Gotowe bibliografie tematyczne / Spores and pollen grains

Gotowa bibliografia na temat „Spores and pollen grains”

Autor: Grafiati
Data publikacji: 25 maja 2024

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych

Wybierz rodzaj źródła:

Spis treści

Zobacz listy aktualnych artykułów, książek, rozpraw, streszczeń i innych źródeł naukowych na temat „Spores and pollen grains”.

Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.

Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.

Artykuły w czasopismach na temat "Spores and pollen grains"

1

Larsson, Kent, Sofie Lindström i Dorothy Guy-Ohlson. "An Early Permian palynoflora from Milorgfjella, Dronning Maud Land, Antarctica". Antarctic Science 2, nr 4 (grudzień 1990): 331–44. http://dx.doi.org/10.1017/s0954102090000463.

Pełny tekst źródła
Streszczenie:
A preliminary palynological study of Beacon Supergroup sedimentary rocks exposed at Milorgfjella, Dronning Maud Land, has yielded a relatively rich and well preserved palynoflora dominated by spores and pollen grains, but also including acritarchs and green algae. The palynoflora is dominated by the pterophyte spores Punctatisporites gretensis, Punctatisporites parvus, Granulatisporites spp., Microbaculispora tentula Horriditriletes spp. and Verrucosisporites andersonii, and the gymnosperm pollen grains Plicatipollenites spp. and Cannanoropollis spp. Also present are the lycopod spore Jayantisporites pseudozonatus, the praecolpate pollen grain Marsupipollenites striatus and the monocolpate pollen grain Cycadopites cymbatus. The palynoflora indicates freshwater conditions or, at least, a major freshwater influence on the depositional environment. Comparison of the palynoflora with others from Gondwana suggests an Early Permian (Asselian–Sakmarian) age.
Style APA, Harvard, Vancouver, ISO itp.
2

Kawahata, Hodaka, Rena Maeda i Hideaki Ohshima. "Fluctuations in Terrestrial–Marine Environments in the Western Equatorial Pacific during the Late Pleistocene". Quaternary Research 57, nr 1 (styczeń 2002): 71–81. http://dx.doi.org/10.1006/qres.2001.2282.

Pełny tekst źródła
Streszczenie:
AbstractLarge heat storage capacity in the western equatorial Pacific has played an important role in modulating global climate. The fluctuation in pollen and spore abundances, together with organic matter (OM) and lithogenics sedimentation, was investigated to reconstruct terrestrial and marine environmental change around New Guinea during the Late Pleistocene. Although appreciable contribution from Indonesian Maritime Continent was expected, the majority of the pollen and spore grains found in core C4402 was transported from New Guinea. Fern spores accounted for 70% (46–90%) of the total pollens and spores. Positive correlation between lithogenic content and the relative abundance of fern spores suggests that lithogenics could be derived from coastal lowland.The mass accumulation rate (MAR) of pollen and spores varied from 44 to 7,031×10−3 grains cm−2 yr−1 with maxima in oxygen isotope stages (OIS) 2, 3, 4, and around the OIS 4/5 boundary. Less rainfall during glacial times generally enhanced transport of pollen by wind to Site C4402. Their scavenging from the water column was promoted by high activity of the biological pump. Pollen record from core C4402 suggests that lower montane group vegetation was dominant relative to lowland vegetation and upper and mid-montane group during glacial times. Although appreciable contribution by terrestrial OM is expected from high correlation of MAR between organic carbon (OC) and pollen and spores, fairly low COrganic/N ratios and δ13C values (around −20‰) of OM demonstrate that OM in core C4402 is mainly of marine origin.
Style APA, Harvard, Vancouver, ISO itp.
3

Katsimpris, Petros, Christos Nikolaidis, Theodora-Eleftheria Deftereou, Dimitrios Balatsouras, Athanasia Printza, Theodoros Iliou, Triantafyllos Alexiadis i in. "Three-year pollen and fungi calendar in a Mediterranean region of the Northeast Greece". Allergologia et Immunopathologia 50, nr 2 (1.03.2022): 65–74. http://dx.doi.org/10.15586/aei.v50i2.491.

Pełny tekst źródła
Streszczenie:
Introduction and objectives: Pollen calendars have been proved clinically important in allergic disease management, as differences in airborne allergens exist not only between different countries but also between regions of the same country as well. This study aims to provide new data regarding the atmospheric pollen and fungi content of a Mediterranean region (Western Thrace/North-East Greece) and discuss seasonal trends, differences in pollen grains and fungi spores’ circulation over the years, and correlations with climate parameters. Material and methods: A 7-day continuously running volumetric trap was used to collect circulating pollen grains and fungi spores. Pollen taxa and fungi were characterized by standard protocols and counted as grains /m3 and average total grains and spores. The primary allergenic pollen season was discovered, and their 10-day averages were measured over time. Correlations with temperature, rain, and humidity were assessed by single linear regression analysis. Results: Pollen grains from nine pollen families were identified, including five arboreal, two nonarboreal taxa, and spores from two fungi species. The three most prevalent taxa were Oleaceae, Poaceae, Pinaceae, and Cladosporium in the fungi. Peak pollen concentrations were detected during April and May, with daily averages exceeding 170 grains/m3. Poaceae presented the longest pollen season of 342 days and Oleaceae the shortest, extending to only 110 days, during the 3years. Cladosporium was the fungus with the highest spore concentration (180,129.9 spores) compared with Alternaria (28,026.1 spores). Correlations with meteorological parameters showed variable associations among different taxa, with rainfall and relative humidity being the most significant determinants. Conclusion: In this study, the pollenic and fungal spectrum of a Mediterranean region and information that can be proved clinically significant for the appropriate diagnostic and therapeutic approach of allergic patients was presented.
Style APA, Harvard, Vancouver, ISO itp.
4

Śliwińska-Wyrzychowska, Anna, Kazimiera Chłopek, Edyta M. Gola i Monika Bogdanowicz. "The usefulness of aerobiological methods in monitoring lycopod sporulation". Plant Ecology and Evolution 151, nr 2 (22.08.2018): 284–89. http://dx.doi.org/10.5091/plecevo.2018.1385.

Pełny tekst źródła
Streszczenie:
Background and aims – The purpose of the study was to determine whether the concentration of lycopod spores present in aeroplankton reflects their release during sporulation and whether it is a good indirect tool to estimate the condition of lycopod populations in Poland.Methods – The study was conducted in Sosnowiec, S Poland. The airborne spores were continuously captured by the volumetric spore trap during a period of eleven years (1998–2008). Plant pollen grains and spores from the trap were macroscopically identified, counted and expressed as daily pollen grain and spore concentrations in 1 m3 of air. Key results – The average monthly sum of captured lycopod spores varied in the analysed period of time from 0.3 to 4.1 spores per year. Their yearly concentration was small in comparison to the ascertained pollen grains and did not exceed 0.5% of all airborne particles captured in a given year. In addition, they showed seasonal fluctuations with the highest concentration of spores usually detected in July. This finding is in accordance with the typical time of lycopod sporulation. In addition, we detected the presence of lycopod spores outside the typical summer sporulation time, i.e. during months of winter and early spring. In our opinion, their presence is related to the phenomenon of lengthened (winter) sporulation of clubmosses.Conclusions – Our results showed only limited transportation of lycopod spores by wind. Therefore, the condition of lycopod populations in Poland can hardly be estimated using aerobiological methods. Nevertheless, the seasonal dynamics of lycopod spore concentration can be recorded by aerobiological methods.
Style APA, Harvard, Vancouver, ISO itp.
5

Luz, Cynthia Fernandes Pinto da, Ortrud Monika Barth i Cleverson Guisan Silva. "Spatial distribution of palynomorphs in the surface sediments of the Lagoa do Campelo lake, North region of Rio de Janeiro State, Brazil". Acta Botanica Brasilica 19, nr 4 (grudzień 2005): 741–52. http://dx.doi.org/10.1590/s0102-33062005000400009.

Pełny tekst źródła
Streszczenie:
Four samples of the surface sediments of the Lagoa do Campelo lake bottom were collected in a transect of 500 m by 500 m from edge to edge, in a northeast/southwest direction, the dominant wind direction in the region. The analysis of pollen grains, fern spores and algae were used to evaluate their spatial deposition and level of deterioration. In total, 58 types of pollen grains were identified, mainly from herbs as Cyperaceae, Poaceae and Typhaceae. Pollen grains occurred in all the analyzed sediments. The area of highest concentration was the northeast side of the lake. The southwest side showed the highest pollen grain and fern spore degradation and mechanical damage, probably as they were carried across the lake by wind-driven currents, confirming the depositional tendency of damaged palynomorphs in the same direction as the dominant wind. Among the pollen of trees and shrubs, Alchornea, Arecaceae, Cecropia, Celtis, Clethra and Myrtaceae were dominant at more than 1,000 pollen grains per gram of sediment. The quantity of fern spores was practically constant in all samples (± 10% of the total of palynomorphs). The algae Pediastrum tetras (Ehrenberg) Ralfs and Mougeotia occurred in all samples, but Spirogyra only in three of them. The results obtained gave new information about the richness, concentration and distribution of palynomorphs in the lake, representing the local and regional vegetation.
Style APA, Harvard, Vancouver, ISO itp.
6

Verma, Divya. "PREVALENCE OF AIRBORNE POLLEN GRAINS AND FUNGAL SPORES IN A CITY OF THAR DESERT, INDIA". Journal of Advanced Scientific Research 13, nr 08 (30.09.2022): 45–53. http://dx.doi.org/10.55218/jasr.202213808.

Pełny tekst źródła
Streszczenie:
Monitoring of bioaerosols i.e., pollen grains and fungal spores, was undertaken for two consecutive years in a city of Thar Desert- Bikaner, using Gravity Slide Method. A total of 32 different pollen taxa were identified with Annual Pollen Integral (API) of 890 pollen grains per sq. cm in the first year and 906 pollen grains per sq. cm in the second year. The pollen count of non-arboreal plants was much more than that of the arboreal plants. The most prominent annual average pollen percentage was credited to Poaceae (25.91%), followed by Chenopodiaceae/Amaranthaceae (17.57%), Papilionaceae (7.86%) and Cyperaceae (5.95%) among non-arboreal plants: and to Prosopis juliflora (14.84%) amongst arboreal taxa. Two peak seasons were observed in both the years i.e., February to April and August to October for both pollen grains as well as fungal spores. 32 types of airborne fungal spores were reported from the atmosphere of Bikaner during the study. A total number of 6717 fungal spores per sq. cm were counted in the first year and 7117 spores per sq. cm in the second year. The commonest fungal spores encountered were of the species of Cladosporium, followed by Alternaria and Curvularia with annual mean percentage of 24.95%, 23.02% and 11.53 respectively.
Style APA, Harvard, Vancouver, ISO itp.
7

Calderón LLosa, Oscar Manuel, Denisse Cevallos Levicek, Germán Ramón, Laura Barrionuevo, Karla Robles, Ivan Tinoco i Iván Chérrez. "Initial study of trap and identification of environmental pollens and fungi spores in Samborondon, Ecuador". Revista Alergia México 71, nr 1 (23.04.2024): 52. http://dx.doi.org/10.29262/ram.v71i1.1322.

Pełny tekst źródła
Streszczenie:
Initial study of trap and identification of environmental pollens and fungi spores in Samborondon, Ecuador Introduction: The identification of local aeroallergens in any geographical area is essential for the specific diagnosis and treatment of allergic diseases. Our objective was to identify and registry the most important aeroallergens trapped at the aerobiology station in the city of Samborondon, Ecuador.Material and methods:Pollen grains and fungal spore counts were performed according to the standardized technique with a Hirst-type collection equipment, Burkard spore trap for seven days, following the recommendations of the National Allergy Bureau (NAB) of the American Academy of Allergy Asthma and Immunology (AAAAI). The equipment was installed on the roof of the Universidad de Especialidades Espiritu Santo (UEES), 25 m above ground level, coordinates: 2°07 ́57 ́ ́S 79°52 ́06 ́ ́W, in the city of Samborondon. The sampling period was performed from November 2022 to April 2023.Results:We identified the following pollen families: Poaceae (258 grains/m3), Apocynaceae (Plumeria rubra pc) 214 grains/m3, Lamiaceae (180 grains/m3), Asteraceae - Ambrosía spp.- (60 grains/m3), Chenopodiacea (27 grains/m3), Myrtaceae (17 grains/m3), Pinaceae (11 grains/m3), Betulaceae (7 grains/m3).Also identified fungical spores: Fuzariella spp./Leptosphaeria spp. (1899/m3), Cladosporium spp. (1407/m3), Nigrospora spp. (1183/m3), Dreschlera/Helmintosporum spp. (329/m3), Alternaria spp. (98/m3), Pithomyces spp. (79/m3), Curvularia spp. (48/m3), Stemphylium spp. (46/m3).Conclusions:We reported the first study of aerobiology (capture and identification of environmental pollens and fungi) in the city of Samborondon. The inhabitants of this area are exposed to different aeroallergens with a predominance of Poaceaes pollen and Fuzzariella spp./Leptosphaeria spp. spores. The identified allergens should be part of the usual allergy studies. The results of this first preliminary study should be compared with information from the forthcoming years, which will help to identify variations in the concentration of seasonal aeroallergens, annual fluctuations, and extend the traps to other parts of the city.Key words: aerobiology, allergic rhinitis, allergic conjunctivitis, pollens.
Style APA, Harvard, Vancouver, ISO itp.
8

Khandelwal, Asha. "Long term monitoring of air-borne pollen and fungal spores and their allergenic significance". Journal of Palaeosciences 51, nr (1-3) (31.12.2002): 153–59. http://dx.doi.org/10.54991/jop.2002.1743.

Pełny tekst źródła
Streszczenie:
The qualitative and quantitative analyses of aerospora at Birbal Sahni Institute of Palaeobotany are assessed for the biogenic pollutants of Lucknow atmosphere. The Impaction method was employed for preparing annual pollen and spore calendars over six years (1969-1970, 1970-1971, 1971-1972, 1983-84, 1984-1985, 1985-1986). As many as 61 types of pollen grains and 27 types of fungal spores have been encountered. The maximum numbers of pollen grains were recorded in the year 1985-86 (24383) and minimum in the year 1969-70 (13005), whilst the maximum number of fungal spores encountered were in 1971-72 (22604) and minimum in the year 1969-70 (12771). It has been visualized that long term pollen/spore monitoring at a particular site provides a strong base for the prediction of aeroallergens as a warning towards the allergenic disorders. The well recognised allergenic pollen and spore of Lucknow area include Argemone mexicana, Amaranthus spinosus, Cannabis sativa, Chenopodium album, Prosopis juliflora, Cyperus rotundus, Ricinus communis, Xanthium strumarium and many species of Aspergillus.
Style APA, Harvard, Vancouver, ISO itp.
9

Kobzar, V., i K. Osmonbaeva. "Aeroallergens as Indicators of the Anthropogenic Triads". Bulletin of Science and Practice, nr 9 (15.09.2023): 43–57. http://dx.doi.org/10.33619/2414-2948/94/05.

Pełny tekst źródła
Streszczenie:
The growing interest in the complex issue of climate change, environmental pollution and aeroallergens is reflected in the queries of Internet users in various search engines. Recently, articles have been published on the impact of changes in the traditional land use system on the concentration and species composition of plant pollen and fungal spores. The total effects of the influence of the anthropogenic triad on plant pollen and fungal spores: 1) an increase in the time of the beginning of the growth of plants and fungi and, consequently, the beginning of their production; 2) earlier terms and lengthening of the pollination season; 3) an increase in the concentration and species composition of pollen of allergenic plants and fungal spores in the air of the regions, especially in the urban environment, along vertical zonality in mountainous conditions; 4) modification, deformation, fragmentation of pollen grains; 5) change in allergenic potential: increase in the number of allergens in pollen; 6) transformation of allergens in fungal spores; 7) change in the geospatial distribution of plant pollen and fungal spores, i.e. transportation of whole pollen, its fragments and spores over long distances; 8) emergence in the regions, on a global scale of new species of allergenic plants and phytopathogens; 9) changes in the qualitative and quantitative composition of pollen and aerospores, due to a change in the traditional system of land use, sowing of new cultivated plants and, accordingly, the introduction of new phytopathogens; 10) vegetation on the pollen of bacteria and fungal spores that change the structure of the pollen grain; 11) trigger effect of aeroallergens in the occurrence of allergic diseases in humans; 12) an increase in the number of indeterminate pollen and spore particles in aerobiological studies.
Style APA, Harvard, Vancouver, ISO itp.
10

Rathnayake, Chathurika M., Nervana Metwali, Thilina Jayarathne, Josh Kettler, Yuefan Huang, Peter S. Thorne, Patrick T. O'Shaughnessy i Elizabeth A. Stone. "Influence of rain on the abundance of bioaerosols in fine and coarse particles". Atmospheric Chemistry and Physics 17, nr 3 (16.02.2017): 2459–75. http://dx.doi.org/10.5194/acp-17-2459-2017.

Pełny tekst źródła
Streszczenie:
Abstract. Assessing the environmental, health, and climate impacts of bioaerosols requires knowledge of their size and abundance. These two properties were assessed through daily measurements of chemical tracers for pollens (sucrose, fructose, and glucose), fungal spores (mannitol and glucans), and Gram-negative bacterial endotoxins in two particulate matter (PM) size modes: fine particles (< 2.5 µm) and coarse particles (2.5–10 µm) as determined by their aerodynamic diameter. Measurements were made during the spring tree pollen season (mid-April to early May) and late summer ragweed season (late August to early September) in the Midwestern US in 2013. Under dry conditions, pollen, and fungal spore tracers were primarily in coarse PM (> 75 %), as expected for particles greater than 2.5 µm. Rainfall on 2 May corresponded to maximum atmospheric pollen tracer levels and a redistribution of pollen tracers to the fine PM fraction (> 80 %). Both changes were attributed to the osmotic rupture of pollen grains that led to the suspension of fine-sized pollen fragments. Fungal spore tracers peaked in concentration following spring rain events and decreased in particle size, but to a lesser extent than pollens. A short, heavy thunderstorm in late summer corresponded to an increase in endotoxin and glucose levels, with a simultaneous shift to smaller particle sizes. Simultaneous increase in bioaerosol levels and decrease in their size have significant implications for population exposures to bioaerosols, particularly during rain events. Chemical mass balance (CMB) source apportionment modeling and regionally specific pollen profiles were used to apportion PM mass to pollens and fungal spores. Springtime pollen contributions to the mass of particles < 10 µm (PM10) ranged from 0.04 to 0.8 µg m−3 (0.2–38 %, averaging 4 %), with maxima occurring on rainy days. Fungal spore contributions to PM10 mass ranged from 0.1 to 1.5 µg m−3 (0.8–17 %, averaging 5 %), with maxima occurring after rain. Overall, this study defines changes to the fine- and coarse-mode distribution of PM, pollens, fungal spores, and endotoxins in response to rain in the Midwestern United States and advances the ability to apportion PM mass to pollens.
Style APA, Harvard, Vancouver, ISO itp.
Więcej źródeł

Rozprawy doktorskie na temat "Spores and pollen grains"

1

Hassett, Maribeth O. "Analysis of the Hygroscopic Properties of Fungal Spores and Pollen Grains inside an Environmental Scanning Electron Microscope (ESEM)". Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1461243940.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
2

Tahi, Ignace. "Palynologie et caractérisation de la matière organique des dépôts Albo/Aptien-Crétacé Supérieur du bassin sédimentaire de Côte d’Ivoire". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS464.

Pełny tekst źródła
Streszczenie:
Les dépôts d’âge Albien-Crétacé supérieur de Côte d’Ivoire, offrent un potentiel important pour l’exploitation des hydrocarbures, car elles comportent à la fois des roches mères et des roches réservoirs. Les travaux palynologiques antérieurs menés dans ce bassin sédimentaire, et d’autres bassins marginaux du Golfe de Guinée, ont permis d’établir des échelles biostratigraphiques, opérationnelles pour l’exploitation, mais incomplètes et parfois incohérences entre elles et avec d’autres marqueurs temporels. Ce travail propose une révision complète des archives palynologiques de l’Albien et du Crétacé supérieur de Côte d’Ivoire, leur biostratigraphie, les paléoenvironnements et leur valeur pour l’exploitation pétrolière. 167 échantillons de carottes provenant de 20 sondages et un sondage de déblais de 98 échantillons, produits dans le cadre des activités de la société PETROCI, ont fait l’objet de cette étude palynologique. Le matériel a livré une diversité de kystes de dinoflagellés (46 espèces) et sporomorphes (148 espèces). Un inventaire qualitatif et quantitatif a été réalisé sur l’ensemble des échantillons. Treize biozones ont pu être caractérisées : la palynozone PCI-I à Cerodinium granulostriatum du Maastrichtien supérieur ; la palynozone PCI-II à Andalusiella ivoirensis du Maastrichtien inférieur ; la palynozone PCI-III à Xenascus ceratioides du Campanien supérieur à moyen ; la palynozone PCI-IV à Trichodinium castanea du Campanien inférieur ; la palynozone PCI-V à Oligosphaeridium complex du Santonien ; la palynozone PCI-VI à Droseridites senonicus du Coniacien ; la palynozone PCI-VII à Tricolpites microstriatus du Turonien ; la palynozone PCI-VIII à Classopollis classoides du Cénomanien supérieur ; la palynozone PCI-IX à Triorites africaensis du Cénomanien moyen ; la palynozone PCI-X à Elaterocolpites castelainii de l’Albien supérieur-Cénomanien inférieur ; la palynozone PCI-XI à Lusatisporis dettmannae- Callialasporites dampieri de l’Albien supérieur ; la palynozone PCI-XII à Appendicisporites spp.-Elaterosporites spp. de l’Albien moyen-supérieur et la palynozone PCI-XIII à Callialasporites trilobatus-Afropollis spp. de l’Albien moyen-inférieur. L’évolution des paléoenvironnements au cours du Crétacé s’accompagne d’une réduction de la microflore d’origine continentale, dominante à l’Albien, et de l’installation de conditions marines, pour atteindre des conditions de mer ouverte au Turonien. Le développement du phytoplancton alguaire d’origine marine s’amorce et évolue jusqu’au Maastrichtien. Quatre paléoenvironnements majeurs peuvent être différenciés d’après les assemblages palynologiques, en cohérence avec les données sédimentologiques : un environnement fluvio-lacustre à littoral marin est associé aux dépôts de l’Albien moyen-inférieur ; des conditions marines, néritiques internes caractérisent les dépôts de l’Albien moyen-supérieur à Cénomanien inférieur-Albien supérieur ; un environnement néritique interne à externe va régner du Turonien au Santonien et un environnement néritique externe à bathyal supérieur caractérisant le Campanien- Maastrichtien. Les analyses de la matière organique ont fourni des valeurs de l’Indice d’Hydrogène (IH) inférieures à 300 mg HC g/TOC dans les échantillons étudiés, et le type de kérogène indique une prédominance de matière organique de Type III susceptibles de renfermer des roches mères potentielles dans le Sénonien inferieur, Cénomanien et Albien. Les roches mères cénomaniennes et albiennes sont matures pour la génération des hydrocarbures
The deposits of Albian- Upper Cretaceous age in the Ivory Coast offer significant hydrocarbon potential. Previous palynological work carried out on this sedimentary basin does not provide consistent and complete biostratigraphic scales. 167 cores samples from 20 wells and a 98 ditch cuttings samples were the subject of this palynological study. The material yielded an abundance of dinocysts (46 species) and sporomorphs (148 species). A qualitative and quantitative inventory was carried out. For biostratigraphy, thirteen biozones were characterized: the palynozone PCI-I with Cerodinium granulostriatum from the Upper Maastrichtian; palynozone PCI-II with Andalusiella ivoirensis of the lower Maastrichtian; upper to middle Campanian palynozone PCI-III with Xenascus ceratioides; Early Campanian palynozone PCI-IV with Trichodinium castanea; Santonian palynozone PCI-V with Oligosphaeridium complex; palynozone PCI-VI with Droseridites senonicus of the Coniacian; the palynozone PCI-VII of Tricolpites microstriatus from the Turonian; Upper Cenomanian palynozone PCI-VIII with Classopollis classoides; palynozone PCI-IX with Triorites africaensis of the Middle Cenomanian; the PCI-X palynozone with Elaterocolpites castelainii of the Lower Cenomanian-Upper Albian; palynozone PCI-XI from Upper Albian with Lusatisporis dettmannae- Callialasporites dampieri; the palynozone PCI-XII of Appendicisporites spp.-Elaterosporites spp. for Upper-middle Albian and palynozone PCI-XIII of Lower-middle Albian with Callialasporites trilobatus-Afropollis spp. Climate change since the Albian sees the microflora of continental origin dominated until the establishment of marine conditions open to the Turonian. The development of algae phytoplankton of marine origin begins and evolves until the Maastrichtian. Four major paleoenvironments: an environment of fluvio-lacustrine facies with a marine littoral is associated with deposits of the Lower-middle Albian; an internal neritic environment characterizes deposits from the Upper-middle-Albian to Lower Cenomanian-Upper Albian; an internal to external neritic environment will reign from the Turonian to the Santonian and an external neritic environment to upper bathyal characterizing the Campanian-Maastrichtian will mark this climatic fluctuation. In general, the values of the Hydrogen Index (HI) are less than 300 mg HC g / TOC in the samples studied, and the type of kerogen indicates a predominance of organic matter Type III likely to contain source rocks in the Lower Senonian, Cenomanian and Albian. Cenomanian and Albian source rocks are mature for the generation of hydrocarbons
Style APA, Harvard, Vancouver, ISO itp.
3

Dutta, Rita Johanna. "Ultrastructure of mesozoic spores and pollen". Thesis, Aberystwyth University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400780.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
4

Crawford, Carlos. "Variations of Indoor and Outdoor Airborne Fungal Spores, Pollen". Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?acc_num=ucin1179518877.

Pełny tekst źródła
Streszczenie:
Thesis (M.S.)--University of Cincinnati, 2007.
Advisors: Tiina Reponen PhD, Sergey Grinshpun PhD, Linda Levin PhD. Title from electronic thesis title page (viewed June 3, 2009). Includes abstract. Keywords: (1-3)Beta-D-Glucan; pollen; fungal spores; variation. Includes bibliographical references.
Style APA, Harvard, Vancouver, ISO itp.
5

Prieu, Charlotte. "Evolution et Developpement des grains de pollen chez les angiospermes". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS201/document.

Pełny tekst źródła
Streszczenie:
Chez les organismes pluricellulaires, la diversité morphologique observée à tous les niveaux est frappante, que ce soit au niveau de la taille, des couleurs, ou de la forme des individus, et des différentes parties qui les composent. La sélection naturelle, ainsi que les contraintes développementales, influencent l’évolution de ces différents attributs, sur le court terme comme sur le long terme. Le modèle choisi ici pour étudier l’évolution des formes est le grain de pollen des plantes à fleurs, qui présente une très grande diversité morphologique. Nous nous sommes focalisés sur un caractère morphologique, les apertures, qui sont des structures de la paroi du grain de pollen impliquées dans la survie et la reproduction. Nous avons étudié l’évolution des apertures à grande échelle taxonomique chez les angiospermes, et nous montrons que s’il existe de nombreuses variations, deux types principaux dominent : un pollen à une aperture chez les Monocotylédones et les angiospermes divergeant à la base, et un pollen à trois apertures chez les Eudicotylédones. En étudiant la dominance du pollen à trois apertures, nous avons pu montrer que la stase chez les Eudicotylédones était vraisemblablement due à une sélection stabilisante plutôt qu’à des contraintes développementales. Nous avons également montré, grâce à l’utilisation de mutants de la plante modèle Arabidopsis thaliana, qu’un nombre d’apertures élevé est défavorable face à un stress osmotique, ce qui pourrait suggérer que les pollens triaperturés représentent un bon compromis entre survie et germination. Enfin, nous nous sommes intéressés à un type particulier de pollen possédant de nombreuses apertures, dont nous avons étudié la distribution chez les angiospermes. L’apparition de ce type de pollen est récurrente, mais il n’est que rarement fixé à grande échelle taxonomique, suggérant l’existence d’un mécanisme de sélection interphylétique éliminant ce type de pollen sur le long terme
Multicellular organisms are morphologically very diverse at every scale, regarding size, color, and shape of individuals and of their different parts. Natural selection and developmental constraints influence evolution of these characteristics, on the short term as well as on the long term. The model chosen here to study form evolution is the pollen grain of flowering plants, which is very diversified morphologically. We focused on specific features called apertures, which are structures of the pollen wall involved in survival and reproduction. We studied aperture evolution at large taxonomic scale in angiosperms, and we showed that in spite of variations, two main pollen types dominate: a pollen with one aperture in Monocots and early diverging angiosperms, and a pollen with three apertures in Eudicots. The study of this pattern showed that the stasis of triaperturate pollen in Eudicots is likely due to stabilizing selection rather than developmental constraints. Experiments on Arabidopsis thaliana mutants also revealed that an increase in aperture number was associated with lower resistance to osmotic stress. This result could suggest that triaperturate pollen grains represent a good trade-off between survival and germination. Moreover, we focused on a particular pollen type with many apertures, to determine its distribution in angiosperms. This type of pollen has many origins, however it is seldom fixed at large taxonomical scale, suggesting the intervention of lineage selection, eliminating this pollen type in the long run
Style APA, Harvard, Vancouver, ISO itp.
6

Mami, Leïla. "Biostratigraphie du crétacé du sud-est constantinois (Algérie) : dinokystes, spores et pollen". Reims, 1993. http://www.theses.fr/1993REIMS007.

Pełny tekst źródła
Streszczenie:
Une etude palynologique des sediments cretaces du sud-est constantinois basee sur deux sondages petroliers: manndra 1 (man1) et oued melah 1 (oum1), et trois coupes de terrain a permis d'approfondir nos connaissances concernant les spores, grains de pollen et surtout les kystes de dinoflagelles du cretace d'algerie. Un inventaire detaille des dinokystes, spores et grains de pollen fossilises dans les formations gafsa, zebbag et el aleg (d'age barremien? a santonien) a ete dresse: 50 genres et 83 especes de dinokystes ont ete reconnus ainsi que 30 genres et 30 especes de spores et pollen dans les 283 echantillons analyses. La distribution verticale de l'ensemble des formes observees nous a conduit a definir: 7 intervalles pour le sondage man1 et 5 pour le sondage oum1 a partir des dinokystes, 5 intervalles pour man1 et 6 pour oum1 a partir des spores et pollen. Une correlation entre les deux puits a pu etre etablie. Compte tenu des quelques donnees fournies par les foraminiferes et des extensions de certains dinokystes, spores ou grains de pollen, precisement connues en d'autres lieux, il a ete possible de proposer un age pour chacun de ces differents intervalles et par la meme pour les formations traversees par ces deux sondages voisins. Concernant les coupes de terrain, nos premieres investigations ont permis de paralleliser la distribution de quelques formes interessantes de dinokystes, spores ou pollen avec la zonation fondee sur les foraminiferes planctoniques. Une comparaison avec les microflores du maroc et de la libye a ete effectuee, et une caracterisation des paleomilieux a ete tentee au niveau du sondage man1
Style APA, Harvard, Vancouver, ISO itp.
7

Hawke, Philip. "The pollen and spores of metropolitan Cape Town and their relationship with meteorological conditions". Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/21887.

Pełny tekst źródła
Streszczenie:
Bibliography: pages 182-202.
Cladosporium, in general, is the dominant atmospheric fungal spore. Fungal spores are, quantitatively, the dominant partner in the atmosphere. Meteorological factors such as wind speed and wind direction, precipitation, temperature, relative humidity, atmospheric pressure and atmospheric stability have been identified as affecting air spora concentrations and an attempt is made to explain the relationships involved. A thorough review of particle behaviour and current sampling methods indicates that the Burkard volumetric sampler was best suited for airspora sampling in Cape Town. Results of the research confirm that Poacear is the dominant pollen, but basidiospores are the dominant nant spores in the atmosphere.
Style APA, Harvard, Vancouver, ISO itp.
8

Tweddle, John C. "A high resolution palynological study of the Holocene vegetational development of central Holderness, eastern Yorkshire, with particular emphasis on the detection of prehistoric human activity". Thesis, University of Sheffield, 2000. http://etheses.whiterose.ac.uk/3507/.

Pełny tekst źródła
Streszczenie:
Compared to upland areas and Scotland, the Holocene vegetational history of lowland England is poorly known. This is particularly the case for the region of Holdemess, eastern Yorkshire, where only a low number of poor temporal resolution pollen diagrams have been published, none of which include analysis of microscopic charcoal content. The records are also largely undated and as a result reliable correlation between sites is not possible, and the timings of the key vegetation changes recorded in the data remain unknown. In this study, high resolution pollen and charcoal records were produced from four small (24 ha) infilled basins located within central Holderness. Complementary techniques of percentage loss-on-ignition and pollen preservation analysis were also employed, and a comprehensive radiocarbon-dating programme was undertaken to provide a secure chronological framework. The palaeoecological records produced provide a high temporal resolution reconstruction of the Holocene development of central Holderness, particularly during the Early-Mid Holocene, and allow consideration of the changing roles that ecological interactions, climate, and human influence have played in determining the Holocene vegetational composition of the region. A number of significant landscape-scale disturbances of inferred anthropogenic origin were identified from ca 9290 BP onwards and shown to vary significantly in timing, duration and character between sites. It is proposed that this palaeoecological data can be used to supplement the poor archaeological record of the area. Several key issues including the role of climatic instability in determining vegetational composition during the Early Holocene, the interpretation of incidences of cereal-type pollen, the use of the charcoal record as a proxy indicator of human activity, and the use of pollen preservation analysis as an interpretational tool are also considered.
Style APA, Harvard, Vancouver, ISO itp.
9

Coetzee, Kim. "Evaluation of the crossability between small grains". Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17796.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
10

Lee, Taekhee. "Bioaerosols in Homes Without Visible Mold Growth: Relationship Between Indoor and Outdoor Levels Determined by Different Methods". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1154619575.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
Więcej źródeł

Książki na temat "Spores and pollen grains"

1

Michel, Petzold, red. Spores & pollen. Cabriés: La Duraulié, 1989.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
2

Renault-Miskovsky, Josette. Spores et pollen. Lausanne: Delachaux et Niestlé, 1992.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
3

Stephen, Blackmore, Barnes S. H, Systematics Association i Linnean Society of London, red. Pollen and spores: Patterns of diversification. Oxford [England]: Published for the Systematics Association by Clarendon Press, 1991.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
4

M, Harley M., Morton C. M, Blackmore Stephen, Royal Botanic Gardens (Kew, England), Linnean Society of London, Natural History Museum (London, England) i Systematics Association, red. Pollen and spores: Morphology and biology. Kew: Royal Botanic Gardens in collaboration with the Linnean Society of London, the Natural History Museum and the Systematics Association, 2000.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
5

Kapp, Ronald O. Ronald O. Kapp's pollen and spores. Wyd. 2. College Station, TX: American Association of Stratigraphic Palynologists Foundation, 2000.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
6

Reille, Maurice. Pollen et spores d'Europe et d'Afrique du Nord. Marseille: Laboratoire de Botanique Historique et Palynologie, 1995.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
7

Reille, Maurice. Pollen et spores d'Europe et d'Afrique du Nord. Marseille: Laboratoire de Botanique historique et Palynologie, 1992.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
8

Raju, A. J. Solomon. Ecology of pollen and fungal spore. New Delhi: Today and Tomorrow's Printers and Publishers, 2010.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
9

Roubik, David W. Pollen and spores of Barro Colorado Island. [St. Louis]: Missouri Botanical Garden, 1991.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
10

Roubik, David W. Pollen and spores of Barro Colorado Island. [St. Louis]: Missouri Botanical Garden, 1991.

Znajdź pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
Więcej źródeł

Części książek na temat "Spores and pollen grains"

1

Reitz, Elizabeth J., i Myra Shackley. "Spores, Pollen, Phytoliths, Starch Grains, and Other Microbotanical Remains". W Manuals in Archaeological Method, Theory and Technique, 263–300. Boston, MA: Springer US, 2012. http://dx.doi.org/10.1007/978-1-4614-3339-2_9.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
2

Traverse, Alfred. "Spores/Pollen Morphology". W Paleopalynology, 87–154. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5610-9_5.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
3

Jain, Sreepat. "Pollen and Spores". W Fundamentals of Invertebrate Palaeontology, 43–65. New Delhi: Springer India, 2019. http://dx.doi.org/10.1007/978-81-322-3962-8_3.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
4

Armstrong, Howard A., i Martin D. Brasier. "Spores and Pollen". W Microfossils, 104–25. Malden, MA USA: Blackwell Publishing, 2013. http://dx.doi.org/10.1002/9781118685440.ch13.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
5

de Vernal, Anne. "Palynology (Pollen, Spores, etc.)". W Encyclopedia of Marine Geosciences, 1–10. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-007-6644-0_87-1.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
6

de Vernal, Anne. "Palynology (Pollen, Spores, etc.)". W Encyclopedia of Marine Geosciences, 1–9. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-007-6644-0_87-2.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
7

de Vernal, Anne. "Palynology (Pollen, Spores, etc.)". W Encyclopedia of Marine Geosciences, 1–9. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-007-6644-0_87-3.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
8

Traverse, Alfred. "Spores/Pollen Basic Biology". W Paleopalynology, 77–85. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5610-9_4.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
9

Cruden, Robert William. "Pollen grains: why so many?" W Pollen and Pollination, 143–65. Vienna: Springer Vienna, 2000. http://dx.doi.org/10.1007/978-3-7091-6306-1_8.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
10

Bernhardt, Christopher E., i Debra A. Willard. "Pollen and spores of terrestrial plants". W Handbook of Sea-Level Research, 218–32. Chichester, UK: John Wiley & Sons, Ltd, 2015. http://dx.doi.org/10.1002/9781118452547.ch14.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.

Streszczenia konferencji na temat "Spores and pollen grains"

1

Kadaikar, Aysha, Benjamin Guinot, Maria Trocan, Frederic Amiel, Patricia Conde-Cespedes, Gilles Oliver, Michel Thibaudon, Roland Sarda-Esteve i Dominique Baisnee. "Automatic Pollen Grains Counter". W 2019 3rd International Conference on Bio-engineering for Smart Technologies (BioSMART). IEEE, 2019. http://dx.doi.org/10.1109/biosmart.2019.8734251.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
2

Dhawale, V. R., J. A. Tidke i S. V. Dudul. "Neural network based classification of pollen grains". W 2013 International Conference on Advances in Computing, Communications and Informatics (ICACCI). IEEE, 2013. http://dx.doi.org/10.1109/icacci.2013.6637150.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
3

Santos, E. M. D. S., i A. R. S. Marcal. "Segmentation of Microscopic Images for Pollen Grains Detection". W 8th International Conference of Pattern Recognition Systems (ICPRS 2017). Institution of Engineering and Technology, 2017. http://dx.doi.org/10.1049/cp.2017.0169.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
4

Osmonbaeva, Kymbatkul B. "Pollinosis in the conditions of climate changes". W Innovations in Medical Science and Education. Dela Press Publishing House, 2022. http://dx.doi.org/10.56199/dpcsms.snvc2974.

Pełny tekst źródła
Streszczenie:
The aim of the study was to study the content of plant pollen and fungal spores in the air of Karakol of the Kyrgyz Republic and assessment of their contribution to the development of pollinosis in the conditions of climate changes. The article is devoted to the current problem of the impact of climate change on aerobiological particles – plant pollen and fungal spores. There is a worldwide trend for rising temperatures. The number of people suffering from allergies – pollinosis – is steadily increasing. Concentration of pollen of allergenic species may increase, the timing and duration of the dusting season may change. Moreover, in recent years, there is a sharp increase in pollen allergy morbidity observed in the country. Data from Karakol city for 2015-2017 showed that pollen of 34 plant taxa and 24 taxa of fungal spores were present in the air. The pollen of leading aeroallergens was contained in the air of Karakol in significant amounts and for a significant period. The novelty of the study was that for the first time in Kyrgyzstan, aerobiological studies were carried out with a volumetric method using volumetric certified Lanzoni apparatus. The idea that there is a need for programs, continuous aeropalynological studies that will predict the number, taxonomic composition and behavior of aeroallergens is substantiated. This has important public health implications, as it will allow an assessment of the allergenic environment, allowing people with allergies to avoid or reduce the severity of the course of the disease.
Style APA, Harvard, Vancouver, ISO itp.
5

Tsuruzoe, Kei, i Kazuhiro Hara. "Micro Sensors for Real-time Monitoring of Mold Spores and Pollen". W International Conference on Biomedical Electronics and Devices. SCITEPRESS - Science and and Technology Publications, 2015. http://dx.doi.org/10.5220/0005279301740179.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
6

Dhawale, V. R., J. A. Tidke i S. V. Dudul. "Efficient classification of pollen grains using computational intelligence approach". W 2014 International Conference for Convergence of Technology (I2CT). IEEE, 2014. http://dx.doi.org/10.1109/i2ct.2014.7092120.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
7

Slatt, Roger M., Neal O’Brien, Carlos Molinares-Blanco, Andrea Serna-Bernal, Emilio Torres i Paul Philp. "Pores, Spores, Pollen and Pellets: Small, but Significant Constituents of Resource Shales". W Unconventional Resources Technology Conference. Society of Exploration Geophysicists, American Association of Petroleum Geologists, Society of Petroleum Engineers, 2013. http://dx.doi.org/10.1190/urtec2013-065.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
8

Wu, Qiongshui, Yaojun Hu, Hengyu Ke, Libo Zeng i Yi Ding. "Study pollen grains in rice by using multispectral imaging techniques". W Biomedical Optics 2005, redaktorzy Gregory H. Bearman, Anita Mahadevan-Jansen i Richard M. Levenson. SPIE, 2005. http://dx.doi.org/10.1117/12.589589.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
9

Korobeynikov, Alexander, Yulia Kamalova, Mikhail Palabugin i Ivan Basov. "The use of convolutional neural network LeNet for pollen grains classification". W The IV International Forum "Instrumentation Engineering, Electronics and Telecommunications – 2018". Publishing House of Kalashnikov ISTU, 2018. http://dx.doi.org/10.22213/2658-3658-2018-38-44.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
10

Wang, Zihao, Yuchen Zhang, Yucheng Zhao i JianQiang Li. "Pollen Grains Image Data Augmentation and Processing Based on Unpaired Translation". W 2022 International Conference on Image Processing, Computer Vision and Machine Learning (ICICML). IEEE, 2022. http://dx.doi.org/10.1109/icicml57342.2022.10009657.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.

Raporty organizacyjne na temat "Spores and pollen grains"

1

Law, Edward, Samuel Gan-Mor, Hazel Wetzstein i Dan Eisikowitch. Electrostatic Processes Underlying Natural and Mechanized Transfer of Pollen. United States Department of Agriculture, maj 1998. http://dx.doi.org/10.32747/1998.7613035.bard.

Pełny tekst źródła
Streszczenie:
The project objective was to more fully understand how the motion of pollen grains may be controlled by electrostatic forces, and to develop a reliable mechanized pollination system based upon sound electrostatic and aerodynamic principles. Theoretical and experimental analyses and computer simulation methods which investigated electrostatic aspects of natural pollen transfer by insects found that: a) actively flying honeybees accumulate ~ 23 pC average charge (93 pC max.) which elevates their bodies to ~ 47 V likely by triboelectrification, inducing ~ 10 fC of opposite charge onto nearby pollen grains, and overcoming their typically 0.3-3.9 nN detachment force resulting in non-contact electrostatic pollen transfer across a 5 mm or greater air gap from anther-to-bee, thus providing a theoretical basis for earlier experimental observations and "buzz pollination" events; b) charge-relaxation characteristics measured for flower structural components (viz., 3 ns and 25 ns time constants, respectively, for the stigma-style vs. waxy petal surfaces) ensure them to be electrically appropriate targets for electrodeposition of charged pollen grains but not differing sufficiently to facilitate electrodynamic focusing onto the stigma; c) conventional electrostatic focusing beneficially concentrates pollen-deposition electric fields onto the pistill tip by 3-fold as compared to that onto underlying flower structures; and d) pollen viability is adequately maintained following exposure to particulate charging/management fields exceeding 2 MV/m. Laboratory- and field-scale processes/prototype machines for electrostatic application of pollen were successfully developed to dispense pollen in both a dry-powder phase and in a liquid-carried phase utilizing corona, triboelectric, and induction particulate-charging methods; pollen-charge levels attained (~ 1-10 mC/kg) provide pollen-deposition forces 10-, 77-, and 100-fold greater than gravity, respectively, for such charged pollen grains subjected to a 1 kV/cm electric field. Lab and field evaluations have documented charged vs. ukncharged pollen deposition to be significantly (a = 0.01-0.05) increased by 3.9-5.6 times. Orchard trials showed initial fruit set on branches individually treated with electrostatically applied pollen to typically increase up to ~ 2-fold vs. uncharged pollen applications; however, whole-tree applications have not significantly shown similar levels of benefit and corrective measures continue. Project results thus contribute important basic knowledge and applied electrostatics technology which will provide agriculture with alternative/supplemental mechanized pollination systems as tranditional pollen-transfer vectors are further endangered by natural and man-fade factors.
Style APA, Harvard, Vancouver, ISO itp.
2

Keller, Maureen D., i Patricia A. Matrai. Optical Characteristics of Pollen Grains in Coastal Waters of the Gulf of Maine. Fort Belvoir, VA: Defense Technical Information Center, wrzesień 1997. http://dx.doi.org/10.21236/ada618368.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
3

Firon, Nurit, Prem Chourey, Etan Pressman, Allen Hartwell i Kenneth J. Boote. Molecular Identification and Characterization of Heat-Stress-Responsive Microgametogenesis Genes in Tomato and Sorghum - A Feasibility Study. United States Department of Agriculture, październik 2007. http://dx.doi.org/10.32747/2007.7591741.bard.

Pełny tekst źródła
Streszczenie:
Exposure to higher than optimal temperatures - heat-stress (HS) - is becoming increasingly common to all crop plants worldwide. Heat stress coinciding with microgametogenesis, especially during the post-meiotic phase that is marked by starch biosynthesis, is often associated with starch-deficient pollen and male sterility and ultimately, greatly reduced crop yields. The molecular basis for the high sensitivity of developing pollen grains, on one hand, and factors involved in pollen heat-tolerance, on the other, is poorly understood. The long-term goal of this project is to provide a better understanding of the genes that control pollen quality under heat-stress conditions. The specific objectives of this project were: (1) Determination of the threshold heat stress temperature(s) that affects tomato and sorghum pollen quality whether: a) Chronic mild heat stress conditions (CMHS), or b) Acute heat stress (AHS). (2) Isolation of heat-responsive, microgametogenesis-specific sequences. During our one-year feasibility project, we have accomplished the proposed objectives as follows: Objectrive 1: We have determined the threshold HS conditions in tomato and sorghum. This was essential for achieving the 2nd objective, since our accumulated experience (both Israeli and US labs) indicate that when temperature is raised too high above "threshold HS levels" it may cause massive death of the developing pollen grains. Above-threshold conditions have additional major disadvantages including the "noise" caused by induced expression of genes involved in cell death and masking of the differences between heatsensitive and heat-tolerant pollen grains. Two different types of HS conditions were determined: a) Season-long CMHS conditions: 32/26°C day/night temperatures confirmed in tomato and 36/26°C day maximum/night minimum temperatures in sorghum. b) Short-term AHS: In tomato, 2 hour exposure to 42-45°C (at 7 to 3 days before anthesis) followed by transfer to 28/22±2oC day/night temperatures until flower opening and pollen maturation, caused 50% reduced germinating pollen in the heat-sensitive 3017 cv.. In sorghum, 36/26°C day/night temperatures 10 to 5 days prior to panicle emergence, occurring at 35 days after sowing (DAS) in cv. DeKalb28E, produced starch-deficient and sterile pollen. Objective 2: We have established protocols for the high throughput transcriptomic approach, cDNA-AFLP, for identifying and isolating genes exhibiting differential expression in developing microspores exposed to either ambient or HS conditions and created a databank of HS-responsivemicrogametogenesis-expressed genes. A subset of differentially displayed Transcript-Derived Fragments (TDFs) that were cloned and sequenced (35 & 23 TDFs in tomato and sorghum, respectively) show close sequence similarities with metabolic genes, genes involved in regulation of carbohydrate metabolism, genes implicated in thermotolerance (heat shock proteins), genes involved in long chain fatty acids elongation, genes involved in proteolysis, in oxidation-reduction, vesicle-mediated transport, cell division and transcription factors. T-DNA-tagged Arabidopsis mutants for part of these genes were obtained to be used for their functional analysis. These studies are planned for a continuation project. Following functional analyses of these genes under HS – a valuable resource of genes, engaged in the HS-response of developing pollen grains, that could be modulated for the improvement of pollen quality under HS in both dicots and monocots and/or used to look for natural variability of such genes for selecting heat-tolerant germplasm - is expected.
Style APA, Harvard, Vancouver, ISO itp.
4

Hristova, Viktoria, i Vladimir Bozukov. Fossil Flower Remains with In Situ Pollen Grains from the Middle Miocene Sediments of the Satovcha Graben (SW Bulgaria). "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, luty 2018. http://dx.doi.org/10.7546/crabs.2018.02.10.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
5

Hristova, Viktoria, i Vladimir Bozukov. Fossil Flower Remains with In Situ Pollen Grains from the Middle Miocene Sediments of the Satovcha Graben (SW Bulgaria). "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, luty 2018. http://dx.doi.org/10.7546/grabs2018.2.10.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
6

Miller, Gad, i Jeffrey F. Harper. Pollen fertility and the role of ROS and Ca signaling in heat stress tolerance. United States Department of Agriculture, styczeń 2013. http://dx.doi.org/10.32747/2013.7598150.bard.

Pełny tekst źródła
Streszczenie:
The long-term goal of this research is to understand how pollen cope with stress, and identify genes that can be manipulated in crop plants to improve reproductive success during heat stress. The specific aims were to: 1) Compare heat stress dependent changes in gene expression between wild type pollen, and mutants in which pollen are heat sensitive (cngc16) or heat tolerant (apx2-1). 2) Compare cngc16 and apx2 mutants for differences in heat-stress triggered changes in ROS, cNMP, and Ca²⁺ transients. 3) Expand a mutant screen for pollen with increased or decreased thermo-tolerance. These aims were designed to provide novel and fundamental advances to our understanding of stress tolerance in pollen reproductive development, and enable research aimed at improving crop plants to be more productive under conditions of heat stress. Background: Each year crop yields are severely impacted by a variety of stress conditions, including heat, cold, drought, hypoxia, and salt. Reproductive development in flowering plants is highly sensitive to hot or cold temperatures, with even a single hot day or cold night sometimes being fatal to reproductive success. In many plants, pollen tube development and fertilization is often the weakest link. Current speculation about global climate change is that most agricultural regions will experience more extreme environmental fluctuations. With the human food supply largely dependent on seeds, it is critical that we consider ways to improve stress tolerance during fertilization. The heat stress response (HSR) has been intensively studied in vegetative tissues, but is poorly understood during reproductive development. A general paradigm is that HS is accompanied by increased production of reactive oxygen species (ROS) and induction of ROS-scavenging enzymes to protect cells from excess oxidative damage. The activation of the HSR has been linked to cytosolic Ca²⁺ signals, and transcriptional and translational responses, including the increased expression of heat shock proteins (HSPs) and antioxidative pathways. The focus of the proposed research was on two mutations, which have been discovered in a collaboration between the Harper and Miller labs, that either increase or decrease reproductive stress tolerance in a model plant, Arabidopsis thaliana (i.e., cngc16--cyclic nucleotide gated channel 16, apx2-1--ascorbate peroxidase 2,). Major conclusions, solutions, achievements. Using RNA-seq technology, the expression profiles of cngc16 and apx2 pollen grains were independently compared to wild type under favourable conditions and following HS. In comparison to a wild type HSR, there were 2,776 differences in the transcriptome response in cngc16 pollen, consistent with a model in which this heat-sensitive mutant fails to enact or maintain a normal wild-type HSR. In a comparison with apx2 pollen, there were 900 differences in the HSR. Some portion of these 900 differences might contribute to an improved HSR in apx2 pollen. Twenty-seven and 42 transcription factor changes, in cngc16 and apx2-1, respectively, were identified that could provide unique contributions to a pollen HSR. While we found that the functional HS-dependent reprogramming of the pollen transcriptome requires specific activity of CNGC16, we identified in apx2 specific activation of flavonol-biosynthesis pathway and auxin signalling that support a role in pollen thermotolerance. Results from this study have identified metabolic pathways and candidate genes of potential use in improving HS tolerance in pollen. Additionally, we developed new FACS-based methodology that can quantify the stress response for individual pollen in a high-throughput fashion. This technology is being adapted for biological screening of crop plant’s pollen to identify novel thermotolerance traits. Implications, both scientific and agricultural. This study has provided a reference data on the pollen HSR from a model plant, and supports a model that the HSR in pollen has many differences compared to vegetative cells. This provides an important foundation for understanding and improving the pollen HSR, and therefor contributes to the long-term goal of improving productivity in crop plants subjected to temperature stress conditions. A specific hypothesis that has emerged from this study is that pollen thermotolerance can be improved by increasing flavonol accumulation before or during a stress response. Efforts to test this hypothesis have been initiated, and if successful have the potential for application with major seed crops such as maize and rice.
Style APA, Harvard, Vancouver, ISO itp.
7

Bringué, M., R. A. Fensome, T. P. Poulton, J M Galloway, J. P. Bujak, M L Golding, M. J. Orchard i G. L. Williams. The 2020 Canada datapack for TimeScale Creator: a new tool for Mesozoic - Cenozoic stratigraphy of the Canadian north. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/326099.

Pełny tekst źródła
Streszczenie:
The Geo-mapping for Energy and Minerals (GEM) program (2010-2020) provided a unique opportunity to advance the current level of understanding of the geological history of the Canadian North. In this contribution, based on the Trans-GEM Event Stratigraphy activity, a compilation of Mesozoic-Cenozoic stratigraphic data from across the GEM program regions and beyond is presented, with a focus on biostratigraphic events, using TimeScale Creator, a JAVA package that facilitates the compilation and comparison of large amounts of stratigraphic data while keeping track of changing absolute ages. The '2020 Canada datapack', which incorporates some information re-evaluated and refined from an earlier datapack, includes schemes using dinoflagellate cysts, spores and pollen, foraminifers and conodonts, and a new synthesis of Canadian Arctic Jurassic ammonite and Buchia bivalve biostratigraphy. This datapack will continue to be augmented after completion of the GEM program and will become a major tool in supporting an understanding of Canada's sedimentary basins, their resource potential and management.
Style APA, Harvard, Vancouver, ISO itp.
8

White, J. M. Figure 4. Percentages of terrestrial palynomorphs from the Mallik 2L-38 well analyzed by J.M. White. a) Terrestrial pollen and spores from the Mallik 2L-38 well; b) 886 - 952 m core; c) 110 - 118 m core. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2009. http://dx.doi.org/10.4095/247353.

Pełny tekst źródła
Style APA, Harvard, Vancouver, ISO itp.
9

Dolby, G. Palynological analysis of Carboniferous outcrop and corehole samples from the 1993–1995 Magdalen Basin NATMAP Project, with updated data files, locality data, and lists of taxa identified, Prince Edward Island, Nova Scotia, New Brunswick, and Quebec. Natural Resources Canada/CMSS/Information Management, 2024. http://dx.doi.org/10.4095/pcqvf1214e.

Pełny tekst źródła
Streszczenie:
Le projet NATMAP du bassin de la Madeleine était un effort de coopération et de collaboration visant à aborder l'histoire géologique de la fin du Paléozoïque et le potentiel de ressources de l'ouest du bassin des Maritimes. Ce bassin se trouve sous une grande partie du golfe du Saint-Laurent et peut être étudié à terre dans certaines parties de cinq provinces de l'est du Canada. Environ trente participants, représentant les services géoscientifiques régionaux et nationaux du gouvernement, des universités et du secteur privé, ont entrepris des études multidisciplinaires des parties terrestres du bassin entre 1993 et ​​1995. Des études stratigraphiques de ce vaste bassin sédimentaire ont soutenu cet effort collectif. De telles études ont été historiquement étayées par la paléontologie des invertébrés, qui permet de situer les roches dans une époque géologique relative. Comme les fossiles utilisés plus traditionnellement sont largement indisponibles dans un bassin dominé par des roches non marines, la palynologie, en particulier l'étude des spores et du pollen, a fourni un outil idéal adapté à l'étude des roches terrestres. Graham Dolby, consultant et l'un des deux seuls spécialistes en palynologie du Carbonifère au Canada à cette époque, a apporté un soutien fondamental aux études tout au long du projet du Bassin de la Madeleine. Les matériaux analysés provenaient en grande partie d'affleurements rocheux de la Nouvelle-Écosse et du sud-est du Nouveau-Brunswick, où se concentraient les activités du projet. La palynologie de certains puits d'exploration forés en Nouvelle-Écosse, à l'Île-du-Prince-Édouard et au Nouveau-Brunswick, ainsi que de plusieurs puits d'hydrocarbures profonds forés au large dans le golfe du Saint-Laurent, a également été analysée. Le but de ce fichier ouvert à plusieurs composants est de rendre publiques les contributions NATMAP de Dolby. Les données palynologiques présentées dans ce dossier ouvert sont aussi précieuses aujourd'hui qu'elles l'étaient dans les années 1990, mais au cours des trente années qui ont suivi, des améliorations significatives dans la compréhension de la distribution du pollen et dans l'application à la stratigraphie du bassin des Maritimes ont été réalisées. Dans la présente version, Dolby a mis à jour les implications stratigraphiques qui peuvent être tirées de ses analyses antérieures des échantillons NATMAP pour refléter des zonages plus actuels. Les données palynologiques mises à jour ont été appliquées par Atkinson et al. (2020), dans leur évaluation des ressources pétrolières du bassin des Maritimes, dans le cadre du programme de projets de conservation marine. Pendant que le projet NATMAP du bassin de la Madeleine était opérationnel, les données palynologiques et l'évaluation de la position biostratigraphique ont été renvoyées au projet en fonction uniquement de l'identification de l'échantillon ou du nom du puits, car les emplacements des échantillons soumis étaient bien connus des géologues participants. Pour remédier à ce manque de données de localisation, les données sommaires, y compris la plupart des emplacements d'échantillonnage ainsi que les listes de taxons récupérés, ont été extraites de BASIN, une base de données d'archives majeure de la Commission géologique du Canada – Atlantique. Ces données sont fournies sous forme de feuille de calcul et sont accessibles dans BASIN ici : https://basin.marine-geo.canada.ca/wells/natmap_index_e.php
Style APA, Harvard, Vancouver, ISO itp.
10

Weiss, David, i Neil Olszewski. Manipulation of GA Levels and GA Signal Transduction in Anthers to Generate Male Sterility. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7580678.bard.

Pełny tekst źródła
Streszczenie:
The original objectives of the research were: i. To study the role of GA in anther development, ii. To manipulate GA and/or GA signal transduction levels in the anthers in order to generate male sterility. iii. To characterize the GA signal transduction repressor, SPY. Previous studies have suggested that gibberellins (GAs) are required for normal anther development. In this work, we studied the role of GA in the regulation of anther development in petunia. When plants were treated with the GA-biosynthesis inhibitor paclobutrazol, anther development was arrested. Microscopic analysis of these anthers revealed that paclobutrazol inhibits post-meiotic developmental processes. The treated anthers contained pollen grains but the connective tissue and tapetum cells were degenerated. The expression of the GA-induced gene, GIP, can be used in petunia as a molecular marker to: study GA responses. Analyses of GIP expression during anther development revealed that the gene is induced only after microsporogenesis. This observation further suggests a role for GA in the regulation of post-meiotic processes during petunia anther development. Spy acts as a negative regulator of gibberellin (GA) action in Arabidopsis. We cloned the petunia Spy homologue, PhSPY, and showed that it can complement the spy-3 mutation in Arabidopsis. Overexpression of Spy in transgenic petunia plants affected various GA-regulated processes, including seed germination, shoot elongation, flower initiation, flower development and the expression of a GA- induced gene, GIP. In addition, anther development was inhibited in the transgenic plants following microsporogenesis. The N-terminus of Spy contains tetratricopeptide repeats (TPR). TPR motifs participate in protein-protein interactions, suggesting that Spy is part of a multiprotein complex. To test this hypothesis, we over-expressed the SPY's TPR region without the catalytic domain in transgenic petunia and generated a dominant- negative Spy mutant. The transgenic seeds were able to germinate on paclobutrazol, suggesting an enhanced GA signal. Overexpression of PhSPY in wild type Arabidopsis did not affect plant stature, morphology or flowering time. Consistent with Spy being an O-GlcNAc transferase (OGT), Spy expressed in insect cells was shown to O-GlcNAc modify itself. Consistent with O-GlcNAc modification playing a role in GA signaling, spy mutants had a reduction in the GlcNAc modification of several proteins. After treatment of the GA deficient, gal mutant, with GA3 the GlcNAc modification of proteins of the same size as those affected in spy mutants exhibited a reduction in GlcNAcylation. GA-induced GlcNAcase may be responsible for this de-GlcNAcylation because, treatment of gal with GA rapidly induced an increase in GlcNAcase activity. Several Arabidopsis proteins that interact with the TPR domain of Spy were identified using yeast two-hybrids screens. One of these proteins was GIGANTEA (GI). Consistent with GI and Spy functioning as a complex in the plant the spy-4 was epistatic to gi. These experiments also demonstrated that, in addition to its role in GA signaling, Spy functions in the light signaling pathways controlling hypocotyl elongation and photoperiodic induction of flowering. A second Arabidopsis OGT, SECRET AGENT (SCA), was discovered. Like SPY, SCA O-GlcNAc modifies itself. Although sca mutants do not exhibit dramatic phenotypes, spy/sca double mutants exhibit male and female gamete and embryo lethality, indicating that Spy and SCA have overlapping functions. These results suggest that O-GlcNAc modification is an essential modification in plants that has a role in multiple signaling pathways.
Style APA, Harvard, Vancouver, ISO itp.
Możesz być także zainteresowany rozszerzonymi bibliografiami na temat „Spores and pollen grains” dla poszczególnych typów źródeł:
Artykuły w czasopismach Rozprawy doktorskie Książki
Oferujemy zniżki na wszystkie plany premium dla autorów, których prace zostały uwzględnione w tematycznych zestawieniach literatury. Skontaktuj się z nami, aby uzyskać unikalny kod promocyjny!

Do bibliografii