2+} level was found in degenerating cells (inhibited pollen tubes, transmitting cells, nucellar cells). The progressing degeneration process of the cells of the transmitting tract of the pollinated pistil was associated with a decrease in the activity of plasmalemma Ca{sup 2+}-ATPase. (author). 30 refs, 19 figs.

  6. Stigma-pollen recognition: a new look

    Directory of Open Access Journals (Sweden)

    C. Dumas

    2014-01-01

    Full Text Available During the last two decades, there have been several conceptual developments in our understanding of pollen-stigma recognition and molecular mechanisms involved. The main models proposed are compared. Based on additional data a hypothesis to complete these models especially for pollen hydration and adhesion is proposed. After attachment of the pollen to the stigma surface a close interaction exists involving lipoproteic membrane-like compounds (pollenkitt and stigma pellicle and pollen agglutinating ability.

  7. Effect of X-rays and u.v.-light on the levels of NAD(P), NAD(P)H and hydroxyproline in Pinus silvestris pollen

    International Nuclear Information System (INIS)

    Zelles, L.

    1978-01-01

    Pollen grains of Pinus Silvestris were irradiated with stimulating and inhibiting doses of X-rays and u.v.-light and the levels of NAD(P), NAD(P)H and hydroxyproline determined during tube growth. Pollen grains irradiated with stimulating doses of X-rays and u.v.-light developed longer tubes, while grains irradiated with inhibiting doses of X-rays and u.v.-light developed shorter tubes than the unirradiated controls. After 32 hr of incubation, the levels of NAD(P), NAD(P)H and hydroxyproline were at their lowest compared with unirradiated pollen. In samples with stimulating doses of irradiation NAD(P) reached its maximum earlier than in samples with inhibiting irradiation. The ratio between the concentrations of NAD(P) and NAD(P)H in the irradiated samples was higher than in the unirradiated control. The hydroxyproline content was higher in irradiated than in unirradiated pollen. (author)

  8. A temporal dimension to the influence of pollen rewards on bee behaviour and fecundity in Aloe tenuior.

    Directory of Open Access Journals (Sweden)

    Karl J Duffy

    Full Text Available The net effect of pollen production on fecundity in plants can range from negative--when self-pollen interferes with fecundity due to incompatibility mechanisms, to positive--when pollen availability is associated with increased pollinator visitation and fecundity due to its utilization as a reward. We investigated the responses of bees to pollen and nectar rewards, and the effects of these rewards on pollen deposition and fecundity in the hermaphroditic succulent shrub Aloe tenuior. Self-pollinated plants failed to set fruit, but their ovules were regularly penetrated by self-pollen tubes, which uniformly failed to develop into seeds as expected from ovarian self-incompatibility (or strong early inbreeding depression. Bees consistently foraged for pollen during the morning and early afternoon, but switched to nectar in the late afternoon. As a consequence of this differential foraging, we were able to test the relative contribution to fecundity of pollen- versus nectar-collecting flower visitors. We exposed emasculated and intact flowers in either the morning or late afternoon to foraging bees and showed that emasculation reduced pollen deposition by insects in the morning, but had little effect in the afternoon. Despite the potential for self-pollination to result in ovule discounting due to late-acting self-sterility, fecundity was severely reduced in artificially emasculated plants. Although there were temporal fluctuations in reward preference, most bee visits were for pollen rewards. Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species.

  9. Gamma Irradiation Effects on Oil Palm (Elaies Guineensis) Pollen Viability, Fruits and Bunch Formations

    International Nuclear Information System (INIS)

    Aida Nazlyn Nazari; Azhar Mohamad; Shuhaimi Shamsuddin

    2014-01-01

    Assessing performance and genetic diversity of the wild material of oil palm is important for understanding genetic structure of natural oil palm populations towards improvement of the crops. This information is important for oil palm breeding programs, and also for continued ex-situ conservation of the germplasm and breeding program in Malaysia. Mutation induction is one of the alternative ways in creating variants for selection in the breeding program. In this study, evaluation on the effect of irradiated pollen towards pollen viability, bunches formation and no. of parthenocarpic fruits were conducted. Series of acute gamma radiation at dose 0, 10, 20, 40, 50, 100, 200, 300, 500, 100 and 2000 Gy were exposed to Elaies guineensis pollen. Increasing level of irradiation higher than 200 Grays (Gy) affects pollen viability based on the 12 consecutive days observation evaluated in situ conditions. Besides, at this level of irradiation (> 200 Gy), the pollen tube formation were disrupted and subsequently unable the pollen to reach the ovule which cause the embryo to aborted and contributed to the formation of parthenocarpic fruits and rotten bunches. These observations suggested that at low levels of irradiation (< 200 Gy) may damage only part of the generative nucleus while maintaining its capacity to fertilise the egg cells and lead to hybridization. (author)

  10. Effect of Pollen Feed on Parasitization and Predatism of Cephalonomia stephanoderis onHypothenemus hampei

    Directory of Open Access Journals (Sweden)

    Dwi Suci Rahayu

    2014-05-01

    Full Text Available Biological control of the coffee berry borer (Hypothenemus hampeiusing parasitoid Cephalonomia stephanoderishas been developed through the improvement of the parasitoid role may using pollens as feed source. The objective of this study was to investigate the effect of cover crop and weed pollens on parasitization and predatism of C. stephanoderis.The applied treatments were pollens of Turnera ulmifolia, Arachis pintoi, Ageratum conyzoidesadded in glass tube that consist of 10 CBB pupaes and a mated female of C. stephanoderis. Number of pupae parasitized and pupae preyed were observed. The result showed that addition of A. Pintoi pollen increased the number of pupae parasitized at 135% whereas addition of T. ulmifolia and A. conyzoides pollens did not affect parasitization of C. Stephanoderis. The predatismof C. stephanoderiswas higher than parasitization to pupae of H. hampei which showed that the behavior of C. stephanoderiswas parasitization. Addition of T. ulmifolia, A. pintoi, and A. conyzoidespollens increased the number of pupae predatism at 132%, 102%, and 225%, respectively. Key words: Ageratum conyzoides, Arachis pintoi, Cephalonomia stephanoderis, Hypothenemus hampei,parasitization, predatism, pollens, Turnera ulmifolia

  11. A Simple, Inexpensive Pollen Trap

    Science.gov (United States)

    P. E. Hoekstra

    1965-01-01

    Pollen plays a role of vital importance in the sexual reproduction of all plants but it is especially important in forestry. With few exceptions, sexual reproduction is the only link between succeeding generations in the forest. To be sure, vegetative reproduction is important for special purposes, but it will probably not be used on a mass scale in timber...

  12. Temperatures during flower bud development affect pollen germination, self-incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.).

    Science.gov (United States)

    Distefano, G; Gentile, A; Hedhly, A; La Malfa, S

    2018-03-01

    One of the key environmental factors affecting plant reproductive systems is temperature. Characterising such effects is especially relevant for some commercially important genera such as Citrus. In this genus, failure of fertilisation results in parthenocarpic fruit development and seedlessness, which is a much-prized character. Here, we characterise the effects of temperature on flower and ovary development, and on pollen-pistil interactions in 'Comune' clementine (Citrus clementina Hort. ex Tan.). We examine flower bud development, in vitro pollen germination and pollen-pistil interaction at different temperatures (15, 20, 25 or 30 °C). These temperatures span the range from 'cold' to 'hot' weather during the flowering season in many citrus-growing regions. Temperature had a strong effect on flower and ovary development, pollen germination, and pollen tube growth kinetics. In particular, parthenocarpic fruit development (indicated by juice vesicle growth) was initiated early if flowers were exposed to warmer temperatures during anthesis. Exposure to different temperatures during flower bud development also alters expression of the self-incompatibility reaction. This affects the point in the pistil at which pollen tube growth is arrested and confirms the role of sub- and supra-optimal temperatures in determining the numbers of pollen tubes reaching the ovary. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  13. Tradescantia cytogenetic tests (root-tip mitosis, pollen mitosis, pollen mother-cell meiosis). A report of the US Environmental Protection Agency gene-tox program

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T H

    1982-01-01

    3 kinds of cytogenetic tests for screening of environmental mutagens were established for Tradescantia, namely, root-tip mitosis, pollen mitosis, and pollen mother-cell meiosis (commonly referred to as the Tradescantia-micronucleus (Trad-MCN) test). All these tests are technically simple, inexpensive, and can yield reliable results in a relatively short time (36 to 72 h). The root-tip mitosis test is suitable only for liquid agents, while pollen mitosis is suitable for both liquid and gaseous agents. Pollen tube mitotic chromosomes are extremely sensitive to mutagens; therefore, they are good materials for detecting very low concentrations of mutagens. Both root-tip mitosis and pollen mitosis tests use chromosome and/or chromatid aberrations as end points for scoring. The Trad-MCN test is suitable for both liquid and gaseous agents. In addition, it is especially suitable for in situ monitoring of water and air pollutants. Of the 12 chemicals tested, 5-fluorouracil and 1,2-dibromoethane indicate that they are very potent mutagens based on the effective dosages used to produce a positive response. Sulfur dioxide, ethyl methanesulfonate, sodium azide, Phosdrin, and Bladex rank next in potency.

  14. In search of ligands and receptors of the pollen tube: the missing link in pollen tube perception

    Czech Academy of Sciences Publication Activity Database

    Hafidh, Said; Potěšil, D.; Fíla, Jan; Feciková, Jana; Čapková, Věra; Zdráhal, Z.; Honys, David

    2014-01-01

    Roč. 42, č. 2 (2014), s. 388-394 ISSN 0300-5127 R&D Projects: GA ČR GPP501/11/P321; GA ČR(CZ) GAP501/11/1462; GA MŠk(CZ) LD13049; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:61389030 Keywords : cell-cell signalling * chemotaxis * palmitoylation Subject RIV: ED - Physiology Impact factor: 3.194, year: 2014

  15. Pollen-Associated Microbiome Correlates with Pollution Parameters and the Allergenicity of Pollen.

    Directory of Open Access Journals (Sweden)

    Andrea Obersteiner

    Full Text Available Pollen allergies have been rapidly increasing over the last decades. Many allergenic proteins and non-allergenic adjuvant compounds of pollen are involved in the plant defense against environmental or microbial stress. The first aim of this study was to analyze and compare the colonizing microbes on allergenic pollen. The second aim was to investigate detectable correlations between pollen microbiota and parameters of air pollution or pollen allergenicity. To reach these aims, bacterial and fungal DNA was isolated from pollen samples of timothy grass (Phleum pratense, n = 20 and birch trees (Betula pendula, n = 55. With this isolated DNA, a terminal restriction fragment length polymorphism analysis was performed. One result was that the microbial diversity on birch tree and timothy grass pollen samples (Shannon/Simpson diversity indices was partly significantly correlated to allergenicity parameters (Bet v 1/Phl p 5, pollen-associated lipid mediators. Furthermore, the microbial diversity on birch pollen samples was correlated to on-site air pollution (nitrogen dioxide (NO2, ammonia (NH3, and ozone (O3. What is more, a significant negative correlation was observed between the microbial diversity on birch pollen and the measured NO2 concentrations on the corresponding trees. Our results showed that the microbial composition of pollen was correlated to environmental exposure parameters alongside with a differential expression of allergen and pollen-associated lipid mediators. This might translate into altered allergenicity of pollen due to environmental and microbial stress.

  16. Transference of genetic information through irradiated pollen

    Energy Technology Data Exchange (ETDEWEB)

    Dryanovska, O A [Bylgarska Akademiya na Naukite, Sofia. Inst. po Genetika

    1983-01-01

    Blossoms are used as mothers of two longistylous with male sterility varieties of Deva and Hera without anthocyan on the stem from L. esculentum (Mill.) (L.), which were pollinated with irradiated dallenform L. peruvianum (L.) with anthocyan on the stem, with 10 AND 200 Kr of gamma-rays, 5 and 10 min from a source of mixed (long and short) UV-rays, at a distance of 20 cm, while the control blossoms were pollinated with a mixture of other cultivated plants. Irradiation with gamma rays was carried out on a gamma device with a dose power of up to 1,500 R/m. The results show that irradiated pollen tube with the male chromatin induces gynogenesis and seconadary diploidization. It is assumed that some of the microfragments irradiated with high doses of radiation contain a functionally active gene or the genes responsible for anthocyan synthesis. These microfragments are capable of combining with the nonirradiated mother chromatin and they become involved and operate in the process of development of the mother sex cells and at the early embryogenesis, as a result of which anthocyan appears in the developing plants.

  17. Transference of genetic information through irradiated pollen

    International Nuclear Information System (INIS)

    Dryanovska, O.A.

    1983-01-01

    Blossoms are used as mothers of two longistylous with male sterility varieties of Deva and Hera without anthocyan on the stem from L. esculentum (Mill.) (L.), which were pollinated with irradiated dallenform L. peruvianum (L.) with anthocyan on the stem, with 10 AND 200 Kr of gamma-rays, 5 and 10 min from a source of mixed (long and short) UV-rays, at a distance of 20 cm, while the control blossoms were pollinated with a mixture of other cultivated plants. Irradiation with gamma rays was carried out on a gamma device with a dose power of up to 1,500 R/m. The results show that irradiated pollen tube with the male chromatin induces gynogenesis and seconadary diploidization. It is assumed that some of the microfragments irradiated with high doses of radiation contain a functionally active gene or the genes responsible for anthocyan synthesis. These microfragments are capable of combining with the nonirradiated mother chromatin and they become involved and operate in the process of development of the mother sex cells and at the early embryogenesis, as a result of which anthocyan appears in the developing plants

  18. Flower associations and nesting of the pollen wasp Quartinia major Kohl, 1898 (Hymenoptera, Vespidae, Masarinae in Morocco

    Directory of Open Access Journals (Sweden)

    Volker Mauss

    2018-02-01

    Full Text Available Females of Quartinia major Kohl were observed to visit flowers of Pulicaria mauritanica Batt., Cladanthus arabicus (L. Cass. and Asteriscus graveolens (Forssk. Less., (all Asteroideae Asteraceae at two localities in southern Morocco. Pollen in the provisions of two brood cells was more than 99% Aster-type (Asteroideae, indicating broad oligolecty. During pollen uptake from P. mauritanica, the females of Q. major employed a hitherto undescribed harvesting technique: They used their mouthparts to squeeze pollen from the corolla tubes of early male phase disc florets. Pollen was ingested immediately after it had been extracted. The nest was a multicellular subterranean burrow excavated in friable soil and surmounted by a turret. The nest walls were stabilized with self-generated silk.

  19. In Vitro Pollen Viability and Pollen Germination in Cherry Laurel (Prunus laurocerasus L.

    Directory of Open Access Journals (Sweden)

    Melekber Sulusoglu

    2014-01-01

    Full Text Available Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.. Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride and IKI (iodine potassium iodide, were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r2 = 0.0614 and r2 = 0.0015, resp.. Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

  20. In vitro pollen viability and pollen germination in cherry laurel (Prunus laurocerasus L.).

    Science.gov (United States)

    Sulusoglu, Melekber; Cavusoglu, Aysun

    2014-01-01

    Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.). Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride) and IKI (iodine potassium iodide), were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r(2) = 0.0614 and r(2) = 0.0015, resp.). Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

  1. Pollen Contents Of Commercial Honeys Of Opi, Nsukka, Enugu ...

    African Journals Online (AJOL)

    Pollen Contents Of Commercial Honeys Of Opi, Nsukka, Enugu State, Nigeria. ... Abstract. Pollen analyses of seven honey samples from Opi-Nsukka Mini market were evaluated for their pollen composition. The results ... HOW TO USE AJOL.

  2. Pollen diversity, viability and floral structure of some Musa genotypes

    African Journals Online (AJOL)

    Pollen diversity, viability and floral structure of some Musa genotypes. ... This experiment was designed to study the floral structure, pollen morphology and the potential pollen viability of five Musa genotypes obtained ... HOW TO USE AJOL.

  3. Effects of gamma irradiation of pollen on parthenogenetic haploid production in muskmelon (Cucumis melo L.)

    International Nuclear Information System (INIS)

    Cuny, F.; Grotte, M.; Dumas de Vaulx, R.; Rieu, A.

    1993-01-01

    The effects of increasing gamma ray exposures on muskmelon pollen of the Védrantais genotype were evaluated after autofertilization and hybridization with the F1.G1 genotype. Regardless of doses of between 0.15 and 1.6 kGy, fruit set and number of seeds per fruit were comparable to those of the control. The pollen tube from pollen irradiated with up to 2.5 kGy grew in styles and reached the ovules. When pollen was cultivated in vitro, relatively high doses of irradiation (1.6 kGy) were needed to reduce the level of germination. Radiation-induced changes in the generative nucleus led to the formation of two chromosomally unbalanced sperm cells (as indicated by the appearance of morphological dimorphism) which induced parthenogenetic development of the egg to form a haploid embryo. Haploid embryo production by gamma-irradiated pollen was genotype dependent. For exposures of between 0.15 and 2.5 kGy, the production of embryos was the same, about 3.4%; a maximum of 70% of these embryos placed in a specific culture medium produced haploid plants. The ploidy of the plantlets in vitro was determined by flow cytometry. No aneuploidy was detected. All resulting plants exhibited normal phenotypes. (author) [fr

  4. A study on compatibilities on transgenic herbicide-resistant rice with wild relatives by using autoradiography of 32P labeled pollen

    International Nuclear Information System (INIS)

    Liu Linli; Qiang Sheng; Song Xiaoling

    2004-01-01

    To evaluate the possibility of gene flow through observation of the sexual compatibilities of transgenic herbicide-resistant rice with wild relative by using isotope tracer to label pollen grains, the experiments on radioactivity, tracer mode, autoradiography film and time were conducted. Better procedure was to label pollen grains of transgenic herbicide-resistant rice by culturing the rice in a 1.48 x 10 7 Bq/L 32 P nutrient liquid, to pollinate the labelled pollen grains on the stigmas of barnyard grass (Echinochloa crusgalli var. mitis), Oryza officinalis and weedy rice (Oryza sativa) respectively, and then 3 hour later, to fix these pistils on a piece of glass plate and cover the film of Luck 400 on it for autoradiography. The autoradiographs show that the tube of the transgenic rice's pollens cannot penetrate the stigma of barnyard grass and arrive at embryo sacs to fertilize, so that the possibility of gene flow between them is the lowest; the tube of the labelled pollens can penetrate the stigma of O officinalis and enter the style but can not arrive at embryo sacs to fertilize, so the possibility of gene flow between them is relatively low; and the pollen tube can arrive at the embryo sacs of the weedy rice, so that the possibility of gene flow is relatively high from transgenic herbicide-resistant rice to weedy rice. (authors)

  5. A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

    Directory of Open Access Journals (Sweden)

    Hélène Sénéchal

    2015-01-01

    Full Text Available This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various produced external or internal subparticles are listed. Physicochemical and biological effects of artificial pollution (gaseous and particulate on pollen from different plants, in different laboratory conditions, are considered. The effects of polluted pollen grains, subparticles, and derived aeroallergens in animal models, in in vitro cell culture, on healthy human and allergic patients are described. Combined effects of atmospheric pollutants and pollen grains-derived biological material on allergic population are specifically discussed. Within the notion of “polluen,” some methodological biases are underlined and research tracks in this field are proposed.

  6. A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

    Science.gov (United States)

    Sénéchal, Hélène; Visez, Nicolas; Charpin, Denis; Shahali, Youcef; Peltre, Gabriel; Biolley, Jean-Philippe; Lhuissier, Franck; Couderc, Rémy; Yamada, Ohri; Malrat-Domenge, Audrey; Pham-Thi, Nhân; Poncet, Pascal; Sutra, Jean-Pierre

    2015-01-01

    This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various produced external or internal subparticles are listed. Physicochemical and biological effects of artificial pollution (gaseous and particulate) on pollen from different plants, in different laboratory conditions, are considered. The effects of polluted pollen grains, subparticles, and derived aeroallergens in animal models, in in vitro cell culture, on healthy human and allergic patients are described. Combined effects of atmospheric pollutants and pollen grains-derived biological material on allergic population are specifically discussed. Within the notion of “polluen,” some methodological biases are underlined and research tracks in this field are proposed. PMID:26819967

  7. Pollen and spores of terrestrial plants

    Science.gov (United States)

    Bernhardt, Christopher E.; Willard, Debra A.; Shennan, Ian; Long, Antony J.; Horton, Benjamin P.

    2015-01-01

    Pollen and spores are valuable tools in reconstructing past sea level and climate because of their ubiquity, abundance, and durability as well as their reciprocity with source vegetation to environmental change (Cronin, 1999; Traverse, 2007; Willard and Bernhardt, 2011). Pollan is found in many sedimentary environments, from freshwater to saltwater, terrestrial to marine. It can be abundant in a minimal amount of sample material, for example half a gram, as concentrations can be as high as four million grains per gram (Traverse, 2007). The abundance of pollen in a sample lends it to robust statistical analysis for the quantitative reconstruction of environments. The outer cell wall is resistant to decay in sediments and allows palynomorphs (pollen and spores) to record changes in plant communities and sea level over millions of years. These characteristics make pollen and spores a powerful tool to use in sea-level research.This chapter describes the biology of pollen and spores and how they are transported and preserved in sediments. We present a methodology for isolating pollen from sediments and a general language and framework to identify pollen as well as light micrographs of a selection of common pollen grains, We then discuss their utility in sea-level research.

  8. Vacuum storage of yellow-poplar pollen

    Science.gov (United States)

    James R. Wilcox

    1966-01-01

    Vacuum-drying, followed by storage in vacuo or in an inert gas, is effective for storing pollen of many species. It permits storage at room environments without rigid controls of either temperature or humidity, an advantage that becomes paramount during long-distance transfers of pollen when critical storage conditions are impossible to maintain. In...

  9. A combinatorial approach to angiosperm pollen morphology.

    Science.gov (United States)

    Mander, Luke

    2016-11-30

    Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot. This represents a raw morphospace. To compare real-world and theoretical morphologies, I map the pollen of 1008 species of Neotropical angiosperms growing on Barro Colorado Island (BCI), Panama, onto this raw morphospace. This highlights that, in addition to their well-documented taxonomic diversity, Neotropical rainforests also represent an enormous reservoir of morphological diversity. Angiosperm pollen morphospace at BCI has been filled mostly by pollen morphotypes that are unique to single plant species. Repetition of pollen morphotypes among higher taxa at BCI reflects both constraint and convergence. This combinatorial approach to morphology addresses the complexity that results from large numbers of discrete character combinations and could be employed in any situation where organismal form can be captured by discrete morphological characters. © 2016 The Author(s).

  10. Pollen viability and membrane lipid composition

    NARCIS (Netherlands)

    Bilsen, van D.G.J.L.

    1993-01-01

    In this thesis membrane lipid composition is studied in relation to pollen viability during storage. Chapter 1 reviews pollen viability, membranes in the dry state and membrane changes associated with cellular aging. This chapter is followed by a study of age-related changes in phospholipid

  11. Feeding Tubes

    Science.gov (United States)

    ... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

  12. Aerobiology and pollen allergy in Islamabad

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, S [Allergy and Asthma Centre, Islamabad (Pakistan); Raza, S M [Rawalpindi Medical College, Rawalpindi (Pakistan); Khan, M A [Quaid-i-Azam University, Islamabad (Pakistan). Dept. of Plant Sciences

    2009-10-15

    Pollen allergies affect a significant proportion of Islamabad residents. Many patients with pollen allergy Are hospitalized in Islamabad in spring (February to April), fall seasons (July to September) and after monsoons. To determine the type and concentration of airborne pollens causing allergic diseases in the susceptible patients in Islamabad. The study was conducted from January 2005 to December 2006 and Burkard Volumetric Spore Trap' provided by the World Allergy Organization was used. This spore trap was placed in the F-10 area of Islamabad and samples were collected on weekly basis during the whole study period. To obtain the sample, the spore trap drum was loaded with a strip of sticky tape every week. The sampled sticky tape was then collected each week at a specified time and replaced with a fresh strip of sticky tape, which was then collected next week. This cycle , continued for whole study period. From each sample seven permanent slides were made and mounted with gelevitol mounting media; The slides were then examined microscopically. A total of 702 individuals irrespective of age or gender were included in the study. Skin prick tests were performed for pollens using allergen extracts of Hollister-Steir, USA and the results were recorded. The two flowering seasons in Islamabad i.e., spring and fall caused maximum pollen allergies. The Broussonetia papyrifera (paper mulberry) tree in spring, and the Cannabis sativa (bhang) weed in the fall season, Produced the highest seasonal pollen counts. In the spring season of 2005, Broussonetia papyrifera produced the highest pollen count, (73%) of the total pollen count, with a maximum count of 1390 pollen/cu meter of air/hour on 20th of March, while in 2006, it accounted for 75% of the total pollen-count with a maximum count of 1430 pollen/cu meter of air/hour on 10th of March. in fall Season of 2005, Cannabis sativa produced maximum pollen counts of 85 pollens/cu meter of air/hr on 18th of August, while in 2006

  13. MICROBIAL QUALITY OF HONEY MIXTURE WITH POLLEN

    Directory of Open Access Journals (Sweden)

    Ján Mareček

    2011-02-01

    Full Text Available Normal 0 21 MicrosoftInternetExplorer4 The aim of this study was evaluation of microbial quality in raw materials (honey, pollen and evaluation of microbial quality in honey mixture with pollen (2.91 % and 3.85 % and also dynamics of microbial groups in honey mixtures with pollen after 14 days storage at the room temperature (approximately 25 °C and in cold store (8 °C. We used dilution plating method for testing of samples. Detections of total plate microbial count (aerobic and anaerobic microorganisms, sporulating bacteria, coliform bacteria, Bifidobacterium sp., Lactobacillus sp. and microscopic fungi were performed. In general, counts of microorganisms decreased in honey mixture with pollen compared to raw pollen and these counts increased compared to natural honey. Total plate count was 5.37 log KTJ.g-1 in pollen; 1.36 log KTJ.g-1 in honey; 2.97 log KTJ.g-1 in honey mixture with 2.91 % pollen and 2.04 log KTJ.g-1 in honey mixture with 3.85 % pollen. Coliform bacteria were detected in pollen (1.77 log KTJ.g-1. Then, we found coliform bacteria in one sample of honey mixtures with pollen (2.91 % - 1.00 log KTJ.g-1.Bifidobacterium species were detected only in raw pollen. We did not findLactobacillus sp. in any of the samples. Microscopic fungi were detected on two cultivating media. Yeasts were present in pollen sample (average 5.39 log KTJ.g-1, honey mixture with 2.91 % pollen (average 2.51 log KTJ.g-1 and honey mixture with 3.85 % pollen (average 1.58 log KTJ.g-1. Filamentous microscopic fungi were detectable in pollen (average 3.38 log KTJ.g-1, in honey (only on one medium: 1.00 log KTJ.g-1, in honey mixture with 2.91 % pollen (average 1.15 log KTJ.g-1 and in honey mixture with 3.85 % pollen (1.71 %. Raw pollen contained microscopic fungi as Absidiasp., Mucor sp., Alternaria sp. andEmericella nidulans. Honey mixture with 2.91 % pollen after storage (14 days contained lower microbial counts when compared with the sample

  14. Aerobiology and pollen allergy in Islamabad

    International Nuclear Information System (INIS)

    Abbas, S.; Raza, S.M.; Khan, M.A.

    2009-01-01

    Pollen allergies affect a significant proportion of Islamabad residents. Many patients with pollen allergy Are hospitalized in Islamabad in spring (February to April), fall seasons (July to September) and after monsoons. To determine the type and concentration of airborne pollens causing allergic diseases in the susceptible patients in Islamabad. The study was conducted from January 2005 to December 2006 and Burkard Volumetric Spore Trap' provided by the World Allergy Organization was used. This spore trap was placed in the F-10 area of Islamabad and samples were collected on weekly basis during the whole study period. To obtain the sample, the spore trap drum was loaded with a strip of sticky tape every week. The sampled sticky tape was then collected each week at a specified time and replaced with a fresh strip of sticky tape, which was then collected next week. This cycle , continued for whole study period. From each sample seven permanent slides were made and mounted with gelevitol mounting media; The slides were then examined microscopically. A total of 702 individuals irrespective of age or gender were included in the study. Skin prick tests were performed for pollens using allergen extracts of Hollister-Steir, USA and the results were recorded. The two flowering seasons in Islamabad i.e., spring and fall caused maximum pollen allergies. The Broussonetia papyrifera (paper mulberry) tree in spring, and the Cannabis sativa (bhang) weed in the fall season, Produced the highest seasonal pollen counts. In the spring season of 2005, Broussonetia papyrifera produced the highest pollen count, (73%) of the total pollen count, with a maximum count of 1390 pollen/cu meter of air/hour on 20th of March, while in 2006, it accounted for 75% of the total pollen-count with a maximum count of 1430 pollen/cu meter of air/hour on 10th of March. in fall Season of 2005, Cannabis sativa produced maximum pollen counts of 85 pollens/cu meter of air/hr on 18th of August, while in 2006

  15. Fruit and seed characteristics of diploid seedless watermelon (citrullus lanatas) cultivars produced by soft-X-irradiated pollen

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Keita; Morishita, Masami [National Research Insti. of Vegetables, Ornamental Plants and Tea, Fukuoka (Japan). Kurume Branch

    2000-11-01

    We compared the differences in number of seeds, size of normal and empty seeds, and fruit quality of seedless fruit induced by soft- X- irradiated pollen to determine which cultivars are best suited for breeding and producing high quality seedless watermelon. Two wild types, eleven Japanese, one Chinese, and three American watermelon cultivars were studied. We also observed the effect of soft- X- rays on pollen germination and elongation of the pollen tube. The germination rates of pollen treated with 1000 to 2000 Gy of soft-X-ray were almost the same as those of the control, whereas the rate was significantly reduced at 3000 Gy. Soft-X- irradiated pollen germinated on a stigma, and the pollen tube elongated in the embryo sac. Watermelon fruit pollinated with pollen irradiated with 800 Gy of soft-X-ray had no normal seeds but only empty ones. To delineate the varietal differences by the number of empty seeds and seed size in seedless fruit, wild types, Japanese, Chinese, and American watermelon cultivars were investigated. The number and size of empty seeds varied among cultivars. A low correlation (r=0.272) existed between the total number of seeds in the control fruit and the number of empty seeds in the seedless fruit. Whereas, a high correlation (seed length: r=0.943, P<0.001, seed width: r=0.883, P < 0.001) was found between the size of normal seeds in control fruit and empty seeds in seedless fruit. Diploid seedless fruit was similar to control fruit in size, shape, color, rind thickness, sugar content, and days from pollination to maturity. (author)

  16. Fruit and seed characteristics of diploid seedless watermelon (citrullus lanatas) cultivars produced by soft-X-irradiated pollen

    International Nuclear Information System (INIS)

    Sugiyama, Keita; Morishita, Masami

    2000-01-01

    We compared the differences in number of seeds, size of normal and empty seeds, and fruit quality of seedless fruit induced by soft- X- irradiated pollen to determine which cultivars are best suited for breeding and producing high quality seedless watermelon. Two wild types, eleven Japanese, one Chinese, and three American watermelon cultivars were studied. We also observed the effect of soft- X- rays on pollen germination and elongation of the pollen tube. The germination rates of pollen treated with 1000 to 2000 Gy of soft-X-ray were almost the same as those of the control, whereas the rate was significantly reduced at 3000 Gy. Soft-X- irradiated pollen germinated on a stigma, and the pollen tube elongated in the embryo sac. Watermelon fruit pollinated with pollen irradiated with 800 Gy of soft-X-ray had no normal seeds but only empty ones. To delineate the varietal differences by the number of empty seeds and seed size in seedless fruit, wild types, Japanese, Chinese, and American watermelon cultivars were investigated. The number and size of empty seeds varied among cultivars. A low correlation (r=0.272) existed between the total number of seeds in the control fruit and the number of empty seeds in the seedless fruit. Whereas, a high correlation (seed length: r=0.943, P<0.001, seed width: r=0.883, P < 0.001) was found between the size of normal seeds in control fruit and empty seeds in seedless fruit. Diploid seedless fruit was similar to control fruit in size, shape, color, rind thickness, sugar content, and days from pollination to maturity. (author)

  17. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

    International Nuclear Information System (INIS)

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-01-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O 3 ) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O 3 fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O 3 fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O 3 , determined from the mRNA levels of the major allergens. We conclude that O 3 can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. - Highlights: → O 3 reduces the viability of ragweed pollen. → ROS and allergens of ragweed pollen were not affected by O 3 exposure. → O 3 enhances the activity of the ROS-generating enzyme NAD(P)H oxidase. → O 3 increases ragweed pollen allergenicity through NAD(P)H-oxidase stimulation. - This study focuses on the effects of the atmospheric pollutant ozone on ROS content and NAD(P)H oxidase activity of ragweed pollen grains.

  18. Steam generator tube extraction

    International Nuclear Information System (INIS)

    Delorme, H.

    1985-05-01

    To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

  19. In vitro pollen quantity, viability and germination tests in quince ...

    African Journals Online (AJOL)

    Quince (Cydonia oblonga Mill.) cvs. Ekmek, Esme, Limon, Ege 2, Ege 22, Ege 25 and Quince-A rootstock pollens were collected in April from the unopened pink balloon-stage flowers on mature trees. The pollen amount was between 20063 pollen/flower ('Ege 25') and 11906 pollen/flower ('Limon') with hemacytometer.

  20. Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development.

    Science.gov (United States)

    Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

    2015-11-01

    A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions - pollen originating from plants raised in charcoal-Purafil(®) filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O3. The O3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O3 × CFA and CFA × O3 crossed plants. This suggests O3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol(-1) O3 (10 h d(-1)) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit - a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O3, and potentially other gaseous pollutants, on reproductive biology during 'risk assessment' exercises. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Sweet attraction: sugarcane pollen-associated volatiles attract gravid Anopheles arabiensis.

    Science.gov (United States)

    Wondwosen, Betelehem; Birgersson, Göran; Tekie, Habte; Torto, Baldwyn; Ignell, Rickard; Hill, Sharon R

    2018-02-21

    Anopheles arabiensis is a key vector for the transmission of human malaria in sub-Saharan Africa. Over the past 10,000 years, humans have successfully cultivated grasses and altered the landscape, creating An. arabiensis favourable environments that contain excellent habitats for both larvae and adults. Sugarcane is the most expanding agricultural system in sub-Saharan Africa, and is linked to the increased threat of malaria in rural communities. The prolific production and wind dispersal of sugarcane pollen, together with standing pools of water, often provide, as a result of irrigation, a nutrient-rich environment for the offspring of gravid malaria mosquitoes. In the present study, sugarcane pollen-associated volatiles from two cultivars are shown to attract gravid An. arabiensis in a still air two-port olfactometer and stimulate egg laying in an oviposition bioassay. Through combined gas chromatography and electroantennographic detection, as well as combined gas chromatography and mass spectrometric analyses, we identified the bioactive volatiles and generated a synthetic blend that reproduced the full behavioural repertoire of gravid mosquitoes in the Y-tube assay. Two subtractive odour blends, when compared with the full blend, were significantly more attractive. These three and four-component subtractive blends share the compounds (1R)-(+)-α-pinene, nonanal and benzaldehyde, of which, (1R)-(+)-α-pinene and nonanal are found in the attractive odour blends from rice plants and maize pollen. In pairwise comparisons, the rice synthetic odour blend was more attractive to gravid mosquitoes than either of the pollen blends, whereas the pollen blends did not differ in attraction. The attraction of gravid females to sugarcane pollen volatiles demonstrated in this study, together with the previously found grass-associated volatiles, raise the potential of developing a bioactive chimeric blend to attract gravid malaria mosquitoes. This is discussed in relation to

  2. PollenCALC: Software for estimation of pollen compatibility of self-incompatible allo- and autotetraploid species

    DEFF Research Database (Denmark)

    Aguirre, Andrea A; Wollenweber, Bernd; Frei, Ursula K

    2012-01-01

    available for predicting pollen haplotype frequencies and pollen compatibility in tetraploid species. Results PollenCALC is a software tool written in C++ programming language that can predict pollen compatibility percentages for polyploid species with a two-locus (S, Z) self-incompatibility system...

  3. Bee Pollen: Chemical Composition and Therapeutic Application

    Directory of Open Access Journals (Sweden)

    Katarzyna Komosinska-Vassev

    2015-01-01

    Full Text Available Bee pollen is a valuable apitherapeutic product greatly appreciated by the natural medicine because of its potential medical and nutritional applications. It demonstrates a series of actions such as antifungal, antimicrobial, antiviral, anti-inflammatory, hepatoprotective, anticancer immunostimulating, and local analgesic. Its radical scavenging potential has also been reported. Beneficial properties of bee pollen and the validity for their therapeutic use in various pathological condition have been discussed in this study and with the currently known mechanisms, by which bee pollen modulates burn wound healing process.

  4. Pollen Flora of Pakistan-LXV, berberidaceae

    International Nuclear Information System (INIS)

    Perveen, A.

    2010-01-01

    Pollen morphology of 12 species representing 2 genera of the family Berberidaceae from Pakistan has been examined by light and scanning electron microscope. Pollen grains usually radially symmetrical, iso polar or apolar, spheroidal or sub-prolate, spiroaperturate rarely colpate (3- more), sexine thicker than nexine. Tectal surface mostly foveolate-fossulate or sub-psilate, often rugulate - reticulate. On the basis of apertutal types and exine ornamentation four distinct pollen types are recognized, viz., Berberis calliobotrys-type, Berberis jaeschkeana-type, Berberis kunawurensis-type and Epimedium elatum-type. (author)

  5. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

  6. Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development

    International Nuclear Information System (INIS)

    Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

    2015-01-01

    A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O_3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions – pollen originating from plants raised in charcoal-Purafil"® filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O_3. The O_3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O_3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O_3 × CFA and CFA × O_3 crossed plants. This suggests O_3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol"−"1 O_3 (10 h d"−"1) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit – a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O_3, and potentially other gaseous pollutants, on reproductive biology during ‘risk assessment’ exercises. - Highlights: • Environmentally-relevant levels of ozone exert negative effects on pollen viability that translate into direct impacts on fruit yield. • Negative impacts of O_3 pollution on reproductive processes were evident regardless of the stage of plant development. • Exposure to environmentally-relevant levels of O_3

  7. Next generation immunotherapy for tree pollen allergies.

    Science.gov (United States)

    Su, Yan; Romeu-Bonilla, Eliezer; Heiland, Teri

    2017-10-03

    Tree pollen induced allergies are one of the major medical and public health burdens in the industrialized world. Allergen-Specific Immunotherapy (AIT) through subcutaneous injection or sublingual delivery is the only approved therapy with curative potential to pollen induced allergies. AIT often is associated with severe side effects and requires long-term treatment. Safer, more effective and convenient allergen specific immunotherapies remain an unmet need. In this review article, we discuss the current progress in applying protein and peptide-based approaches and DNA vaccines to the clinical challenges posed by tree pollen allergies through the lens of preclinical animal models and clinical trials, with an emphasis on the birch and Japanese red cedar pollen induced allergies.

  8. Pollen flora of pakistan-lxxi. rosaceae

    International Nuclear Information System (INIS)

    Perveen, A.; Qaiser, M.

    2014-01-01

    Pollen morphology of 50 species representing 17 genera of the family Rosaceae i.e., Alchemilla, Argimonia, Cotoneaster, Crataegus, Duchesnea, Fragaria, Eriybotyra, Filipandula, Geum, Malus, Prunus, Potentilla, Pyrus , Rosa, Sibbaldia, Sorbaria and Sorbus has been studied from Pakistan by light and scanning electron microscope. Pollen grains are usually free, radially symmetrical, isopolar, prolate-spheroidal to subprolate or oblate-spheroidal rarely perprolate, tricolporate rarely tricolpate. Tectum mostly coarsely-finely striate, rarely striate-rugulate, scabrate or spinulose often reticulate. Rosaceae is more or less eurypalynous family. Significant variation is found in P/E ratio, shape and exine ornamentation and on the basis of these characters family has been divided into seven pollen types viz., Agrimonia eupatoria-type, Alchemilla ypsilotoma-type, Cotoneaster affinis-type, Fragaria nubicola-type, Geum roylei-type, Malus pumila-type, Potentilla pamirica-type. Pollen data is useful at specific and generic level. (author)

  9. Pollen-projektiga Rootsis / Lembit Jakobson

    Index Scriptorium Estoniae

    Jakobson, Lembit

    2009-01-01

    Avastusõppe projektist "Pollen" Eesti (2006-2009) mille eesmärk on kõiki lapsi kaasav uurimisõpe. Kevadisel koolivaheajal tutvus kümmekond Eesti õpetajat uurimisõppega Stockholmi kahes algkoolis

  10. Pollen as indicator of radionuclide pollution

    International Nuclear Information System (INIS)

    Kirkham, M.B.; Corey, J.C.

    1977-01-01

    To assess hazards of radioactivity in the environment, agricultural scientists must identify plant and animal species which can be used as biological indicators of radionuclide contamination. In this experiments, the pollen-bee-honey system was chosen to study movement of radioactive elements in the plant-animal-man food chain. Pollen, bees, and honey were collected from different locations at a nuclear facility in South Carolina. They were analyzed for nine radionuclides and 22 stable elements. The results showed that pollen is a more sensitive indicator of pollution than bees or honey. If pollen-monitoring shows that an area has become polluted, hives and other sources of human and animal food should not be placed in the region until it is no longer contaminated. (author)

  11. Juniper Pollen Hotspots in the Southwest

    Science.gov (United States)

    Bunderson, L. D.; VandeWater, P.; Luvall, J.; Levetin, E.

    2013-01-01

    Rationale: Juniperus pollen is a major allergen in Texas, Oklahoma, and New Mexico. While the bulk of pollen may be released in rural areas, large amounts of pollen can be transported to urban areas. Major juniper species in the region include: Juniperus ashei, J. virginiana, J. pinchotii, and J. monosperma. Pollen release is virtually continuous beginning in late September with J. pinchotii and ending in May with J. monosperma. Urban areas in the region were evaluated for the potential of overlapping seasons in order to inform sensitive individuals. Methods: Burkard volumetric pollen traps were established for two consecutive spring seasons at 6 sites in northern New Mexico and 6 sites for two consecutive winter and fall seasons in Texas and Oklahoma Standard methods were used in the preparation and analysis of slides. Results: The Dallas-Fort Worth Metroplex is home to over 6 million people. It is adjacent to populations of J. pinchotii, J. virginiana, and J. ashei. Peak concentration near Dallas for J. ashei in 2011 was 5891 pollen grains/m3 in January 7th. The peak date for J. pinchotii at an upwind sampling location in San Marcos, TX was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was February 20, 2011. Amarillo, TX is adjacent to J. pinchotii, J. ashei, and J. monosperma populations and may be subject to juniper pollen from September through May. Conclusions: Considering the overlapping distributions of juniper trees and the overlapping temporal release of pollen, sensitive patients may benefit from avoiding hotspots.

  12. Ragweed (Ambrosia) pollen source inventory for Austria.

    Science.gov (United States)

    Karrer, G; Skjøth, C A; Šikoparija, B; Smith, M; Berger, U; Essl, F

    2015-08-01

    This study improves the spatial coverage of top-down Ambrosia pollen source inventories for Europe by expanding the methodology to Austria, a country that is challenging in terms of topography and the distribution of ragweed plants. The inventory combines annual ragweed pollen counts from 19 pollen-monitoring stations in Austria (2004-2013), 657 geographical observations of Ambrosia plants, a Digital Elevation Model (DEM), local knowledge of ragweed ecology and CORINE land cover information from the source area. The highest mean annual ragweed pollen concentrations were generally recorded in the East of Austria where the highest densities of possible growth habitats for Ambrosia were situated. Approximately 99% of all observations of Ambrosia populations were below 745m. The European infection level varies from 0.1% at Freistadt in Northern Austria to 12.8% at Rosalia in Eastern Austria. More top-down Ambrosia pollen source inventories are required for other parts of Europe. A method for constructing top-down pollen source inventories for invasive ragweed plants in Austria, a country that is challenging in terms of topography and ragweed distribution. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  13. Influence of pollen nutrition on honey bee health: do pollen quality and diversity matter?

    Science.gov (United States)

    Di Pasquale, Garance; Salignon, Marion; Le Conte, Yves; Belzunces, Luc P; Decourtye, Axel; Kretzschmar, André; Suchail, Séverine; Brunet, Jean-Luc; Alaux, Cédric

    2013-01-01

    Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen) necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens) and diversity (polyfloral pollen diet) on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level), and on the tolerance to the microsporidian parasite Nosemaceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification), phenoloxidase (immunity) and alkaline phosphatase (metabolism)). We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context) of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.

  14. Influence of pollen nutrition on honey bee health: do pollen quality and diversity matter?

    Directory of Open Access Journals (Sweden)

    Garance Di Pasquale

    Full Text Available Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens and diversity (polyfloral pollen diet on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level, and on the tolerance to the microsporidian parasite Nosemaceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification, phenoloxidase (immunity and alkaline phosphatase (metabolism. We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.

  15. The effect of oleander glycosides on the germination of pollen grains and the mitosis of the generative nucleus in Tradescantia bracteata Small and Allium cepa L.

    Directory of Open Access Journals (Sweden)

    J. A. Tarkowska

    2015-01-01

    Full Text Available The effect of water solution of a mixture of glycosides from oleander (Nerium oleander L. on the germination of pollen grains and on the mitosis of the generative nucleus in Tradescantia bracteata Small and Allium cepa L. has been studied. An inhibition of the germination and of the growth of pollen tubes was observed, proportionally to the concentration of glycosides. The pollen grains of A. cepa are more sensitive. The disturbances in mitosis lead to the formation of two or more uneven-sized doughter nuclei, or to the formation of restitution nuclei. These anomalies are more numerous in T. bracteata. From these results d t appears that pollen grains of A. cepa are characterized by a generally high physiological sensitivity and a small mitotic sensitivity, wheras for T. bracteata the opposite is true.

  16. Seasonal variation in diurnal atmospheric grass pollen concentration profiles

    DEFF Research Database (Denmark)

    Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

    2014-01-01

    the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

  17. Electron tube

    Science.gov (United States)

    Suyama, Motohiro [Hamamatsu, JP; Fukasawa, Atsuhito [Hamamatsu, JP; Arisaka, Katsushi [Los Angeles, CA; Wang, Hanguo [North Hills, CA

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  18. Storage and irradiation of Cucumis pollen and their influence on pollen vitality

    International Nuclear Information System (INIS)

    Oost, E.H.; Nijs, A.P.M. den

    1979-01-01

    In connection with an interspecific hybridization programme and a mentor pollen experiment in Cucumis, the optimal storage conditions and in vitro germination medium for both fresh and irradiated pollen of the cultivated cucumber and two wild African Cucumis species have been searched for. (Auth.)

  19. Pollen of Southeast Asian Alchornea (Euphorbiaceae), with an overview of the pollen fossil record

    NARCIS (Netherlands)

    Bulalacao, L.J.; Ham, van der R.W.J.M.

    2003-01-01

    In order to evaluate pollen morphological descriptions of Alchornea in the literature, which are almost completely based on African and American species, the pollen of eight Southeast Asian species of Alchornea was investigated, using light and scanning electron microscopy. Very little variation

  20. Chest tube insertion

    Science.gov (United States)

    Chest drainage tube insertion; Insertion of tube into chest; Tube thoracostomy; Pericardial drain ... Be careful there are no kinks in your tube. The drainage system should always sit upright and be placed ...

  1. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualini, Stefania, E-mail: spas@unipg.it [Department of Applied Biology, University of Perugia, Perugia (Italy); Tedeschini, Emma; Frenguelli, Giuseppe [Department of Applied Biology, University of Perugia, Perugia (Italy); Wopfner, Nicole; Ferreira, Fatima [Department of Molecular Biology, CD Laboratory for Allergy Diagnosis and Therapy, University of Salzburg, Salzburg (Austria); D' Amato, Gennaro [Division of Respiratory and Allergic Diseases, ' A. Cardarelli' High Speciality Hospital, Naples (Italy); Ederli, Luisa [Department of Applied Biology, University of Perugia, Perugia (Italy)

    2011-10-15

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O{sub 3}) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O{sub 3} fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O{sub 3} fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O{sub 3}, determined from the mRNA levels of the major allergens. We conclude that O{sub 3} can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. - Highlights: > O{sub 3} reduces the viability of ragweed pollen. > ROS and allergens of ragweed pollen were not affected by O{sub 3} exposure. > O{sub 3} enhances the activity of the ROS-generating enzyme NAD(P)H oxidase. > O{sub 3} increases ragweed pollen allergenicity through NAD(P)H-oxidase stimulation. - This study focuses on the effects of the atmospheric pollutant ozone on ROS content and NAD(P)H oxidase activity of ragweed pollen grains.

  2. Preliminary results relating to gamma irradiations of the pollen in the pineapple (Ananas comosus (L.) Merr)

    International Nuclear Information System (INIS)

    Benaga, R.; Vicedo, L.; Isidron, M.; Arias, E.; Campanioni, L.; Fernandez, J.; Castillo, E.; Romero, M.

    1993-01-01

    As a way to know the radiosensitivity of the pollen of pineapple, in order to get to know haploid plants, the anthers of red Espanola of the type Pinarena and smooth Cayena from the Serrana (Ciego de Avila) were exposed to 60C o gamma radiations in the irradiator at CENSA, with fractional doses ranging from zero to 5KGy. The percentage of germination and length pollinic tube is analysed in vitro; a decrease in the above mentioned parameters is observed, with the main doses in the two cultures although red Espanola showed a slight recovery at doses of 3 and 4KGy as well as the major values of germination of the pollen

  3. Cucumber (Cucumis sativus L.) embryo development in situ after pollination with irradiated pollen

    International Nuclear Information System (INIS)

    Faris, N.M.; Niemirowicz-Szczytt, K.

    1999-01-01

    Embryological studies were undertaken to compare the normal development of cucumber endosperm and embryo with that observed after pollination with gamma-irradiated pollen (0.1 and 0.3 kGy). Delayed penetration of the pollen tube occurred at both irradiation doses. Endosperm and embryo development was also delayed, but was initiated within 6 days after pollination in 100% of embryo sacs at 0.1 kGy and in 70-80% at 0.3 kGy. Various abnormalities in endosperm and embryo cell structure confirmed progressive degeneration, which occurred earlier with the higher dose of irradiation. Degeneration increased dramatically; only 30-40% of the embryos reached the globular stage 15 days after pollination. (author)

  4. Proteomic analysis of MG132-treated germinating pollen reveals expression signatures associated with proteasome inhibition.

    Directory of Open Access Journals (Sweden)

    Candida Vannini

    Full Text Available Chemical inhibition of the proteasome has been previously found to effectively impair pollen germination and tube growth in vitro. However, the mediators of these effects at the molecular level are unknown. By performing 2DE proteomic analysis, 24 differentially expressed protein spots, representing 14 unique candidate proteins, were identified in the pollen of kiwifruit (Actinidia deliciosa germinated in the presence of the MG132 proteasome inhibitor. qPCR analysis revealed that 11 of these proteins are not up-regulated at the mRNA level, but are most likely stabilized by proteasome inhibition. These differentially expressed proteins are predicted to function in various pathways including energy and lipid metabolism, cell wall synthesis, protein synthesis/degradation and stress responses. In line with this evidence, the MG132-induced changes in the proteome were accompanied by an increase in ATP and ROS content and by an alteration in fatty acid composition.

  5. Pollen and spore monitoring in the world.

    Science.gov (United States)

    Buters, J T M; Antunes, C; Galveias, A; Bergmann, K C; Thibaudon, M; Galán, C; Schmidt-Weber, C; Oteros, J

    2018-01-01

    Ambient air quality monitoring is a governmental duty that is widely carried out in order to detect non-biological ("chemical") components in ambient air, such as particles of monitoring networks are publicly funded and air quality data are open to the public. The situation for biological particles that have detrimental effects on health, as is the case of pollen and fungal spores, is however very different. Most pollen and spore monitoring networks are not publicly funded and data are not freely available. The information regarding which biological particle is being monitored, where and by whom, is consequently often not known, even by aerobiologists themselves. This is a considerable problem, as local pollen data are an important tool for the prevention of allergic symptoms. The aim of this study was to review pollen monitoring stations throughout the world and to create an interactive visualization of their distribution. The method employed to collect information was based on: (a) a review of the recent and historical bibliography related to pollen and fungal spore monitoring, and (b) personal surveys of the managers of national and regional monitoring networks. The interactive application was developed using the R programming language. We have created an inventory of the active pollen and spore monitoring stations in the world. There are at least 879 active pollen monitoring stations in the world, most of which are in Europe (> 500). The prevalent monitoring method is based on the Hirst principle (> 600 stations). The inventory is visualised as an interactive and on-line map. It can be searched, its appearance can be adjusted to the users' needs and it is updated regularly, as new stations or changes to those that already exist can be submitted online. The map shows the current situation of pollen and spore monitoring and facilitates collaboration among those individuals who are interested in pollen and spore counts. It might also help to improve the

  6. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  7. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  8. Pollen Characterization in Size Segregated Atmospheric Aerosol

    Science.gov (United States)

    Kolpakova, Anna; Hovorka, Jan; Klán, Miroslav

    2017-12-01

    The first stage of a High Volumetric Cascade Impactor - HiVol (BGI-900), used for sampling of aerosol particles larger than 10 micrometres in aerodynamic diameter, was tested for bioaerosol sampling. Low air flow-rate and low pressure-drop at the jets of the first stage and high air volume are advantageous parameters, which would favour the use of the first stage for bioaerosol sampling. The sampling went in urban, rural and background localities, Prague, Brezno and Laz respectively in the Czech Republic, in summer and autumn. Pollen was separated from the impaction substrate, polyurethane foam, into homogeneous deposit on Nylon filter. The homogeneity of the deposit varied within 4%. Representative portion of the deposit was analysed by a scanning electron microscopy - SEM. There were taken 485 SEM images from 12 samples in 3 localities. Pollen grains were identified in 295 SEM images and determined into 9 genus and 4 families. Median pollen grain concentrations/deformities were 9m-3/24%, 3m-3/18%, 8m-3/50% for Prague, Brezno and Láz localities respectively. The pollen grains of the Poaceae family were found with the highest frequency in all localities. Number of pollen increased with total aerosol mass in Prague locality only. There were also identified brochosomes, rather unique insect secretion products, in the samples from the Láz locality.

  9. Spatial variability in airborne pollen concentrations.

    Science.gov (United States)

    Raynor, G S; Ogden, E C; Hayes, J V

    1975-03-01

    Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

  10. Occupational Allergy to Peach (Prunus persica) Tree Pollen and Potential Cross-Reactivity between Rosaceae Family Pollens.

    Science.gov (United States)

    Jiang, Nannan; Yin, Jia; Mak, Philip; Wen, Liping

    2015-10-01

    Orchard workers in north China are highly exposed to orchard pollens, especially peach and other Rosaceae family pollens during pollination season. The aim of this study was to investigate whether occupational allergy to peach tree pollen as a member of Rosaceae family is IgE-mediated and to evaluate the cross-reactivity among Rosaceae family pollens. Allergen skin test and conjunctival challenge test were performed; enzyme linked immune-sorbent assay (ELISA), inhibiting ELISA, western immunoblotting and inhibiting western immunoblotting were done with Rosaceae family orchard pollens, including peach, apricot, cherry, apple and pear tree pollens. Mass spectrometry was also performed to probe the main allergen component and cross-reactive protein. Sensitizations to peach pollen were found in both skin test and conjunctival challenge in the patients. Serum specific IgE to three pollens (peach, apricot and cherry) were detected through ELISA. When peach pollen used as solid phase, ELISA inhibition revealed other four kinds of pollens capable of inducing partial to strong inhibitions (45% to 87%), with the strongest inhibition belonging to apricot pollen (87%). Western blotting showed predominant IgE binding to a 20 KD protein among these pollens, which appeared to be a cross-reactive allergen component through western blotting inhibition. It was recognized as a protein homologous to glutathione s-transferase 16 from Arabidopsis thaliana. Peach and other Rosaceae family tree pollen may serve as a potential cause of IgE mediated occupational respiratory disease in orchard workers in north China.

  11. Influence of gamma irradiation on pollen viability, germination ability ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... minor cross-incompatibilities and physiological studies of incompatibility ... campanula shape of the flowers attractive for insect. (bees are ..... irradiation of cacao (Theobroma cacao L.) pollen: Effect on pollen grain viability ...

  12. Pollen parameters estimates of genetic variability among newly ...

    African Journals Online (AJOL)

    Pollen parameters estimates of genetic variability among newly selected Nigerian roselle (Hibiscus sabdariffa L.) genotypes. ... Estimates of some pollen parameters where used to assess the genetic diversity among ... HOW TO USE AJOL.

  13. Effects of palm pollen on folliculogenesis process after treatment ...

    African Journals Online (AJOL)

    Effects of palm pollen on folliculogenesis process after treatment with cyclophosphamide among rats. ... Background and purpose: Palm pollen is a good source of natural antioxidants and has a high level of health ... HOW TO USE AJOL.

  14. In vitro pollen quantity, viability and germination tests in quince

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... rootstock pollens were collected in April from the unopened pink balloon-stage flowers on mature trees ..... their pollen characteristics to be used in cross breeding ... viability and germination levels for pistachio and terebinth in.

  15. Pollen morphology and variability of Tulipa hungarica Borb

    African Journals Online (AJOL)

    Yomi

    2012-01-10

    Jan 10, 2012 ... Pollen morphology of the endemic species Tulipa hungarica Borb was investigated with the goal of ... pollen size may balance the competitive advantages of .... (2009). Comparative analysis of microspore size variability in the.

  16. Differential skin test reactivity to pollens in pollen food allergy syndrome versus allergic rhinitis.

    Science.gov (United States)

    Ta, Von; Scott, David R; Chin, William K; Wineinger, Nathan E; Kelso, John M; White, Andrew A

    2015-01-01

    Pollen food allergy syndrome (PFAS), also called oral allergy syndrome, is a form of food allergy in which uncooked foods cause allergic symptoms generally limited to the oral mucosa. It occurs in a subset of patients with pollen allergy, although not all patients have prominent rhinitis symptoms. PFAS is related to antigenic similarity between the pollen and food allergen. The size of skin test reactions in a group of subjects with pollen sensitivity with PFAS was compared with a group of subjects who were pollen sensitive and without PFAS. Self-reported rhinitis symptoms between the two groups were compared to identify if symptom severity differed. Twenty subjects with PFAS and 20 subjects with seasonal allergic rhinitis without PFAS were enrolled in the study. All the subjects underwent standard skin-prick testing to a panel of common allergens, including select fresh fruits and vegetables. The subjects completed a Mini Rhinoconjunctivitis Quality of Life Questionnaire as part of their clinical evaluation. The subjects with PFAS and those without PFAS were compared statistically. The subjects with PFAS had significantly larger-sized skin-prick test results specific to pollens (p PFAS reported milder nasal symptoms in relation to pollen skin test result size when compared with allergic rhinitis controls without PFAS. Our study outlined basic differences between two seemingly similar patient groups with a particularly striking discordance between skin test result sizes and rhinitis symptoms. This discordance should be explored further to increase mechanistic understanding of allergen cross-reactivity in PFAS.

  17. Nitric Oxide Binds to and Modulates the Activity of a Pollen Specific Arabidopsis Diacylglycerol Kinase

    KAUST Repository

    Wong, Aloysius Tze

    2014-06-01

    Nitric oxide (NO) is an important signaling molecule in plants. In the pollen of Arabidopsis thaliana, NO causes re-orientation of the growing tube and this response is mediated by 3′,5′-cyclic guanosine monophosphate (cGMP). However, in plants, NO-sensors have remained somewhat elusive. Here, the findings of an NO-binding candidate, Arabidopsis thaliana DIACYLGLYCEROL KINASE 4 (ATDGK4; AT5G57690) is presented. In addition to the annotated diacylglycerol kinase domain, this molecule also harbors a predicted heme-NO/oxygen (H-NOX) binding site and a guanylyl cyclase (GC) catalytic domain which have been identified based on the alignment of functionally conserved amino acid residues across species. A 3D model of the molecule was constructed, and from which the locations of the kinase catalytic center, the ATP-binding site, the GC and H-NOX domains were estimated. Docking of ATP to the kinase catalytic center was also modeled. The recombinant ATDGK4 demonstrated kinase activity in vitro, catalyzing the ATP-dependent conversion of sn-1,2-diacylglycerol (DAG) to phosphatidic acid (PA). This activity was inhibited by the mammalian DAG kinase inhibitor R59949 and importantly also by the NO donors diethylamine NONOate (DEA NONOate) and sodium nitroprusside (SNP). Recombinant ATDGK4 also has GC activity in vitro, catalyzing the conversion of guanosine-5\\'-triphosphate (GTP) to cGMP. The catalytic domains of ATDGK4 kinase and GC may be independently regulated since the kinase but not the GC, was inhibited by NO while Ca2+ only stimulates the GC. It is likely that the DAG kinase product, PA, causes the release of Ca2+ from the intracellular stores and Ca2+ in turn activates the GC domain of ATDGK4 through a feedback mechanism. Analysis of publicly available microarray data has revealed that ATDGK4 is highly expressed in the pollen. Here, the pollen tubes of mis-expressing atdgk4 recorded slower growth rates than the wild-type (Col-0) and importantly, they showed altered

  18. The revised edition of korean calendar for allergenic pollens.

    Science.gov (United States)

    Oh, Jae-Won; Lee, Ha-Baik; Kang, Im-Joo; Kim, Seong-Won; Park, Kang-Seo; Kook, Myung-Hee; Kim, Bong-Seong; Baek, Hey-Sung; Kim, Joo-Hwa; Kim, Ja-Kyung; Lee, Dong-Jin; Kim, Kyu-Rang; Choi, Young-Jin

    2012-01-01

    The old calendar of pollens did not reflect current pollen distribution and concentrations that can be influenced by changes of weather and environment of each region in South Korea. A new pollen calendar of allergenic pollens was made based on the data on pollen concentrations obtained in eight regions nationwide between 1997 and 2009. The distribution of pollen was assessed every day at 8 areas (Seoul, Guri, Busan, Daegu, Jeonju, Kwangju, Kangneung, and Jeju) for 12 years between July 1, 1997 and June 30, 2009. Pollens were collected by using Burkard 7-day sampler (Burkard Manufacturing Co Ltd, UK). Pollens which were stained with Calberla's fuchsin staining solution were identified and counted. Pine became the highest pollen in May, and the pollen concentrations of oak and birch also became high. Ragweed appeared in the middle of August and showed the highest pollen concentration in the middles of September. Japanese hop showed a high concentration between the middle of August and the end of September, and mugwort appeared in the middles of August and its concentration increased up until early September. In Kangneung, birch appeared earlier, pine showed a higher pollen concentration than in the other areas. In Daegu, Oriental thuja and alder produced a large concentration of pollens. Pine produced a large concentration of pollens between the middle of April and the end of May. Weeds showed higher concentrations in September and mugwort appeared earlier than ragweed. In Busan the time of flowering is relatively early, and alder and Oriental thuja appeared earliest among all areas. In Kwangju, Oriental thuja and hazelnut appeared in early February. Japanese cedar showed the highest pollen concentration in March in Jeju. In conclusion, update information on pollen calendar in South Korea should be provided for allergic patients through the website to manage and prevent the pollinosis.

  19. The clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults

    DEFF Research Database (Denmark)

    Osterballe, M.; Hansen, T.K.; Mørtz, Charlotte G

    2005-01-01

    BACKGROUND: Previous studies have described cross-reactivity between fresh fruits, vegetables and pollen. However, no data demonstrates the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults with and without symptoms in the pollen...... season. OBJECTIVE: The aim of this study was to estimate the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults and to examine the diagnostic value of skin-prick test (SPT), histamine release and specific IgE compared with the outcome...... of oral challenge. METHODS: In total, 936 unselected adults (female : male 479 : 457, median age 33.7 years) were examined for pollen sensitization and clinical cross-reactivity with pollen-related fruits and vegetables by questionnaire, SPT, histamine release, specific IgE and oral challenge. RESULTS...

  20. Pollen Dispersion Forecast At Regional Scale

    Science.gov (United States)

    Mangin, A.; Asthma Forecast System Team

    The forecast of the pollen concentration is generally based on an identification of sim- ilar coincidence of measured pollen at given points and meteorological data that is searched in an archive and which, with the help of experts, allows building a predicted value. This may be classified under the family of statistical approaches for forecast- ing. While palynologists make these methods more and more accurate with the help of innovative techniques of regression against empirical rules and/or evolving mathe- matical structures (e.g. neural networks), the spatial dispersion of the pollen is not or poorly considered, mainly because it requires a lot of means and technique that are not familiar to this scientific discipline. The research on pollen forecasts are presently mainly focused on the problematic of modeling the behavior of pollen trends and sea- sons at one location regardless of the topography, the locations of emitters, the relative strengths of emitter, in one word the Sspatial backgroundT. This research work was a & cedil;successful attempt to go a step further combining this SlocalT approach with a trans- & cedil;port/dispersion modeling allowing the access to mapping of concentration. The areas of interest that were selected for the demonstration of feasibility were 200x200km zones centered on Cordoba, Barcelona and Bologna and four pollen types were ex- amined, namely: Cupressaceae, Olea europaea, Poaceae and Parietaria. At the end of this three-year European project in December 2001, the system was fully deployed and validated. The multidisciplinary team will present the original methodologies that were derived for modeling the numerous aspects of this problem and also some con- clusions regarding potential extent to other areas and taxa.

  1. Saccharomyces cerevisiae Fermentation Effects on Pollen: Archaeological Implications

    Directory of Open Access Journals (Sweden)

    Crystal A. Dozier

    2016-03-01

    Full Text Available Pollen is the reproductive agent of flowering plants; palynology is utilized by archaeologists because sporopollenin, a major component in the exine of pollen grains, is resistant to decay and morphologically distinctive. Wine, beer, and mead have been identified in the archaeological record by palynological assessment due to indicator species or due to a pollen profile similar to that recovered from honey, a common source of sugar in a variety of fermented beverages. While most palynologists have assumed that pollen grains are resistant to alcoholic fermentation, a recent study in food science implies that pollen is a yeast nutrient because pollen-enriched meads produce more alcohol. The experiment presented here explores the potential distortion of the pollen record through fermentation by brewing a traditional, pollen-rich mead with Saccharomyces cerevisiae. In this experiment, the pollen grains did not undergo any discernible morphological changes nor were distorted in the pollen profile. Any nutrition that the yeast garners from the pollen therefore leaves sporopollenin intact. These results support palynological research on residues of alcoholic beverages and confirms that the fermentation process does not distort the pollen profile of the original substance. The paper concludes with the potential and limits of palynological study to assess fermentation within the archaeological record.

  2. Pollen irradiation and possible gene transfer in Nicotiana species

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1985-01-01

    , and Petunia parodii with irradiated pollen from N. alata and Petunia hybrida showed no evidence of gene transfer, nor did experiments with irradiated mentor pollen. This indicates that gene transfer with irradiated pollen between non-crossing species or between species giving sterile hybrids is probably...

  3. Inherent optical properties of pollen particles: a case study for the morning glory pollen.

    Science.gov (United States)

    Liu, Chao; Yin, Yan

    2016-01-25

    Biological aerosols, such as bacteria, fungal spores, and pollens, play an important role on various atmospheric processes, whereas their inherent optical property is one of the most uncertainties that limit our ability to assess their effects on weather and climate. A numerical model with core-shell structure, hexagonal grids and barbs is developed to represent one kind of realistic pollen particles, and their inherent optical properties are simulated using a pseudo-spectral time domain method. Both the hexagonal grids and barbs substantially affect the modeled pollen optical properties. Results based on the realistic particle model are compared with two equivalent spherical approximations, and the significant differences indicate the importance of considering pollen geometries for their optical properties.

  4. Arabidopsis WRKY2 and WRKY34 transcription factors interact with VQ20 protein to modulate pollen development and function.

    Science.gov (United States)

    Lei, Rihua; Li, Xiaoli; Ma, Zhenbing; Lv, Yan; Hu, Yanru; Yu, Diqiu

    2017-09-01

    Plant male gametogenesis is tightly regulated, and involves complex and precise regulations of transcriptional reprogramming. WRKY transcription factors have been demonstrated to play critical roles in plant development and stress responses. Several members of this family physically interact with VQ motif-containing proteins (VQ proteins) to mediate a plethora of programs in Arabidopsis; however, the involvement of WRKY-VQ complexes in plant male gametogenesis remains largely unknown. In this study, we found that WRKY2 and WKRY34 interact with VQ20 both in vitro and in vivo. Further experiments displayed that the conserved VQ motif of VQ20 is responsible for their physical interactions. The VQ20 protein localizes in the nucleus and specifically expresses in pollens. Phenotypic analysis showed that WRKY2, WRKY34 and VQ20 are crucial for pollen development and function. Mutations of WRKY2, WRKY34 and VQ20 simultaneously resulted in male sterility, with defects in pollen development, germination and tube growth. Further investigation revealed that VQ20 affects the transcriptional functions of its interacting WRKY partners. Complementation evidence supported that the VQ motif of VQ20 is essential for pollen development, as a mutant form of VQ20 in which LVQK residues in the VQ motif were replaced by EDLE did not rescue the phenotype of the w2-1 w34-1 vq20-1 triple-mutant plants. Further expression analysis indicated that WRKY2, WRKY34 and VQ20 co-modulate multiple genes involved in pollen development, germination and tube growth. Taken together, our study provides evidence that VQ20 acts as a key partner of WRKY2 and WKRY34 in plant male gametogenesis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  5. Pollen morphology of some European Rosaceae

    NARCIS (Netherlands)

    Reitsma, Tj.

    1966-01-01

    In this preliminary investigation attention was paid to pollen morphology of West-European species of the Rosaceae. Some new terms were used like fastigium, endocingulus etc. The terminology of Iversen and Troels-Smith has been followed in addition to improvements by Erdtman. A key is given to the

  6. Airborne pollen trends in the Iberian Peninsula.

    Science.gov (United States)

    Galán, C; Alcázar, P; Oteros, J; García-Mozo, H; Aira, M J; Belmonte, J; Diaz de la Guardia, C; Fernández-González, D; Gutierrez-Bustillo, M; Moreno-Grau, S; Pérez-Badía, R; Rodríguez-Rajo, J; Ruiz-Valenzuela, L; Tormo, R; Trigo, M M; Domínguez-Vilches, E

    2016-04-15

    Airborne pollen monitoring is an effective tool for studying the reproductive phenology of anemophilous plants, an important bioindicator of plant behavior. Recent decades have revealed a trend towards rising airborne pollen concentrations in Europe, attributing these trends to an increase in anthropogenic CO2 emissions and temperature. However, the lack of water availability in southern Europe may prompt a trend towards lower flowering intensity, especially in herbaceous plants. Here we show variations in flowering intensity by analyzing the Annual Pollen Index (API) of 12 anemophilous taxa across 12 locations in the Iberian Peninsula, over the last two decades, and detecting the influence of the North Atlantic Oscillation (NAO). Results revealed differences in the distribution and flowering intensity of anemophilous species. A negative correlation was observed between airborne pollen concentrations and winter averages of the NAO index. This study confirms that changes in rainfall in the Mediterranean region, attributed to climate change, have an important impact on the phenology of plants. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Grass Pollen Pollution from Biofuels Farming

    Czech Academy of Sciences Publication Activity Database

    Ratajová, A.; Tříska, Jan; Vrchotová, Naděžda; Kolář, L.; Kužel, S.

    2013-01-01

    Roč. 26, č. 4 (2013), s. 199-203 ISSN 2151-321X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : grass pollen pollution * biofuels farming * temperate climate * PK-fertilization * N-fertilization * phenolic Subject RIV: EH - Ecology, Behaviour Impact factor: 0.556, year: 2013

  8. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen.

    Science.gov (United States)

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-10-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O(3)) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O(3) fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O(3), determined from the mRNA levels of the major allergens. We conclude that O(3) can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Forensic Pollen Evidence from Clothes by the Tape Adhesive Method

    Directory of Open Access Journals (Sweden)

    Chun-Liang Wu

    2006-06-01

    Full Text Available Collection and identification of pollen is becoming important in forensic applications. Many criminal cases have been reported to link suspects to the crime scene by analysis of pollen. Several methods have been used in the pollen collection and analysis, but they are expensive and tedious. Therefore, it is important to develop a simple method to collect pollen grains from clothes. We tried to recover pollen from clothing surface by using the sticky tapes method. The tape adhesive method has been widely used for sample collection for various purposes, but the efficiency of recovery of invisible pollen from clothes has rarely been reported. Therefore, to test the efficiency of the tape adhesive method in recovering pollen from clothes is important. The first author wore clothes that were made from textile S made by the mixture of cotton 60% and polyester fiber 40% to collect pollen from 26 different areas mostly in the northern part of Taiwan and then used cellophane tape D (Sirchie Finger Print Lab., Inc-No. 131LT4 to recover them from different body parts. Twenty-six pollen taxa were detected in different parts of clothes depending upon what kind of plant the first author stayed near. From the results, we concluded that the tape adhesive method is suitable in recovering pollen from clothes. We have suggested that the tape adhesive method could be part of methods for collecting pollen from clothes of suspects. It is simpler, faster and less expensive than other methods.

  10. Pollen Processing Behavior of Heliconius Butterflies: A Derived Grooming Behavior

    Science.gov (United States)

    Hikl, Anna-Laetitia; Krenn, Harald W.

    2011-01-01

    Pollen feeding behaviors Heliconius and Laparus (Lepidoptera: Nymphalidae) represent a key innovation that has shaped other life history traits of these neotropical butterflies. Although all flower visiting Lepidoptera regularly come in contact with pollen, only Heliconius and Laparus butterflies actively collect pollen with the proboscis and subsequently take up nutrients from the pollen grains. This study focused on the behavior of pollen processing and compared the movement patterns with proboscis grooming behavior in various nymphalid butterflies using video analysis. The proboscis movements of pollen processing behavior consisted of a lengthy series of repeated coiling and uncoiling movements in a loosely coiled proboscis position combined with up and down movements and the release of saliva. The proboscis-grooming behavior was triggered by contamination of the proboscis in both pollen feeding and non-pollen feeding nymphalid butterflies. Proboscis grooming movements included interrupted series of coiling and uncoiling movements, characteristic sideways movements, proboscis lifting, and occasionally full extension of the proboscis. Discharge of saliva was more pronounced in pollen feeding species than in non-pollen feeding butterfly species. We conclude that the pollen processing behavior of Heliconius and Laparus is a modified proboscis grooming behavior that originally served to clean the proboscis after contamination with particles. PMID:22208893

  11. Eustachian tube patency

    Science.gov (United States)

    Eustachian tube patency refers to how much the eustachian tube is open. The eustachian tube runs between the middle ear and the throat. It controls the pressure behind the eardrum and middle ear space. This helps keep ...

  12. Feeding tube - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

  13. The importance of cross-reactivity in grass pollen allergy

    Directory of Open Access Journals (Sweden)

    Aleksić Ivana

    2014-01-01

    Full Text Available According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions. [Projekat Ministarstva nauke Republike Srbije, br. 172049 i br. 172024

  14. Ultrastructure of Withania Somnifera (L.) Dunal pollen grains

    International Nuclear Information System (INIS)

    Alwadie, H.M.

    2002-01-01

    Light, scanning and transmission electron microscopy were used to study the morphology and ultrastructure of Withania Somnifera (L.) Dunall pollen grains. Light microscopic examination revealed that the pollen grains are tri- or tetrazonocoplate grains, approximately as long as broad, measuring 29-um. Scanning electron microscopic observation showed that surface sculpturing of the pollen is scarbate-granulate. Ultrathin sections as examined by transmission electron microscope showed that the pollen contained numerous starch grains, lipid droplets, endoplasmic reticulum and vesicles of dictyosomes. Two layers of the pollen wall were also distinguished, the outer wall (exine) divided into ektexine and endexine as well as the inner layer (intine). The nutritive values of Withania pollen are discussed. The importance of studying the ultrastructure of pollen grains as a new tool in palynology is also discussed. (author)

  15. Monitoring, modelling and forecasting of the pollen season

    DEFF Research Database (Denmark)

    Scheifinger, Helfried; Belmonte, Jordina; Buters, Jeroen

    2013-01-01

    The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications of aeropaly......The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications...... of aeropalynology in agriculture and the European Pollen Information System. Three data sources are directly related with aeropalynology: phenological observations, pollen counts and remote sensing of the vegetation activity. The main future challenge is the assimilation of these data streams into numerical pollen...

  16. The effect of irradiation on date palm pollen grains

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, M M; Alajaily, F R [The National Academy for Scientific Research Tripoli (Libyan Arab Jamahiriya)

    1995-10-01

    The evaluation of male date palm is very important in date palm culture, it is very well known that the source of pollen has its influence on fruit set, physical and chemical characters of the fruits. Date pollen was collected from previously studied male date palm trees. The pollen was subjected to the following irradiation treatments: 0,5, 10, 20, 40, 80 krad. The irradiated pollen was treated with acetocarmine and its viability was studied under the light microscope. No differences were observed between the treated pollen and the control. The pollen was germinated on agar, sucrose and boric acid media in an incubator at 27 degree C for hours. Germination count under the light microscope indicated that there were no significant differences between 5, 10, 20 krad treatments and the control, but the high doses reduced the germination percentage. The irradiated pollen used to pollinate date palm trees and the effect of metaxynia was studied. 3 tabs.

  17. Aerobiology of Juniperus Pollen in Oklahoma, Texas, and New Mexico

    Science.gov (United States)

    Levetin, Estelle; Bunderson, Landon; VandeWater, Pete; Luvall, Jeff

    2014-01-01

    Pollen from members of the Cupressaceae are major aeroallergens in many parts of the world. In the south central and southwest United States, Juniperus pollen is the most important member of this family with J. ashei (JA) responsible for severe winter allergy symptoms in Texas and Oklahoma. In New Mexico, pollen from J. monosperma (JM) and other Juniperus species are important contributors to spring allergies, while J. pinchotii (JP) pollinates in the fall affecting sensitive individuals in west Texas, southwest Oklahoma and eastern New Mexico. Throughout this region, JA, JM, and JP occur in dense woodland populations. Generally monitoring for airborne allergens is conducted in urban areas, although the source for tree pollen may be forested areas distant from the sampling sites. Improved pollen forecasts require a better understanding of pollen production at the source. The current study was undertaken to examine the aerobiology of several Juniperus species at their source areas for the development of new pollen forecasting initiatives.

  18. Exceptional preservation of Miocene pollen: plasmolysis captured in salt?

    Energy Technology Data Exchange (ETDEWEB)

    Durska, W.

    2016-07-01

    Exceptionally well-preserved Miocene pollen from the Bochnia salt mine of southern Poland is reported herein. The halite deposits within the salt mine belonging to Late Badenian (Miocene) marine evaporites originated in the Paratethys. Rounded and angular structures are present inside pollen grains. On the basis of the similarity with plasmolyzed pollen grains of modern plants, these structures are considered to represent cytoplasms plasmolyzed in the condensed brine prior to fossilization. Two forms of plasmolyzed cytoplasms (concave and convex) can be observed in modern pollen. Both are distinguished in the investigated fossil material. In porate and colporate grains the shape of the plasmolyzed cellular content is concave while in inaperturate it is convex. The plasmolysis form depends on the type of apertures and pollen shape. The percentage of pollen with fossilized cytoplasms within individual taxa is a valuable environmental indicator, as it depends on the proximity of the pollen-producing plant assemblages to the depositional setting. (Author)

  19. Post-treatment efficacy of discontinuous treatment with 300IR 5-grass pollen sublingual tablet in adults with grass pollen-induced allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Didier, A; Malling, H-J; Worm, Marcel

    2013-01-01

    Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis.......Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis....

  20. Drought, pollen and nectar availability, and pollination success.

    Science.gov (United States)

    Waser, Nickolas M; Price, Mary V

    2016-06-01

    Pollination success of animal-pollinated flowers depends on rate of pollinator visits and on pollen deposition per visit, both of which should vary with the pollen and nectar "neighborhoods" of a plant, i.e., with pollen and nectar availability in nearby plants. One determinant of these neighborhoods is per-flower production of pollen and nectar, which is likely to respond to environmental influences. In this study, we explored environmental effects on pollen and nectar production and on pollination success in order to follow up a surprising result from a previous study: flowers of Ipomopsis aggregata received less pollen in years of high visitation by their hummingbird pollinators. A new analysis of the earlier data indicated that high bird visitation corresponded to drought years. We hypothesized that drought might contribute to the enigmatic prior result if it decreases both nectar and pollen production: in dry years, low nectar availability could cause hummingbirds to visit flowers at a higher rate, and low pollen availability could cause them to deposit less pollen per visit. A greenhouse experiment demonstrated that drought does reduce both pollen and nectar production by I. aggregata flowers. This result was corroborated across 6 yr of variable precipitation and soil moisture in four unmanipulated field populations. In addition, experimental removal of pollen from flowers reduced the pollen received by nearby flowers. We conclude that there is much to learn about how abiotic and biotic environmental drivers jointly affect pollen and nectar production and availability, and how this contributes to pollen and nectar neighborhoods and thus influences pollination success.

  1. Tube holding system

    International Nuclear Information System (INIS)

    Cunningham, R.C.

    1978-01-01

    A tube holding rig is described for the lateral support of tubes arranged in tight parcels in a heat exchanger. This tube holding rig includes not less than two tube supporting assemblies, with a space between them, located crosswise with respect to the tubes, each supporting assembly comprising a first set of parallel components in contact with the tubes, whilst a second set of components is also in contact with the tubes. These two sets of parts together define apertures through which the tubes pass [fr

  2. Pollen sources in the Bojanów forest complex identified on honeybee pollen load by microscopic analysis

    Directory of Open Access Journals (Sweden)

    Ernest Stawiarz

    2017-11-01

    Full Text Available The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland. Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area. Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5 were recorded in one sample. The pollen of Brassicaceae (“others”, Taraxacum type, Solidago type, and Rumex had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of Rubus type, Poaceae (“others”, Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, Aster type, Melampyrum, Quercus, Cornus, and Veronica were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix, and Vaccinium. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens, and Solidago, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall.

  3. Role of macrophage migration inhibitory factor (MIF in pollen-induced allergic conjunctivitis and pollen dermatitis in mice.

    Directory of Open Access Journals (Sweden)

    Yuka Nagata

    Full Text Available Pollen is a clinically important airborne allergen and one of the major causes of allergic conjunctivitis. A subpopulation of patients with atopic dermatitis (AD are also known to have exacerbated skin eruptions on the face, especially around the eyelids, after contact with pollen. This pollen-induced skin reaction is now known as pollen dermatitis. Macrophage migration inhibitory factor (MIF is a pluripotent cytokine that plays an essential role in allergic inflammation. Recent findings suggest that MIF is involved in several allergic disorders, including AD. In this study, MIF knockout (KO, MIF transgenic (Tg and WT littermate mice were immunized with ragweed (RW pollen or Japanese cedar (JC pollen and challenged via eye drops. We observed that the numbers of conjunctiva- and eyelid-infiltrating eosinophils were significantly increased in RW and JC pollen-sensitized MIF Tg compared with WT mice or MIF KO mice. The mRNA expression levels of eotaxin, interleukin (IL-5 and IL-13 were increased in pollen-sensitized eyelid skin sites of MIF Tg mice. An in vitro analysis revealed that high eotaxin expression was induced in dermal fibroblasts by MIF combined with stimulation of IL-4 or IL-13. This eotaxin expression was inhibited by the treatment with CD74 siRNA in fibroblasts. These findings indicate that MIF can induce eosinophil accumulation in the conjunctiva and eyelid dermis exposed to pollen. Therefore, targeted inhibition of MIF might result as a new option to control pollen-induced allergic conjunctivitis and pollen dermatitis.

  4. Can we improve pollen season definitions by using the symptom load index in addition to pollen counts?

    International Nuclear Information System (INIS)

    Bastl, Katharina; Kmenta, Maximilian; Geller-Bernstein, Carmi; Berger, Uwe; Jäger, Siegfried

    2015-01-01

    Airborne pollen measurements are the foundation of aerobiological research and provide essential raw data for various disciplines. Pollen itself should be considered a relevant factor in air quality. Symptom data shed light on the relationship of pollen allergy and pollination. The aim of this study is to assess the spatial variation of local, regional and national symptom datasets. Ten pollen season definitions are used to calculate the symptom load index for the birch and grass pollen seasons (2013–2014) in Austria. (1) Local, (2) regional and (3) national symptom datasets are used to examine spatial variations and a consistent pattern was found. In conclusion, national datasets are suitable for first insights where no sufficient local or regional dataset is available and season definitions based on percentages provide a practical solution, as they can be applied in regions with different pollen loads and produce more constant results. - Highlights: • The definition of the pollen season has an impact on the calculated symptom load. • Pollen season definitions based on percentages of total pollen are a practical solution. • The symptom load index is a robust tool to assess the allergy burden in a population. • Local, regional and national burdens of pollen allergy sufferers are comparable. - The symptom load index is a robust tool to assess the allergy burden in a population. Local, regional and national burdens of pollen allergy sufferers are comparable

  5. ROPES reveals past land cover and pollen productivity estimates from single pollen records

    Science.gov (United States)

    Theuerkauf, Martin; Couwenberg, John

    2018-04-01

    Quantitative reconstructions of past vegetation cover commonly require pollen productivity estimates (PPEs). PPEs are calibrated in extensive and rather cumbersome surface-sample studies, and are so far only available for selected regions. Moreover, it may be questioned whether present-day pollen-landcover relationships are valid for palaeo-situations. We here introduce the ROPES approach that simultaneously derives PPEs and mean plant abundances from single pollen records. ROPES requires pollen counts and pollen accumulation rates (PARs, grains cm-2 year-1). Pollen counts are used to reconstruct plant abundances following the REVEALS approach. The principle of ROPES is that changes in plant abundance are linearly represented in observed PAR values. For example, if the PAR of pine doubles, so should the REVEALS reconstructed abundance of pine. Consequently, if a REVEALS reconstruction is ‘correct’ (i.e. ‘correct’ PPEs are used) the ratio ‘PAR over REVEALS’ is constant for each taxon along all samples of a record. With incorrect PPEs, the ratio will instead vary. ROPES starts from random (likely incorrect) PPEs, but then adjusts them using an optimization algorithm with the aim to minimize variation in the ‘PAR over REVEALS’ ratio across the record. ROPES thus simultaneously calculates mean plant abundances and PPEs. We illustrate the approach with test applications on nine synthetic pollen records. The results show that good performance of ROPES requires data sets with high underlying variation, many samples and low noise in the PAR data. ROPES can deliver first landcover reconstructions in regions for which PPEs are not yet available. The PPEs provided by ROPES may then allow for further REVEALS-based reconstructions. Similarly, ROPES can provide insight in pollen productivity during distinct periods of the past such as the Lateglacial. We see a potential to study spatial and temporal variation in pollen productivity for example in relation to site

  6. Considerations for the preparation of peat samples for palynology, and for the counting of pollen and non-pollen palynomorphs

    Directory of Open Access Journals (Sweden)

    F.M. Chambers

    2011-09-01

    Full Text Available Peat deposits are valuable archives for studying palaeoclimate, the history of local and regional vegetation, and human impact. The most widely applied laboratory analytical technique has been palynology (pollen analysis, which is often limited to the study of pollen and a few easily recognisable spores; however, a variety of other microfossils can be studied in peat deposits and can provide information on past environmental conditions. Among the so-called non-pollen palynomorphs (NPPs are fungal and algal spores that can be used as indicators for local hydrological changes and trophic conditions. This article provides an overview of aspects to consider and sample preparation methods for pollen, spores and other non-pollen palynomorph microfossils in peat deposits; advice on aids to pollen identification and counting; and a brief guide to the range of NPPs that can be counted from prepared subfossil-pollen microslides.

  7. SEC8, a Subunit of the Putative Arabidopsis Exocyst Complex, Facilitates Pollen Germination and Competitive Pollen Tube Growth

    Czech Academy of Sciences Publication Activity Database

    Cole, R.A.; Synek, L.; Žárský, Viktor; Fowler, J.E.

    2005-01-01

    Roč. 138, č. 4 (2005), s. 2005-2018 ISSN 0032-0889 R&D Projects: GA AV ČR IAA6038410 Grant - others: National Science Foundation(US) IBN–0111078 Institutional research plan: CEZ:AV0Z50380511 Keywords : ELECTRON TOMOGRAPHIC ANALYSIS * MALE GAMETOPHYTE DEVELOPMENT * NEURITE OUTGROWTH Subject RIV: EF - Botanics Impact factor: 6.114, year: 2005

  8. Identification of sweet chesnut pollen in bee pollen pellet using using molecular analysis.

    Directory of Open Access Journals (Sweden)

    Jana Žiarovská

    2015-10-01

    Full Text Available Castanea sativa posses many characteristics that are used by human for different purposes, not only as a part of the food. One of them is the utilization of the sweet chesnut pollen for its pharmacological benefits. Actually, no information about the DNA based identification of the sweet chesnut exist. Here, an identification of Castanea sativa based on the specific DNA fragment amplification is described for the first time. Sweet chesnut identification was performed in the very complex sample of bee pollen pellets that were identified as to contain sweet chesnut pollen grains by morphological analysis. First, bioinformatic analysis was performed to find a Castanea sativa conservative part of galactol synthase gene. BLAST alignment of the CDS of GolS1 gene was performed by BLASTtn against plants nucleotide sequences in the NCBI database to ensure for the specifity or existing nucleotide differences. Then, specific primers were subsequently designed and PCR amplification was performed. All the PCRs have run in duplicates for pollen pellet sample and two independent samples of Castanea sativa pure pollen. Restriction cleavage of the PCR amplified fragment was performed to confirm the specifity of the obtained PCR product with the positive confirmation as the predicted three restriction fragments were obtained that fully correspond by the length to those from virtual clevage. Restriction endonuclease Hpy166II was used in restriction cleavage analysis. Castanea sativa pollen grains were confirmed reliable in multifloral pollen pellet by PCR and this approach has the potential to be used effectively for the authentication purposes of sweet chesnut.

  9. Flotation preferentially selects saccate pollen during conifer pollination.

    Science.gov (United States)

    Leslie, Andrew B

    2010-10-01

    • Among many species of living conifers the presence of pollen with air bladders (saccate pollen) is strongly associated with downward-facing ovules and the production of pollination drops. This combination of features enables saccate pollen grains captured in the pollination drop to float upwards into the ovule. Despite the importance of this mechanism in understanding reproduction in living conifers and in extinct seed plants with similar morphologies, experiments designed to test its effectiveness have yielded equivocal results. • In vitro and in vivo pollination experiments using saccate and nonsaccate pollen were performed using modeled ovules and two Pinus species during their natural pollination period. • Buoyant saccate pollen readily floated through aqueous droplets, separating these grains from nonbuoyant pollen and spores. Ovules that received saccate pollen, nonsaccate pollen or a mixture of both all showed larger amounts and higher proportions of saccate pollen inside ovules after drop secretion. • These results demonstrate that flotation is an effective mechanism of pollen capture and transport in gymnosperms, and suggest that the prevalence of saccate grains and downward-facing ovules in the evolutionary history of seed plants is a result of the widespread use of this mechanism.

  10. [Allergic responses to date palm and pecan pollen in Israel].

    Science.gov (United States)

    Waisel, Y; Keynan, N; Gil, T; Tayar, D; Bezerano, A; Goldberg, A; Geller-Bernstein, C; Dolev, Z; Tamir, R; Levy, I

    1994-03-15

    Date palm (Phoenix dactylifera) and pecan (Carya illinoensis) trees are commonly planted in Israel for fruit, for shade, or as ornamental plants. Pollen grains of both species are allergenic; however, the extent of exposure to such pollen and the incidence of allergic response have not been studied here. We therefore investigated skin-test responses to pollen extracts of 12 varieties of palm and 9 of pecan in 705 allergic patients living in 3 cities and 19 rural settlements. Sensitivity to the pollen extracts of both species was much higher among residents of rural than of urban communities. Moreover, there was a definite relationship between the abundance of these trees in a region and the incidence of skin responders to their pollen. Sensitivity was frequent in settlements rich in these 2 species, such as those with nearby commercial date or pecan plantations. In general, sensitivity to date pollen extracts was lower than to pecan. However, differences in skin responses to pollen extracts of various clones were substantiated. Air sampling revealed that pollen pollution decreased considerably with distance from the trees. At approximately 100 m from a source concentrations of airborne pollen were low. Since planting of male palm and pecan trees in population centers would increase pollen pollution, it should be avoided.

  11. Pollen Ultrastructure of Genus Dendrobium Orchids as a Learning Resource

    Directory of Open Access Journals (Sweden)

    Lika Dwi Apriani

    2016-11-01

    Full Text Available Anggrek genus Dendrobium merupakan salah satu genus dari divisi spermatophyta yang merupakan kelompok tumbuhan yang berkembang dengan menggunakan biji. Tumbuhan berbiji tentu memiliki bunga sebagai alat perkembangan generatifnya. Perkembangan generatif pada bunga artinya pertemuan antara sel gamet jantan dan sel gamet betina. Sel gamet betina pada tumbuhan dihasilkan oleh putik, sedangkan sel gamet jantan disebut serbuk sari atau pollen. Genus Dendrobium merupakan salah satu kekayaan alam Indonesia, jumlahnya diperkirakan mencapai 275 spesies. Penelitian ini bertujuan untuk mengetahui bagaimana ultrastruktur pollen anggrek genus Dendrobium dari sepuluh spesies yang diamati menggunakan SEM. Jenis penelitian ini adalah deskriptif kualitatif. Hasil penelitian menunjukkan unit pollen untuk semua spesies yaitu kategori pollinia, sedangkan untuk polaritas pollen adalah apolar. Jenis aperture kesepuluh spesies yang diamati mempunyai aperture dengan pola yang tidak beraturan dan lebih dari enam yang disebut colpate. Bentuk pollen dari semua spesies yang diteliti bentuknya adalah subprolate hingga prolate dan ukuran pollen termasuk dalam kategori minuta hingga media. Ornamentasi pollen atau skluptur pollen tidak teridentifikasi dikarenakan ukuran pollen yang terlalu kecil, permukaan pollen terlihat kurang jelas. Sumber belajar yang digunakan adalah atlas.

  12. Consumptive emasculation: the ecological and evolutionary consequences of pollen theft.

    Science.gov (United States)

    Hargreaves, Anna L; Harder, Lawrence D; Johnson, Steven D

    2009-05-01

    Many of the diverse animals that consume floral rewards act as efficient pollinators; however, others 'steal' rewards without 'paying' for them by pollinating. In contrast to the extensive studies of the ecological and evolutionary consequences of nectar theft, pollen theft and its implications remain largely neglected, even though it affects plant reproduction more directly. Here we review existing studies of pollen theft and find that: (1) most pollen thieves pollinate other plant species, suggesting that theft generally arises from a mismatch between the flower and thief that precludes pollen deposition, (2) bees are the most commonly documented pollen thieves, and (3) the floral traits that typically facilitate pollen theft involve either spatial or temporal separation of sex function within flowers (herkogamy and dichogamy, respectively). Given that herkogamy and dichogamy occur commonly and that bees are globally the most important floral visitors, pollen theft is likely a greatly under-appreciated component of floral ecology and influence on floral evolution. We identify the mechanisms by which pollen theft can affect plant fitness, and review the evidence for theft-induced ecological effects, including pollen limitation. We then explore the consequences of pollen theft for the evolution of floral traits and sexual systems, and conclude by identifying key directions for future research.

  13. Quality of durable cookies enriched with rape bee pollen

    Directory of Open Access Journals (Sweden)

    Miriam Solgajová

    2014-03-01

    Full Text Available The objective of this study was to enrich durable cookies with different additions of rape (Brassica napus var. napus bee pollen to increase nutritional properties of cookie samples and to improve technological and sensorial properties as well. Bee pollen is an important raw material due to its nutritional and functional properties. Cookie samples were prepared by substituting wheat flour with rape bee pollen in the amount of 16 % (1 g of bee pollen per cookie and 32 % (2 g of bee pollen per cookie using bee pollen from two localities Lenártovce and Nové Zámky. In baked samples beside sensory properties also chemical parameters and technological parameters of cookies were evaluated. It was found out that with the gradual addition of rape bee pollen the amount of ash content increased and the highest ash content was analysed in variants II and IV (0.71 and 0.77 % using 32 % addition of rape bee pollen. In terms of reducing sugars, addition of bee pollen caused that the content of reducing sugars in the products increased slightly. The highest reducing sugar content was determined in variant II. (24.59 %. On the other hand amount of crude protein the most considerably raised by addition of 2 g of pollen per cookie. The highest content of crude protein was analysed in variants II and IV (8.72 and 9.00 %. From the results of a linear models in which the dependent variables were the ash, crude protein and moisture it was determined the significant effect (p <0.05 only of the pollen addition. In the case of the model with the dependent variable reducing sugars it was found out significant effect (p<0.0001 of pollen addition and locality and their interactions. With the gradual addition of bee pollen values of technological parameters such as diameter and weight of cookies increased and thickness of products decreased. Based on sensory scores using a 9-point Hedonic scale the best sensorial acceptability (7.4 was found in variant I (1 g of bee

  14. Bender/Coiler for Tubing

    Science.gov (United States)

    Stoltzfus, J. M.

    1983-01-01

    Easy-to-use tool makes coils of tubing. Tubing to be bend clamped with stop post. Die positioned snugly against tubing. Operator turns handle to slide die along tubing, pushing tubing into spiral groove on mandrel.

  15. Measurement of IgG antibodies to house dust mite and grass pollen by a solid-phase radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Delespesse, G; Debisschop, M J; Flament, J [Hopital Saint Pierre, Louvain (Belgium). Lab. de Recherches de la Clinique Medicale

    1979-09-01

    A solid-phase radioimmunoassay was used to measure specific IgG antibodies to either Dermatophagoides pteronyssinus (DPT) or grass pollens. Radiolabelled protein A from Staphylococcus aureus (SpA) was used to determine the IgG antibodies attached to the microtubes. The binding of IgG from either normal or allergic sera to DPT-coated tubes was antigen specific and mediated by the Fab fragment of the immunoglobulin. IgG antibodies from non-allergic serum competed with IgE antibodies to DPT. IgE antibodies did not significantly interfere with the assay. Indeed heating a reaginic serum resulted in a striking reduction of the (/sup 125/I) anti- IgE binding to allergen-coated tubes without modifying the (/sup 125/I)-SpA binding. Furthermore, filtration of a reaginic serum through Sephacryl S-200 separated a peak of IgE antibodies. The solid phase method was more sensitive than a double-antibody technique employing the same DPT extract as labelled antigen. Non-allergic subjects had less IgG antibodies to DPT or grass pollens than allergic patients. In untreated patients, there was a good correlation between levels of IgG and IgE antibodies to grass pollens but not to DPT. Patients hyposensitized to house dust mite had on the average three times more specific IgG antibodies than untreated cases. (author).

  16. Measurement of IgG antibodies to house dust mite and grass pollen by a solid-phase radioimmunoassay

    International Nuclear Information System (INIS)

    Delespesse, G.; Debisschop, M.J.; Flament, J.

    1979-01-01

    A solid-phase radioimmunoassay was used to measure specific IgG antibodies to either Dermatophagoides pteronyssinus (DPT) or grass pollens. Radiolabelled protein A from Staphylococcus aureus (SpA) was used to determine the IgG antibodies attached to the microtubes. The binding of IgG from either normal or allergic sera to DPT-coated tubes was antigen specific and mediated by the Fab fragment of the immunoglobulin. IgG antibodies from non-allergic serum competed with IgE antibodies to DPT. IgE antibodies did not significantly interfere with the assay. Indeed heating a reaginic serum resulted in a striking reduction of the ( 125 I) anti- IgE binding to allergen-coated tubes without modifying the ( 125 I)-SpA binding. Furthermore, filtration of a reaginic serum through Sephacryl S-200 separated a peak of IgE antibodies. The solid phase method was more sensitive than a double-antibody technique employing the same DPT extract as labelled antigen. Non-allergic subjects had less IgG antibodies to DPT or grass pollens than allergic patients. In untreated patients, there was a good correlation between levels of IgG and IgE antibodies to grass pollens but not to DPT. Patients hyposensitized to house dust mite had on the average three times more specific IgG antibodies than untreated cases. (author)

  17. Comparative Analysis of the Arabidopsis Pollen Transcriptome

    Czech Academy of Sciences Publication Activity Database

    Honys, David; Twell, D.

    2003-01-01

    Roč. 132, - (2003), s. 640ů652 ISSN 0032-0889 R&D Projects: GA AV ČR IAA5038207 Grant - others:Royal Society(GB) NATO Postdoctoral Fellowship (to D.H.) Institutional research plan: CEZ:AV0Z5038910; CEZ:MSM 113100003 Keywords : transcriptome profiling * Arabidopsis pollen * male gametophyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.634, year: 2003

  18. Lack of visible post-pollination effects in pollen grains of two Dendrobium cultivars: relationship with pollinia ACC, pollen germination, and pollen tube growth

    NARCIS (Netherlands)

    Luangsuwalai, K.; Ketsa, S.; Wisutiamonkul, A.; Doorn, van W.G.

    2008-01-01

    Dendrobium flowers, pollinated with pollinia from individuals of the same cultivar or other cultivars, usually show rapid post-pollination effects such as. oral epinasty, a change in flower colour and early perianth senescence. However, pollination with the pollinia of cv. Karen or cv. Kenny flowers

  19. Citrus allergy from pollen to clinical symptoms.

    Directory of Open Access Journals (Sweden)

    Rosa Anna Iorio

    Full Text Available Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39% to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica, confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 α and β in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade.

  20. Pollen-gamma irradiation on pineapple and pollination using irradiated pollen

    International Nuclear Information System (INIS)

    Benega, R.; Cisneros, A.; Martinez, J.; Arias, E.; Yabor, L.; Isidron, M.; Castillo, E.; Fernandez, J.

    1997-01-01

    In order to try to induce haploid plants, pineapple (Ananas comosus (L.) ;err.) pollen grains were gamma-rays irradiated with a Co 60 source at rates of doses from 0 to 300 Gy. The effect of gamma-rays on the generative-nucleus division and vitro pollen viability as well as, seed contents and plantlets obtained after pollinations was analysed. The were reducing in the division frequencies of generative nucleus at all assayed doses. The LD50 was achieved among 200 and 250 Gy. There were not differences on pollen viability in the rates of assayed doses. Seed contents were dose-dependent. The percentages of seed full and seed containing only embryos decreases at increasing of irradiation doses. Contrary effect was observed on the seed empty. Some plantlets regenerated from the different irradiation doses showed phenotypes with small and leaves and short inter nodes

  1. Urtica dioica pollen allergy: Clinical, biological, and allergomics analysis.

    Science.gov (United States)

    Tiotiu, Angelica; Brazdova, Andrea; Longé, Cyril; Gallet, Patrice; Morisset, Martine; Leduc, Virginie; Hilger, Christiane; Broussard, Cédric; Couderc, Rémy; Sutra, Jean-Pierre; Sénéchal, Hélène; Poncet, Pascal

    2016-11-01

    The most emblematic members of Urticaceae at allergic risk level are wall pellitories (Parietaria), whereas nettle (Urtica) pollen is considered as poorly allergenic. No allergen from nettle pollen has yet been characterized, whereas 4 are listed for Parietaria pollen by the International Union of Immunological Societies. Clinical and biological profiles of 2 adult men who developed symptoms against nettle pollen and/or leaves were studied. To characterize the allergic reaction and identify the potential nettle pollen sensitizing allergens. IgE-mediated reaction to nettle pollen extract was evaluated by skin prick test, immunoassay, nasal provocation, and basophil activation test. To characterize specific nettle pollen allergens, an allergomic (IgE immunoproteomic) analysis was performed combining 1- and 2-dimensional electrophoresis, IgE immunoblots of nettle pollen extract, identification of allergens by mass spectrometry, and database queries. The results of biological and immunochemical analyses revealed that the allergic rhinitis was due to Urtica dioica pollen in both patients. The allergomic analysis of nettle pollen extract allowed the characterization of 4 basic protein allergens: a thaumatin-like protein (osmotin) with a relative molecular mass of 27 to 29 kDa, a pectinesterase (relative molecular mass, 40 kDa), and 2 other basic proteins with relative molecular masses of 14 to 16 kDa and 43 kDa. There is no or only very weak allergen associations between pellitory and nettle pollen. Exposure to nettle pollen can be responsible of allergic symptoms, and several allergens were characterized. Unravelling the allergens of this underestimated allergy might help to improve diagnosis and care for patients, to predict cross-reactivities and design adapted specific immunotherapy. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  2. MICROBIOTA OF PINUS POLLEN AS ADJUVANT FACTOR OF ALLERGY

    OpenAIRE

    Tetiana Shevtsova; Miroslava Kačániová; Jana Petrová; Ján Brindza; Kateryna Garkava

    2016-01-01

    Bacteria, their endotoxin and mold found on pollen can be a reason of respiratory symptoms in sensitized individuals. This question concerns an anemophilous pollen more acute. In this work quantitative by dilution plating method and qualitative microbial analysis by MALDI-TOF MS Biotyper of pollen and other plants organs of Pinus sylvestris L., P. nigra Arnold, P. mugo Turra, P. armandii Franch., P. wallichiana A.B. Jacks from Nitra, Slovakia are performed which shows quantitative and species...

  3. SCFSLF-mediated cytosolic degradation of S-RNase is required for cross-pollen compatibility in S-RNase-based self-incompatibility in Petunia hybrida

    Directory of Open Access Journals (Sweden)

    Yongbiao eXue

    2014-07-01

    Full Text Available Many flowering plants adopt self-incompatibility (SI to maintain their genetic diversity. In species of Solanaceae, Plantaginaceae and Rosaceae, SI is genetically controlled by a single S-locus with multiple haplotypes. The S-locus has been shown to encode S-RNases expressed in pistil and multiple SLF (S-locus F-box proteins in pollen controlling the female and male specificity of SI, respectively. S-RNases appear to function as a cytotoxin to reject self-pollen. In addition, SLFs have been shown to form SCF (SKP1/Cullin1/F-box complexes to serve as putative E3 ubiquitin ligase to interact with S-RNases. Previously, two different mechanisms, the S-RNase degradation and the S-RNase compartmentalization, have been proposed as the restriction mechanisms of S-RNase cytotoxicity allowing compatible pollination. In this study, we have provided several lines of evidence in support of the S-RNase degradation mechanism by a combination of cellular, biochemical and molecular biology approaches. First, both immunogold labeling and subcellular fractionation assays showed that two key pollen SI factors, PhSLF-S3L and PhSSK1 (SLF-interacting SKP1-like1 from Petunia hybrida, a Solanaceous species, are co-localized in cytosols of both pollen grains and tubes. Second, PhS3L-RNases are mainly detected in the cytosols of both self and non-self pollen tubes after pollination. Third, we found that both PhS3-RNases and PhS3L-RNases directly interact with PhSLF-S3L by yeast two-hybrid and co-immunoprecipitation assays. Fourth, S-RNases are specifically degraded in compatible pollen tubes by non-self SLF action. Taken together, our results demonstrate that SCFSLF-mediated non-self S-RNase degradation occurs in the cytosol of pollen tube through the ubiquitin/26S proteasome system serving as the major mechanism to neutralize S-RNase cytotoxicity during compatible pollination in P. hybrida.

  4. Securing maximum diversity of Non Pollen Palynomorphs in palynological samples

    DEFF Research Database (Denmark)

    Enevold, Renée; Odgaard, Bent Vad

    2015-01-01

    Palynology is no longer synonymous with analysis of pollen with the addition of a few fern spores. A wide range of Non Pollen Palynomorphs are now described and are potential palaeoenvironmental proxies in the palynological surveys. The contribution of NPP’s has proven important to the interpreta......Palynology is no longer synonymous with analysis of pollen with the addition of a few fern spores. A wide range of Non Pollen Palynomorphs are now described and are potential palaeoenvironmental proxies in the palynological surveys. The contribution of NPP’s has proven important...

  5. Fraxinus pollen as a source of environmental pollution

    Directory of Open Access Journals (Sweden)

    María Fernández-González

    2016-06-01

    Full Text Available In Southern Europe there are but a few studies focused on the allergenic impact of ash (Fraxinus pollen as a result of its scarce distribution. In the city of Ourense this type of pollen represents 2% of the total atmospheric pollen recorded. The goal of this study is to determine the atmospheric concentrations of Fraxinus pollen and its allergen in Ourense’s atmosphere in 2015, and to assess their relationship with the main meteorological variables. The aim is to assess whether the pollen counts match the actual exposure conditions for allergen-sensitive patients. A Lanzoni VPPS-2000 volumetric sampler was used for pollen sampling, whereas a Burkard Cyclone sampler was used for allergen detection.The flowering period of Fraxinus was long, having a duration of 76 days between the third week of January and the rst week of April as consequence of the asynchronous flowering of the different species growing in the study area. The presence of the ash allergen in the atmosphere can be detected using the main olive tree allergen, Ole e 1. Our study indicates that the combination of pollen counts and allergen quanti cation should be contemplated to estimate the real exposure of sensitive people. In the case of Fraxinus pollen, there may be allergy risk periods before and after the occurrence of the highest pollen concentrations in the atmosphere as a result of special rain and humidity conditions during its flowering period.

  6. Pollen Flora of Yuenyang Lake Nature Preserve, Taiwan (IV

    Directory of Open Access Journals (Sweden)

    Yu-Fa Wang

    2002-06-01

    Full Text Available Yuenyang Lake is an acidic lake situated within a nature preserve in northern Taiwan. The pollen of nineteen taxa, belonging to five families, was collected from this nature preserve and investigated with light and scanning electron microscopy. The results of this investigation are supplementary work to the previous publications in this journal (Chen and Wang, 1999, 2001; Wang and Chen, 2001. A total of 4 pollen classes were identified on the basis of the aperture on the pollen wall: 3-colpate, 6-colpate, 3-colporate, and 4-7-colporate pollen. These results could be useful in the reconstruction of vegetation history around the Yuenyang Lake.

  7. A DNA barcoding approach to characterize pollen collected by honeybees.

    Directory of Open Access Journals (Sweden)

    Andrea Galimberti

    Full Text Available In the present study, we investigated DNA barcoding effectiveness to characterize honeybee pollen pellets, a food supplement largely used for human nutrition due to its therapeutic properties. We collected pollen pellets using modified beehives placed in three zones within an alpine protected area (Grigna Settentrionale Regional Park, Italy. A DNA barcoding reference database, including rbcL and trnH-psbA sequences from 693 plant species (104 sequenced in this study was assembled. The database was used to identify pollen collected from the hives. Fifty-two plant species were identified at the molecular level. Results suggested rbcL alone could not distinguish among congeneric plants; however, psbA-trnH identified most of the pollen samples at the species level. Substantial variability in pollen composition was observed between the highest elevation locality (Alpe Moconodeno, characterized by arid grasslands and a rocky substrate, and the other two sites (Cornisella and Ortanella at lower altitudes. Pollen from Ortanella and Cornisella showed the presence of typical deciduous forest species; however in samples collected at Ortanella, pollen of the invasive Lonicera japonica, and the ornamental Pelargonium x hortorum were observed. Our results indicated pollen composition was largely influenced by floristic local biodiversity, plant phenology, and the presence of alien flowering species. Therefore, pollen molecular characterization based on DNA barcoding might serve useful to beekeepers in obtaining honeybee products with specific nutritional or therapeutic characteristics desired by food market demands.

  8. A statistical mixture model for estimating the proportion of unreduced pollen grains in perennial ryegrass (Lolium perenne L.) via the size of pollen grains

    NARCIS (Netherlands)

    Jansen, R.C.; Nijs, A.P.M. den

    1993-01-01

    The size of pollen grains is commonly used to indicate the ploidy level of pollen grains. In this paper observations of the diameter of pollen grains are evaluated from one diploid accession of perennial ryegrass (Lolium perenne L.), which was expected to produce diploid (unreduced) pollen grains in

  9. Loss of the Arabidopsis thaliana P₄-ATPase ALA3 reduces adaptability to temperature stresses and impairs vegetative, pollen, and ovule development.

    Directory of Open Access Journals (Sweden)

    Stephen C McDowell

    Full Text Available Members of the P4 subfamily of P-type ATPases are thought to help create asymmetry in lipid bilayers by flipping specific lipids between the leaflets of a membrane. This asymmetry is believed to be central to the formation of vesicles in the secretory and endocytic pathways. In Arabidopsis thaliana, a P4-ATPase associated with the trans-Golgi network (ALA3 was previously reported to be important for vegetative growth and reproductive success. Here we show that multiple phenotypes for ala3 knockouts are sensitive to growth conditions. For example, ala3 rosette size was observed to be dependent upon both temperature and soil, and varied between 40% and 80% that of wild-type under different conditions. We also demonstrate that ala3 mutants have reduced fecundity resulting from a combination of decreased ovule production and pollen tube growth defects. In-vitro pollen tube growth assays showed that ala3 pollen germinated ∼2 h slower than wild-type and had approximately 2-fold reductions in both maximal growth rate and overall length. In genetic crosses under conditions of hot days and cold nights, pollen fitness was reduced by at least 90-fold; from ∼18% transmission efficiency (unstressed to less than 0.2% (stressed. Together, these results support a model in which ALA3 functions to modify endomembranes in multiple cell types, enabling structural changes, or signaling functions that are critical in plants for normal development and adaptation to varied growth environments.

  10. Quantifying pollen-vegetation relationships to reconstruct ancient forests using 19th-century forest composition and pollen data

    Science.gov (United States)

    Dawson, Andria; Paciorek, Christopher J.; McLachlan, Jason S.; Goring, Simon; Williams, John W.; Jackson, Stephen T.

    2016-01-01

    Mitigation of climate change and adaptation to its effects relies partly on how effectively land-atmosphere interactions can be quantified. Quantifying composition of past forest ecosystems can help understand processes governing forest dynamics in a changing world. Fossil pollen data provide information about past forest composition, but rigorous interpretation requires development of pollen-vegetation models (PVMs) that account for interspecific differences in pollen production and dispersal. Widespread and intensified land-use over the 19th and 20th centuries may have altered pollen-vegetation relationships. Here we use STEPPS, a Bayesian hierarchical spatial PVM, to estimate key process parameters and associated uncertainties in the pollen-vegetation relationship. We apply alternate dispersal kernels, and calibrate STEPPS using a newly developed Euro-American settlement-era calibration data set constructed from Public Land Survey data and fossil pollen samples matched to the settlement-era using expert elicitation. Models based on the inverse power-law dispersal kernel outperformed those based on the Gaussian dispersal kernel, indicating that pollen dispersal kernels are fat tailed. Pine and birch have the highest pollen productivities. Pollen productivity and dispersal estimates are generally consistent with previous understanding from modern data sets, although source area estimates are larger. Tests of model predictions demonstrate the ability of STEPPS to predict regional compositional patterns.

  11. Quantifying pollen-vegetation relationships to reconstruct ancient forests using 19th-century forest composition and pollen data

    Science.gov (United States)

    Dawson, Andria; Paciorek, Christopher J.; McLachlan, Jason S.; Goring, Simon; Williams, John W.; Jackson, Stephen T.

    2016-04-01

    Mitigation of climate change and adaptation to its effects relies partly on how effectively land-atmosphere interactions can be quantified. Quantifying composition of past forest ecosystems can help understand processes governing forest dynamics in a changing world. Fossil pollen data provide information about past forest composition, but rigorous interpretation requires development of pollen-vegetation models (PVMs) that account for interspecific differences in pollen production and dispersal. Widespread and intensified land-use over the 19th and 20th centuries may have altered pollen-vegetation relationships. Here we use STEPPS, a Bayesian hierarchical spatial PVM, to estimate key process parameters and associated uncertainties in the pollen-vegetation relationship. We apply alternate dispersal kernels, and calibrate STEPPS using a newly developed Euro-American settlement-era calibration data set constructed from Public Land Survey data and fossil pollen samples matched to the settlement-era using expert elicitation. Models based on the inverse power-law dispersal kernel outperformed those based on the Gaussian dispersal kernel, indicating that pollen dispersal kernels are fat tailed. Pine and birch have the highest pollen productivities. Pollen productivity and dispersal estimates are generally consistent with previous understanding from modern data sets, although source area estimates are larger. Tests of model predictions demonstrate the ability of STEPPS to predict regional compositional patterns.

  12. Pollen food allergy syndrome in Turkey: Clinical characteristics and evaluation of its association with skin test reactivity to pollens.

    Science.gov (United States)

    Özdemir, Seςil Kepil; Özgüςlü, Selcan

    2017-09-17

    There is limited data regarding pollen food allergy syndrome (PFAS) in Turkey. To investigate the clinical characteristics and possible risk factors of PFAS in Turkey, and to evaluate if there was an association between skin test reactivity to pollens and presence of PFAS. A total of 254 consecutive adult patients with pollen sensitivity were prospectively recruited. Patients were interviewed with a questionnaire including a list of pollen-associated foods. Patients were classified as having PFAS if they reported clear allergic symptoms compatible with PFAS. All participants underwent skin prick tests (SPT) to a panel of common aeroallergens, prick-to-prick tests with culprit fresh foods were performed in patients who gave consent. Self-reported PFAS was observed in 49 patients (19.3%). The most common culprit foods were kiwi, peach, tomato, melon and watermelon. Multiple logistic regression analysis showed that potential risk factors for PFAS were having asthma (OR=2.392, P=0.044) and tree pollen sensitization (OR=2.904, P=0.004). There were no significant differences in the SPT wheal sizes to individual pollen extracts between patients with and without PFAS with a positive SPT result for that pollen extract (P> 0.05). PFAS is frequent in pollen sensitized adults in Turkey. The most commonly implicated foods are kiwi, peach,tomato, melon and watermelon, in our geographical region. SPT wheal sizes to pollen extracts seems to be similar in patients with and without PFAS.

  13. Inbreeding and oubreeding effects on pollen fitness and zygote survival in Silene nutans (Caryophyllaceae)

    DEFF Research Database (Denmark)

    Hauser, Thure Pavlo; Siegismund, H.R.

    2000-01-01

    inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival......inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival...

  14. Tracking maize pollen development by the Leaf Collar Method.

    Science.gov (United States)

    Begcy, Kevin; Dresselhaus, Thomas

    2017-12-01

    An easy and highly reproducible nondestructive method named the Leaf Collar Method is described to identify and characterize the different stages of pollen development in maize. In plants, many cellular events such as meiosis, asymmetric cell division, cell cycle regulation, cell fate determination, nucleus movement, vacuole formation, chromatin condensation and epigenetic modifications take place during pollen development. In maize, pollen development occurs in tassels that are confined within the internal stalk of the plant. Hence, identification of the different pollen developmental stages as a tool to investigate above biological processes is impossible without dissecting the entire plant. Therefore, an efficient and reproducible method is necessary to isolate homogeneous cell populations at individual stages throughout pollen development without destroying the plant. Here, we describe a method to identify the various stages of pollen development in maize. Using the Leaf Collar Method in the maize inbreed line B73, we have determined the duration of each stage from pollen mother cells before meiosis to mature tricellular pollen. Anther and tassel size as well as percentage of pollen stages were correlated with vegetative stages, which are easily recognized. The identification of stage-specific genes indicates the reproducibility of the method. In summary, we present an easy and highly reproducible nondestructive method to identify and characterize the different stages of pollen development in maize. This method now opens the way for many subsequent physiological, morphological and molecular analyses to study, for instance, transcriptomics, metabolomics, DNA methylation and chromatin patterns during normal and stressful conditions throughout pollen development in one of the economically most important grass species.

  15. Impact of cytomixis on meiosis, pollen viability and pollen size in ...

    Indian Academy of Sciences (India)

    Srinivas

    prefers light woodlands, moist soils, rock crevices and grows among ... Well-filled pollen grains with stained nuclei were regarded as apparently .... individuals of the Bhairon Ghati population, as they did not depict any .... Ajay and Sarbhoy 1987; Haroun 1995), pollution ( Haroun ... effect of some chlorinated pesticides II.

  16. Variations in pollen counts largely explained by climate and weather

    Science.gov (United States)

    Jung, Stephan; Damialis, Athanasios; Estrella, Nicole; Jochner, Susanne; Menzel, Annette

    2017-04-01

    The interaction between climate and vegetation is well studied within phenology. Climatic / weather conditions affect e.g. flowering date, length of vegetation period, start and end of the season and the plant growth. Besides phenological stages also pollen counts can be used to investigate the interaction between climate and vegetation. Pollen emission and distribution is directly influenced by temperature, wind speed, wind direction and humidity/precipitation. The objective of this project is to study daily/sub daily variations in pollen counts of woody and herbaceous plant species along an altitudinal gradient with different climatic conditions during the vegetation period. Measurements of pollen were carried out with three volumetric pollen traps installed at the altitudes 450 m a.s.l (Freising), 700 m a.s.l (Garmisch-Partenkirchen), and 2700 m a.s.l (Schneefernerhaus near Zugspitze) representing gradient from north of Munich towards the highest mountain of Germany. Airborne pollen concentrations were recorded during the years 2014-2015. The altitudinal range of these three stations accompanied by different microclimates ("space for time approach") can be used as proxy for climate change and to assess its impact on pollen counts and thus allergenic risk for human health. For example the pollen season is shortened and pollen amount is reduced at higher sites. For detailed investigations pollen of the species Plantago, Quercus, Poaceae, Cupressaceae, Cyperacea, Betula and Platanus were chosen, because those are found in appropriate quantities. In general, pollen captured in the pollen traps to a certain extent has its origin from the immediate surrounding. Thus, it mirrors local species distribution. But furthermore the distance of pollen transport is also based on (micro-) climatic conditions, land cover and topography. The pollen trap shortly below the summit of Zugspitze (Schneefernerhaus) has an alpine environment without vegetation nearby. Therefore, this

  17. X-ray tubes

    International Nuclear Information System (INIS)

    Young, R.W.

    1979-01-01

    A form of x-ray tube is described which provides satisfactory focussing of the electron beam when the beam extends for several feet from gun to target. Such a tube can be used for computerised tomographic scanning. (UK)

  18. Pressure tube type reactors

    International Nuclear Information System (INIS)

    Komada, Masaoki.

    1981-01-01

    Purpose: To increase the safety of pressure tube type reactors by providing an additional ECCS system to an ordinary ECCS system and injecting heavy water in the reactor core tank into pressure tubes upon fractures of the tubes. Constitution: Upon fractures of pressure tubes, reduction of the pressure in the fractured tubes to the atmospheric pressure in confirmed and the electromagnetic valve is operated to completely isolate the pressure tubes from the fractured portion. Then, the heavy water in the reactor core tank flows into and spontaneously recycles through the pressure tubes to cool the fuels in the tube to prevent their meltdown. By additionally providing the separate ECCS system to the ordinary ECCS system, fuels can be cooled upon loss of coolant accidents to improve the safety of the reactors. (Moriyama, K.)

  19. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    Feeding - gastrostomy tube - bolus; G-tube - bolus; Gastrostomy button - bolus; Bard Button - bolus; MIC-KEY - bolus ... KEY, 3 to 8 weeks after surgery. These feedings will help your child grow strong and healthy. ...

  20. Feeding tube insertion - gastrostomy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

  1. Neural Tube Defects

    Science.gov (United States)

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

  2. Niche separation of pollen beetle parasitoids

    Directory of Open Access Journals (Sweden)

    Josef eBerger

    2015-05-01

    Full Text Available Species with similar resource requirements are commonly assumed to competitively exclude each other, unless they differentiate their ecological niches. Hence, parasitoid wasps that use the same host species need to find some way to avoid competition. The aim of this study was to identify the role of volatile cues from oilseed rape plants and the larval host in niche separation between three coexisting parasitoid species. We examined how Phradis interstitialis, Phradis morionellus and Tersilochus heterocerus, sympatric parasitoids of Brassicogethes aeneus, differ in their abundances, distribution on buds and flowers, and oviposition behavior in the field. Furthermore, we tested their preferences for odours from uninfested and infested oilseed rape plants in the bud and flowering stage, and their preferences for odours from three developmental stages of pollen beetle larvae in a two-choice olfactometer bioassay.P. interstitialis was active in the field early in the season, preferred odours of infested buds versus uninfested, and oviposited into buds which contained only pollen beetle eggs, while P. morionellus was active late in the season, preferred odours of infested buds as well as odours of infested flowers over uninfested, and oviposited into buds which contained only larvae. T. heterocerus was active throughout the season, and preferred odours of infested flowers over uninfested. Neither Phradis species were attracted to larval odours, whereas T. heterocerus was attracted to odours from first-instar pollen beetle larvae both in the absence of plant odours, and when presented simultaneously with uninfested plant odour.This suggests that the two Phradis species are separated on a temporal scale and that they parasitize different host stages, while the larval parasitoids P. morionellus and T. heterocerus are separated by choice of microhabitat. The former oviposits into larvae in buds, and the latter in flowers.

  3. Allelic interaction of F1 pollen sterility loci and abnormal chromosome behaviour caused pollen sterility in intersubspecific autotetraploid rice hybrids.

    Science.gov (United States)

    He, J H; Shahid, M Q; Li, Y J; Guo, H B; Cheng, X A; Liu, X D; Lu, Y G

    2011-08-01

    The intersubspecific hybrids of autotetraploid rice has many features that increase rice yield, but lower seed set is a major hindrance in its utilization. Pollen sterility is one of the most important factors which cause intersubspecific hybrid sterility. The hybrids with greater variation in seed set were used to study how the F(1) pollen sterile loci (S-a, S-b, and S-c) interact with each other and how abnormal chromosome behaviour and allelic interaction of F(1) sterility loci affect pollen fertility and seed set of intersubspecific autotetraploid rice hybrids. The results showed that interaction between pollen sterility loci have significant effects on the pollen fertility of autotetraploid hybrids, and pollen fertility further decreased with an increase in the allelic interaction of F(1) pollen sterility loci. Abnormal ultra-structure and microtubule distribution patterns during pollen mother cell (PMC) meiosis were found in the hybrids with low pollen fertility in interphase and leptotene, suggesting that the effect-time of pollen sterility loci interaction was very early. There were highly significant differences in the number of quadrivalents and bivalents, and in chromosome configuration among all the hybrids, and quadrivalents decreased with an increase in the seed set of autotetraploid hybrids. Many different kinds of chromosomal abnormalities, such as chromosome straggling, chromosome lagging, asynchrony of chromosome disjunction, and tri-fission were found during the various developmental stages of PMC meiosis. All these abnormalities were significantly higher in sterile hybrids than in fertile hybrids, suggesting that pollen sterility gene interactions tend to increase the chromosomal abnormalities which cause the partial abortion of male gametes and leads to the decline in the seed set of the autotetraploid rice hybrids. © 2011 The Author(s).

  4. The importance of pollen counts in the air: an example

    Directory of Open Access Journals (Sweden)

    Francisco José González Minero

    2016-06-01

    Full Text Available The Bay of Cádiz in general and Sanlúcar de Barrameda in particular were pioneering places for aerobiological analysis in Spain. This study presents unpublished pollen data collected with a Hirst spore trap during a year. Results are structured in pollen calendar form which is easy to interpret by health professionals. This article also intends to pay tribute to those medical pioneers who began their studies in Sanlúcar de Barrameda. On this subject, we discuss the data obtained in 1941 and we relate them with data collected in 2009. The Mediterranean climate and the geographical location of Sanlúcar de Barrameda bring about an archetypical pollen calendar of the towns of the Iberian Peninsula’s southern coast. A total of 21 pollen types are quanti ed, Olea europaea L. (25.1%, Quercus (17.5%, Pinaceae (12.3%, Poaceae (10.2% and Cupressaceae (8.1% being the more abundant types . The months of highest pollen concentration are April and May. The maximum daily concentration was reached on May 13 with 825 grains/m3 of Olea europaea L. pollen. Daily concentrations of grass pollen and other herbaceous plants are not exceptionally high, but they do have a continued presence throughout the year, so the risk of pollen allergies cannot be con ned to spring.

  5. Differential Effects of Carbohydrates on Arabidopsis Pollen Germination.

    Science.gov (United States)

    Hirsche, Jörg; García Fernández, José M; Stabentheiner, Edith; Großkinsky, Dominik K; Roitsch, Thomas

    2017-04-01

    Pollen germination as a crucial process in plant development strongly depends on the accessibility of carbon as energy source. Carbohydrates, however, function not only as a primary energy source, but also as important signaling components. In a comprehensive study, we analyzed various aspects of the impact of 32 different sugars on in vitro germination of Arabidopsis pollen comprising about 150 variations of individual sugars and combinations. Twenty-six structurally different mono-, di- and oligosaccharides, and sugar analogs were initially tested for their ability to support pollen germination. Whereas several di- and oligosaccharides supported pollen germination, hexoses such as glucose, fructose and mannose did not support and even considerably inhibited pollen germination when added to germination-supporting medium. Complementary experiments using glucose analogs with varying functional features, the hexokinase inhibitor mannoheptulose and the glucose-insensitive hexokinase-deficient Arabidopsis mutant gin2-1 suggested that mannose- and glucose-mediated inhibition of sucrose-supported pollen germination depends partially on hexokinase signaling. The results suggest that, in addition to their role as energy source, sugars act as signaling molecules differentially regulating the complex process of pollen germination depending on their structural properties. Thus, a sugar-dependent multilayer regulation of Arabidopsis pollen germination is supported, which makes this approach a valuable experimental system for future studies addressing sugar sensing and signaling. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. Pollen viability and germination in Jatropha ribifolia and Jatropha ...

    African Journals Online (AJOL)

    The aim of this work is to assess pollen viability using the staining technique and in vitro germination with different concentrations of sucrose in Jatropha ribifolia and Jatropha mollissima, contributing to the knowledge of the reproductive biology and subsidizing their conservation, management and utilization. Pollen viability ...

  7. Cytological evidences of pollen abortion in Ornithogalum caudatum Ait

    African Journals Online (AJOL)

    Administrator

    2011-10-19

    Oct 19, 2011 ... Ornithogalum caudatum Ait exhibits strong physiological adaptability; however, it suffers a serious menace of pollen abortion, as almost no seed is formed in the plants. In the current study, chromosome karyotype of root-tip cells (RTC) during mitosis, and chromosome behavior of pollen mother cells.

  8. Do urban canyons influence street level grass pollen concentrations?

    DEFF Research Database (Denmark)

    Peel, Robert George; Kennedy, Roy; Smith, Matt

    2014-01-01

    In epidemiological studies, outdoor exposure to pollen is typically estimated using rooftop monitoring station data, whilst exposure overwhelmingly occurs at street level. In this study the relationship between street level and roof level grass pollen concentrations was investigated for city cent...

  9. Modern pollen data from the Canadian Arctic, 1972-1973

    Science.gov (United States)

    Nichols, Harvey; Stolze, Susann

    2017-05-01

    This data descriptor reports results of a 1972-73 baseline study of modern pollen deposition in the Canadian Arctic to originally aid interpretation of Holocene pollen diagrams from that region, especially focussed on the arctic tree-line. The data set is geographically unique due to its extent, and allows the assessment of the effects of modern climate change on northern ecosystems, including fluctuations of the a arctic tree-line. Repeated sampling was conducted along an interior transect at 29 sites from the Boreal Forest to the High Arctic, with five additional coastal sites covering a total distance of 3,200 km. Static pollen samplers captured both local pollen and long-distance pollen wind-blown from the Boreal Forest. Moss and lichen polsters provided multi-year pollen fallout to assess the effectiveness of the static pollen samplers. The local vegetation was recorded at each site. This descriptor provides information on data archived at the World Data Center PANGAEA, which includes spreadsheets detailing site and sample information as well as raw and processed pollen data obtained on over 500 samples.

  10. Modern pollen data from the Canadian Arctic, 1972–1973

    Science.gov (United States)

    Nichols, Harvey; Stolze, Susann

    2017-01-01

    This data descriptor reports results of a 1972–73 baseline study of modern pollen deposition in the Canadian Arctic to originally aid interpretation of Holocene pollen diagrams from that region, especially focussed on the arctic tree-line. The data set is geographically unique due to its extent, and allows the assessment of the effects of modern climate change on northern ecosystems, including fluctuations of the a arctic tree-line. Repeated sampling was conducted along an interior transect at 29 sites from the Boreal Forest to the High Arctic, with five additional coastal sites covering a total distance of 3,200 km. Static pollen samplers captured both local pollen and long-distance pollen wind-blown from the Boreal Forest. Moss and lichen polsters provided multi-year pollen fallout to assess the effectiveness of the static pollen samplers. The local vegetation was recorded at each site. This descriptor provides information on data archived at the World Data Center PANGAEA, which includes spreadsheets detailing site and sample information as well as raw and processed pollen data obtained on over 500 samples. PMID:28509898

  11. Birch pollen allergy: molecular characterization and hypoallergenic products

    NARCIS (Netherlands)

    Schenk, M.F.

    2008-01-01

    Allergic diseases, such as hay fever and food allergy, affect a substantial part of the population in westernized countries. Pollen of the European white birch (Betula pendula) is a considerable cause of hay fever (seasonal allergic rhinitis) in northern and central Europe. The major birch pollen

  12. Promising method advancement in palynology: a supplement to pollen analysis

    DEFF Research Database (Denmark)

    Enevold, Renée; Odgaard, Bent Vad

    2016-01-01

    The analysis of Non Pollen Palynomorphs (NPPs) has evolved over the last few decades to be a fruitful supplement to palynological surveys and has especially proven to be a useful addition when interpreting anthropogenic disturbance of the natural environment. NPPs in anthropogenic soils...... from sediment-, pollen- and macrofossil analyses. Fungal ascospore x1000. Photo: Renée Enevold...

  13. Standardization of different media for in vitro pollen germination of ...

    African Journals Online (AJOL)

    Almond is an important nut crop which, mostly for fruit set, needs the pollination of flowers followed by fertilization. Therefore, pollen viability and its germination capability are essential. To optimize the pollen culture medium of almond and standardization of the best medium, the present study was carried out with 48 different ...

  14. Pollen loads and specificity of native pollinators of lowbush blueberry.

    Science.gov (United States)

    Moisan-Deserres, J; Girard, M; Chagnon, M; Fournier, V

    2014-06-01

    The reproduction of lowbush blueberry (Vaccinium angustifolium Aiton) is closely tied to insect pollination, owing to self-incompatibility. Many species are known to have greater pollination efficiency than the introduced Apis mellifera L., commonly used for commercial purposes. In this study, we measured the pollen loads of several antophilous insect species, mostly Apoidea and Syrphidae, present in four lowbush blueberry fields in Lac-St-Jean, Québec. To measure pollen loads and species specificity toward V. angustifolium, we net-collected 627 specimens of pollinators, retrieved their pollen loads, identified pollen taxa, and counted pollen grains. We found that the sizes of pollen loads were highly variable among species, ranging from a few hundred to more than 118,000 pollen grains per individual. Bombus and Andrena species in particular carried large amounts of Vaccinium pollen and thus may have greater pollination efficiency. Also, two species (Andrena bradleyi Viereck and Andrena carolina Viereck) showed nearly monolectic behavior toward lowbush blueberry. Finally, we identified alternative forage plants visited by native pollinators, notably species of Acer, Rubus, Ilex mucronata, Ledum groenlandicum, and Taraxacum. Protecting these flowering plants should be part of management practices to maintain healthy pollinator communities in a lowbush blueberry agroecosystem.

  15. Cytological evidences of pollen abortion in Ornithogalum caudatum Ait

    African Journals Online (AJOL)

    Ornithogalum caudatum Ait exhibits strong physiological adaptability; however, it suffers a serious menace of pollen abortion, as almost no seed is formed in the plants. In the current study, chromosome karyotype of root-tip cells (RTC) during mitosis, and chromosome behavior of pollen mother cells (PMC) during meiosis in ...

  16. Banana nectar as a medium for testing pollen viability and ...

    African Journals Online (AJOL)

    Administrator

    2007-05-16

    May 16, 2007 ... The accession TMB2x 8075 - 7 showed no significant pollen germination in nectar and sucrose. Eleven genotypes (55%) showed significant increase in pollen ..... SAS (1999) SAS Institute Inc. Cary, USA. Sara CC, José OF, ...

  17. Tetrazolium chloride as an indicator of pine pollen germinability

    Science.gov (United States)

    Stanton A. Cook; Robert G. Stanley

    1960-01-01

    Controlled pollination in forest tree breeding requires pollen of known germination capacity. Methods of determining pollen viability include germination in a hanging drop, in a moist atmosphere, on agar gel, or in a sugar solution (DUFFIELD, 1954; DILLON et al., 1957). Errors commonly arise in the application of these techniques because maximum...

  18. Characterisation of particulate matter on airborne pollen grains

    International Nuclear Information System (INIS)

    Ribeiro, Helena; Guimarães, Fernanda; Duque, Laura; Noronha, Fernando; Abreu, Ilda

    2015-01-01

    A characterization of the physical–chemical composition of the atmospheric PM adsorbed to airborne pollen was performed. Airborne pollen was sampled using a Hirst-type volumetric spore sampler and observed using a Field Emission Electron Probe Microanalyser for PM analysis. A secondary electron image was taken of each pollen grain and EDS spectra were obtained for individually adsorbed particles. All images were analysed and the size parameters of the particles adsorbed to pollen was determined. The measured particles’ equivalent diameter varied between 0.1 and 25.8 μm, mostly in the fine fraction. The dominant particulates identified were Si-rich, Organic-rich, SO-rich, Metals & Oxides and Cl-rich. Significant daily differences were observed in the physical–chemical characteristics of particles adsorbed to the airborne pollen wall. These differences were correlated with weather parameters and atmospheric PM concentration. Airborne pollen has the ability to adsorb fine particles that may enhance its allergenicity. - Highlights: • Airborne pollen sorbs other PM found in suspension. • 84% of the particles sorbed belonged to the fine aerosol fraction. • Adsorbed PM presented daily physical–chemical variations. • Particles sorbed dominated by Si-rich, Organic-rich, SO-rich, Fe-rich and Cl-rich. - Airborne pollen is able to transport finer particulate matter, which presents daily physical–chemical variations.

  19. Borassodendron (Palmae) in the Southeast Asian fossil pollen record

    NARCIS (Netherlands)

    Maloney, B.K.

    2000-01-01

    Borassodendron machadonis pollen occurred throughout the Holocene pollen record of Nong Thale Song Hong, Thailand, until about 4000 BP. It was also present in one sample from Khok Phanom Di, Thailand, and in the Mahakam Delta, Kalimantan, records, but B. machadonis has not been reported from the

  20. The Paleocene and lower Eocene pollen flora of Guyana

    NARCIS (Netherlands)

    Leidelmeyer, P.

    1966-01-01

    A description is given of a Paleocene and Lower Eocene pollen flora of two bore-holes in Guana. Some new species are described and some remarks are made on their stratigraphical significance. Pollen diagrams are presented, one probably representing the entire Paleocene and a part of the Eocene.

  1. ASSESSING HUMAN EXPOSURE TO GRASS POLLEN IN DENMARK

    DEFF Research Database (Denmark)

    Peel, Robert George; Hertel, Ole; Herbert, Rob

    Objectives: Exposure to pollen is typically assessed using data collected at fixed roof-top monitoring stations, which give a general picture of airborne pollen concentrations over a wide region. Actual exposure levels can be obtained through personal exposure monitoring. This is typically done u...

  2. Oral allergy syndrome to chicory associated with birch pollen allergy

    NARCIS (Netherlands)

    Cadot, P.; Kochuyt, A.-M.; van Ree, R.; Ceuppens, J. L.

    2003-01-01

    BACKGROUND: A few cases of IgE-mediated chicory allergy with oral, cutaneous, and/or respiratory symptoms are reported. We present 4 patients with inhalant birch pollen allergy and oral allergy syndrome to chicory. IgE-binding proteins in chicory and cross-reactivity with birch pollen were studied.

  3. Determination of pollen viability, germination ratios and morphology ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... Key words: Flower biology, malatya, Prunus armeniaca, scanning electron microscope .... *Different letters indicate significant differences based on LSD .... Table 4. Pollen number for apricot (Prunus armeniaca) genotypes. .... Acta. Hort. 701: 64-69. Pırlak L (2002). The effects of temperature on pollen germi ...

  4. Pollen aroma fingerprint of two sunflower (Helianthus annuus L.) genotypes characterized by different pollen colors.

    Science.gov (United States)

    Bertoli, Alessandra; Fambrini, Marco; Doveri, Silvia; Leonardi, Michele; Pugliesi, Claudio; Pistelli, Luisa

    2011-09-01

    Samples of fresh pollen grains, collected from capitula in full bloom from two genotypes of sunflower (Helianthus annuus L.) and characterized by a different color, i.e., white-cream (WC) and orange (O), were analyzed by the HS-SPME (headspacesolid phase microextraction)/GC/MS technique. This study defined for the first time the fingerprint of the sunflower pollen, separated from the disc flowers, to define its contribution to the inflorescence aroma. In the GC/MS fingerprints of the WC and O genotypes, 61 and 62 volatile compounds were identified, respectively. Monoterpene hydrocarbons (34% in O vs. 28% in WC) and sesquiterpene hydrocarbons (37% in O vs. 31% in WC) were ubiquitous in all samples analyzed and represented the main chemical classes. α-Pinene (21% in O vs. 20% in WC) and sabinene (11% in O vs. 6% in WC) were the dominant volatiles, but also a full range of aliphatic hydrocarbons and their oxygenated derivatives gave a decisive contribution to the aroma composition (10% in O vs. 12% in WC). In addition, dendrolasin (3% in O vs. 4% in WC) and some minor constituents such as (E)-hex-2-en-1-ol (0.4% in O vs. 0.1% in WC) were pointed out not only for their contribution to the pollen scent, but also for their well-known role in the plant ecological relationships. Having evaluated two pollen morphs with different carotenoid-based colors, the study sought to highlight also the presence of some volatile precursors or derivatives of these pigments in the aroma. However, the pollen aroma of the two selected genotypes made a specific chemical contribution to the sunflower inflorescence scent without any influence on carotenoid derivatives. 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  5. Pollen morphology of the Onobrychis sect. Heliobrychis in Iran

    Directory of Open Access Journals (Sweden)

    Roya Karamian

    2010-01-01

    Full Text Available Pollen morphology of 20 species belonging to Onobrychis sect. Heliobrychis was studied in Iran. The pollen grains from the herbarium specimens were prepared by acetolysis method and then 8 quantitative characters were studied by light microscopy. Data analysis was carried out by cluster analysis and principal component analysis methods. Pollen grains of the sections were 3-colpate with reticulate ornamentation. Results of the study showed that although the pollen grains in the section were comparatively homogenous, but had a considerable variation in the studied quantitative characters. However among the studied characters, equatorial and polar diameters of pollen grains were the most significant characters. The members of the section can be divided into 3 groups based on these characters.

  6. Application of pollen treated with ionizing radiation in grapes breeding

    International Nuclear Information System (INIS)

    Semin, V.S.

    1988-01-01

    Problem concerning the priority of investigations into transformation inducing using plant pollen irradiation method is raised. Data on investigations into grape predominant type pollen irradiation with rigid 1-100 Gy dose gamma rays are considered. Using grape seedling morphological index analysis it is shown that gene transformation inducing is possible using high dose pollen irradiation for cross pollination process. Advantages of the given method are indicated: application of irradiated pollen for pollination allows one to transmit certain characters to progeny at some stages - without impregnation (1); with pollen irradiation dose increase the number of male plant characters transmitted to progeny is reduced (2); deep recessive characters of one of the parent plants can be manifested in progeny or valuable neoplasms can even occur

  7. Antibacterial Activity of Pollen Extracts on Pathogenic Microflora from Milk

    Directory of Open Access Journals (Sweden)

    Liviu Alexandru Marghitas

    2016-11-01

    Full Text Available Bee-pollen was used for thousands of years as functional food and medicinal plant product. Various beneficial effects were attributed to it and its consumption was increased over the years. The tests have been made on 16 pollen samples of the following families: Rosaceae, Salicaceae, Fabaceae, Tiliaceae, Asteraceae, Brassicaceae and two polifloral pollen assortment, using difuzimetric method. Among the tested bacteria, the Onobrychis viciifolia pollen has the highest sensitivity 11.86±1.79 mm while the low antibacterial activity was registered for Brassica sp. pollen  8.65±2.65 mm. As the use of antibiotic substances over a long period of time resulted in larger doses of residues in milk and representing a potential biohazard, the use of ethanol extracts from beepollen is a real alternative in the treatment of cows with various diseases.

  8. Pollinators, geitonogamy and a model of pollen transfer

    International Nuclear Information System (INIS)

    Di Pasquale, C.

    1995-12-01

    A model of pollination that considers the amount of geitonogamous pollen transfer in different flowers and plants is presented. We assumed in this work self-incompatible plant species and we studied how pollination is affected by different round trips described by pollinator from its nest, taking into account the fraction geitonogamy and the fraction pollen export. A deterministic model and a stochastic model of pollen transfer were developed from which we found that when pollinators describe a uniform sequence (visit the same number of flowers in each plant), individuals receive the maximum outcross pollen or minimum self pollen. That is, from the point of view of fertilization, the optimal number of flowers visited in each plant depends on the number of flowers of the plant, the length of the visit and the number of individuals. (author). 18 refs, 1 fig

  9. In vitro pollen germination of five citrus species

    International Nuclear Information System (INIS)

    Khan, S.A.; Perveen, A.

    2014-01-01

    The aim of present study is In vitro germination of the pollen grains of five Citrus species belonging to the family Rutaceae viz., Citrus aurantium L. var., aurantium Hook.f., C. limon (L.) Brum. f., C. paradisii Macfad, C. reticulata Blanco and C. sinensis (L.) Osbeck. using hanging drop technique. The germination was checked up to 48 weeks, for the pollen stored at different temperatures like 4 degree C, -20 degree C, -30 degree C and -60 degree C. The study indicates that low temperature and low relative humidity is better than high temperature and humidity with respect to pollen germination capacity and viability. Freeze dryer (-60 degree C) seems to be the best method to maintain pollen viability of stored pollen grains for a long period of time. Among five species Citrus aurantium, C. limon and C. sinensis showed high percentage of germination as compared to C. reticulata and C. paradisii. (author)

  10. POLLEN MORPHOLOGY OF CROCUS L.(IRIDACEAE IN BULGARIA

    Directory of Open Access Journals (Sweden)

    UZUNDZHALIEVA KATYA SPASOVA

    2012-06-01

    Full Text Available The pollen of the wild species from the genus Crocus L., spread in Bulgaria has been analyzed. The investigations, made by light microscope show that the pollen of these species is spherical in shape and round in outlines, comparatively big. These morphological characteristics of the pollen of the wild Bulgarian Crocuses define it as a primitive one [6]. The Scanning Electron Microscope investigations, made by Beug [1], established two types of pollen morphology. The results of our investigation led to the conclusion that the same types are also presented in Bulgarian species: – C.biflorus –type, or syncolpate and C.vernus – type, or inaperturate. Eight of the species belong to the first type and only C. pallasii belongs to the second. The pollen of C. reticulatus is with quite unclear aperture – maybe transition to the inaperturate type.

  11. STUDY ON POLLEN VIABILITY AS BIOINDICATOR OF AIR QUALITY

    Directory of Open Access Journals (Sweden)

    Florentina ŞTEFLEA

    2012-01-01

    Full Text Available The aim of this research is to estimate the relationship between pollen viability and atmospheric pollution (in polluted and non-polluted conditions. The study was carried out in the city of Timisoara. Two areas, with different intensity of road traffic (very high and absent but all characterized by the presence of the same plant species, were selected. The pollen of herbaceous spontaneous species, arboreal species and a shrub species was used (Robinia pseudacacia, Aesculus x carnea, Catalpa bignonioides, Albizzia julibrissin, Rosa canina, Sambucus nigra, Malva neglecta, Ranunculus acer, Trifolium repens, Cichorium intybus. The pollen of these species was treated with TTC (2, 3, 5 Tryphenil-Tetrazolium-Chloride staining solution and viability was then estimated by light microscopy. The results of the mean pollen viability percentage of the examined species are reported. Pollen viability of herbaceous plants is significantly different between the two environments.

  12. Pollen flow of wheat under natural conditions in the Huanghuai River Wheat Region, China

    Science.gov (United States)

    Sun, Ai-Qing; Zhang, Chun-Qing; Wu, Cheng-Lai; Gao, Qing-Rong

    2015-01-01

    abstract The transgenic pollen spread is the main pathway of transgenic plant gene flow. The maximum distance of pollen dispersal (horizontal), the spatial dynamics of pollen movement (vertical), and the patterns of pollen dispersal are important considerations in biosafety assessments of genetically modified crops. To evaluate wheat (Triticum aestivum) pollen dispersal, we measured the pollen suspension velocity and analyzed pollen dispersal patterns under natural conditions in the Huanghuai River wheat-growing region in 2009. The pollen suspension velocity was 0.3–0.4 m/s. The highest pollen densities were detected in the north, northwest, and south of the pollen source. Pollen was dispersed over distances greater than 245 m in the northwest and northeast directions. At the pollen source center, pollen density decreased with increasing vertical height. In the north of the pollen source, the pollen density from 65 m to 225 m showed a wave-mode decrease with increasing height. The horizontal transport of pollen over longer distances fitted polynomial equations. In the north, the pollen density was highest at 45 m from the pollen source, and decreased with increasing distance. In the northwest, the pollen density showed a double-peak trend. In the northeast, pollen density was highest from 45 m to 125 m from the source. Wind speeds greater than the pollen suspension velocity and the duration of continuous gusts were the main factors affecting pollen dispersal. This information will be useful for determining the spatial isolation distances for hybrid seed production and for the commercial production of transgenic wheat. PMID:25658025

  13. Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia

    Science.gov (United States)

    Prtenjak, Maja Telišman; Srnec, Lidija; Peternel, Renata; Madžarević, Valentina; Hrga, Ivana; Stjepanović, Barbara

    2012-11-01

    We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m3) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m3. Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

  14. 21 CFR 868.5800 - Tracheostomy tube and tube cuff.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheostomy tube and tube cuff. 868.5800 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5800 Tracheostomy tube and tube cuff. (a) Identification. A tracheostomy tube and tube cuff is a device intended to be placed into a...

  15. Considerations for the preparation of peat samples for palynology, and for the counting of pollen and non-pollen palynomorphs

    NARCIS (Netherlands)

    Chambers, F.M.; van Geel, B.; van der Linden, M.

    2011-01-01

    Peat deposits are valuable archives for studying palaeoclimate, the history of local and regional vegetation, and human impact. The most widely applied laboratory analytical technique has been palynology (pollen analysis), which is often limited to the study of pollen and a few easily recognisable

  16. Immunochemical Characterization of Acacia Pollen Allergens and Evaluation of Cross-Reactivity Pattern with the Common Allergenic Pollens

    Science.gov (United States)

    Shamsbiranvand, Mohammad-Hosein; Khodadadi, Ali; Assarehzadegan, Mohammad-Ali; Borsi, Seyed Hamid; Amini, Akram

    2014-01-01

    Pollen from the Acacia has been reported as an important source of pollinosis in tropical and subtropical regions of the world. The aim of this study was to characterize the IgE binding protein of Acacia farnesiana pollen extract and evaluate cross-reactivity with the most allergenic pollens. In this study, pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting and specific ELISA using forty-two Acacia allergic patients. Potential cross-reactivity among Acacia and selected allergenic plants was evaluated with ELISA and immunoblotting inhibition experiments. There were several resolved protein fractions on SDS-PAGE which ranged from 12 to 85 kDa. Several allergenic protein bands with molecular weights approximately between 12 and 85 kDa were recognized by IgE-specific antibodies from Acacia allergic patients in the immunoblot assay. The inhibition by the Prosopis juliflora pollen extract was more than those by other pollen extracts. Moreover, the wheal diameters generated by the Acacia pollen extract were highly correlated with those of P. juliflora pollen extracts. The findings suggest that several proteins such as 15, 23, 45, and 50 kDa proteins could be used as diagnostic and therapeutic reagents for patients allergic to A. farnesiana and P. juliflora. PMID:24949020

  17. Antimicrobial effect of bee collected pollen extract to Enterobacteriaceae genera after application of bee collected pollen in their feeding

    Directory of Open Access Journals (Sweden)

    Lukáš Hleba

    2013-10-01

    Full Text Available In this study we researched antimicrobial activity of bee pollen extracts to Enterobacteriaceae genera isolated from chicken intestinal tract after application of bee collected pollen in their feeding. We used well plate agar diffusion method for antimicrobial testing of bee pollen extract and disc diffusion method for antibiotic susceptibility testing of bacteria by EUCAST. Identification of bacteria was done by test kit Enterotest 24. We identified tree bacterial strains: E. coli, P. mirabilis and K. oxytoca. We determined that K. oxytoca was resistant to ampicillin only and others identified strain were sensitive to used antibiotics. Also we determined antimicrobial effect of bee pollen extract to all tested strains of Enterobacteriaceae genera which were isolated from intestinal tract of chicken after application of bee collected pollen extract in their feeding. From obtained results we could be conclude that bacteria isolated from chicken after application of bee pollen extract had more resistance to bee collected pollen extract in in vitro experiment as E. coli CCM 3988, which did not be in contact with bee pollen extract.

  18. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Gugel, G.

    1976-01-01

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  19. Pollen Contaminated With Field-Relevant Levels of Cyhalothrin Affects Honey Bee Survival, Nutritional Physiology, and Pollen Consumption Behavior.

    Science.gov (United States)

    Dolezal, Adam G; Carrillo-Tripp, Jimena; Miller, W Allen; Bonning, Bryony C; Toth, Amy L

    2016-02-01

    Honey bees are exposed to a variety of environmental factors that impact their health, including nutritional stress, pathogens, and pesticides. In particular, there has been increasing evidence that sublethal exposure to pesticides can cause subtle, yet important effects on honey bee health and behavior. Here, we add to this body of knowledge by presenting data on bee-collected pollen containing sublethal levels of cyhalothrin, a pyrethroid insecticide, which, when fed to young honey bees, resulted in significant changes in lifespan, nutritional physiology,and behavior. For the first time, we show that when young, nest-aged bees are presented with pollen containing field-relevant levels of cyhalothrin, they reduce their consumption of contaminated pollen. This indicates that, at least for some chemicals, young bees are able to detect contamination in pollen and change their behavioral response, even if the contamination levels do not prevent foraging honey bees from collecting the contaminated pollen.

  20. Intercostal drainage tube or intracardiac drainage tube?

    Directory of Open Access Journals (Sweden)

    N Anitha

    2016-01-01

    Full Text Available Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  1. Intercostal drainage tube or intracardiac drainage tube?

    Science.gov (United States)

    Anitha, N; Kamath, S Ganesh; Khymdeit, Edison; Prabhu, Manjunath

    2016-01-01

    Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  2. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

  3. Microwave-Assisted Drying for the Conservation of Honeybee Pollen

    Directory of Open Access Journals (Sweden)

    Angelo Canale

    2016-05-01

    Full Text Available Bee pollen is becoming an important product thanks to its nutritional properties, including a high content of bioactive compounds such as essential amino acids, antioxidants, and vitamins. Fresh bee pollen has a high water content (15%–30% wt %, thus it is a good substrate for microorganisms. Traditional conservation methods include drying in a hot air chamber and/or freezing. These techniques may significantly affect the pollen organoleptic properties and its content of bioactive compounds. Here, a new conservation method, microwave drying, is introduced and investigated. The method implies irradiating the fresh pollen with microwaves under vacuum, in order to reduce the water content without reaching temperatures capable of thermally deteriorating important bioactive compounds. The method was evaluated by taking into account the nutritional properties after the treatment. The analyzed parameters were phenols, flavonoids, with special reference to rutin content, and amino acids. Results showed that microwave drying offers important advantages for the conservation of bee pollen. Irrespective of microwave power and treatment time, phenol and flavonoid content did not vary over untreated fresh pollen. Similarly, rutin content was unaffected by the microwave drying, suggesting that the microwave-assisted drying could be a powerful technology to preserve bioprotective compounds in fresh pollen.

  4. Food allergy to apple and specific immunotherapy with birch pollen

    DEFF Research Database (Denmark)

    Hansen, K.S.; Khinchi, M.S.; Skov, P.S.

    2004-01-01

    Conflicting results concerning the effect of specific pollen immunotherapy (SIT) on allergy to plant foods have been reported. The aim of this study was to investigate the effect of SIT using a birch pollen extract on food allergy with focus on allergy to apple. Seventy-four birch pollen-allergic......Conflicting results concerning the effect of specific pollen immunotherapy (SIT) on allergy to plant foods have been reported. The aim of this study was to investigate the effect of SIT using a birch pollen extract on food allergy with focus on allergy to apple. Seventy-four birch pollen......-allergic patients were included in a double-blind, double-dummy, and placebo-controlled comparison of sublingual-swallow (SLIT) and subcutaneous (SCIT) administration of a birch pollen extract. Sixty-nine percent of these patients reported allergy to apple. The clinical reactivity to apple was evaluated by open...... oral challenges with fresh apple and a questionnaire. The immunoglobulin E (IgE)-reactivity was assessed by skin prick test (SPT), specific IgE, and leukocyte histamine release (HR). Forty patients were included in the final evaluation of the effect of SIT. The challenges were positive in 9 (SCIT), 6...

  5. Pollen characters of Firmiana malayana Kostem. (Malvaceae: Sterculoideae) in Malaysia

    Science.gov (United States)

    Amirul-Aiman, A. J.; Noraini, T.; Nurul-Aini, C. A. C.; Idris, S.; Suhaniza, R.

    2018-04-01

    Firmiana malayana also known as "Bullocks eye or Mata Lembu" in Malaysia and can be found along riverbanks and open forests in Peninsular Malaysia and seldom planted in populated areas. The flowers of the Firmiana malayana are vivid orange in colour, on tassels up to 12 cm long. Usually this species will shed its leaves after a dry period and remains bare for six to eight weeks. The objective of this study is to determine the pollen morphological characteristics of the Firmiana malayana in order to add more information on the species under the family of Sterculiaceae in Malaysia. Methods for this study includes acetolysis technique for the pollens and viewed under light microscope and scanning electron microscope. Results shown that the pollens of the species Firmiana malayana appeared to be monad and dyad with tricolporate class with both porate and colpus present. The shape of this species is prolate with P/E index of 1.49. This species was considered as medium-size pollens as the pollens ranges from 26 - 36 µm. The ornamentation of the pollen is reticulate where the ornamentation is network-like pattern formed by exine elements of lumen and murus. Based on the results obtained, pollen morphology is a great tool that can aid in plant identification and classification as well having taxonomic values.

  6. Analysis of airborne pollen grains in Konya, Turkey, 2005

    International Nuclear Information System (INIS)

    Altunoglu, M.K.; Bicakci, A.; Temel, M.; Kargioglu, M.

    2010-01-01

    In this study, airborne pollen grains of Konya province were investigated using Durham sampler from January to December 2005. A total of 4420 pollen grains/cm/sup 2/ which belonged to 29 taxa and 9 unidentified pollen grains were recorded. From identified taxa, 19 belong to arboreal and 10 taxa to non-arboreal plants. Total pollen grains consist of 87,49% arboreal, 12,31% non-arboreal plants and 0,20% unidentified pollen grains. In the investigated region, from arboreal plant taxa Pinus spp. (21,63%), Fraxinus spp. (21,13%), Cupressaceae (15,84%), Ailanthus spp. (7,47%), Platanus spp. (3,80%), Acer spp. (3,28%), Populus spp. (1,86%), Sophora spp. (3,85%) and from non-arboreal plant taxa Chenopodiaceae / Amaranthaceae (4,77%), Poaceae (3,67%) were responsible for the greatest amount of pollen. During the study period, the pollen fall reached its highest level in March. (author)

  7. Poaceae pollen as the leading aeroallergen worldwide: A review.

    Science.gov (United States)

    García-Mozo, H

    2017-12-01

    The Poaceae family comprises over 12 000 wind-pollinated species, which release large amounts of pollen into the atmosphere. Poaceae pollen is currently regarded as the leading airborne biological pollutant and the chief cause of pollen allergy worldwide. Sensitization rates vary by country, and those variations are reviewed here. Grass pollen allergens are grouped according to their protein structure and function. In Poaceae, although species belonging to different subfamilies are characterized by distinct allergen subsets, there is a considerable degree of cross-reactivity between many species. Cross-reactivity between grass pollen protein and fresh fruit pan-allergens is associated with the appearance of food allergies. The additional influence of urban pollution may prompt a more severe immunological response. The timing and the intensity of the pollen season are governed by species genetics, but plant phenology is also influenced by climate; as a result, climate changes may affect airborne pollen concentrations. This article reviews the findings of worldwide research which has highlighted the major impact of climate change on plant phenology and also on the prevalence and severity of allergic disease. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

  8. Therapeutic effect of bee pollens on acute radiation sickness

    International Nuclear Information System (INIS)

    Wang Mingsuo; Huang Chaoqun; Chen Zhen; Huang Meiying; Jiang Ying; Wang Tao

    1997-09-01

    The therapeutic effect of bee pollens on acute radiation sickness were evaluated by observing the changes in the peripheral white blood cell (PWBC) count, the total activity of superoxide dismutase (SOD) and the levels of lipid peroxides (LPO) in sera of the irradiated rats following P.O. administration of bee pollens. It was found that bee pollens could remarkably help irradiated rats recover from radiation-induced injury. The functions of bee pollens might be summarized as follows: (1) Stimulating Proliferation of PWBC. The PWBC count of the bee pollens group showed no significant difference as compared with the normal control group on the 30 th day postirradiation. (2) Enhancing antioxidative effect of clearing free radicals. The total activity of serum SOD in the bee pollens group increased by 6.48% as compared with the normal control group on the 30 th day after irradiation, and the LPO levels i.e. MDA and POV in sera of the irradiated rats decreased by 54.73% and 21.60% respectively. The result suggests that using bee pollens as antiradiation and health-promoting agents in clinical treatment of acute radiation sickness and during radiotherapy of patients with tumors may has certain practical value. (12 refs., 2 figs., 2 tabs.)

  9. Morphology and viability of castor bean genotypes pollen grains

    Directory of Open Access Journals (Sweden)

    Maria Selma Alves Silva Diamantino

    2016-01-01

    Full Text Available The objective of this work was to characterize the morphology and viability of the pollen of 15 genotypes of castor bean (Ricinus communis L. and to generate information that can assist in the selection of highly promising male parents for future use in genetic improvement programs aimed at producing seeds for oil extraction. Acetolysis and scanning electron microscopy was used to characterize the morphology of the pollen. The viability of the pollen grains was estimated by in vitro germination and colorimetric analysis (acetocarmine 2% and 2, 3, 5-triphenyltetrazolium chloride 1%. For the in vitro germination, pollen grains were grown in 10 types of solidified culture medium consisting of different concentrations of sucrose, boric acid, calcium nitrate, magnesium sulfate and potassium nitrate. The pollen grains had the following characteristics: medium size, isopolar and subspheroidal shape, radial symmetry, circular ambit, 3-colporate, elongated endoapertures, tectate exine and granulated sexine. The acetocarmine dye overestimated pollen viability. The media M5 and M8 were the most efficient at promoting the germination of pollen grains. The studied genotypes had high levels of viability and can therefore be used as male parents in genetic improvement programs.

  10. On the Relationship between Pollen Size and Genome Size

    Directory of Open Access Journals (Sweden)

    Charles A. Knight

    2010-01-01

    Full Text Available Here we test whether genome size is a predictor of pollen size. If it were, inferences of ancient genome size would be possible using the abundant paleo-palynolgical record. We performed regression analyses across 464 species of pollen width and genome size. We found a significant positive trend. However, regression analysis using phylogentically independent contrasts did not support the correlated evolution of these traits. Instead, a large split between angiosperms and gymnosperms for both pollen width and genome size was revealed. Sister taxa were not more likely to show a positive contrast when compared to deeper nodes. However, significantly more congeneric species had a positive trend than expected by chance. These results may reflect the strong selection pressure for pollen to be small. Also, because pollen grains are not metabolically active when measured, their biology is different than other cells which have been shown to be strongly related to genome size, such as guard cells. Our findings contrast with previously published research. It was our hope that pollen size could be used as a proxy for inferring the genome size of ancient species. However, our results suggest pollen is not a good candidate for such endeavors.

  11. Pediatric cuffed endotracheal tubes

    Directory of Open Access Journals (Sweden)

    Neerja Bhardwaj

    2013-01-01

    Full Text Available Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H 2 O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

  12. Influence of Pollen Nutrition on Honey Bee Health: Do Pollen Quality and Diversity Matter?

    OpenAIRE

    Di Pasquale, Garance; Salignon, Marion; Le Conte, Yves; Belzunces, Luc P.; Decourtye, Axel; Kretzschmar, Andr?; Suchail, S?verine; Brunet, Jean-Luc; Alaux, C?dric

    2013-01-01

    Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen) necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pol...

  13. Impact of cytomixis on meiosis, pollen viability and pollen size in ...

    Indian Academy of Sciences (India)

    Srinivas

    mother cells of Medicago sativa L.; J. Heredity 94 512–516. Bhat T A, Parveen S and Khan A H 2006 MMS-induced cytomixis in pollen mother cells of broad bean (Vicia faba L.); Turk. J. Bot. 30 273–279. Bione N C P, Pagliarini M S and de Toledo J F F 2000 Meiotic behavior of several Brazilian soybean varieties; Genet.

  14. Formation and function of a new pollen aperture pattern in angiosperms: The proximal sulcus of Tillandsia leiboldiana (Bromeliaceae).

    Science.gov (United States)

    Albert, Béatrice; Matamoro-Vidal, Alexis; Raquin, Christian; Nadot, Sophie

    2010-02-01

    Pollen grains are generally surrounded by an extremely resistant wall interrupted in places by apertures that play a key role in reproduction; pollen tube growth is initiated at these sites. The shift from a proximal to distal aperture location is a striking innovation in seed plant reproduction. Reversals to proximal aperture position have only very rarely been described in angiosperms. The genus Tillandsia belongs to the Bromeliaceae family, and its aperture pattern has been described as distal monosulcate, the most widespread aperture patterns recorded in monocots and basal angiosperms. Here we report developmental and functional elements to demonstrate that the sulcate aperture in Tillandsia leiboldiana is not distal as previously described but proximal. Postmeitotic tetrad observation indicates unambiguously the proximal position of the sulcus, and in vitro germination of pollen grains confirms that the aperture is functional. This is the first report of a sulcate proximal aperture with proximal germination. The observation of microsporogenesis reveals specific features in the patterns of callose thickenings in postmeiotic tetrads.

  15. Variation patterns of pollen production in palm flowers

    DEFF Research Database (Denmark)

    Alapetite, Elodie; Barfod, Anders; Albert, Beatrice

    2016-01-01

    pollen production and stamen number has never been so far investigated. The diversity in stamen number observed among palms species and genera provides an ideal case study to test for such a correlation, taking into account phylogenetic constraints. Based on a survey of flowers from 82 species...... representative of the various palm tribes and compared it to stamen number, we show that pollen production in palms ranges from hundreds to millions grains. There is a relationship between stamen number and pollen production in our sampling, particularly in Coryphoideae and Arecoideae where there is a tendency...

  16. Lunar Lava Tube Sensing

    Science.gov (United States)

    York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

    1992-01-01

    Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

  17. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube......’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within...

  18. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1983-08-01

    A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 (0.30 percent) in 1981. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that used all-volatile treatment since start-up. At one reactor a large number of degraded tubes were repaired by sleeving which is expected to become an important method of tube repair in the future

  19. The formation of pollen in male flowers and yearly atmospheric pollen counts of Cryptomeria japonica in the following year

    Directory of Open Access Journals (Sweden)

    Hideaki Taira

    1998-01-01

    Full Text Available Prediction of yearly atmospheric pollen counts is a very important component in the prevention of allergenic symptoms. We investigated the relationship between atomspheric pollen counts and the formation of male flowers of Cryptomeriajaponica D. Don (C. japonica. An atmospheric pollen survey of C. japonica was conducted from 1983 to 1996 using a Durham’s sampler. A regression analysis was performed between the total pollen count and July temperature in previous years. The atmospheric pollen counts of C. japonica had a high positive correlation with the mean temperature in July of the previous year. However, the predicted using average mean July temperature records of the previous year were insufficient, especially in years following high pollen count. In experimental conditions, using 60 C. japonica trees in pots, the formation of male flowers was shown to increase with a rise in incubation temperature. In a forest of C. japonica, our results showed that the length and weight of new needle growth from old needles, which produced many flowers in the previous year, were shorter and lighter, respectively. These aerobiological and plant physiological studies provide evidence that a smaller number of pollen counts are a common result in a year following one in which many male flowers are produced, even if the mean July temperature of that year was high.

  20. Rectangular drift tube characteristics

    International Nuclear Information System (INIS)

    Denisov, D.S.; Musienko, Yu.V.

    1985-01-01

    Results on the study of the characteristics of a 50 x 100 mm aluminium drift tube are presented. The tube was filled with argon-methane and argon-isobutane mixtures. With 16 per cent methane concentration the largest deviation from a linear relation between the drift time and the drift path over 50 mm is less than 2 mm. The tube filled with argon-isobutane mixture is capable of operating in a limited streamer mode

  1. Categorising YouTube

    OpenAIRE

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a...

  2. Pressure tube reactor

    International Nuclear Information System (INIS)

    Susuki, Akira; Murata, Shigeto; Minato, Akihiko.

    1993-01-01

    In a pressure tube reactor, a reactor core is constituted by arranging more than two units of a minimum unit combination of a moderator sealing pipe containing a calandria tube having moderators there between and a calandria tube and moderators. The upper header and a lower header of the calandria tank containing moderators are communicated by way of the moderator sealing tube. Further, a gravitationally dropping mechanism is disposed for injecting neutron absorbing liquid to a calandria gas injection portion. A ratio between a moderator volume and a fuel volume is defined as a function of the inner diameter of the moderator sealing tube, the outer diameter of the calandria tube and the diameter of fuel pellets, and has no influence to intervals of a pressure tube lattice. The interval of the pressure tube lattice is enlarged without increasing the size of the pressure tube, to improve production efficiency of the reactor and set a coolant void coefficient more negative, thereby enabling to improve self controllability and safety. Further, the reactor scram can be conducted by injecting neutron absorbing liquid. (N.H.)

  3. Heated Tube Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Heated Tube Facility at NASA GRC investigates cooling issues by simulating conditions characteristic of rocket engine thrust chambers and high speed airbreathing...

  4. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1984-10-01

    A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization

  5. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Tapping, R.L.; Stipan, L.

    1992-03-01

    A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

  6. Grass pollen symptoms interfere with the recollection of birch pollen symptoms - a prospective study of suspected, asymptomatic skin sensitization

    DEFF Research Database (Denmark)

    Assing, K; Bødtger, Uffe; Poulsen, L K

    2007-01-01

    of seasonal allergic symptoms and prospective seasonal symptom registration among subjects with AS. METHODS: On the basis of a population survey, autumn 2002, including skin prick tests (positive if > or =3 mm) and a screening questionnaire, 87 subjects with AS to birch and/or grass pollen, birch and/or grass...... days. RESULTS: Eleven AS subjects (birch: n = 10) subsequently developed allergic symptoms, yet nine admitted, at follow up, to have had symptoms before inclusion, or even denied pollen-related symptoms despite a significant diary. Compared with AS subjects sensitized to grass pollen, AS subjects...

  7. Pollen analyses of Pleistocene hyaena coprolites from Montenegro and Serbia

    Directory of Open Access Journals (Sweden)

    Argant Jacqueline

    2007-01-01

    Full Text Available The results of pollen analyses of hyaena coprolites from the Early Pleistocene cave of Trlica in northern Montenegro and the Late Pleistocene cave of Baranica in southeast Serbia are described. The Early Pleistocene Pachycrocuta brevirostris, and the Late Pleistocene Crocuta spelaea are coprolite-producing species. Although the pollen concentration was rather low, the presented analyses add considerably to the much-needed knowledge of the vegetation of the central Balkans during the Pleistocene. Pollen extracted from a coprolite from the Baranica cave indicates an open landscape with the presence of steppe taxa, which is in accordance with the recorded conditions and faunal remains. Pollen analysis of the Early Pleistocene samples from Trlica indicate fresh and temperate humid climatic conditions, as well as the co-existence of several biotopes which formed a mosaic landscape in the vicinity of the cave.

  8. Pollen Viability and Autogamy Fitness in Bauhinia forficata Link (Fabaceae

    Directory of Open Access Journals (Sweden)

    Luana Camila Capitani

    2018-05-01

    Full Text Available ABSTRACT Bauhinia forficata (Fabaceae occurs in many phytophysiognomies of southern Brazil, however its ecological relevance is not well understood. The present study was developed in the Central Depression of Rio Grande do Sul and aimed to determine variations in pollen viability along flowering, ability to perform autogamy and dye efficiency for the viability test. Pollen viability was determined by colorimetry as well as the ability to perform autogamy by isolating floral buds, being evaluated in eleven matrices. Average pollen viability was 81.43%, with the highest average value obtained with the dye 2,3,5- Triphenyltetrazolium Chloride (TTC (84.11%. Safranin was not a good indicator at the tested concentration. No correlation was found between pollen viability and flowering time. The species demonstrated an inability to perform autogamy.

  9. Regulatory networks in pollen development under cold stress

    Directory of Open Access Journals (Sweden)

    Kamal Dev Sharma

    2016-03-01

    Full Text Available Cold stress modifies anthers’ metabolic pathways to induce pollen sterility. Cold-tolerant plants, unlike the susceptible ones, produce high proportion of viable pollen. Anthers in susceptible plants, when exposed to cold stress, increase abscisic acid (ABA metabolism and reduce ABA catabolism. Increased ABA negatively regulates expression of tapetum cell wall bound invertase and monosaccharide transport genes resulting in distorted carbohydrate pool in anther. Cold-stress also reduces endogenous levels of the bioactive gibberellins (GAs, GA4 and GA7, in susceptible anthers by repression of the GA biosynthesis genes. Here we discuss recent findings on mechanisms of cold susceptibility in anthers which determine pollen sterility. We also discuss differences in regulatory pathways between cold-stressed anthers of susceptible and tolerant plants that decide pollen sterility or viability.

  10. Evaluation of pollen viability, stigma receptivity and fertilization ...

    African Journals Online (AJOL)

    AJL

    2013-11-13

    Nov 13, 2013 ... by field artificial pollination were analyzed in this study. The maximum pollen viability .... the day before anthesis to avoid self-pollination. Subsequently, between ..... The Lagerstroemia handbook/checklist. Ameri. Association ...

  11. Cytological evidences of pollen abortion in Ornithogalum caudatum Ait

    African Journals Online (AJOL)

    Administrator

    2011-10-19

    Oct 19, 2011 ... sterility. INTRODUCTION. Genus Ornithogalum caudatum Ait, with common name ..... chromosome association in F1 hybrids Triticum aestivum × Secale ... nutrient metabolism and pollen abortion of male sterile lines in Lycium.

  12. Pollen genetic markers for detection of mutagens in the environment

    International Nuclear Information System (INIS)

    Nilan, R.A.; Rosichan, J.L.; Arenaz, P.; Hodgdon, A.L.; Kleinhofs, A.

    1980-01-01

    To utilize and exploit pollen for in situ mutagen monitoring, screening and toxicology, the range of genetic traits in pollen must be identified and analyzed. To be useful for the development of mutagen detection systems proteins should be: (1) activity stainable or immunologically identifiable in the pollen, (2) the products of one to three loci; and (3) gametophytic and nuclear in origin. Several proteins, including alcohol dehydrogenase in maize, which meet these criteria are discussed. The waxy locus in barley and maize which controls starch deposition for pollen screening and mutant detection. Thirty waxy mutant lines, induced by sodium azide and gamma-rays are characterized for spontaneous and induced reversion frequencies, allelism, karyotype, amylose content, and UDPglucose glucosyltransferase (waxy gene product) activity. Twelve mutant alleles are being mapped by recombinant frequencies

  13. Pollen morphology of European bladderworts (Utricularia L., Lentibulariaceae)

    Czech Academy of Sciences Publication Activity Database

    Beretta, M.; Rodondi, G.; Adamec, Lubomír; Andreis, C.

    2014-01-01

    Roč. 205, č. 1 (2014), s. 22-30 ISSN 0034-6667 Institutional support: RVO:67985939 Keywords : Utricularia * pollen morphology * determination key Subject RIV: EF - Botanics Impact factor: 1.940, year: 2014

  14. rainfall and temperature effects on flowering and pollen productions ...

    African Journals Online (AJOL)

    RAINFALL AND TEMPERATURE EFFECTS ON FLOWERING AND POLLEN. PRODUCTIONS IN COCOA ... chocolate or for extracting cocoa butter. Although, all cultivated .... healthy flowers of the selected clones. These flowers were stored in ...

  15. Banana nectar as a medium for testing pollen viability and ...

    African Journals Online (AJOL)

    Administrator

    2007-05-16

    May 16, 2007 ... A quick and reliable method for evaluating pollen quality is essential in a breeding program, especially in a crop such as ..... most plants are sucrose, glucose, fructose, xylose. (Nicolson and Van .... HPLC/UV determination of.

  16. Assessment of Bollgard II cotton pollen mediated transgenes flow to ...

    African Journals Online (AJOL)

    Assessment of Bollgard II cotton pollen mediated transgenes flow to conventional cotton in the farming conditions of Burkina ... This has led to experiment on Bt cotton from 2003 to 2007. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  17. Pollen diversity, viability and floral structure of some Musa genotypes

    African Journals Online (AJOL)

    Prof. Ogunji

    Pollen diversity, viability and floral structure of some Musa genotypes ... at the Faculty of Agriculture & Natural Resources Management farm, Ebonyi State University,. Abakaliki. ..... Roots, tuber, plantains and bananas in human nutrition. Rome,.

  18. Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor.

    Science.gov (United States)

    Dong, Shanshan; Liu, Yan; Yu, Cigang; Zhang, Zhenhua; Chen, Ming; Wang, Changyong

    2016-01-01

    Pollen-mediated gene flow (PMGF) is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV) as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow.

  19. Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor.

    Directory of Open Access Journals (Sweden)

    Shanshan Dong

    Full Text Available Pollen-mediated gene flow (PMGF is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow.

  20. Steam generator tube failures

    International Nuclear Information System (INIS)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  1. Pollen analysis of geopropolis and propolis from stingless bees

    OpenAIRE

    Freitas, Alex Da Silva; Vit Olivier, Patricia; Barth Ortrud, Monika

    2013-01-01

    The present study aims to review palynological analysis of geopropolis and propolis obtained from stingless bees in South America. Such studies are scarce and most analyzed samples are from Brazil, with a few from Bolivia and Venezuela. High diversity in pollen types, along with plant tissue fragments, hyphae, fungal spores, and amorphous organic matter were found. Sand or clay were always present. Pollen analysis of geopropolis helps to characterize vegetation surrounding the collection site...

  2. Individual lifetime pollen and nectar foraging preferences in bumble bees

    Science.gov (United States)

    Hagbery, Jessica; Nieh, James C.

    2012-10-01

    Foraging specialization plays an important role in the ability of social insects to efficiently allocate labor. However, relatively little is known about the degree to which individual bumble bees specialize on collecting nectar or pollen, when such preferences manifest, and if individuals can alter their foraging preferences in response to changes in the colony workforce. Using Bombus impatiens, we monitored all foraging visits made by every bee in multiple colonies and showed that individual foragers exhibit consistent lifetime foraging preferences. Based upon the distribution of foraging preferences, we defined three forager types (pollen specialists, nectar specialists, and generalists). In unmanipulated colonies, 16-36 % of individuals specialized (≥90 % of visits) on nectar or pollen only. On its first day of foraging, an individual's foraging choices (nectar only, pollen only, or nectar and pollen) significantly predicted its lifetime foraging preferences. Foragers that only collected pollen on their first day of foraging made 1.61- to 1.67-fold more lifetime pollen foraging visits (as a proportion of total trips) than foragers that only collected nectar on their first foraging day. Foragers were significantly larger than bees that stayed only in the nest. We also determined the effect of removing pollen specialists at early (brood present) or later (brood absent) stages in colony life. These results suggest that generalists can alter their foraging preferences in response to the loss of a small subset of foragers. Thus, bumble bees exhibit individual lifetime foraging preferences that are established early in life, but generalists may be able to adapt to colony needs.

  3. Effect of gamma-radiation on grapevine pollen

    International Nuclear Information System (INIS)

    Bozhinova-Boneva, I.

    1974-01-01

    A test was performed in 1968-1971. Pollen of the Bolgar and Muscat of Hamburg varieties was irradiated with doses of 0.5, 1.0, 1.5, 10, 20, 30, 40 and 60 kR. Variously treated pollen was used for pollinating 10-20 catkins of Chaoush variety. The viability of treated pollen was checked on 1% agarmedium at 25 0 C. Low doses of 0.5 and 1.0 kR have exerted a stimulant effect on the pollen sprouting. A dose of 60 kR did not bring about full loss of pollen viability. As the dose increased the number of hybrid seeds produced declined. The Chaoush x Bolgar cross as a control yielded 459 seeds; 580 from 0.5 kR-treated pollen; 530 from 1.0 kR-treated pollen; 324 from 1.5 kR-; 287 from 7 kR-; 202 from 10 kR-; 96 from 20 kR-; 46 from 30 kR-; 19 from 40 kR- and no seeds from 60 kR-treated pollen were obtained. A similar picture was obtained for the other cross. The Chaoush x Bolgar cross produced the following number of hybrid seeds: control - 13; 0.5 kR - 16; 1.0kR - 14; 5 kR - 14; 7 kR - 10; 10 kR - 6 seeds and from over 20 kR - nil

  4. Pollen analysis of honey and beebread derived from Brazilian mangroves

    OpenAIRE

    Luz, Cynthia Fernandes Pinto da; Barth, Ortrud Monika

    2012-01-01

    Pollen analyses were performed on honey and beebread from hives in apiaries located in two distinct mangrove areas dominated by Laguncularia racemosa (L.) C.F. Gaernt. One apiary was located at the edge of Guanabara Bay, Rio de Janeiro State, and the other near Maranguá Bay, Bahia State, Brazil. We investigated the contribution of nectar and pollen from mangrove vegetation to Apis mellifera L. honey and beebread stocks. Intensive visitation to this plant species by honeybees and the presence ...

  5. Isolation of allergenically active glycoprotein from Prosopis juliflora pollen.

    Science.gov (United States)

    Thakur, I S

    1989-03-01

    An allergenically active glycoprotein was homogeneously isolated from the aqueous extract of Prosopis juliflora pollen by ConA-Sepharose affinity chromatography. The molecular weight of this glycoprotein was 20,000 dalton, determined by gel filtration and SDS-PAGE. This fraction showed a total carbohydrate concentration of 25%. The purified glycoprotein revealed immunochemically most antigenic or allergenic and demonstrated homogeneous after reaction with P. juliflora pollen antiserum, characterized by gel diffusion, Immunoelectrophoresis and Radioallergosorbent test.

  6. How far can we simplify in vitro diagnostics for grass pollen allergy?: A study with 17 whole pollen extracts and purified natural and recombinant major allergens

    NARCIS (Netherlands)

    van Ree, R.; van Leeuwen, W. A.; Aalberse, R. C.

    1998-01-01

    BACKGROUND: Current diagnostics for grass pollen allergy are composed of mixtures of pollen of different grass species. Their complex composition hampers accurate standardization. OBJECTIVE: The aim of the study was to investigate whether mixtures of grass pollen extracts can be replaced by a single

  7. Method for shaping polyethylene tubing

    Science.gov (United States)

    Kramer, R. C.

    1981-01-01

    Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

  8. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

    Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

  9. Modelling past land use using archaeological and pollen data

    Science.gov (United States)

    Pirzamanbein, Behnaz; Lindström, johan; Poska, Anneli; Gaillard-Lemdahl, Marie-José

    2016-04-01

    Accurate maps of past land use are necessary for studying the impact of anthropogenic land-cover changes on climate and biodiversity. We develop a Bayesian hierarchical model to reconstruct the land use using Gaussian Markov random fields. The model uses two observations sets: 1) archaeological data, representing human settlements, urbanization and agricultural findings; and 2) pollen-based land estimates of the three land-cover types Coniferous forest, Broadleaved forest and Unforested/Open land. The pollen based estimates are obtained from the REVEALS model, based on pollen counts from lakes and bogs. Our developed model uses the sparse pollen-based estimations to reconstruct the spatial continuous cover of three land cover types. Using the open-land component and the archaeological data, the extent of land-use is reconstructed. The model is applied on three time periods - centred around 1900 CE, 1000 and, 4000 BCE over Sweden for which both pollen-based estimates and archaeological data are available. To estimate the model parameters and land use, a block updated Markov chain Monte Carlo (MCMC) algorithm is applied. Using the MCMC posterior samples uncertainties in land-use predictions are computed. Due to lack of good historic land use data, model results are evaluated by cross-validation. Keywords. Spatial reconstruction, Gaussian Markov random field, Fossil pollen records, Archaeological data, Human land-use, Prediction uncertainty

  10. Physicochemical characteristics of pollen collected by Amazonian stingless bees

    Directory of Open Access Journals (Sweden)

    Kemilla Sarmento Rebelo

    2016-05-01

    Full Text Available ABSTRACT: The purpose of this study was to determine the physicochemical characteristics of pollen collected by the Amazonian stingless bees Melipona seminigra and Melipona interrupta , in order to verify whether their characteristics meet the physicochemical requirements established by the Brazilian Technical Regulation for Identity and Quality of Bee Pollen. Physicochemical analyses were performed through official analytical methods. Results of pollen analyses collected by M. seminigra and M. interrupta were respectively as follows: moisture: 53.39 and 37.12%; protein: 37.63 and 24.00%; lipids: 10.81 and 6.47%; ash: 4.03 and 2.74%; crude fiber: 9.30 and 13.65%; carbohydrates: 25.66 and 44.27%; energy: 350.47 and 331.33kcal%; pH: 3.70 and 3.34; total solids: 46.60 and 62.87%, and water activity: 0.91 and 0.85. The percentages of moisture and pH in pollen collected by both studied bees are not in agreement with the Technical Regulation for bee pollen. Since some characteristics, which are inherent to the Melipona pollen, were not in conform to the current Regulation, we recommend that further studies should be conducted to better characterize it, and correct the Regulation, if necessary.

  11. Allergenic pollen in the subdesert areas of the Iberian peninsula.

    Science.gov (United States)

    Cariñanos, P; Galán, C; Alcázar, P; Domínguez, E

    2000-01-01

    The yearly distribution of Artemisia and Chenopodiaceae-Amaranthaceae, two of the most common types of pollen in a rural area located in the southeastern part of the Iberian peninsula, was studied over a 3-year period (1995-1997). The particular bioclimatic conditions of the area, such as its subdesert climate, extreme dryness and high mountain location (1,000 m above sea level), have led to the adaptation and abundance of these species in this area. They usually flower in the second half of the year, and are the main pollen types collected in the samples in that time period. The Artemisia pollen levels recorded are the highest in Spain, since there are several species in the area which flower at different times. Chenopodiaceae-Amaranthaceae pollen counts are also very high. The severity of both pollen types was also analyzed. The height of the sampler was taken into account because the quantities at human height can be considerably higher than those recorded at 20 m off the ground. It was concluded that both pollen types should be considered some of the main causes of allergy in this area.

  12. Nursing protects honeybee larvae from secondary metabolites of pollen.

    Science.gov (United States)

    Lucchetti, Matteo A; Kilchenmann, Verena; Glauser, Gaetan; Praz, Christophe; Kast, Christina

    2018-03-28

    The pollen of many plants contains toxic secondary compounds, sometimes in concentrations higher than those found in the flowers or leaves. The ecological significance of these compounds remains unclear, and their impact on bees is largely unexplored. Here, we studied the impact of pyrrolizidine alkaloids (PAs) found in the pollen of Echium vulgare on honeybee adults and larvae. Echimidine, a PA present in E. vulgare pollen, was isolated and added to the honeybee diets in order to perform toxicity bioassays. While adult bees showed relatively high tolerance to PAs, larvae were much more sensitive. In contrast to other bees, the honeybee larval diet typically contains only traces of pollen and consists predominantly of hypopharyngeal and mandibular secretions produced by nurse bees, which feed on large quantities of pollen-containing bee bread. We quantified the transfer of PAs to nursing secretions produced by bees that had previously consumed bee bread supplemented with PAs. The PA concentration in these secretions was reduced by three orders of magnitude as compared to the PA content in the nurse diet and was well below the toxicity threshold for larvae. Our results suggest that larval nursing protects honeybee larvae from the toxic effect of secondary metabolites of pollen. © 2018 The Authors.

  13. Nursing protects honeybee larvae from secondary metabolites of pollen

    Science.gov (United States)

    Lucchetti, Matteo A.; Kilchenmann, Verena; Glauser, Gaetan; Praz, Christophe

    2018-01-01

    The pollen of many plants contains toxic secondary compounds, sometimes in concentrations higher than those found in the flowers or leaves. The ecological significance of these compounds remains unclear, and their impact on bees is largely unexplored. Here, we studied the impact of pyrrolizidine alkaloids (PAs) found in the pollen of Echium vulgare on honeybee adults and larvae. Echimidine, a PA present in E. vulgare pollen, was isolated and added to the honeybee diets in order to perform toxicity bioassays. While adult bees showed relatively high tolerance to PAs, larvae were much more sensitive. In contrast to other bees, the honeybee larval diet typically contains only traces of pollen and consists predominantly of hypopharyngeal and mandibular secretions produced by nurse bees, which feed on large quantities of pollen-containing bee bread. We quantified the transfer of PAs to nursing secretions produced by bees that had previously consumed bee bread supplemented with PAs. The PA concentration in these secretions was reduced by three orders of magnitude as compared to the PA content in the nurse diet and was well below the toxicity threshold for larvae. Our results suggest that larval nursing protects honeybee larvae from the toxic effect of secondary metabolites of pollen. PMID:29563265

  14. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  15. Efficacy of recombinant birch pollen vaccine for the treatment of birch-allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Pauli, Gabrielle; Larsen, Tina H; Rak, Sabina

    2008-01-01

    BACKGROUND: Recombinant DNA technology has the potential to produce allergen-specific immunotherapy vaccines with defined composition. OBJECTIVE: To evaluate the effectiveness of a new recombinant birch pollen allergen vaccine in patients with birch pollen allergy. METHODS: A multicenter, randomi......-treated group. CONCLUSION: The rBet v 1-based vaccine was safe and effective in treating birch pollen allergy, and induced a highly specific immune response.......BACKGROUND: Recombinant DNA technology has the potential to produce allergen-specific immunotherapy vaccines with defined composition. OBJECTIVE: To evaluate the effectiveness of a new recombinant birch pollen allergen vaccine in patients with birch pollen allergy. METHODS: A multicenter......, randomized, double-blind, placebo-controlled trial was undertaken to compare the following 3 vaccines in 134 adults with birch pollen allergy: recombinant birch pollen allergen vaccine (rBet v 1a), licensed birch pollen extract, natural purified birch pollen allergen (nBet v 1), and placebo. Patients...

  16. Viable suspensions of maize (Zea mays L.) pollen with exogenous DNA

    Energy Technology Data Exchange (ETDEWEB)

    Broglia, M. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Innovazione

    1996-12-01

    A viable suspension of maize pollen in aqueous medium containing exogenous DNA would be a suitable tool in attempting maize genetic transformation via pollen grains by different techniques. In this work the effects of addition of DNA to hypertonic aqueous media able to preserve maize pollen viability were investigated. An almost total loss of viability was found when pollen was incubated with native DNA in water or sucrose medium due to the immediate sticking of DNA on the pollen wall. Calcium in the incubation medium avoided DNA sticking preserving pollen fertilization ability. Pre-washing of pollen in hypertonic sucrose solution was proved to remove DNA binding components from the pollen wall. PEG 20%, that is known to inhibit pollen, and silk nucleases, was also used instead of sucrose, without any reduction in the seed-set yields.

  17. Determination of pollen quality and quantity in mulberry (morus alba l.)

    International Nuclear Information System (INIS)

    Erdogan, U.

    2015-01-01

    In this study, the pollen grains of eight different mulberry types in I.spir and Pazaryolu districts of Erzurum were tested for the determination of viability, germination rates, pollen production levels and morphologically homogeneity. Viability of the pollens was determined by TTC (2, 3, 5-triphenly tetrazolium chlorid) and IKI (iodine + potassium iodide) tests. Pollen germination experiments were performed with Agar-plate (1%) method in sucrose solutions of 0, 5, 10, 15, 20 and 25% concentrations. In addition, pollen production and morphologically homogeneity were determined by the Hemacytometric method. The pollen viability of all types used in this study was obtained in high ratios. Pollen germination rates were the highest for 15% and 20% sucrose solutions. The highest pollen production level was obtained from the genotype 6. The morphologically homogeneity levels of pollens changed from 97.36 to 98.86% in types. (author)

  18. A Taxonomic Reduced-Space Pollen Model for Paleoclimate Reconstruction

    Science.gov (United States)

    Wahl, E. R.; Schoelzel, C.

    2010-12-01

    Paleoenvironmental reconstruction from fossil pollen often attempts to take advantage of the rich taxonomic diversity in such data. Here, a taxonomically "reduced-space" reconstruction model is explored that would be parsimonious in introducing parameters needing to be estimated within a Bayesian Hierarchical Modeling context. This work involves a refinement of the traditional pollen ratio method. This method is useful when one (or a few) dominant pollen type(s) in a region have a strong positive correlation with a climate variable of interest and another (or a few) dominant pollen type(s) have a strong negative correlation. When, e.g., counts of pollen taxa a and b (r >0) are combined with pollen types c and d (r logistic generalized linear model (GLM). The GLM can readily model this relationship in the forward form, pollen = g(climate), which is more physically realistic than inverse models often used in paleoclimate reconstruction [climate = f(pollen)]. The specification of the model is: rnum Bin(n,p), where E(r|T) = p = exp(η)/[1+exp(η)], and η = α + β(T); r is the pollen ratio formed as above, rnum is the ratio numerator, n is the ratio denominator (i.e., the sum of pollen counts), the denominator-specific count is (n - rnum), and T is the temperature at each site corresponding to a specific value of r. Ecological and empirical screening identified the model (Spruce+Birch) / (Spruce+Birch+Oak+Hickory) for use in temperate eastern N. America. α and β were estimated using both "traditional" and Bayesian GLM algorithms (in R). Although it includes only four pollen types, the ratio model yields more explained variation ( 80%) in the pollen-temperature relationship of the study region than a 64-taxon modern analog technique (MAT). Thus, the new pollen ratio method represents an information-rich, reduced space data model that can be efficiently employed in a BHM framework. The ratio model can directly reconstruct past temperature by solving the GLM equations

  19. First report of modern pollen deposition in moss polsters in a semiarid area of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Daiane Alves dos Santos

    2015-12-01

    Full Text Available Recent studies have shown that pollen analyses of natural substrates can produce data valuable for understanding the local pollen productivity and dispersal, deposition, and preservation potential of pollen grains. In this study, we aimed to acquire novel information about the dynamics and preservation of pollen in Caatinga environment through the palynological study of moss polsters. Samples of moss polsters in soil (MPS and on rock (MPR were collected from the Canudos Biological Station in the Bahia State (Brazil and subjected to standard chemical treatments for the extraction of pollen residues. In total, 372 pollen types were recorded from the samples of which the taxonomical affinity of 140 was determined. The most represented families were Fabaceae (23 pollen types/16.42% and Asteraceae (12 pollen types/8.57%. The MPS samples had a higher pollen concentration (21,042.04 pollen grains/cm² than the MPR samples (7,829.35 pollen grains/cm². On the other hand, the MPR samples had a greater diversity (68.26% of the identified pollen types. Qualitative analysis showed that the plants of shrub and subshrub habits had the greatest representation among the pollen types (35.0%. Overall, moss polsters proved to be excellent natural air pollen collectors in Caatinga environment, provided they had moist microhabitats for their development.

  20. Sucrose Synthase Is Associated with the Cell Wall of Tobacco Pollen Tubes

    NARCIS (Netherlands)

    Persia, D.; Cai, G.; Casino, C.; Willemse, M.T.M.; Cresti, M.

    2008-01-01

    Sucrose synthase (Sus; EC 2.4.1.13) is a key enzyme of sucrose metabolism in plant cells, providing carbon for respiration and for the synthesis of cell wall polymers and starch. Since Sus is important for plant cell growth, insights into its structure, localization, and features are useful for

  1. Flavonols and fertilization in Petunia hybrida: localization and mode of action during pollen tube growth

    NARCIS (Netherlands)

    Ylstra, B.; Busscher, J.; Franken, J.; Hollman, P.C.H.; Mol, J.N.M.; Tunen, van A.J.

    1995-01-01

    Flavonols form an important class of flavonoids which serve an essential function during plant reproduction. Flavonoid biosynthesis is initiated by the enzyme chalcone synthase (CHS). A high abundance of flavonols and chs mRNA was demonstrated in male and female reproductive organs of Petunia

  2. Analysis of exocyst subunit EXO70 family reveals distinct membrane polar domains in Tobacco pollen tubes

    Czech Academy of Sciences Publication Activity Database

    Sekereš, Juraj; Pejchar, Přemysl; Šantrůček, J.; Vukašinović, Nemanja; Žárský, Viktor; Potocký, Martin

    2017-01-01

    Roč. 173, č. 3 (2017), s. 1659-1675 ISSN 0032-0889 R&D Projects: GA ČR GA13-19073S; GA ČR GA15-24711S Grant - others:OPPK(XE) CZ.2.16/3.1.00/21519 Institutional support: RVO:61389030 Keywords : PLASMA-MEMBRANE * ARABIDOPSIS-THALIANA * CELL-MIGRATION Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 6.456, year: 2016

  3. Exocyst SEC3 and Phosphoinositides Define Sites of Exocytosis in Pollen Tube Initiation and Growth

    Czech Academy of Sciences Publication Activity Database

    Bloch, D.; Pleskot, Roman; Pejchar, Přemysl; Potocký, Martin; Trpkošová, Pavlína; Cwiklik, Lukasz; Vukašinović, Nemanja; Sternberg, H.; Yalovsky, S.; Žárský, Viktor

    2016-01-01

    Roč. 172, č. 2 (2016), s. 980-1002 ISSN 0032-0889 R&D Projects: GA ČR GA13-19073S Institutional support: RVO:61389030 ; RVO:61388955 Keywords : polar cell-growth * arabidopsis-thaliana * plasma-membrane * vesicle trafficking * affects endocytosis * subunit sec3 * force-field * tip growth * complex * tobacco Subject RIV: EB - Genetics ; Molecular Biology; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 6.456, year: 2016

  4. Identification of IgE- binding pollen protein from Cannabis sativa in pollen-hypersensitive patients from north Pakistan.

    Science.gov (United States)

    Choudhary, Shazia; Murad, Sheeba; Hayat, Muhammad Qasim; Shakoor, Zahid; Arshad, Muhammad

    2017-01-01

    Cannabis sativa (C.sativa) is well-known for its medicinal, industrial and recreational use. However, allergies in relation to Cannabis sativa (C.sativa) are rarely reported. C. sativa is one of the common weeds found in Pakistan and its pollen grains are common in spring and fall season. Although categorized as an aeroallergen, there are limited number of reports regarding allergenic potential in C. sativa. Therefore, the current study is aimed at exploring the IgE- binding potential among the C. sativa pollen in local pollen allergic patients. Initial screening of C. sativa sensitized individuals was carried out by dot blot from the sera of pollen allergic patients. Proteins from the pollen grains were extracted and resolved on 10% gel. Eight bands were visible on gel however only one protein fragment i.e. of 14KDa size was found to bind to IgE as analyzed through protein gel blot analysis. Strong IgE affinity of a 14 kDa protein fragment from C. sativa pollen extract suggests its allergenic potential. Further study is required to find the exact nature of this protein fragment.

  5. Calcium in pollen-pistil interaction in Petunia hybrida Hort. I. Localization of Ca2+ ions in mature pollen grain using pyroantimonate and autoradiographic methods.

    Science.gov (United States)

    Bednarska, E; Butowt, R

    1994-01-01

    The localization of Ca2+ in the mature pollen grain and the flow of these ions from the somatic tissues of the anther to the pollen grains has been studied using pyroantimonate and autoradiographic methods. In the pollen grain, Ca2+ ions have been localized in the sporoderm and in the cytoplasmic vesicles of probably dictyosomal origin. Calcium ions were transported into the sporoderm together with the compounds of degenerating tapetum. The material of degenerating tapetum forms pollen coat surrounding the mature pollen grain.

  6. Calcium in pollen-pistil interaction in 'Petunia hybrida Hor'. Pt. 1. Localization of Ca2+ ions in mature pollen grain using pyroantimonate and autoradiographic methods

    International Nuclear Information System (INIS)

    Bednarska, E.; Butowt, R.

    1994-01-01

    The localization of Ca 2+ in the mature pollen grain and the flow of these ions the somatic tissues of the anther to the pollen grains has been studied using pyroantimonate and autoradiographic methods. In the pollen grain, Ca 2+ ions have been localized in the sporoderm in the cytoplasmic vesicles of probably dictyosomal origin. Calcium ions were transported into the sporoderm together with the compounds of degenerating tapetum. The material of degenerating tapetum forms pollen coat surrounding the mature pollen grains. (author). 18 refs, 9 figs

  7. Calcium in pollen-pistil interaction in `Petunia hybrida Hor`. Pt. 1. Localization of Ca{sup 2+} ions in mature pollen grain using pyroantimonate and autoradiographic methods

    Energy Technology Data Exchange (ETDEWEB)

    Bednarska, E.; Butowt, R. [Uniwersytet Mikolaja Kopernika, Torun (Poland)

    1994-12-31

    The localization of Ca{sup 2+} in the mature pollen grain and the flow of these ions the somatic tissues of the anther to the pollen grains has been studied using pyroantimonate and autoradiographic methods. In the pollen grain, Ca{sup 2+} ions have been localized in the sporoderm in the cytoplasmic vesicles of probably dictyosomal origin. Calcium ions were transported into the sporoderm together with the compounds of degenerating tapetum. The material of degenerating tapetum forms pollen coat surrounding the mature pollen grains. (author). 18 refs, 9 figs.

  8. Effect of radiation on fruit pollen germination and distant hybridization compatibility

    International Nuclear Information System (INIS)

    Li Jing; Shang Xiaoli

    2006-01-01

    Pollens of Zhouxingshantao peach trees, apricot cultivar Katy and plum cultivar Friar were irradiated by different doses of 60 Co γ-rays and ultraviolet to study the radiation effect on the pollen germination and distant hybridization settings. The germination percentages of the pollen irradiated by 60 Co γ-rays and ultraviolet were lower than those of the controls. The pollens of the tested fruits have different sensitivities of 60 Co γ-rays and ultraviolet: the Friar pollen was the most sensitive to the radiation, and the Katy was the least. With the germinate percentages of the irradiated pollen dropping, the distant hybridization fruit setting percentage also lowered. (authors)

  9. Automation in tube finishing bay

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Satyadev, B.; Raghuraman, S.; Syama Sundara Rao, B.

    1997-01-01

    Automation concept in tube finishing bay, introduced after the final pass annealing of PHWR tubes resulted in integration of number of sub-systems in synchronisation with each other to produce final cut fuel tubes of specified length, tube finish etc. The tube finishing bay which was physically segregated into four distinct areas: 1. tube spreader and stacking area, 2. I.D. sand blasting area, 3. end conditioning, wad blowing, end capping and O.D. wet grinding area, 4. tube inspection, tube cutting and stacking area has been studied

  10. Current glimpse of airborne allergenic pollen in Indian subcontinent

    Directory of Open Access Journals (Sweden)

    Kavita Ghosal

    2015-12-01

    Full Text Available Respiratory allergic diseases such as bronchial asthma, rhinitis, urticaria, atopic dermatitis have been steadily increasing all over the world, including India. Owing to its alarming trend, several aerobiological surveys have been undertaken in different parts of India to delineate the variety of pollen and spore load. In this review, we have reported the current state of aerobiological knowladge in India with particular reference to allergenic airborn pollen occurence in 2001–2015. Pollen have been found to contribute a significant proportion in the air and caused allergy symptoms in the local inhabitants. Aerobiological records, a questionnaire survey and hospitalization records have been employed for the analysis. Holoptelea integrifolia, Amaranthus spinosus in northern region, Sorghum vulgare, Pennisetum, Gynandropsis gynandra, Parthenium hysterophorus, Dolichandrone platycalyx in southern regions, and Parthenium hysterophorus from the western region; Cynodon dactylon, Cenchrus ciliaris in the central area; Acacia auriculiformis, Cleome gynandra, Catharanthus roseus, Phoenix sylvestris, Areca catechu, and Lantana camara in the eastern regions as potential aeroallergens in India. The statistical approach confirmed the correlation between hospitalization rate associated with allergy-related health troubles and the prevalent allergenic pollen in the air. The Poaceae group has been found to be dominant throughout India. Immuno-biochemical studies identified various protein with allergenic potential found in the pollen recorded. Epitope identification and homology of the major allergenic protein Cat r1 of Catharanthus sp and Par j 1 of Parietaria judaica have been found. Identification of allergenic pollen grains and the modern approach concerning cross-reactivity and epitope revelation of dominant airborne pollen have important clinical implications for the prevention, diagnosis and treatments of allergic diseases in India.

  11. Characterizing aeroallergens by infrared spectroscopy of fungal spores and pollen.

    Directory of Open Access Journals (Sweden)

    Boris Zimmermann

    Full Text Available Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens.The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR. The experimental set includes 71 spore (Basidiomycota and 121 pollen (Pinales, Fagales and Poales samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years.The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps.

  12. Trends in airborne pollen and pollen-season-related features of anemophilous species in Jaen (south Spain): A 23-year perspective

    Science.gov (United States)

    Ruiz-Valenzuela, Luis; Aguilera, Fátima

    2018-05-01

    Over the last few decades, global warming is prompting phenological changes in numerous plant species across Europe, and a trend towards rising airborne pollen concentrations has been detected. This study, focused on the most frequent pollen types from arboreal and herbaceous species in the airborne spectrum of Jaen (southern Spain), revealed significant changes in airborne pollen intensity and duration of the pollen season over the 23-year study period. Here Cupressaceae, Olea, Pinus, Platanus, Quercus as arboreal taxa and Plantago as herbaceous taxa were the most important with notable changes of at least three pollen season characteristics. Airborne pollen trends from arboreal taxa with high to very high allergenic potential are rising in line with the local temperature increasing trend, and their pollen seasons tend to end later and last longer. However, both the pollen concentrations and the duration of the pollen season of some herbaceous taxa are declining. The climate conditions projected for south Europe under different greenhouse emissions scenarios could continue to prompt greater pollen release and longer pollen season in tree species, especially those that flowering in winter and early spring, but these warming trends might be adverse for the local development of some herbaceous species and favorable for others sharing the same ecological niche. If similar warming trends accompany long-term climate change, greater exposure times to seasonal allergens may occur with subsequent effects on health.

  13. Use of MODIS Satellite Data to Evaluate Juniperus spp. Pollen Phenology to Support a Pollen Dispersal Model, PREAM, to Support Public Health Allergy Alerts

    Science.gov (United States)

    Luvall, J. C.; Sprigg, W. A.; Levetin, E.; Huete, A.; Nickovic, S.; Prasad, A.; Pejanovic, G. A.; Vukovic, A.; VandeWater, P. K.; Budge, A. M.; hide

    2013-01-01

    Pollen can be transported great distances. Van de Water et. al., 2003 reported Juniperus spp. pollen was transported 200-600 km. Hence local observations of plant phenology may not be consistent with the timing and source of pollen collected by pollen sampling instruments. The DREAM (Dust REgional Atmospheric Model) is a verified model for atmospheric dust transport modeling using MODIS data products to identify source regions and concentrations of dust. We are modifying the DREAM model to incorporate pollen transport. Pollen emission is based on MODIS-derived phenology of Juniperus spp. communities. Ground-based observational records of pollen release timing and quantities will be used as model verification. This information will be used to support the Centers for Disease Control and Prevention s National Environmental Public Health Tracking Program and the State of New Mexico environmental public health decision support for asthma and allergies alerts

  14. Use of MODIS Satellite Data to Evaluate Juniperus spp. Pollen Phenology to Support a Pollen Dispersal Model, PREAM, to Support Public Health Allergy Alerts

    Science.gov (United States)

    Luvall, J. C.; Sprigg, W. A.; Levetin, E.; Huete, A. R.; Nickovic, S.; Prasad, A. K.; Pejanovic, G.; Vukovic, A.; Van De Water, P. K.; Budge, A.; Hudspeth, W. B.; Krapfl, H.; Toth, B.; Zelicoff, A.; Myers, O.; Bunderson, L.; Ponce-Campos, G.; Menache, M.; Crimmins, T. M.; Vujadinovic, M.

    2012-12-01

    Pollen can be transported great distances. Van de Water et. al., 2003 reported Juniperus spp. pollen was transported 200-600 km. Hence local observations of plant phenology may not be consistent with the timing and source of pollen collected by pollen sampling instruments. The DREAM (Dust REgional Atmospheric Model, Nickovic et al. 2001) is a verified model for atmospheric dust transport modeling using MODIS data products to identify source regions and concentrations of dust. We are modifying the DREAM model to incorporate pollen transport. Pollen emission is based on MODIS-derived phenology of Juniperus spp. communities. Ground-based observational records of pollen release timing and quantities will be used as model verification. This information will be used to support the Centers for Disease Control and Prevention's National Environmental Public Health Tracking Program and the State of New Mexico environmental public health decision support for asthma and allergies alerts.

  15. Long-term storage method for soft X-ray irradiated 'Hyuganatsu' pollen

    International Nuclear Information System (INIS)

    Yano, S.; Tanaka, M.; Ohara, N.

    2008-01-01

    The long-term storage conditions for 'Hyuganatsu ' pollen that had been irradiated with soft X-rays was examined. This study, was aimed at production of 'Tosa-buntan' without formation of nuclear fruit. 1. We evaluated the germination rate of pollen that had been irradiated with soft X-ray (500 or 1,000 Gy) and stored at 3 deg C, -20 deg C, and -40 deg C. The germination rate was the same as that of unirradiated pollen, even after storage for 1 year. Soft X-ray irradiation did not influence the storage attributes of pollen. 2. In unirradiated pollen and pollen that had been irradiated with soft X-ray (500 or 1,000 Gy), temperature conditions necessary for storing from 3 months to 1 year were -20 deg C or less, and pollen stored at -40 deg C had a higher germination rate after 1 year. 3. The germination rate was 1% or less in 4 months if silica gel was sealed into a gas barrier bag with 1,000 Gy-irradiated pollen at a rate of 10:1 (w/w). The ability to germinate was completely lost after 1 year in these conditions. 4. We evaluated the effect of sealing methods on 1,000 Gy-irradiated pollen stored at -20 deg C. There was no difference in germination rates among pollen stored in gas-barrier bags, vacuum-packaged pollen, and pollen stored with nitrogen in gas-barrier bags. Moreover, the germination rate of 750 Gy-irradiated pollen stored at -20 deg C decreased from 3 months onwards when pollen was stored with a free-oxygen absorber (Ageless ZP). 5. Pollen that was treated with acetone before or after soft X-ray irradiation (750 Gy) withstood long-term storage of 1 year. Long-term storage was possible if pollen was stored at -20 deg C, as is the case for rough pollen

  16. Divergent rules for pollen and nectar foraging bumblebees--a laboratory study with artificial flowers offering diluted nectar substitute and pollen surrogate.

    Directory of Open Access Journals (Sweden)

    Sabine Konzmann

    Full Text Available Almost all bees collect nectar and pollen from flowers. Female bees collect pollen to provision their nest cells, whereas they use nectar for individual energy supply and nest cell provisioning. Bees fine-tune nectar foraging to the amount and to the concentration of nectar, but the individual bees' response to variability of amount and concentration of pollen reward has not yet been studied thoroughly in laboratory settings. We developed an experimental set-up in which bumblebees simultaneously collected sugar solution and pollen from artificial flowers; natural pollen was mixed with cellulose powder or glass powder as a pollen surrogate. Here we show that bumblebee (Bombus terrestris workers do not specialise in nectar or pollen collection, but regularly collect both rewards on the same day. When offered a fixed pollen reward and varied amounts and concentrations of sugar solution, the bumblebees fine-tuned sugar solution foraging dependent on both the volume and concentration, with strong preferences for the highest concentration and the greatest volume. In the reciprocal tests, when offered a fixed sugar reward and varied amounts and concentrations of pollen mixed with a nutrient-free pollen surrogate, the bumblebees follow more an all-or-none rule for pollen, accepting all amounts and concentrations except pure surrogate. It is discussed how the bumblebees' ability to sense sugar, and their apparent inability to sense the pollen protein content, shaped their foraging behaviour. It is argued that the rarity of nectar mimicry and the frequency of pollen mimicry in natural flowers might be interpreted in the context of divergent abilities of nectar and pollen recognition in bees.

  17. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  18. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1982-04-01

    The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. The number of failed tubes was also lower, 0.14% of the tubes in service in 1980 compared with 0.20% of those in service in 1979. Analysis of the causes of these failures indicates that stress corrosion cracking was the leading failure mechanism. Reactors that used all-volatile treatment of secondary water, with or without full-flow condensate demineralization since start-up showed the lowest incidence of corrosion-related defects

  19. X-ray tube

    International Nuclear Information System (INIS)

    Webley, R.S.

    1975-01-01

    The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

  20. Fuel assembly guide tube

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1979-01-01

    This invention is directed toward a nuclear fuel assembly guide tube arrangement which restrains spacer grid movement due to coolant flow and which offers secondary means for supporting a fuel assembly during handling and transfer operations

  1. Bull Moose Tube Company

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against the Bull Moose Tube Company, a business located at 1819 Clarkson Road, Chesterfield, MO, 63017, for alleged violations at the facility located at 406 East Industrial Drive,

  2. Tracheostomy tube - eating

    Science.gov (United States)

    Trach - eating ... take your first bites. Certain factors may make eating or swallowing harder, such as: Changes in the ... easier to swallow. Suction the tracheostomy tube before eating. This will keep you from coughing while eating, ...

  3. Streak tube development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of a high-speed, high-resolution streak image tube is described. This is one task in the development of a streak camera system with digital electronic readout, whose primary application is for diagnostics in underground nuclear testing. This program is concerned with the development of a high-resolution streak image tube compatible with x-ray input and electronic digital output. The tube must be capable of time resolution down to 100 psec and spatial resolution to provide greater than 1000 resolution elements across the cathode (much greater than presently available). Another objective is to develop the capability to make design changes in tube configurations to meet different experimental requirements. A demountable prototype streak tube was constructed, mounted on an optical bench, and placed in a vacuum system. Initial measurements of the tube resolution with an undeflected image show a resolution of 32 line pairs per millimeter over a cathode diameter of one inch, which is consistent with the predictions of the computer simulations. With the initial set of unoptmized deflection plates, the resolution pattern appeared to remain unchanged for static deflections of +- 1/2-inch, a total streak length of one inch, also consistent with the computer simulations. A passively mode-locked frequency-doubled dye laser is being developed as an ultraviolet pulsed light source to measure dynamic tube resolution during streaking. A sweep circuit to provide the deflection voltage in the prototype tube has been designed and constructed and provides a relatively linear ramp voltage with ramp durations adjustable between 10 and 1000 nsec

  4. Researching YouTube

    OpenAIRE

    Arthurs, Jane; Drakopoulou, Sophia; Gandini, Alessandro

    2018-01-01

    ‘Researching YouTube’ introduces the special issue of Convergence which arose out of an international academic conference on YouTube that was held in London at Middlesex University in September 2016. The conference aimed to generate a robust overview of YouTube’s changing character and significance after its first ten years of development by creating a productive dialogue between speakers from different disciplines and cultures, and between YouTube-specific research and wider debates in media...

  5. Tubing crimping pliers

    Science.gov (United States)

    Lindholm, G.T.

    1981-02-27

    The disclosure relates to pliers and more particularly to pliers for crimping two or more pieces of copper tubing together prior to their being permanently joined by brazing, soldering or the like. A die containing spring-loaded pins rotates within a cammed ring in the head of the pliers. As the die rotates, the pins force a crimp on tubing held within the pliers.

  6. Climate Change and Future Pollen Allergy in Europe.

    Science.gov (United States)

    Lake, Iain R; Jones, Natalia R; Agnew, Maureen; Goodess, Clare M; Giorgi, Filippo; Hamaoui-Laguel, Lynda; Semenov, Mikhail A; Solomon, Fabien; Storkey, Jonathan; Vautard, Robert; Epstein, Michelle M

    2017-03-01

    Globally, pollen allergy is a major public health problem, but a fundamental unknown is the likely impact of climate change. To our knowledge, this is the first study to quantify the consequences of climate change upon pollen allergy in humans. We produced quantitative estimates of the potential impact of climate change upon pollen allergy in humans, focusing upon common ragweed ( Ambrosia artemisiifolia ) in Europe. A process-based model estimated the change in ragweed's range under climate change. A second model simulated current and future ragweed pollen levels. These findings were translated into health burdens using a dose-response curve generated from a systematic review and from current and future population data. Models considered two different suites of regional climate/pollen models, two greenhouse gas emissions scenarios [Representative Concentration Pathways (RCPs) 4.5 and 8.5], and three different plant invasion scenarios. Our primary estimates indicated that sensitization to ragweed will more than double in Europe, from 33 to 77 million people, by 2041-2060. According to our projections, sensitization will increase in countries with an existing ragweed problem (e.g., Hungary, the Balkans), but the greatest proportional increases will occur where sensitization is uncommon (e.g., Germany, Poland, France). Higher pollen concentrations and a longer pollen season may also increase the severity of symptoms. Our model projections were driven predominantly by changes in climate (66%) but were also influenced by current trends in the spread of this invasive plant species. Assumptions about the rate at which ragweed spreads throughout Europe had a large influence upon the results. Our quantitative estimates indicate that ragweed pollen allergy will become a common health problem across Europe, expanding into areas where it is currently uncommon. Control of ragweed spread may be an important adaptation strategy in response to climate change. Citation: Lake IR

  7. An experimental test of whether habitat corridors affect pollen transfer.

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Patricia A.; Levey, Douglas J.

    2005-02-01

    Abstract. Negative effects of habitat fragmentation are thought to be diminished when habitat patches are joined by a corridor. A key assumption is that corridors facilitate exchange rates of organisms between otherwise isolated patches. If the organisms are pollinators, corridors may be important for maintaining genetically viable populations of the plants that they pollinate. We tested the hypothesis that corridors increase the movement of insect pollinators into patches of habitat and thereby increase pollen transfer for two species of plants, one pollinated by butterflies (Lantana camara) and the other by bees and wasps (Rudbeckia hirta). We worked in an experimental landscape consisting of 40 greater than or equal to 1-ha patches of early-successional habitat in a matrix of forest. Within each of eight experimental units, two patches were connected by a corridor (150 X 25 m), and three were not. Patch shape varied to control for the area added by the presence of a corridor. Differences in patch shape also allowed us to test alternative hypotheses of how corridors might function. The Traditional Corridor Hypothesis posits that corridors increase immigration and emigration by functioning as movement conduits between patches. The Drift Fence Hypothesis posits that corridors function by ‘‘capturing’’ organisms dispersing through the matrix, redirecting them into associated habitat patches. Using fluorescent powder to track pollen, we found that pollen transfer by butterflies between patches connected by a corridor was significantly higher than between unconnected patches (all values mean plus or minus 1 SE: 59% plus or minus 9.2% vs. 25% plus or minus 5.2% of flowers receiving pollen). Likewise, pollen transfer by bees and wasps was significantly higher between connected patches than between unconnected patches (30% plus or minus 4.2% vs. 14.5% plus or minus 2.2%). These results support the Traditional Corridor Hypothesis. There was little support, however

  8. Dose-response relationship of a new Timothy grass pollen allergoid in comparison with a 6-grass pollen allergoid.

    Science.gov (United States)

    Pfaar, O; Hohlfeld, J M; Al-Kadah, B; Hauswald, B; Homey, B; Hunzelmann, N; Schliemann, S; Velling, P; Worm, M; Klimek, L

    2017-11-01

    Subcutaneous allergen immunotherapy with grass pollen allergoids has been proven to be effective and safe in the treatment of patients with allergic rhinoconjunctivitis. Based on the extensive cross-reactivity among Pooideae species, it has been suggested that grass pollen extracts could be prepared from a single species, rather than from a multiple species mixture. To find the optimal dose of a Phleum pratense (P. pratense) allergoid preparation and compare its efficacy and safety to a 6-grass pollen allergoid preparation. In this double-blind, placebo-controlled study (EudraCT: 2011-000674-58), three doses of P. pratense allergoid (1800 therapeutic units (TU), standard-dose 6000 TU and 18 000 TU) were compared with placebo and the marketed 6-grass pollen allergoid (6000 TU). In a pre-seasonal dosing regimen, 102 patients were randomized to five treatment groups and received nine subcutaneous injections. The primary efficacy endpoint was the change in weal size (late-phase reaction [LPR]) in response to the intracutaneous testing (ICT) before and after treatment, comparing the active allergoids to placebo. Secondary outcomes were the change in Total Nasal Symptom Score (TNSS) assessed in the allergen exposure chamber (AEC), the changes in P. pratense-serum-specific IgG 4 and the incidence of adverse events (AEs). All three doses of the P. pratense and the 6-grass pollen allergoid preparations were significantly superior to placebo for the primary outcome, whereas there were no significant differences in the change in TNSS. Compared to the standard-dose, the high-dose of P. pratense did not produce any additional significant benefit, but showed a slight increase in AEs. Yet this increase in AEs was lower than for the 6-grass pollen preparation. The standard-dose of the new P. pratense allergoid was comparable to the marketed 6-grass pollen preparation at equal dose for the parameters measured. © 2017 The Authors. Clinical & Experimental Allergy Published by John

  9. Pressure tube reactor

    International Nuclear Information System (INIS)

    Seki, Osamu; Kumasaka, Katsuyuki.

    1988-01-01

    Purpose: To remove the heat of reactor core using a great amount of moderators at the periphery of the reactor core as coolants. Constitution: Heat of a reactor core is removed by disposing a spontaneous recycling cooling device for cooling moderators in a moderator tank, without using additional power driven equipments. That is, a spontaneous recycling cooling device for cooling the moderators in the moderator tank is disposed. Further, the gap between the inner wall of a pressure tube guide pipe disposed through the vertical direction of a moderator tank and the outer wall of a pressure tube inserted through the guide pipe is made smaller than the rupture distortion caused by the thermal expansion upon overheating of the pressure tube and greater than the minimum gap required for heat shiels between the pressure tube and the pressure tube guide pipe during usual operation. In this way, even if such an accident as can not using a coolant cooling device comprising power driven equipment should occur in the pressure tube type reactor, the rise in the temperature of the reactor core can be retarded to obtain a margin with time. (Kamimura, M.)

  10. Pollen morphology of Rhizophora L. in Peninsular Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Mohd-Arrabe' , A. B.; Noraini, Talip Noraini [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2013-11-27

    Rhizophora L. are common mangrove genus in Peninsular Malaysia, it contains 3 species and 1 hybrid (R. apiculata Blume, R. mucronata Lam., R. stylosa Griff., R. x lamarckii Montrouz). This genus has some unique adaptation towards extreme environment. Rhizophora has looping aerial stilt-root and uniformly viviparous. The aim of this study is to investigate the variation in the pollen morphology of Rhizophora that can be related to their habitat. Methods include in this study is pollen observation under light and acetolysis method under scanning electron microscope. Pollen type of Rhizophora species studied except hybrid species is classified tricolporate, shape spheroidal based on ratio of length polar axis/ length of equatorial axis (1.03 - 1.09). The exine ornamentation is perforate-reticulate for R. apiculata and R. mucronata, while R. stylosa is perforate. For the only hybrid in Peninsular Malaysia, R. x lamarckii (R. apiculata x R. stylosa) differs from others, tricolpate with the absence of porate, shape is subprolate and exine ornamentation is reticulate and striate in equatorial region. Pollenkitt is present due to the salty and extreme environment. This may enhance the volume of pollenkitt present surrounding the pollen grains in Rhizophora for protection and adaptation purposes. Based on these findings, it is evident that pollen morphology is somehow related to its natural habitat.

  11. Induced sterility in petunia correlation between pollen and ovule fertilities

    International Nuclear Information System (INIS)

    Singh, I.S.

    1976-01-01

    An estimation of ovular fertility in petunia was carried out in order to show an eventual correlation between pollen and ovule fertilities. Two lines, TL-h 1 and Sf-1a, their F 1 hybrid and some pollen sterile plants isolated in M 1 after mutagenic treatments were vegetatively maintained in greenhouse. Data pollen fertility, number of ovules per ovary and number of seeds per capsule were obtained from each genotype. The ovule fertility was calculated as follows: mean number of seeds per capsule/mean number of ovules per ovary x 100. The analysis of variance detected: a highly significance variance component among genotypes, a highly significant differences between the sexes, and, a highly significant genotypes x sexes interaction. A highly significant positive correlation coefficient was found between pollen and ovule fertilities. Thus, it can be concluded that pollen and ovule fertilities may be affected in the same direction in the different mutant clones studied, but in a different manner from genotype to genotype [fr

  12. Urticaceae pollen concentration in the atmosphere of North Western Spain.

    Science.gov (United States)

    Vega-Maray, Ana Maria; Valencia-Barrera, Rosa; Fernandez-Gonzalez, Delia; Fraile, Roberto

    2003-01-01

    Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.

  13. Biometeorological and autoregressive indices for predicting olive pollen intensity.

    Science.gov (United States)

    Oteros, J; García-Mozo, H; Hervás, C; Galán, C

    2013-03-01

    This paper reports on modelling to predict airborne olive pollen season severity, expressed as a pollen index (PI), in Córdoba province (southern Spain) several weeks prior to the pollen season start. Using a 29-year database (1982-2010), a multivariate regression model based on five indices-the index-based model-was built to enhance the efficacy of prediction models. Four of the indices used were biometeorological indices: thermal index, pre-flowering hydric index, dormancy hydric index and summer index; the fifth was an autoregressive cyclicity index based on pollen data from previous years. The extreme weather events characteristic of the Mediterranean climate were also taken into account by applying different adjustment criteria. The results obtained with this model were compared with those yielded by a traditional meteorological-based model built using multivariate regression analysis of simple meteorological-related variables. The performance of the models (confidence intervals, significance levels and standard errors) was compared, and they were also validated using the bootstrap method. The index-based model built on biometeorological and cyclicity indices was found to perform better for olive pollen forecasting purposes than the traditional meteorological-based model.

  14. Commercial Bee Pollen with Different Geographical Origins: A Comprehensive Approach

    Science.gov (United States)

    Nogueira, Carla; Iglesias, Antonio; Feás, Xesus; Estevinho, Leticia M.

    2012-01-01

    Since the primordial of humanity, pollen has been considered a good source of nutrients and energy. Its promising healing properties have also been referred to. The present study aimed to characterize, for the first time, eight commercial pollens from Portugal and Spain available on the market studying the legislation on labeling, pollinic origin, physicochemical and microbiological analyses and identification of yeasts. Eleven botanical families were found amongst the samples. The most abundant family and the most dominant pollen was Cistaceae. The moisture content, ash, aw, pH, reducing sugars, carbohydrates, proteins, lipids and energy were analyzed and the specific parameters were within the specifications required by some countries with legislation regarding these parameters. Microbiologically commercial pollen showed acceptable safety for the commercial quality and hygiene. All samples showed negative results for toxigenic species. The microorganisms studied were aerobic mesophiles, yeasts and moulds, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulfite-reducing Clostridium. During the work, six yeasts species were isolated from pollen, with Rhodotorula mucilaginosa being the most abundant, as it was present in four samples. PMID:23109845

  15. Pollen morphology of Rhizophora L. in Peninsular Malaysia

    International Nuclear Information System (INIS)

    Mohd-Arrabe', A. B.; Noraini, Talip Noraini

    2013-01-01

    Rhizophora L. are common mangrove genus in Peninsular Malaysia, it contains 3 species and 1 hybrid (R. apiculata Blume, R. mucronata Lam., R. stylosa Griff., R. x lamarckii Montrouz). This genus has some unique adaptation towards extreme environment. Rhizophora has looping aerial stilt-root and uniformly viviparous. The aim of this study is to investigate the variation in the pollen morphology of Rhizophora that can be related to their habitat. Methods include in this study is pollen observation under light and acetolysis method under scanning electron microscope. Pollen type of Rhizophora species studied except hybrid species is classified tricolporate, shape spheroidal based on ratio of length polar axis/ length of equatorial axis (1.03 - 1.09). The exine ornamentation is perforate-reticulate for R. apiculata and R. mucronata, while R. stylosa is perforate. For the only hybrid in Peninsular Malaysia, R. x lamarckii (R. apiculata x R. stylosa) differs from others, tricolpate with the absence of porate, shape is subprolate and exine ornamentation is reticulate and striate in equatorial region. Pollenkitt is present due to the salty and extreme environment. This may enhance the volume of pollenkitt present surrounding the pollen grains in Rhizophora for protection and adaptation purposes. Based on these findings, it is evident that pollen morphology is somehow related to its natural habitat

  16. Commercial Bee Pollen with Different Geographical Origins: A Comprehensive Approach

    Directory of Open Access Journals (Sweden)

    Leticia M. Estevinho

    2012-09-01

    Full Text Available Since the primordial of humanity, pollen has been considered a good source of nutrients and energy. Its promising healing properties have also been referred to. The present study aimed to characterize, for the first time, eight commercial pollens from Portugal and Spain available on the market studying the legislation on labeling, pollinic origin, physicochemical and microbiological analyses and identification of yeasts. Eleven botanical families were found amongst the samples. The most abundant family and the most dominant pollen was Cistaceae. The moisture content, ash, aw, pH, reducing sugars, carbohydrates, proteins, lipids and energy were analyzed and the specific parameters were within the specifications required by some countries with legislation regarding these parameters. Microbiologically commercial pollen showed acceptable safety for the commercial quality and hygiene. All samples showed negative results for toxigenic species. The microorganisms studied were aerobic mesophiles, yeasts and moulds, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulfite-reducing Clostridium. During the work, six yeasts species were isolated from pollen, with Rhodotorula mucilaginosa being the most abundant, as it was present in four samples.

  17. Tube spacer grid for a heat-exchanger tube bundle

    International Nuclear Information System (INIS)

    Scheidl, H.

    1976-01-01

    A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

  18. Specialist bees collect Asteraceae pollen by distinctive abdominal drumming (Osmia) or tapping (Melissodes, Svastra)

    Science.gov (United States)

    Four species of western US Osmia (Cephalosmia) bees that are Asteraceae specialists (oligoleges) were observed to employ a heretofore unappreciated, stereotypical means of collecting pollen, abdominal drumming, to gather pollen from 19 flowering species representing nine tribes of Asteraceae. Abdom...

  19. Chemotaxonomy as a tool for interpreting the cryptic diversity of Poaceae pollen

    NARCIS (Netherlands)

    Julier, A.C.M.; Jardine, P.E.; Coe, A.L.; Gosling, W.D.; Lomax, B.H.; Fraser, W.T.

    2016-01-01

    The uniform morphology of different species of Poaceae (grass) pollen means that identification to below family level using light microscopy is extremely challenging. Poor taxonomic resolution reduces recoverable information from the grass pollen record, for example, species diversity and

  20. Xanthium strumarium L. pollen concentration in aeroplankton of Lublin in the years 2003-2005

    Directory of Open Access Journals (Sweden)

    Elżbieta Weryszko-Chmielewska

    2012-12-01

    Full Text Available Xanthium strumarium (common cocklebur pollen grains are included in allergenic types. During a three-year study (2003-2005 conducted by using the gravimetric method at two trap sites in Lublin, daily concentrations, maximum concentrations and annual sums of pollen grains, as well as the length of pollen seasons of this species were compared. The pollen season of common cocklebur starts in the first or second decade of July and lasts until the third decade of September. The length of the pollen season is 70-80 days. The highest cocklebur pollen concentrations, amounting to 40-59 z·cm-2, occurred between 8 and 18 August. The maximum cocklebur pollen concentrations differed slightly in particular trap sites over the period of three years of study. A statistically significant correlation between the Xanthium strumarium pollen concentration and average temperature was demonstrated only in one year of study (2004.

  1. [Pollen quality of Pinus pithyusa Stev. in natural stands of the South Crimea].

    Science.gov (United States)

    Koba, V P

    2005-01-01

    Results of long-term research of germination rate, vitality and dynamics of in vitro growth of P. pithyusa pollen are shown. Dynamics of pollen quality under the action of external factors has been defined.

  2. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI YouTube Videos >> NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  3. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home » NEI YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  4. Evaluation of the botanical origin of commercial dry bee pollen load batches using pollen analysis: a proposal for technical standardization

    Directory of Open Access Journals (Sweden)

    Ortrud M. Barth

    2010-12-01

    Full Text Available High quality of bee pollen for commercial purpose is required. In order to attend the consumer with the best identification of the botanical and floral origin of the product, 25 bee pollen batches were investigated using two techniques of pollen grain preparation. The first started to identify pollen loads of different colors in two grams of each well mixed batch, and the second to identify pollen grains in a pool made of all the pollen loads comprised in two grams. The best result was obtained by this last technique, when a pollen grain suspension was dropped on a microscope slide and circa 500 pollen grains were counted per sample. This analysis resulted in the recognition of monofloral and bifloral pollen batches, while the use of the first technique resulted in all samples receiving a heterofloral diagnosis.É exigida alta qualidade para a comercialização de pólen apícola. A fim de atender o consumidor com a melhor identificação da origem botânica e floral do produto, 25 partidas de pólen apícola feram investigadas usande duas diferentes técnicas na preparação dos grãos de pólen. A primeira partiu da identificação das cargas polínicas contidas em dois gramas de cada partida bem misturada segundo suas cores. A segunda visava identificar os grãos de pólen de um agrupamento ("pool" de todas as cargas polínicas contidas em dois gramas de cada amostra. O melhor resultado foi obtido pela última técnica, quando uma suspensão de grãos de pólen era gotejada sobre uma lâmina de microscopia e cerca de 500 grãos de pólen eram centades por amostra. Esta análise resultou no reconhecimento de partidas monoflorais e biflorais de pólen apícola, enquanto que usando a primeira técnica, todas as amostras receberam a diagnose heterefloral.

  5. The Effects of Pollen Protein Content on Colony Development of the Bumblebee, Bombus Terrestris L.

    Directory of Open Access Journals (Sweden)

    Baloglu Güney Hikmet

    2015-06-01

    Full Text Available The effects of pollen protein content on the colony development of Bombus terrestris were investigated by feeding queens and queenright colonies with four different pollen diets. We used three kinds of commercially available pure pollen (Cistus spp. 11.9%, Papaver somniferum 21.4%, and Sinapis arvensis 21.8% crude protein. We also used a mixture which was made up of equal weights of these pure pollens (18.4 % crude protein. All queens and colonies were fed with sugar syrup and pollen diets ad libitum (28 ± 1 ℃, 65 ± 5% RH. Until there were 50 workers reached, colonies fed with the Cistus pollen diet (167.4 ± 28.9 g consumed significantly more pollen than colonies fed with the Papaver pollen diet (140.7 ± 15.7 g, the mixed pollen diet (136.2 ± 20.1 g or colonies fed with the Sinapis pollen diet (132.4 ± 22.6 g. The date when there were 50 workers reached was approximately one week later in the colonies fed with the Cistus, and colonies fed with the Papaver diet than in the colonies fed with the Sinapis diet, and for colonies fed with the mixed pollen diets. Considering 8 tested criteria, the best performances were observed using the Sinapis, and using the mixed pollen diets. The lowest performances were observed using the Cistus pollen diet. Results showed that pollen sources play an important role in commercial bumblebee rearing. Results also showed that the polyfloral pollen diets are more suitable for mass rearing of bumblebees than the unifloral pollen diets.

  6. Effect of land uses and wind direction on the contribution of local sources to airborne pollen.

    Science.gov (United States)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-12-15

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

  7. Airborne pollen in Funchal city, (Madeira Island, Portugal) - First pollinic calendar and allergic risk assessment.

    Science.gov (United States)

    Camacho, Irene Câmara

    2015-01-01

    Nowadays, pollen calendars are useful tools for clinical guidance intended for allergy sufferers, because they can be used to prevent and manage allergic respiratory diseases, thus improving the quality of life. An aeropalinological study was performed in the city of Funchal with the purpose of establishing a pollen calendar and determining allergic risk, based on a seven year study (2003-2009). The airborne pollen monitoring was carried out with a Hirst type volumetric spore trap, following well-established guidelines. The mean annual pollen index was 1,635.09 and comprised 42 different pollen types. Airborne pollen levels were higher between March - June, accounting for 57.9% of the annual counts. Arboreal pollen grains (52.72%) prevailed in the atmosphere together with herbs and grasses (44.64%), while fern spores (2.29%) and unidentified pollen (0.35%) were scarce. The main pollen types were Urticaceae (20.64%), Poaceae (16.02%), Cupressaceae (13.61%), Pinaceae (9.07%), Myrtaceae (5.93%) and Ericaceae (5.02%). The pollen calendar comprised a total of 14 taxa and is similar to Mediterranean regions, with the exception of Olea europaea, Quercus sp., Betula sp. and Alnus sp. pollen types which are rare or absent. The main pollen season of major pollen taxa is significantly longer in Funchal (on average 239 days) than other European sites, especially for Urticaceae and Poaceae, but the pollen peaks were substantially lower. The pollen calendar for Funchal is the first ever created for Madeira region. Taking into account the low pollen index and number of allergy-risk days recorded (39 days in 7 years), the air quality of Funchal can be considered good.

  8. Analysis of IgE binding proteins of mesquite (Prosopis juliflora) pollen and cross-reactivity with predominant tree pollens.

    Science.gov (United States)

    Dhyani, Anamika; Arora, Naveen; Gaur, Shailendra N; Jain, Vikram K; Sridhara, Susheela; Singh, Bhanu P

    2006-01-01

    Pollen from the mesquite tree, Prosopis juliflora, is an important source of respiratory allergy in tropical countries. Our aim was to partially characterize the IgE binding proteins of P. juliflora pollen extract and study cross-reactivity with prevalent tree pollen allergens. Intradermal tests with P. juliflora and five other tree pollen extracts were performed on respiratory allergy patients from Bikaner (arid) and Delhi (semi arid). Prosopis extract elicited positive skin reactions in 71/220 of the patients. Sera were collected from 38 of these 71 patients and all demonstrated elevated specific IgE to P. juliflora. Immunoblotting with pooled patients' sera demonstrated 16 IgE binding components, with components of 24, 26, 29, 31, 35, 52, 58, 66 and 95 kDa recognized by more than 80% of individual patients' sera. P. juliflora extract is allergenically potent requiring 73 ng of self-protein for 50% inhibition of IgE binding in ELISA inhibition. Cross-inhibition assays showed close relationship among P. juliflora, Ailanthus excelsa, Cassia siamea and Salvadora persica. IgE binding components of 14, 41, 52 and 66 kDa were shared allergens whereas 26 and 29 kDa were specific to P. juliflora. The findings suggest that purification of cross-reactive allergens will be helpful for diagnosis and immunotherapy of tree pollen allergic patients.

  9. The dose effect of irradiated rice pollen on double fertilization

    International Nuclear Information System (INIS)

    Wang Houcong; Chen Zhengming; Chen Ruming; Qiu Simi; Yang Juemin; Yang Huijie

    1995-01-01

    The mature panicles of rice were treated with 60 Co γ-rays in the range of 0∼0.372 kGy. The male sterile line used as the female plants were fertilized with γ-irradiated pollen manually. The dose effect of the irradiated pollen on double fertilization was investigated. It was found that double fertilization of the irradiated pollen was suppressed to different degrees as compared with the control. The effect was noticeable as that the fusion time of the male nucleolus with the female one was delayed with the increasing of γ-radiation dose. The delayed time was less than 13 hours when the dose was below 0.186 kGy and it was more than 15 hours when the dose was above 0.279 kGy. Furthermore, several types of deformed embryonic cells and endosperm nuclei were observed

  10. Pollen and spores as a passive monitor of ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    Wesley Toby Fraser

    2014-04-01

    Full Text Available Sporopollenin is the primary component of the outer walls of pollen and spores. The chemical composition of sporopollenin is responsive to levels of ultraviolet (UV radiation exposure, via a concomitant change in the concentration of phenolic compounds. This relationship offers the possibility of using fossil pollen and spore chemistry as a novel proxy for past UV flux. Phenolic compounds in sporopollenin can be quantified using Fourier Transform infrared spectroscopy. The high potential for preservation of pollen and spores in the geologic record, and the conservative nature of sporopollenin chemistry across the land plant phylogeny, means that this new proxy has the potential to reconstruct UV flux over much longer timescales than has previously been possible. This new tool has important implications for understanding the relationship between UV flux, solar insolation and climate in the past, as well as providing a possible means of assessing paleoaltitude, and ozone thickness.

  11. Statistical Models for Inferring Vegetation Composition from Fossil Pollen

    Science.gov (United States)

    Paciorek, C.; McLachlan, J. S.; Shang, Z.

    2011-12-01

    Fossil pollen provide information about vegetation composition that can be used to help understand how vegetation has changed over the past. However, these data have not traditionally been analyzed in a way that allows for statistical inference about spatio-temporal patterns and trends. We build a Bayesian hierarchical model called STEPPS (Spatio-Temporal Empirical Prediction from Pollen in Sediments) that predicts forest composition in southern New England, USA, over the last two millenia based on fossil pollen. The critical relationships between abundances of tree taxa in the pollen record and abundances in actual vegetation are estimated using modern (Forest Inventory Analysis) data and (witness tree) data from colonial records. This gives us two time points at which both pollen and direct vegetation data are available. Based on these relationships, and incorporating our uncertainty about them, we predict forest composition using fossil pollen. We estimate the spatial distribution and relative abundances of tree species and draw inference about how these patterns have changed over time. Finally, we describe ongoing work to extend the modeling to the upper Midwest of the U.S., including an approach to infer tree density and thereby estimate the prairie-forest boundary in Minnesota and Wisconsin. This work is part of the PalEON project, which brings together a team of ecosystem modelers, paleoecologists, and statisticians with the goal of reconstructing vegetation responses to climate during the last two millenia in the northeastern and midwestern United States. The estimates from the statistical modeling will be used to assess and calibrate ecosystem models that are used to project ecological changes in response to global change.

  12. Characterization of chemical composition of bee pollen in China.

    Science.gov (United States)

    Yang, Kai; Wu, Dan; Ye, Xingqian; Liu, Donghong; Chen, Jianchu; Sun, Peilong

    2013-01-23

    Bee pollen has been praised for its good nutrition and therapeutic values. China is the largest producer in the world. Twelve common varieties of monofloral bee pollen collected from China's main producing regions were selected for nutritional composition analysis, including proximate contents, dietary fibers, amino acid distribution, fatty acid composition, and mineral elements. The proximate compositions mostly met the specifications regulating pollen load quality of China. Proline and glutamic acids were found to be the predominant amino acids in the form of both total amino and free amino acids. Lysine was the relative limiting amino acid. The percentage of total essential amino acids (TEAA) to total amino acids (TAA) reached the nutrition recommendation of the Food and Agricultural Organization (FAO). The major fatty acids, presented as mean values, were C18:3 (25.1%), C16:0 (19.6%), C18:1 (17.3%), C18:2 (8.78%), C22:0 (4.07%), and C18:0 (2.96%) acids. The proportions of C18:3 were generally higher than those of C18:2, and the ratio of total unsaturated fatty acids (TUS) to total saturated fatty acids (TS) was >1.0, except for Nelumbo nucifera Gaertn. pollen for the characteristic absence of C18:3 acids. High levels of beneficial elements such as K, Ca, Mg, Zn, Fe, Mn. and Cu were observed in pollen samples. The contents of detrimental trace elements of Cd, Pb, and Hg were primarily lower or not detected. However, more attention should be paid to a large amount of Al, with a concentration of >100 mg/kg DW in most samples. There were some significant differences between samples. On the whole, the Chinese bee pollen was evaluated as a good complement to diet.

  13. Review of probabilistic pollen-climate transfer methods

    Science.gov (United States)

    Ohlwein, Christian; Wahl, Eugene R.

    2012-01-01

    Pollen-climate transfer methods are reviewed from a Bayesian perspective and with a special focus on the formulation of uncertainties. This approach is motivated by recent developments of spatial multi-proxy Bayesian hierarchical models (BHM), which allow synthesizing local reconstructions from different proxies for a spatially complete picture of past climate. In order to enhance the pollen realism in these models we try to bridge the gap between spatial statistics and paleoclimatology and show how far classical pollen-climate transfer concepts such as regression methods, mutual climatic range, modern analogues, plant functional types, and biomes can be understood in novel ways by refining the data models used in BHMs. As a case study, we discuss modeling of uncertainty by introducing a new probabilistic pollen ratio model, which is a simplified variation of the modern analogue technique (MAT) including the concept of response surfaces and designed for later inclusion in a spatial multiproxy BHM. Applications to fossil pollen data from varved sediments in three nearby lakes in west-central Wisconsin, USA and for a Holocene fossil pollen record from southern California, USA provide local climate reconstructions of summer temperature for the past millennium and the Holocene respectively. The performance of the probabilistic model is generally similar in comparison to MAT-derived reconstructions using the same data. Furthermore, the combination of co-location and precise dating for the three fossil sites in Wisconsin allows us to study the issue of site-specific uncertainty and to test the assumption of ergodicity in a real-world example. A multivariate ensemble kernel dressing approach derived from the post-processing of climate simulations reveals that the overall interpretation based on the individual reconstructions remains essentially unchanged, but the single-site reconstructions underestimate the overall uncertainty.

  14. Abnormal pollen mitoses (PM I and PM II) in an interspecific hybrid ...

    Indian Academy of Sciences (India)

    Unknown

    sporocytes and pollen grains were prepared by squashing and stained with 0.5% propionic carmine. All meiotic phases and stages of pollen development were evaluated. More than 6000 microspores and pollen grains were care- fully analysed. Keywords. Brachiaria decumbens; Brachiaria ruziziensis; interspecific hybrid; ...

  15. IgE-binding capacity of recombinant timothy grass (Phleum pratense) pollen allergens

    NARCIS (Netherlands)

    Laffer, S.; Vrtala, S.; Duchêne, M.; van Ree, R.; Kraft, D.; Scheiner, O.; Valenta, R.

    1994-01-01

    A panel of 60 cDNA clones coding for IgE-binding proteins from timothy grass pollen was immunocharacterized with sera from 30 patients allergic to grass pollen and antibodies raised against natural grass pollen allergens. In the cases of five representative patients in whom the IgE reactivity

  16. Microbial characterization of bee pollen from the Vesuvius area collected by using three different traps

    Science.gov (United States)

    De Prisco, Annachiara; Di Prisco, Gennaro; La Storia, Antonietta; Caprio, Emilio

    2017-01-01

    Flower pollen is collected by honeybee foragers, adhered on their rear legs and transported into the hives in the form of pellets. Once in the hives, bee pollen is moisturised with nectar and bee mouth secretions and due to enzymatically modifications it becomes the so-called bee-bread, the protein reservoir of young bees. Bee pollen can be artificially removed from bee legs and collected by using specific systems, the bee pollen traps. Bee pollen is commercialized for human consumption as fresh product and after freezing or drying. Although bee pollen is nowadays largely consumed in developed countries, as food or food supplement according to local legislation, little is known on its safety related to microbiological hazards. In this work, we aimed to characterize for the first time the microbiological profile of Italian bee pollen in fresh, frozen and dried form collected along an entire harvesting season. Moreover, monthly microbiological analyses were performed on frozen (storage at -18°C) and dried (storage at room temperature) bee pollen over a 4 months period. Further aim of this work was the evaluation of the possible impact on production level of three different traps used for pollen collection. Our results on microbial contamination of fresh and frozen bee pollen show that a more comprehensive microbiological risk assessment of bee pollen is required. On the other side, dried pollen showed very low microbial contamination and no pathogen survived after the drying process and during storage. PMID:28934240

  17. Challenges in estimating past plant diversity from fossil pollen data: statistical assessment, problems, and possible solutions.

    NARCIS (Netherlands)

    Weng, C.; Hooghiemstra, H.; Duivenvoorden, J.F.

    2006-01-01

    Fossil pollen data from sediment cores may be used as a measure for past plant diversity. According to the theory of probability, palynological richness is positively related to the pollen count. In a low pollen count, only common taxa are detected, whereas rare taxa are only detected by chance. The

  18. PREHISTORIC CEREAL GATHERING AND FARMING IN THE NEAR-EAST - THE POLLEN EVIDENCE

    NARCIS (Netherlands)

    BOTTEMA, S

    1992-01-01

    In this contribution the use of Cerealia-type pollen as an indicator of the presence of wild cereal species or their domesticated derivatives is discussed, especially for the Near East. Various aspects of pollen analysis in connection with modern as well as subfossil pollen are studied. The

  19. Dispersal of Airborne Pollen in Chatienshan Nature Reserve, Northern Taiwan, with Emphasis on Taiwan Beech

    Directory of Open Access Journals (Sweden)

    Chuan Ku

    2012-12-01

    Full Text Available In this first study on the pollen rain in natural forest in Taiwan using pollen traps, the dispersal patterns of airborne pollen were determined, with emphasis on Fagus hayatae and some major plant species, and the relationship between pollen assemblages and vegetation was elucidated. Seventeen pollen traps were installed on the western slope of Mt. Takai, northern Taiwan, from March 21 to May 10, 2008. Pollen and spores belonging to 37 families and 43 genera were identified. The results of correspondence analysis suggested differentiation of three vertical zones of pollen assemblages that corresponded to three vegetation types. Three patterns of occurrence were identified for the major pollen taxa, namely ubiquitous occurrence, local occurrence, and peak occurrence. The pollen influx of F. hayatae, a taxon characterized by local occurrence, was remarkably lower at a distance of over 200 m away from the pure stands. This suggests that pollen-mediated gene flow between the beech populations in Taiwan is unlikely. Besides providing basic data on the pollen dispersal of some important taxa in the middle altitudes of Taiwan, the present study also points out that caution should be taken in interpreting pollen percentage data from sediments.

  20. Effect of a home-made pollen substitute on honey bee colony development

    NARCIS (Netherlands)

    Steen, van der J.J.M.

    2007-01-01

    In 2001 and 2002, studies were conducted on a pollen substitute formulated for easy home preparation. Tests were done with free flying honey bee colonies. In 2001, pollen supply was restricted with pollen traps in 9 experimental colonies. Colonies were then equally divided among three treatments:

  1. Carbohydrate metabolism before and after dehiscence in the recalcitrant pollen of pumpkin (Cucurbita pepo L.).

    Science.gov (United States)

    Carrizo García, C; Guarnieri, M; Pacini, E

    2015-05-01

    Pumpkin (Cucurbita pepo L.) pollen is starchy, sucrose-poor and recalcitrant, features opposite to those of several model species; therefore, some differences in carbohydrate metabolism could be expected in this species. By studying pumpkin recalcitrant pollen, the objective was to provide new biochemical evidence to improve understanding of how carbohydrate metabolism might be involved in pollen functioning in advanced stages. Four stages were analysed: immature pollen from 1 day before anthesis, mature pollen, mature pollen exposed to the environment for 7 h, and pollen rehydrated in a culture medium. Pollen viability, water and carbohydrate content and activity of enzymes involved in carbohydrate metabolism were quantified in each stage. Pollen viability and water content dropped quickly after dehiscence, as expected. The slight changes in carbohydrate concentration and enzyme activity during pollen maturation contrast with major changes recorded with ageing and rehydration. Pumpkin pollen seems highly active and closely related to its surrounding environment in all the stages analysed; the latter is particularly evident among insoluble sucrolytic enzymes, mainly wall-bound acid invertase, which would be the most relevant for sucrose cleavage. Each stage was characterised by a particular metabolic/enzymatic profile; some particular features, such as the minor changes during maturation, fast sucrolysis upon rehydration or sharp decrease in insoluble sucrolytic activity with ageing seem to be related to the lack of dormancy and recalcitrant nature of pumpkin pollen. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  2. Selective suppression of antibody production with the aid of radiolabelled birch pollen allergen

    International Nuclear Information System (INIS)

    Filipp, G.; Biro, G.; Hartung, W.D.; Lehmann, G.

    1981-01-01

    In accordance with the clonal selection theory we intended to prevent the development of artificially induced birch pollen allergy in rabbits with the aid of of the radiolabelled pollen allergen (75-1000 μCi 125 I-pollen/animal) intravenously administered prior to pollen sensitization. The birch pollen allergen, in accordance with Burnet's working hypothesis, reacts only with a genetically determining B cell subpopulation. The fixation of the radiolabelled birch pollen allergen to the receptors of the competent B cell clone causes the lesion of the latter. Compared with the control group, this group of rabbits showed an extensive suppression of anaphylactic reagin-like PCA-antibodies, and haemagglutinating antibodies in the blood as well as in nasal secretion. In addition, we tried to influence the already ongoing synthesis of the antibodies with the aid of a subsequent intravenously administered radiolabelled birch pollen allergen (750-1000μCi 125 I-pollen/animal). An intensive suppression of the synthesis of antibodies could also be proved in this case. The simultaneous immunization of the control rabbits with birch pollen and egg albumin resulted in the production of antibodies against both antigens, as expected. The hot-labelled birch pollen antigen intravenously injected before or after immunization with egg albumin and birch pollen led selectively to suppression of anti-birch-pollen PCA antibodies. The synthesis of anti-egg albumin PCA antibodies was unaffected. (author)

  3. Fractionation and immunochemical characterization of Prosopis juliflora pollen allergen.

    Science.gov (United States)

    Thakur, I S

    1986-12-01

    Prosopis juliflora pollen grain crude extract gave six different molecular weight fractions varied from 81,000 to 13,000 dalton on Sephadex G-100 gel filtration. The purity of fractions of Prosopis juliflora pollen extract were checked by polyacrylamide gel electrophoresis. The fraction had an molecular weight 20,000 dalton showed four absorption maxima whereas other fractions had single absorption maxima. Allergenic activity and nature of allergens were evaluated by in vitro Radioallergosorbent test and in vivo Passive Cutaneous Anaphylaxis test. All these tests indicated that most allergenic fractions were in the 20,000 molecular weight.

  4. Tube plug removal machine

    International Nuclear Information System (INIS)

    Hawkins, P.J.

    1987-01-01

    In a nuclear steam generator wherein some faulty tubes have been isolated by mechanical plugging, to remove a selected plug without damaging the associated tube, a plug removal machine is used. The machine drills into a plug portion with a tap drill bit having a drill portion a tap portion and a threaded portion, engaging that plug portion with the threaded portion after the drilled hole has been threaded by the tap portion thereof, and removing a portion of the plug in the tube with a counterbore drill bit mounted concentrically about the tap drill bit. A trip pin and trip spline disengage the tap drill bit from the motor. The counterbore drill bit is thereafter self-centered with respect to the tube and plug about the now stationary tap drill bit. After a portion of the plug has been removed by the counterbore drill bit, pulling on the top drill bit by grippers on slots will remove the remaining plug portion from the tube. (author)

  5. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  6. Measuring of tube expansion

    International Nuclear Information System (INIS)

    Vogeleer, J. P.

    1985-01-01

    The expansion of the primary tubes or sleeves of the steam generator of a nuclear reactor plant are measured while the tubes or sleeves are being expanded. A primary tube or sleeve is expanded by high pressure of water which flows through a channel in an expander body. The water is supplied through an elongated conductor and is introduced through a connector on the shank connected to the conductor at its outer end. A wire extends through the mandrel and through the conductor to the end of the connector. At its inner end the wire is connected to a tapered pin which is subject to counteracting forces produced by the pressure of the water. The force on the side where the wire is connected to the conductor is smaller than on the opposite side. The tapered pin is moved in the direction of the higher force and extrudes the wire outwardly of the conductor. The tapered surface of the tapered pin engages transverse captive plungers which are maintained in engagement with the expanding tube or sleeve as they are moved outwardly by the tapered pin. The wire and the connector extend out of the generator and, at its outer end, the wire is connected to an indicator which measures the extent to which the wire is moved by the tapered pin, thus measuring the expansion of the tube or sleeve as it progresses

  7. Effect of land uses and wind direction on the contribution of local sources to airborne pollen

    International Nuclear Information System (INIS)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-01-01

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

  8. Effect of land uses and wind direction on the contribution of local sources to airborne pollen

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-12-15

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen

  9. Effect of space flight on meiosis of pollen mother cells and its derived pollens in impatiens balsamina

    International Nuclear Information System (INIS)

    Tang Zesheng; Yang Jun; Yuan Haiyun; Zhao Yan

    2005-01-01

    Effects of space flight on meiosis of pollen mother cells and meiosis of microspores in Impatiens balsamina were investigated. It was found that meiosis showed abnormal in most plants germinated from seeds after space flight, and chromosome fragment, chromosomal bridge and lagging chromosome were observed in the process of meiosis in these plants. Disproportional segregation of chromosome, multipolar division and multinucleus were also observed in most plants, which developed into paraspores with different chromosome number. Mitosis of microspores was found to be abnormal in most plants, and the number of chromosome in microspore unequal. The fertility of the pollens was tested with iodic solution; it was found that the fertility of pollens varied in different plants. (authors)

  10. Advanced evacuated tube collectors

    Science.gov (United States)

    Schertz, W. W.; Hull, J. R.; Winston, R.; Ogallagher, J.

    1985-04-01

    The essence of the design concept for these new collectors is the integration of moderate levels of nonimaging concentration inside the evacuated tube itself. This permanently protects the reflection surfaces and allows the use of highly reflecting front surface mirrors with reflectances greater than 95%. Previous fabrication and long term testing of a proof-of-concept prototype has established the technical success of the concept. Present work is directed toward the development of a manufacturable unit that will be suitable for the widest possible range of applications. Design alternatives include scaling up the original prototype's tube diameter from 5 cm to 10 cm, using an internal shaped metal concentrating reflector, using a variety of profile shapes to minimize so-called gap losses and accommodate both single ended and double-ended flow geometries, and allowing the use of heat pipes for the absorber tube.

  11. Square through tube

    International Nuclear Information System (INIS)

    Akita, Junji; Honma, Toei.

    1975-01-01

    Object: To provide a square through tube involving thermal movement in pipelines such as water supply pump driving turbine exhaust pipe (square-shaped), which is wide in freedom with respect to shape and dimension thereof for efficient installation at site. Structure: In a through tube to be airtightly retained for purpose of decontamination in an atomic power plant, comprising a seal rubber plate, a band and a bolt and a nut for securing said plate, the seal rubber plate being worked into the desired shape so that it may be placed in intimate contact with the concrete floor surface by utilization of elasticity of rubber, thereby providing airtightness at a corner portion of the square tube. (Kamimura, M.)

  12. SG tube identification

    International Nuclear Information System (INIS)

    Hoogstraten, P. van

    1994-01-01

    A ''Tracker'' system is described which is designed to identify any tube in a reactor steam generator quickly and safely. Occupational radiation doses to maintenance workers are reduced by using a Tracker and emergency down times are shortened. The system employs a television camera and light source in a stainless steel box with a large window. Both the camera and spotlight can be panned and tilted to reach any point on the tubesheet and are remotely controlled. An operator at a safe working distance can identify any tube visible on a real time video by comparison with the tubesheet pattern stored earlier in the computer memory. The identified tube can then be spotlighted and dealt with quickly by a maintenance worker inside the channel head. (UK)

  13. Honey bee (Apis mellifera nurses do not consume pollens based on their nutritional quality.

    Directory of Open Access Journals (Sweden)

    Vanessa Corby-Harris

    Full Text Available Honey bee workers (Apis mellifera consume a variety of pollens to meet the majority of their requirements for protein and lipids. Recent work indicates that honey bees prefer diets that reflect the proper ratio of nutrients necessary for optimal survival and homeostasis. This idea relies on the precept that honey bees evaluate the nutritional composition of the foods provided to them. While this has been shown in bumble bees, the data for honey bees are mixed. Further, there is controversy as to whether foragers can evaluate the nutritional value of pollens, especially if they do not consume it. Here, we focused on nurse workers, who eat most of the pollen coming into the hive. We tested the hypothesis that nurses prefer diets with higher nutritional value. We first determined the nutritional profile, number of plant taxa (richness, and degree of hypopharyngeal gland (HG growth conferred by three honey bee collected pollens. We then presented nurses with these same three pollens in paired choice assays and measured consumption. To further test whether nutrition influenced preference, we also presented bees with natural pollens supplemented with protein or lipids and liquid diets with protein and lipid ratios equal to the natural pollens. Different pollens conferred different degrees of HG growth, but despite these differences, nurse bees did not always prefer the most nutritious pollens. Adding protein and/or lipids to less desirable pollens minimally increased pollen attractiveness, and nurses did not exhibit a strong preference for any of the three liquid diets. We conclude that different pollens provide different nutritional benefits, but that nurses either cannot or do not assess pollen nutritional value. This implies that the nurses may not be able to communicate information about pollen quality to the foragers, who regulate the pollens coming into the hive.

  14. Honey bee (Apis mellifera) nurses do not consume pollens based on their nutritional quality.

    Science.gov (United States)

    Corby-Harris, Vanessa; Snyder, Lucy; Meador, Charlotte; Ayotte, Trace

    2018-01-01

    Honey bee workers (Apis mellifera) consume a variety of pollens to meet the majority of their requirements for protein and lipids. Recent work indicates that honey bees prefer diets that reflect the proper ratio of nutrients necessary for optimal survival and homeostasis. This idea relies on the precept that honey bees evaluate the nutritional composition of the foods provided to them. While this has been shown in bumble bees, the data for honey bees are mixed. Further, there is controversy as to whether foragers can evaluate the nutritional value of pollens, especially if they do not consume it. Here, we focused on nurse workers, who eat most of the pollen coming into the hive. We tested the hypothesis that nurses prefer diets with higher nutritional value. We first determined the nutritional profile, number of plant taxa (richness), and degree of hypopharyngeal gland (HG) growth conferred by three honey bee collected pollens. We then presented nurses with these same three pollens in paired choice assays and measured consumption. To further test whether nutrition influenced preference, we also presented bees with natural pollens supplemented with protein or lipids and liquid diets with protein and lipid ratios equal to the natural pollens. Different pollens conferred different degrees of HG growth, but despite these differences, nurse bees did not always prefer the most nutritious pollens. Adding protein and/or lipids to less desirable pollens minimally increased pollen attractiveness, and nurses did not exhibit a strong preference for any of the three liquid diets. We conclude that different pollens provide different nutritional benefits, but that nurses either cannot or do not assess pollen nutritional value. This implies that the nurses may not be able to communicate information about pollen quality to the foragers, who regulate the pollens coming into the hive.

  15. Bee pollen: a dangerous food for allergic children. Identification of responsible allergens.

    Science.gov (United States)

    Martín-Muñoz, M F; Bartolome, B; Caminoa, M; Bobolea, I; Ara, M C Garcia; Quirce, S

    2010-01-01

    Bee pollen has been proposed as a food supplement, but it can be a dangerous food for people with allergy. We study an allergic reaction after ingestion of bee pollen in a 4-year-old boy who had developed rhinitis in the last spring and autumn. We performed a prick-by-prick test with bee pollen and skin prick tests with the most important local pollens, house dust mites, common fungi, and animal danders. The levels of serum tryptase, serum total IgE and specific IgE against bee venom and local pollen extracts were determined. The composition of the bee pollen was analysed and SDS-PAGE immunoblotting and blotting-inhibition were carried out. Prick tests were positive to bee pollen and all local pollens extracts and negative to any other allergen sources. The bee pollen sample contained pollens from Quercus genus, and Asteraceae (Compositae) and Rosaceae families. Total IgE was 435 kU/l. Serum specific IgE to bee pollen was 6 kU/l and greater than 0.35 kU/L against pollens from Artemisia vulgaris, Taraxacum officinalis, Cupressus arizonica, Olea europaea, Platanus acerifolia and Lolium perenne as well as to n Art v 1 and other pollen marker allergens. Tryptase level was 3.5 mcg/mL. SDS-PAGE immunoblotting-inhibition points to Asteraceae pollen as the possible cause of the allergic reaction. Foods derived from bees can be dangerous to people with allergy to pollen. Copyright © 2009 SEICAP. Published by Elsevier Espana. All rights reserved.

  16. Honey bee (Apis mellifera) nurses do not consume pollens based on their nutritional quality

    Science.gov (United States)

    Snyder, Lucy; Meador, Charlotte; Ayotte, Trace

    2018-01-01

    Honey bee workers (Apis mellifera) consume a variety of pollens to meet the majority of their requirements for protein and lipids. Recent work indicates that honey bees prefer diets that reflect the proper ratio of nutrients necessary for optimal survival and homeostasis. This idea relies on the precept that honey bees evaluate the nutritional composition of the foods provided to them. While this has been shown in bumble bees, the data for honey bees are mixed. Further, there is controversy as to whether foragers can evaluate the nutritional value of pollens, especially if they do not consume it. Here, we focused on nurse workers, who eat most of the pollen coming into the hive. We tested the hypothesis that nurses prefer diets with higher nutritional value. We first determined the nutritional profile, number of plant taxa (richness), and degree of hypopharyngeal gland (HG) growth conferred by three honey bee collected pollens. We then presented nurses with these same three pollens in paired choice assays and measured consumption. To further test whether nutrition influenced preference, we also presented bees with natural pollens supplemented with protein or lipids and liquid diets with protein and lipid ratios equal to the natural pollens. Different pollens conferred different degrees of HG growth, but despite these differences, nurse bees did not always prefer the most nutritious pollens. Adding protein and/or lipids to less desirable pollens minimally increased pollen attractiveness, and nurses did not exhibit a strong preference for any of the three liquid diets. We conclude that different pollens provide different nutritional benefits, but that nurses either cannot or do not assess pollen nutritional value. This implies that the nurses may not be able to communicate information about pollen quality to the foragers, who regulate the pollens coming into the hive. PMID:29324841

  17. Taxonomic description of in situ bee pollen from the middle Eocene of Germany.

    Science.gov (United States)

    Grímsson, FriĐgeir; Zetter, Reinhard; Labandeira, Conrad C; Engel, Michael S; Wappler, Torsten

    2017-01-02

    The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees

  18. PRODUCTION OF URANIUM TUBING

    Science.gov (United States)

    Creutz, E.C.

    1958-04-15

    The manufacture of thin-walled uranium tubing by the hot-piercing techique is described. Uranium billets are preheated to a temperature above 780 d C. The heated billet is fed to a station where it is engaged on its external surface by three convex-surfaced rotating rollers which are set at an angle to the axis of the billet to produce a surface friction force in one direction to force the billet over a piercing mandrel. While being formed around the mandrel and before losing the desired shape, the tube thus formed is cooled by a water spray.

  19. Guide tube sleeve

    International Nuclear Information System (INIS)

    Attix, D.J.

    1983-01-01

    The invention increases the operating capacity of a nuclear reactor by causing a modification in the flow pattern of the coolant which enhances the coolant's effectiveness. The apparatus provides a thin-walled tubular sleeve closely surrounding but not attached to the exterior surface of a guide tube in a fuel assembly. The wall of the sleeve has tabs projecting outwardly into adjacent flow channels. The sleeve is attached to the wall of a cellular void through which passes the guide tube associated with said sleeve. The tabs increase the flow of water in the channel and thus increase the heat transfer

  20. Pressure tube type research reactor

    International Nuclear Information System (INIS)

    Ueda, Hiroshi.

    1976-01-01

    Object: To prevent excessive heat generation due to radiation of a pressure tube vessel. Structure: A pressure tube encasing therein a core comprises a dual construction comprising inner and outer tubes coaxially disposed. High speed cooling water is passed through the inner tube for cooling. In addition, in the outer periphery of said outer tube there is provided a forced cooling tube disposed coaxially thereto, into which cooling fluid, for example, such as moderator or reflector is forcibly passed. This forced cooling tube has its outer periphery surrounded by the vessel into which moderator or reflector is fed. By the provision of the dual construction of the pressure tube and the forced cooling tube, the vessel may be prevented from heat generation. (Ikeda, J.)

  1. Skin tests of pollen grains of taxodiaceae and cupressaceae in children with bronchial asthma.

    Science.gov (United States)

    Midoro-Horiuti, T; Nouno, S; Seino, Y

    1992-10-01

    Atmospheric cedar pollen in the southern region of Okayama Prefecture (situated in south-western Japan) has been counted since 1988. Pollen of different species of the Taxodiaceae family (Cryptomeria japonica, Sequoia sempervirens and Metasequoia glyptostroboides) and Japanese juniper (Juniperus rigida) in the Cupressaceae family, which are propagated mainly in the southern region of Okayama Prefecture, were found among the atmospheric pollen. Scratch tests using the pollen extract from Taxodiaceae and Cupressaceae were performed on children with bronchial asthma. Forty (25%) and 30 (18.8%) of the 160 patients reacted positively to an allergen extract from the pollen grains of Japanese cedar (Cryptomeria japonica) and Japanese juniper, respectively.

  2. Cloning and characterisation of a putative pollen-specific polygalacturonase gene (CpPG1) differentially regulated during pollen development in zucchini (Cucurbita pepo L.).

    Science.gov (United States)

    Carvajal, F; Garrido, D; Jamilena, M; Rosales, R

    2014-03-01

    Studies in zucchini (Cucurbita pepo L. spp. pepo) pollen have been limited to the viability and morphology of the mature pollen grain. The enzyme polygalacturonase (PG) is involved in pollen development and pollination in many species. In this work, we study anther and pollen development of C. pepo and present the cloning and characterisation of a putative PG CpPG1 (Accession no. HQ232488) from pollen cDNA in C. pepo. The predicted protein for CpPG1 has 416 amino acids, with a high homology to other pollen PGs, such as P22 from Oenothera organensis (76%) and PGA3 from Arabidopsis thaliana (73%). CpPG1 belongs to clade C, which comprises PGs expressed in pollen, and presents a 34 amino acid signal peptide for secretion towards the cell wall. DNA-blot analysis revealed that there are at least another two genes that code for PGs in C. pepo. The spatial and temporal accumulation of CpPG1 was studied by semi-quantitative- and qRT-PCR. In addition, mRNA was detected only in anthers, pollen and the rudimentary anthers of bisexual flowers (only present in some zucchini cultivars under certain environmental conditions that trigger anther development in the third whorl of female flowers). However, no expression was detected in cotyledons, stem or fruit. Furthermore, CpPG1 mRNA was accumulated throughout anther development, with the highest expression found in mature pollen. Similarly, exo-PG activity increased from immature anther stages to mature anthers and mature pollen. Overall, these data support the pollen specificity of this gene and suggest an involvement of CpPG1 in pollen development in C. pepo. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  3. Behavior of profilins in the atmosphere and in vitro, and their relationship with the performance of airborne pollen

    Science.gov (United States)

    Aloisi, Iris; Del Duca, Stefano; De Nuntiis, Paola; Vega Maray, Ana M.; Mandrioli, Paolo; Gutiérrez, Pablo; Fernández-González, Delia

    2018-04-01

    Most pollen allergens in the air are carried by pollen grains, but the presence of airborne smaller respirable particles containing pollen allergens has also been demonstrated. Meteorological factors drastically affect the occurrence of pollen, allergen release in the air and diffusion of the latest. In order to shed light on this phenomenon, the dynamics of pollen and the pollen panallergen profilin in the air of two European cities (León, Spain and Bologna, Italy) having different weather conditions, were analyzed. Pollen sampling was performed continuously from March to June 2015 using two seven-day recording volumetric trap of Hirst-type, while the particles for aeroallergen quantification were sampled with a Burkard Cyclone sampler and the profilin content in aerosol samples was quantified using an indirect double-antibody sandwich ELISA. In both cities, pollen and profilin concentrations followed a similar trend and showed a significant correlation; however, peaks were often misaligned, with the profilin peaks following those of pollen. Several meteorological parameters, such as relative humidity, significantly influenced pollen and allergen dispersion. In vitro pollen tests were thus performed in order to mimic pollen rehydration, occurring in natural conditions and a massive protein release from allergenic pollen was detected during the early stages of pollen rehydration when profilin was also extruded from the grains. The different timing and protein amounts released from different pollen during hydration might explain, at least in part, the non-synchronous pollen and profilin peaks detected in the atmosphere.

  4. Double wall steam generator tubing

    International Nuclear Information System (INIS)

    Padden, T.R.; Uber, C.F.

    1983-01-01

    Double-walled steam generator tubing for the steam generators of a liquid metal cooled fast breeder reactor prevents sliding between the surfaces due to a mechanical interlock. Forces resulting from differential thermal expansion between the outer tube and the inner tube are insufficient in magnitude to cause shearing of base metal. The interlock is formed by jointly drawing the tubing, with the inside wall of the outer tube being already formed with grooves. The drawing causes the outer wall of the inner tube to form corrugations locking with the grooves. (author)

  5. Montane pollen from the Tertiary of NW. Borneo

    NARCIS (Netherlands)

    Muller, J.

    1966-01-01

    In NW. Borneo thick series of Tertiary sediments occur which are rich in fossil pollen and spores. The majority of these plant microfossils were derived from the various types of tropical lowland vegetation such as mangrove (Muller, 1964), mixed peat swamp forest and mixed Dipterocarp forest. Some

  6. Pollen morphology of Amygdalus L. (Rosaceae in Iran

    Directory of Open Access Journals (Sweden)

    Mahnaz Vafadar

    2011-01-01

    Full Text Available Pollen grain of 16 species and three hybrids of the genus Amygdalus L., representing two subgenera and two sections distributed in Iran were examined by light and scanning electron microscopy. All pollen grains are tricolporate. The shape of grains varies from subprolate through prolate. Regarding outline, in polar view, pollen grains are triangular-circular and in equatorial view, elliptic. Regarding sculpturing of exine, the frequent type like many members of family Rosaceae is striate with or without perforations that can be subdivided into three subtypes: type I (A-B, type II (A-B and type V. In three species, A. trichamygdalus, A. spinosissima and A. orientalis, exine sculpture type is completely different. In the first species is rugulate, in the second species is reticulate and in A. orientalis, it is gemmate-perforate. Ornamentation of ridges (muri in the striate sculpture is parallel to ectocolpus. Number of perforations in tectum, diameter of them, striae intervals and the thickness of ridges varies among studied taxa. The striae have different depth and slope. Results showed that among pollen grain characters, shape is useful character solely for separating of taxonomic ranks in Iranian Amygdalus specially in subgeneric or section level.

  7. Pollen diversity, viability and floral structure of some Musa genotypes

    African Journals Online (AJOL)

    Prof. Ogunji

    This is related to sterility due to triploidy, variation in genome size and structure ... Pollen grains are structures that house the male gametophytes generation of .... the mean value for all the genotypes was recorded for PITA 14, an 11TA hybrid.

  8. Pollen cone anatomy of Classostrobus crossii sp. nov. (Cheirolepidiaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Rothwell, Gar W.; Mapes, Gene [Department of Environmental and Plant Biology, Ohio University, Athens OH 45701 (United States); Hilton, Jason [Department of Earth Sciences, School of Geography, Earth and Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Hollingworth, Neville T. [Centre for Ecology and Hydrology, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset, DT2 8ZD (United Kingdom)

    2007-01-02

    Discovery of a permineralized fossil cone in Mesozoic deposits of southern England provides an opportunity to document the first detailed evidence of internal pollen cone anatomy for the extinct conifer family Cheirolepidiaceae. The specimen, described here as Classostrobus crossii sp. nov., occurs in a calcareous nodule recovered from Middle Jurassic marine sediments of the Lower Callovian Sigaloceras calloviense biozone, Kellaways, near Cirencester, England. The cone is 2.0 cm long and 1.8 cm wide. Sporophylls diverge helically from the axis. Each sporophyll displays a narrow stalk and a distal lamina approx. 11 mm long that tapers to a pointed tip. There is also a basal keel that bends inward at the bottom and sides to form a shallow pocket. A single vascular bundle diverges from the cone axis, extends distally into the sporophyll stalk at the contact of two distinctly different histological zones, and further expands into the distal lamina as transfusion tracheids. Several pollen sacs are attached abaxially at the juncture of the sporophyll stalk and keel. Pollen is roughly spheroidal, 26-35 {mu}m in diameter, with unequal polar caps separated by a striated belt with a subequatorial furrow. This specimen helps clarify the range of variation in the morphology of Mesozoic conifer pollen cones. (author)

  9. Pollen of Syzygium (Myrtaceae) from SE Asia, especially Thailand

    NARCIS (Netherlands)

    Parnell, J.

    2003-01-01

    Pollen of 57 species of Syzygium from SE Asia were surveyed by SEM. The grains are all ± triangular in polar view, uniformly small (mean diameter 10.4 μm) with few surface sculpturing features. All species examined exhibit a distinct apocolpium and, usually, apocolpial field. The presence of an

  10. Fullerene-Based Symmetry in Hibiscus rosa-sinensis Pollen

    Science.gov (United States)

    Andrade, Kleber; Guerra, Sara; Debut, Alexis

    2014-01-01

    The fullerene molecule belongs to the so-called super materials. The compound is interesting due to its spherical configuration where atoms occupy positions forming a mechanically stable structure. We first demonstrate that pollen of Hibiscus rosa-sinensis has a strong symmetry regarding the distribution of its spines over the spherical grain. These spines form spherical hexagons and pentagons. The distance between atoms in fullerene is explained applying principles of flat, spherical, and spatial geometry, based on Euclid’s “Elements” book, as well as logic algorithms. Measurements of the pollen grain take into account that the true spine lengths, and consequently the real distances between them, are measured to the periphery of each grain. Algorithms are developed to recover the spatial effects lost in 2D photos. There is a clear correspondence between the position of atoms in the fullerene molecule and the position of spines in the pollen grain. In the fullerene the separation gives the idea of equal length bonds which implies perfectly distributed electron clouds while in the pollen grain we suggest that the spines being equally spaced carry an electrical charge originating in forces involved in the pollination process. PMID:25003375

  11. Towards evidence-based medicine in specific grass pollen immunotherapy.

    Science.gov (United States)

    Calderon, M; Mösges, R; Hellmich, M; Demoly, P

    2010-04-01

    When initiating grass pollen immunotherapy for seasonal allergic rhinoconjunctivitis, specialist physicians in many European countries must choose between modalities of differing pharmaceutical and regulatory status. We applied an evidence-based medicine (EBM) approach to commercially available subcutaneous and sublingual Gramineae grass pollen immunotherapies (SCIT and SLIT) by evaluating study design, populations, pollen seasons, treatment doses and durations, efficacy, quality of life, safety and compliance. After searching MEDLINE, Embase and the Cochrane Library up until January 2009, we identified 33 randomized, double-blind, placebo-controlled trials (including seven paediatric trials) with a total of 440 specific immunotherapy (SIT)-treated subjects in seven trials (0 paediatric) for SCIT with natural pollen extracts, 168 in three trials (0 paediatric) for SCIT with allergoids, 906 in 16 trials (five paediatric) for natural extract SLIT drops, 41 in two trials (one paediatric) for allergoid SLIT tablets and 1605 in five trials (two paediatric) for natural extract SLIT tablets. Trial design and quality varied significantly within and between SIT modalities. The multinational, rigorous trials of natural extract SLIT tablets correspond to a high level of evidence in adult and paediatric populations. The limited amount of published data on allergoids prevented us from judging the level of evidence for this modality.

  12. A model to predict the beginning of the pollen season

    DEFF Research Database (Denmark)

    Toldam-Andersen, Torben Bo

    1991-01-01

    for fruit trees are generally applicable, and give a reasonable description of the growth processes of other trees. This type of model can therefore be of value in predicting the start of the pollen season. The predicted dates were generally within 3-5 days of the observed. Finally the possibility of frost...

  13. Bee pollen as a bioindicator of environmental pesticide contamination.

    Science.gov (United States)

    de Oliveira, Renata Cabrera; Queiroz, Sonia Claudia do Nascimento; da Luz, Cynthia Fernandes Pinto; Porto, Rafael Silveira; Rath, Susanne

    2016-11-01

    Honeybees and bee products are potential bioindicators of the presence of contaminants in the environment, enabling monitoring of large areas due to the long distances travelled by bees. This work evaluates the use of bee pollen as a bioindicator of environmental contamination by pesticides. A GC-MS/MS analytical method for multiresidue determination of 26 different pesticides in pollen was developed and validated in accordance with the recommendations of the European Union SANCO guide. Environmental monitoring was conducted using the analysis of 145 pollen samples collected from ten beehives in the experimental apiary of Embrapa in Jaguariúna (São Paulo State, Brazil). Bioallethrin and pendimethalin were identified in four and eighteen samples, respectively, at concentrations below the LOQ of the method (25 ng g(-1)). Passive sampling with polyurethane foam discs was used as a control, and no pesticides were found. The detection of pesticide residues in seven samples (33%) from commercial apiaries in Ribeirão Preto (São Paulo State) confirmed the efficiency of the analytical method and the need for environmental monitoring for the presence of pesticide residues. The results demonstrated the potential of bee pollen as a bioindicator of environmental contamination by pesticides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Pollen-vegetation richness and diversity relationships in the tropics

    NARCIS (Netherlands)

    Gosling, W.D.; Julier, A.C.M.; Adu-Bredu, S.; Djagbletey, G.D.; Fraser, W.T.; Jardine, P.E.; Lomax, B.H.; Malhi, Y.; Manu, E.A.; Mayle, F.E.; Moore, S.

    Tracking changes in biodiversity through time requires an understanding of the relationship between modern diversity and how this diversity is preserved in the fossil record. Fossil pollen is one way in which past vegetation diversity can be reconstructed. However, there is limited understanding of

  15. La longévité du pollen de colza

    Directory of Open Access Journals (Sweden)

    Pierre Jacqueline

    2002-01-01

    Full Text Available Connaître la longévité d’un pollen est une donnée particulièrement intéressante dans le cadre des études de risques de dissémination du pollen. En effet, cela permet de savoir combien de temps une parcelle dont la floraison est terminée reste une source de pollen fécondant. Par ailleurs, une étude de la longévité du pollen pourrait permettre de mieux comprendre les résultats en apparence contradictoires obtenus au cours de diverses expérimentations menées sur la dissémination du pollen de colza. Ainsi, alors que des travaux montrent que ce pollen est peu anémophile [1] et qu’au niveau de la parcelle sa dispersion se fait sur de courtes distances [2-4], des cas de contaminations sur de grandes distances ont été signalés [5] et les relevés palynologiques effectués sur des filtres (placés à 10 m de hauteur, voire plus confirment que ce pollen peut se disperser sur de grandes distances [6]. Toutefois, on ignore si le pollen ainsi collecté est viable ou non. Si l’on fait l’hypothèse que cette dernière dispersion se fait par le biais de la mise en suspension du pollen dans l’air dans les couches de l’atmosphère et que son transport dure un certain temps, il devient également nécessaire de connaître la durée de vie du pollen pour mieux évaluer les risques de ce type de dissémination. Au plan méthodologique, mesurer la longévité du pollen peut a priori paraître simple. Cependant les critères retenus peuvent être nombreux et divers : mesure de la viabilité, mesure du pouvoir germinatif in vitro ou in vivo, mesure du pouvoir fécondant réel. Dans chacun des cas, les techniques appliquées sont différentes et chacune comporte des biais parfois importants tels que des faux-positifs dans les tests colorimétriques de viabilité, l’incidence du milieu de culture dans les tests de germination in vitro, sans parler des tests présentant des risques carcinogènes pour l’expérimentateur [7]. De plus

  16. Updated site compilation of the Latin American Pollen Database

    NARCIS (Netherlands)

    Flantua, S.G.A.; Hooghiemstra, H.; Grimm, E.C.; Behling, H.; Bush, M.B; González-Arrango, C.; Gosling, W.D.; Ledru, M.-P.; Lozano-Garciá, S.; Maldonado, A.; Prieto, A.R.; Rull, V.; van Boxel, J.H.

    2015-01-01

    The updated inventory of the Latin American Pollen Database (LAPD) offers a wide range of new insights. This paper presents a systematic compilation of palynological research in Latin America. A comprehensive inventory of publications in peer-reviewed and grey literature shows a major expansion of

  17. Structure of the Pollen Exine of Rhoiptelea chiliantha

    Directory of Open Access Journals (Sweden)

    Annie Skarby

    2009-06-01

    Full Text Available The exine of mature pollen grains of Rhoiptelea chiliantha was studied. The size of the pollen grains is about 23 by 27 μm. They are tricolporate with short colpi that are 1-2 μm wide and 10-12 long. The spinules of Rhoiptelea are similar in form and size to those of Gentianales. The spinules consist of rods of ca 70 nm in width. These rods are evident throughout the tectum and columellae. The columellae are of two distinct sizes. The smaller ones are ca 70 nm wide and join the tectum and the larger columellae. These larger ones appear to be composed of several 70 nm in width rods. They join the distal surface of the foot layer. The proximal surface of the foot layer is marked by a white line (referred to as a junction plane where it joins the endexine. The endexine consists of a solid-appearing component adjacent to the foot layer (referred to as endexine-1 and laminar components (endexine-2 that are attached to and apparently become a part of endexine-1. There is no indication of an arcus. In well preserved grains the aperture is covered by an operculum or operculum-like component. In well-rehydrated pollen grains there is an oncus of considerable complexity under the aperture and over the intine. The Ubisch bodies have an exine ornamented with widely-spaced spinules like the spinules on the pollen exine.

  18. Differential effects of carbohydrates on arabidopsis pollen germination

    Czech Academy of Sciences Publication Activity Database

    Hirsche, J.; Fernández, J. M. G.; Stabentheiner, E.; Großkinsky, D.K.; Roitsch, Thomas

    2017-01-01

    Roč. 58, č. 4 (2017), s. 691-701 ISSN 0032-0781 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Arabidopsis thaliana * Carbohydrates * Metabolic regulation * Pollen germination * Signaling * Structure-function relationship Subject RIV: EF - Botanics OBOR OECD: Cell biology Impact factor: 4.760, year: 2016

  19. MICROBIOTA OF PINUS POLLEN AS ADJUVANT FACTOR OF ALLERGY

    Directory of Open Access Journals (Sweden)

    Tetiana Shevtsova

    2016-06-01

    Full Text Available Bacteria, their endotoxin and mold found on pollen can be a reason of respiratory symptoms in sensitized individuals. This question concerns an anemophilous pollen more acute. In this work quantitative by dilution plating method and qualitative microbial analysis by MALDI-TOF MS Biotyper of pollen and other plants organs of Pinus sylvestris L., P. nigra Arnold, P. mugo Turra, P. armandii Franch., P. wallichiana A.B. Jacks from Nitra, Slovakia are performed which shows quantitative and species differences in mesophilic aerobic (0.00-6.27 log cfu/g and anaerobic bacteria (0.00-3.70 log cfu/g, enterococci (0.00 log cfu/g, coliform bacteria (0.00-5.29 log cfu/g, lactobacilli (0.00-4.20 log cfu/g, microscopic fungi and yeasts (2.60-5.29 log cfu/g content. Representatives of Pseudomonas (14, Bacillus (2, Acinetobacter (1, Arthrobacter (1, Pantoea (1, Klebsiella (1, Penicillium (6, Aspergillus (4, Cladosporium (1, Debaryomyces (1 genera were revealed on pine trees. The allergenic potential of the identified association of microorganisms on pollen has been evaluated based on published data. The results may be useful for aerobiologists, allergists and microbiologists, at least at the local level.

  20. Seasonal and Spatial Variations of Indoor Pollen in a Hospital

    Directory of Open Access Journals (Sweden)

    Santiago Fernández-Rodríguez

    2009-12-01

    Full Text Available The airborne indoor pollen in a hospital of Badajoz (Spain was monitored over two years using a personal Burkard sampler. The air was sampled in four places indoors—one closed room and one open ward on each of the ground and the third floors—and one place outdoors at the entrance to the hospital. The results were compared with data from a continuous volumetric sampler. While 32 pollen types were identified, nearly 75% of the total counts were represented by just five of them. These were: Quercus, Cupressaceae, Poaceae, Olea, and Plantago. The average indoor concentration was 25.2 grains/m3, and the average indoor/outdoor ratio was 0.27. A strong seasonal pattern was found, with the highest levels in spring and winter, and the indoor concentrations were correlated with the outdoor one. Indoor air movement led to great homogeneity in the airborne pollen presence: the indoor results were not influenced by whether or not the room was isolated, the floor level, or the number of people in or transiting the site during sampling. The presence of ornamental vegetation in the area surrounding the building affected the indoor counts directly as sources of the pollen.