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Pollen Grains (pollen + grain)
Selected AbstractsAirborne fungal spores, pollen grains, and vegetable cells in routine Papanicolaou smearsDIAGNOSTIC CYTOPATHOLOGY, Issue 6 2004Ph.D., Rafael Martínez-Girón M.D. Abstract The objective was to demonstrate the presence of airborne fungal spores, pollen grains, and vegetable cells in smears and establish their significance. Microscopic examination was of smears stained by the Papanicolaou technique. We found several types of airborne spores (Alternaria, Exserohilum, Aspergillus, Cladosporium, Epicoccum, Curvularia, and Ascosmycete), pollen grains (Lilium, bullrush, Pinus, Acacia, hazelnut, and oak), and several types of vegetable cells. The existence of these structures may be due to intrinsic or to extrinsic contamination of the sample. Anemophilous fungi spores and pollen grains have been shown to possess great allergenic capacity. Pollen grains and vegetable cells may be mistaken for certain microorganisms or malignant cells. Diagn. Cytopathol. 2004;30:381,385. © 2004 Wiley-Liss, Inc. [source] Pollen morphology of Alcea L. and Althaea L. genera (Malvaceae) in TurkeyFEDDES REPERTORIUM, Issue 7-8 2009E. Cabi Pollen grains of 22 taxa from Alcea L. and Althaea L. genera (Malvaceae) were examined using light microscope and scanning electron microscope to assess whether pollen traits can be used to delimitate at generic and specific levels. Furthermore quantitative data were subjected to cluster analysis. The pollen grains of Althaea genus are spheroidal, pantoporate, echinate which is characterized by having subglobose pattern at the base of echinae. The pollen of Alcea are spheroidal, pantoporate, echinate and baculate. Distances between pori are longer in Althaea (9.04,12.75 ,m) pollens than pollens of Alcea (5.12,7.28 ,m). The results of this study confirmed that differences about pollen characteristics among the taxa are not functional in separating taxa at specific level especially in Alcea genus, whereas there have been clear differences based on pollen morphology between two closely related genera. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Lactoferrin decreases pollen antigen-induced allergic airway inflammation in a murine model of asthmaIMMUNOLOGY, Issue 2 2006Marian L. Kruzel Summary Pollen grains contain reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidases and in contact with mucosal surfaces generate superoxide anion (O2,,). In the presence of iron, O2,, may be converted to more reactive oxygen radicals, such as to H2O2 and/or ,OH, which may augment antigen-induced airway inflammation. The aim of the study was to examine the impact of lactoferrin (LF), an iron-binding protein, on ragweed (Ambrosia artemisiifolia) pollen extract (RWE)-induced cellular oxidative stress levels in cultured bronchial epithelial cells and accumulation of inflammatory and mucin-producing cells in airways in a mouse model of allergic airway inflammation. Results show that LF lowered RWE-induced increase in cellular reactive oxygen species (ROS) levels in bronchial epithelial cells. Most importantly, LF significantly decreased accumulation of eosinophils into airways and subepithelium of intranasally challenged, sensitized mice. LF also prevented development of mucin-producing cells. Amb a 1, the major allergenic ragweed pollen antigen lacking NAD(P)H oxidase activity, induced low-grade airway inflammation. When administered along with glucose oxidase (G-ox), a superoxide-generating enzyme, Amb a 1 induced robust airway inflammation, which was significantly lowered by LF. Surprisingly, LF decreased also inflammation caused by Amb a 1 alone. Iron-saturated hololactoferrin had only a marginal effect on RWE-induced cellular ROS levels and RWE- or Amb a 1 plus G-ox-induced inflammation. We postulate that free iron in the airways chemically reduces O2,, to more reactive species which augment antigen-induced inflammation in a mouse model of asthma. Our results suggest the utility of LF in human allergic inflammatory disorders. [source] Nectar and Pollen Sources for Honeybee (Apis cerana cerana Fabr.) in Qinglan Mangrove Area, Hainan Island, ChinaJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 11 2006Yi-Feng Yao Abstract In the present study, nectar and pollen sources for honeybee (Apis cerana cerana Fabr.) were studied in Qinglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load (corbicular and gut contents) from honeybees collected in October and November 2004. Qualitative and quantitative melittopalynological analysis of the natural honey sample showed that the honey is of unifloral type with Mimosa pudica L. (Mimosaceae) as the predominant (89.14%) source of nectar and pollen for A. cerana cerana in October. Members of Araceae are an important minor (3%-15%) pollen type, whereas those of Arecaceae are a minor (<3%) pollen type. Pollen grains of Nypa fruticans Wurmb., Rhizophora spp., Excoecaria agallocha L., Lumnitzera spp., Bruguiera spp., Kandelia candel Druce, and Ceriops tagal (Perr.) C. B. Rob. are among the notable mangrove taxa growing in Qinglan mangrove area recorded as minor taxa in the honey. The absolute pollen count (i.e. the number of pollen grains/10 g honey sample) suggests that the honey belongs to Group V (>1 000 000). Pollen analysis from the corbicular and gut contents of A. cerana cerana revealed the highest representation (95.60%) of members of Sonneratia spp. (Sonneratiaceae), followed by Bruguiera spp. (Rhizophoraceae), Euphorbiaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardiaceae, and Rubiaceae. Of these plants, those belonging to Sonneratia plants are the most important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November. (Managing editor: Ya-Qin Han) [source] Palynotaxonomy of Brazilian species of Polygala subgenus HebecladaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2008ANA CRISTINA ANDRADE DE AGUIAR This study used pollen morphology to address taxonomic controversies related to several species belonging to subgenus Hebeclada of the genus Polygala (Polygalaceae). According to the last traditionally accepted revision of this subgenus, it comprises 40 species. Nevertheless, a recent taxonomic treatment applying more comprehensive criteria reduced this number to only nine species. Our work focused on 15 traditionally accepted species that occur in Brazil, fourteen of which have been considered as only six species in this recent taxonomic study. Pollen grains from floral buds at pre-anthesis were collected from herbarium specimens and analysed using both visible light and scanning electron microscopy. Most of the traditionally accepted species were distinguished by different combinations of several pollen-related features, in particular colpi number (13 or 15), pollen size and shape, and endoaperture type (endocingulate or not) and arrangement (parallel or sinuous). The species accepted in the recent taxonomic treatment could not be discriminated by pollen characters. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 609,619. [source] Cytogenetics of species of Chamaecrista (Leguminosae , Caesalpinioideae) native to southern BrazilBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2006ELAINE BIONDO Chromosome numbers, karyotypes, meiotic behaviour and pollen analysis are presented for species of Chamaecrista Moench (Leguminosae, Caesalpinioideae, Cassieae) native to southern Brazil: C. nictitans ssp. patellaria, C. nictitans ssp. disadena, C. repens, C. rotundifolia, C. flexuosa, C. vestita and C. desvauxii. Meiotic behaviour is reported for the first time for all the taxa and was very regular; only bivalents were formed at diakinesis and metaphase I, chromosome disjunction and segregation were regular at anaphases I and II, meiotic indexes were over 99% and pollen fertility was over 92%. Pollen grains were subprolate in C. flexuosa and C. vestita and prolate,spheroidal in the other taxa. Karyotypes were symmetrical in all six species and the data are original, except for C. nictitans ssp. patellaria. Chromosome number is presented for the first time for C. repens (2n = 16) and has been confirmed for the other taxa: 2n = 14 for C. desvauxii, 2n = 32 for the tetraploid C. nictitans ssp. patellaria and C. nictitans ssp. disadena, and 2n = 16 for the other species. These two basic numbers found in the genus, x = 7 and x = 8, point to chromosome evolution by dysploidy, which has also been accompanied by polyploidy. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 150, 429,439. [source] The exine ultrastructure of pollen grains in Gnetum (Gnetaceae) from China and its bearing on the relationship with the ANITA GroupBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2004YI-FENG YAO Pollen grains of six species of Gnetum, G. parvifolium, G. hainanense, G. luofuense, G. pendulum, G. cleistostachyum and G. montanum, collected from China were examined using light, scanning and transmission electron microscopy. Pollen grains of Gnetum are subspheroidal or irregular-apolar, inaperturate, 11.21,22.44 µm in long axis and 9.34,20.47 µm in short axis. The exine surface is covered with spinules, 0.50(0.30,0.71) µm long spaced on average 1.12(0.81,1.46) µm apart. The exine is about 0.55 µm thick and comprises ectexine and endexine. The ectexine includes a thin tectum and an infratectal granular layer. The tectum protrudes outwards, forming the spinules. The endexine is composed of discontinuous lamellae, with lacunae between lamellae. The pollen grains of Gnetum are compared with those of Ephedra and Welwitschia, and also those of the ANITA Group of angiosperms, including Amborellaceae, Nymphaeales, Illiciales, Trimeniaceae and Austrobaileyaceae. The exine ultrastructures of Gnetum, Ephedra and Welwitschia are quite similar, consisting of tectum, granular layer and lamellated endexine. The exine ultrastructure of Gnetum is also similar to that of Nymphaea colorata (Nymphaeaceae) in the transitional region between the proximal and distal poles, but differs from that of Amborellaceae, Illicium religiosum (Illiciaceae), Schisandra (Schisandraceae), Trimeniaceae and Austrobaileyaceae. This comparison of exine ultrastructure provides new evidence for consideration of the relationship between Gnetum and the ANITA Group. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 415,425. [source] Eucalyptus pollen grain emptying by two Australian nectarivorous psittacinesJOURNAL OF AVIAN BIOLOGY, Issue 3 2001B. D. Gartrell The relative importance of pollen as a source of protein to vertebrates is controversial. In nectarivorous psittacine birds, field studies support its importance, but an experimental study in a nectarivorous parrot showed that less than 7% of pollen grains were emptied. We investigated pollen grain emptying by two nectarivorous Australian parrots, the Swift Parrot Lathamus discolor and the Musk Lorikeet Glossopsitta concinna. We used a controlled experiment, and examined pollen located at different levels through the alimentary tract of wild L. discolor. There was significant emptying of pollen grains (x=45.4%±1.91 s.e.) by all birds in the experimental trials. There was also a progressive increase in the percentage of pollen grains emptied at different sites along the alimentary tract in wild birds (crop x=24.2%±4.44 s.e., proventriculus x=34.0%±7.29 s.e., duodenum x=54.3%±5.42 s.e. and distal intestine x=64.2%±4.68 s.e.). The percentage of pollen grains emptied by captive L. discolor in the experimental trial (x=44.1%±2.77 s.e.) was not significantly different from that found in wild L. discolor (x=40.3%±4.25 s.e.). Both species of nectarivorous parrot were able to rapidly ingest large quantities of Eucalyptus pollen and appeared to empty the pollen grains efficiently. Eucalyptus pollen appears to be an important source of protein for these birds. [source] Application of microscopy in authentication of traditional Tibetan medicinal plant Halenia ellipticaMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2008Jie Li Abstract Halenia elliptica D. Don, a popularly used ethnodrug from Qinghai-Tibetan plateau, was studied to reveal the indispensable morphoanatomic details. The fixed, sectioned, and stained plant materials as well as the epidermis, powder, and maceration materials were studied using light microscope according to the usual microscopic techniques. The results of the microscopic features were systematic described and illustrated. In the root, an endodermal cell was divided into 8-16-22 and 38-50-62 daughter cells in transverse section and in face view, respectively, and 9-11-13 phloem strands were present in primary structure; in the stem, stone cells were observed in the cortex, pericycle, and external phloem while 17-19-21 internal phloem strands were present in an incontinuous ring; in the pedicel, 8-10-12 internal phloem strands were observed to form an incontinuous ring; anisocytic and anomocytic stomata were present in leaf and sepal epidermis; pollen grain was with three germinal apertures and furrows; a few tracheids, a large number of spiral vessels, and various fibers were observed. Also, semiquantitative and quantitative micrographic parameter tables were simultaneously presented. Further, the key authentication parameters were concluded. The study indicated that light microscopy and related techniques could be unambiguously applied to the authentication of Halenia elliptica. Microsc. Res. Tech., 2008. © 2007 Wiley-Liss, Inc. [source] Airborne fungal spores, pollen grains, and vegetable cells in routine Papanicolaou smearsDIAGNOSTIC CYTOPATHOLOGY, Issue 6 2004Ph.D., Rafael Martínez-Girón M.D. Abstract The objective was to demonstrate the presence of airborne fungal spores, pollen grains, and vegetable cells in smears and establish their significance. Microscopic examination was of smears stained by the Papanicolaou technique. We found several types of airborne spores (Alternaria, Exserohilum, Aspergillus, Cladosporium, Epicoccum, Curvularia, and Ascosmycete), pollen grains (Lilium, bullrush, Pinus, Acacia, hazelnut, and oak), and several types of vegetable cells. The existence of these structures may be due to intrinsic or to extrinsic contamination of the sample. Anemophilous fungi spores and pollen grains have been shown to possess great allergenic capacity. Pollen grains and vegetable cells may be mistaken for certain microorganisms or malignant cells. Diagn. Cytopathol. 2004;30:381,385. © 2004 Wiley-Liss, Inc. [source] The impact of an alien plant on a native plant,pollinator network: an experimental approachECOLOGY LETTERS, Issue 7 2007Martha E. Lopezaraiza, Mikel Abstract Studies of pairwise interactions have shown that an alien plant can affect the pollination of a native plant, this effect being mediated by shared pollinators. Here we use a manipulative field experiment, to investigate the impact of the alien plant Impatiens glandulifera on an entire community of coflowering native plants. Visitation and pollen transport networks were constructed to compare replicated I. glandulifera invaded and I. glandulifera removal plots. Invaded plots had significantly higher visitor species richness, visitor abundance and flower visitation. However, the pollen transport networks were dominated by alien pollen grains in the invaded plots and consequently higher visitation may not translate in facilitation for pollination. The more generalized insects were more likely to visit the alien plant, and Hymenoptera and Hemiptera were more likely to visit the alien than Coleoptera. Our data indicate that generalized native pollinators can provide a pathway of integration for alien plants into native visitation systems. [source] FLIES AND FLOWERS IN DARWIN'S RACEEVOLUTION, Issue 1 2009Anton Pauw The idea of coevolution originated with Darwin's proposal that long-proboscid pollinators and long-tubed flowers might be engaged in reciprocal selection, but this has not been demonstrated. Here we test key aspects of Darwin's hypothesis of reciprocal selection in an experiment with naturally interacting populations of extremely long-proboscid flies (Moegistorhynchus longirostris: Nemestinidae) and long-tubed irises (Lapeirousia anceps: Iridaceae). We show that the benefit derived by both the fly (volume of nectar consumed) and the plant (number pollen grains received) depends on the relative length of their interacting organs. Each trait is shown to act both as agent and target in directional reciprocal selection, potentially leading to a race. This understanding of how fitness in both species varies in relation to the balance of their armament allows us to make tentative predictions about the nature of selection across multiple communities. We find that in each community a core group of long-tubed plant species might together be involved in diffuse coevolution with the fly. In poorly matched populations, the imbalance in armament is too great to allow reciprocal selection to act, and these species might instead experience one-sided selection that leads to convergence with the core species. Reciprocal selection drives the evolution of the community, then, additional species become attached to the network of interacting mutualists by convergence. [source] TOWARD THE EVOLUTIONARY GENOMICS OF GAMETOPHYTIC DIVERGENCE: PATTERNS OF TRANSMISSION RATIO DISTORTION IN MONKEYFLOWER (MIMULUS) HYBRIDS REVEAL A COMPLEX GENETIC BASIS FOR CONSPECIFIC POLLEN PRECEDENCEEVOLUTION, Issue 12 2008Lila Fishman Conspecific pollen precedence (CPP) is a major component of reproductive isolation between many flowering plant taxa and may reveal mechanisms of gametophytic evolution within species, but little is known about the genetic basis and evolutionary history of CPP. We systematically investigated the genetic architecture of CPP using patterns of transmission ratio distortion (TRD) in F2 and backcross hybrids between closely related species of Mimulus (Phrymaceae) with divergent mating systems. We found that CPP in Mimulus hybrids was polygenic and was the majority source of interspecific TRD genome-wide, with at least eight genomic regions contributing to the transmission advantage of M. guttatus pollen grains on M. guttatus styles. In aggregate, these male-specific transmission ratio distorting loci (TRDLs) were more than sufficient to account for the 100% precedence of pure M. guttatus pollen over M. nasutus pollen in mixed pollinations of M. guttatus. All but one of these pollen TRDLs were style-dependent; that is, we observed pollen TRD in F1 and/or M. guttatus styles, but not in M. nasutus styles. These findings suggest that species-specific differences in pollen tube performance accumulate gradually and may have been driven by coevolution between pollen and style in the predominantly outcrossing M. guttatus. [source] EFFECTS OF POLLEN LOAD SIZE ON SEED PATERNITY IN WILD RADISH: THE ROLES OF POLLEN COMPETITION AND MATE CHOICEEVOLUTION, Issue 8 2007Diane L. Marshall For sexual selection to be important in plants, it must occur at pollen load sizes typical of field populations. However, studies of the impact of pollen load size on pollen competition have given mixed results, perhaps because so few of these studies directly examined the outcome of mating when pollen load size was varied. We asked whether seed paternity after mixed pollination of wild radish was affected by pollen load sizes ranging from 22 to 220 pollen grains per stigma. We examined the seed siring abilities of 12 pollen donors across 11 maternal plants. Seed paternity was statistically indistinguishable across the pollen load sizes even though, overall, the pollen donors sired different numbers of seeds. This lack of effect of pollen load size on seed paternity may have occurred because fruit abortion and early abortion or failure of fertilization of seeds increased as load size decreased. Thus, failures of fruits and seeds sired by poorer pollen donors may keep seed paternity constant across pollen load sizes. [source] A palynological study of Galium L. (Rubiaceae) in Egypt and its systematic implicationFEDDES REPERTORIUM, Issue 7-8 2007K. Abdel Khalik A pollen morphological investigation of eleven species and one subspecies of the genus Galium L. from Egypt were undertaken by using light microscope (LM) and scanning electron microscope (SEM). Pollen shape, size, exine ornamentation, number of apertures present powerful characters for distinguishing between species. The pollen grains were zonocolpate. The number of colpi ranges from 5 to 10. Their shape varies from prolate spheroidal, oblate spheroidal, spheroidal to suboblate. Three groups can be distinguished based on the size pollen grains. It was found used to distinguish between closely related species G. aparine and G. spurium and between G. tricornutum and G. ceratopodum. Two different types of exine ornamentation were recognized. The ornamentation was found useful to distinguish among closely related species such as Galium aparine and G. spurium. A key for the identification of the investigated taxa based on pollen grains characters is provided. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Eine palynologische Studie der Gattung Galium L. (Rubiaceae) in Ägypten und ihre Bedeutung für die Systematik Die Pollenmorphologie von elf Arten und einer Unterart der Gattung Galium L. aus Ägypten wurde mittels Licht- und Elektronenmikroskopie untersucht. Pollenform, Größe und Muster der Exine und die Anzahl der Aperturen repräsentieren gute Merkmale zur Unterscheidung der betrachteten Arten. Alle Pollen sind zonocolpat. Die Anzahl der Colpi liegt zwischen 5 bis 10. Ihre äußere Form variiert von prolat über sphäroidal, oblat-sphäroidal, sphäroidal bis suboblat. Auf Grund der Pollengröße lassen sich drei Gruppen unterscheiden. Es zeigte sich, dass diese drei Gruppen genutzt werden können, um die eng verwandten Arten Galium aparine und G. spurium sowie G.tricornatum und G. ceratopodum von einander zu trennen. Zwei Typen der Exine-Muster ließen sich erkennen. Sie sind geeignet um z. B. so eng verwandte Arten wie Galium aparine und G. spurium zu trennen. Ein Schlüssel, der geeignet ist, die untersuchten Taxa auf der Basis ihrer Pollenmerkmale zu bestimmen beschließt die Arbeit. [source] Pollen morphology, leaf surfaces, mycobiota diversity and leaf spots of three species of Zygophyllum growing along Cairo-Suez desert road, Eastern (Arabian) desert in EgyptFEDDES REPERTORIUM, Issue 1-2 2007S. M. El Naggar Three native species of Zygophyllum: Z. coccinum L., Z. decumbens L. and Z. simplex L. (Zygophyllaceae) have been investigated morphologically, palynologically and mycologically. Twenty-two fungal species belonging to 11 genera were collected from leaf surfaces (11 genera and 22 species) and anthers/ pollen grains (7, 13) of Zygophyllum coccinum, Z. decumbens and Z. simplex on Czapek-Dox agar at 25 °C. Fungal diversity of the two microhabitats is basically similar and the most prevalent fungi were Alternaria alternata /A. phragmospora, Cladosporium cladosporioides /C. herbarum and Ulocladium botrytis /U. consortiale. Alternaria alternata, Cladosporium cladosporioides and C. herbarum -leaf spots were rarely recorded in the three studied plant species. Leaf lamina size and sculpture of the studied taxa almost seem to be the most reliable factors of the fungal biodiversity on the studied plant species. On the other hand, reticulate-micro reticulate pollen type is the only pollen type recorded in the present study which reflects that the very narrow range of spectrum of fungal biodiversity between the studied plant species. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Pollenmorphologie, Blattoberfläche, mykobiotische Diversität und Blattflecken von drei Zygophyllum -Arten entlang der Wüstenstraße Kairo,Suez, Östliche (Arabische) Wüste Ägyptens Drei einheimische Zygophyllum -Arten (Z. coccinum, Z. decumbens und Z. simplex (Zygophyllaceae) wurden morphologisch, palynologisch und mykologisch untersucht. 22 Pilzarten aus elf Gattungen wurden von Blattoberflächen gesammelt (11 Gattungen, 22 Arten) und Antheren/Pollenkörner (7, 13) von Zygophyllum coccinum, Z. decumbens und Z. simplex mittels Czapek-Dox agar bei 25 °C untersucht. Die Pilzdiversität beider Mikrohabitate ist basisähnlich und die häufigsten Taxa sind: Alternaria alternata /A. phragmospora, Cladosporium cladosporioides /C. herbarum und Ulocladium botrytis /U. consor- tiale. Blattflecken von Alternaria alternata, Cladosporium cladosporioides und C. herbarum wurden auf den untersuchten Pflanzen selten verzeichnet. Die Größe der Blattlamina und die Skulptur der untersuchten Taxa scheinen die zuverlässigsten (häufigsten) Faktoren für die Pilz-Biodiversität auf den untersuchten Pflanzen zu sein. Andererseits ist der retikulate-microretikulate Pollentyp in vorliegender Studie der einzige Pollentyp, der dieses enge Spektrum der Pilz-Biodiversität zwischen den untersuchten Pflanzen aufzeigt (widerspiegelt). [source] Mimicry in plant-parasitic fungiFEMS MICROBIOLOGY LETTERS, Issue 2 2006Henry K. Ngugi Abstract Mimicry is the close resemblance of one living organism (the mimic) to another (the model), leading to misidentification by a third organism (the operator). Similar to other organism groups, certain species of plant-parasitic fungi are known to engage in mimetic relationships, thereby increasing their fitness. In some cases, fungal infection can lead to the formation of flower mimics (pseudoflowers) that attract insect pollinators via visual and/or olfactory cues; these insects then either transmit fungal gametes to accomplish outcrossing (e.g. in some heterothallic rust fungi belonging to the genera Puccinia and Uromyces) or vector infectious spores to healthy plants, thereby spreading disease (e.g. in the anther smut fungus Microbotryum violaceum and the mummy berry pathogen Monilinia vaccinii-corymbosi). In what is termed aggressive mimicry, some specialized plant-parasitic fungi are able to mimic host structures or host molecules to gain access to resources. An example is M. vaccinii-corymbosi, whose conidia and germ tubes, respectively, mimic host pollen grains and pollen tubes anatomically and physiologically, allowing the pathogen to gain entry into the host's ovary via stigma and style. We review these and other examples of mimicry by plant-parasitic fungi and some of the mechanisms, signals, and evolutionary implications. [source] The paleoecology and archaeology of long-term water storage in a Hohokam reservoir, southwestern Arizona, U.S.A.GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2004James M. Bayman Water storage reservoirs were an important feature of economic organization among ancient societies in the North American Southwest. Analyses of reservoir sediments from a Hohokam archaeological site in the Sonoran Desert yielded taxonomic species of ostracodes (microscopic crustaceans) and pollen grains that are indicative of a past water-rich environment. The discovery that this reservoir was capable of storing water on a long-term basis indicates that archaeological models for the region, which have relied on direct historic analogy, must be reexamined. In contrast to the local ethnographic record, paleoecological data generated by this study imply that the Hohokam could establish permanent desert settlements with water storage reservoirs away from perennial rivers and streams. Moreover, residents of these areas were geographically positioned to facilitate the circulation of marine resources (i.e., salt and shell) from the Gulf of California to territories within and beyond the Hohokam region. © 2004 Wiley Periodicals, Inc. [source] Palynological evidence for late Holocene environmental change on the Gimhae fluvial plain, Southern Korean peninsula: Reconstructing the rise and fall of Golden Crown Gaya StateGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2003Sangheon Yi This paper presents the results of detailed studies of palynomorphs recovered from two cores collected near the Yeanri burial mound on the Gimhae fluvial plain. Two local pollen zones were recognized on the basis of variations in the palynofloral assemblage: a lower Pollen Zone I, dominated by a Pinus-Quercus assemblage, and an upper Pollen Zone II, dominated by a Pinus-Quercus -Gramineae assemblage. The palynological and molluscan analyses indicate that the depositional environments changed from a lower intertidal flat of a shallow bay environment to an upper intertidal flat in a shallow bay (before 1280 ± 110 14C yr B.P.), and finally to a fluvial plain similar to that of today. This environmental change may have resulted from uplift along the Yangsan Fault. Afterward, the exposed area was modified by human activities, as indicated by a sudden increase in grassland herbaceous pollen grains. The loss of this bay likely had a dramatic effect on the Golden Crown Gaya State (3rd,7th centuries A.D.), which used it as a major port for regional trade, and may explain why it eventually merged with the Shilla State. © 2003 Wiley Periodicals, Inc. [source] Aspects on the relief of living surfaces using atomic force microscopy allow "art" to imitate natureINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 3 2010Rosa POLYMENI Abstract The visualization of the surface of biological samples using an atomic force microscope reveals features of the external relief and can resolve very fine and detailed features of the surface. We examined specimens from the skin of the amphibians Salamandra salamandra Linnaeus, 1758, Lyciasalamandra luschani basoglui Baran & Atatür, 1980 and Mesotriton alpestris Laurenti, 1768, and from the surface of pollen grains of the plant species Cyclamen graecum Link, 1835 and Cistus salviifolius Linnaeus, 1753, which exhibit certain interesting features, imaged at the nanoscale level. It is likely that the relief influences the attributes of the interfaces between the tissues and the environment. We found that the microsculpture increases in size the surface of the examined tissues and this might be particularly important for their performance in the field. Microsculpturing of amphibians' skin may affect water regulation, dehydration and rehydration, and cutaneous gas exchange. Pollen grain relief might affect the firmness of the contact between pollen surface and water droplets. High resolution imaging of the external relief showed that roughening might induce wetting and influence the water status of the specimens. In addition, roughness affects the radius of water droplets retained in between the projections of the external relief. Roughness of the tissues was highly correlated with their vertical distance, whereas surface distances were highly correlated with horizontal distances. By enabling a more detailed characterization of the external sculptures, through sophisticated techniques, a more comprehensive examination of the samples indicates similarities among different living tissues, originated from different kingdoms, which can be attributed to environmental conditions and physiological circumstances. [source] Palynological, physico-chemical and colour characterization of Moroccan honeys.INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2003Summary The palynological, physico-chemical and chromatic properties of twelve samples of Moroccan orange honeys were measured. A minimum of 10% of Citrus sp. pollen is considered enough to consider a honey as unifloral. These honeys are poor in pollen grains (PG) , eleven of the twelve samples show less than 20 000 PG per 10 g of honey. The presence of Eucalyptus, Plantago, Anthemis arvensis, Sinapis arvensis, Olea europaea, Acacia and Quercus pollen allows the differentiation of these honeys from those with a different geographical origin. From the physico-chemical point of view, the honeys present a low level of sucrose, ash and minerals content, and medium,high values for the water content, electrical conductivity, free acidity and maltose. Melezitose is not present in any samples. As for the chromatic parameters, the luminance (Y), along with the lightness (L*) and chroma showed very low values. [source] Life Cycle, Feeding and Production of Isoptena serricornis(Pictet, 1841) (Plecoptera, Chloroperlidae)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 2 2004Derka Abstract Some aspects of the biology and ecology (life cycle, feeding and production) of a population of Isoptena serricornis in the Rudava River (Slovakia) are studied, reported and discussed. The life cycle is annual, with slow growth in autumn-winter and fast growth in late summer and spring. The growth decreased two weeks before the Fall Equinox and increased two weeks after the Spring Equinox. The flight period spans from the end of May to the beginning of July. The presence of large sand particles in the gut of all studied nymphs is of note, and indicates that I. serricornis acts as a deposit-collector species. Nymphal food is principally composed of detritus, unicellular organisms and, in nymphs of intermediate or large size, Chironomidae larvae. Adult food is composed fundamentally of different types of pollen grains. Males usually have lower food content than females. Annual production of this species (,694,750 mg · m,2) is very high in relation to other previously studied Chloroperlidae. This is probably largely responsible for I. serricornis being one of the most abundant components of the macroinvertebrate community in its habitat in the Rudava River. A negative correlation between production and temperature was observed. [source] The influence of pollinator abundance on the dynamics and efficiency of pollination in agricultural Brassica napus: implications for landscape-scale gene dispersalJOURNAL OF APPLIED ECOLOGY, Issue 6 2006KATRINA E. HAYTER Summary 1It is important to understand the pollination processes that generate landscape-scale gene dispersal in plants, particularly in crop plants with genetically modified (GM) varieties. In one such crop, Brassica napus, the situation is complicated by uncertainty over the relative importance of two pollen vectors, wind and insects. 2We investigated pollination in two fields of B. napus that bloomed at different times of year (April vs. July) and attracted different abundances of foraging social bees. Rates of pollen transfer were quantified by counting the pollen grains deposited on stigmas and remaining in the anthers at intervals after flower opening. 3Flowers open in April were adequately pollinated only after 5 days and only 10% received even a single bee visit. Flowers open in July received three bee visits per hour and were fully pollinated within 3 h. 4Based on published measurements of airborne pollen dispersal, we estimate that wind-pollination from a hypothetical field 1 km distant could have fertilized up to 0·3% of the field's seed when bees were scarce in April but only up to 0·007% when bees were abundant in July. 5The efficiency of pollination (the proportion of pollen released from anthers that landed on receptive stigmas) was seven times greater in July (1·5%) than in April (0·2%). The relatively high efficiency of insect pollination may help to explain the evolutionary maintenance of entomophily. 6Synthesis and applications. Our results begin to resolve a long-standing inconsistency among previous studies by suggesting that the susceptibility of fields of B. napus to long-distance cross-pollination by wind depends on the level of bee activity. Models for predicting GM gene flow at the landscape-scale in this crop should take this into account. [source] Eucalyptus pollen grain emptying by two Australian nectarivorous psittacinesJOURNAL OF AVIAN BIOLOGY, Issue 3 2001B. D. Gartrell The relative importance of pollen as a source of protein to vertebrates is controversial. In nectarivorous psittacine birds, field studies support its importance, but an experimental study in a nectarivorous parrot showed that less than 7% of pollen grains were emptied. We investigated pollen grain emptying by two nectarivorous Australian parrots, the Swift Parrot Lathamus discolor and the Musk Lorikeet Glossopsitta concinna. We used a controlled experiment, and examined pollen located at different levels through the alimentary tract of wild L. discolor. There was significant emptying of pollen grains (x=45.4%±1.91 s.e.) by all birds in the experimental trials. There was also a progressive increase in the percentage of pollen grains emptied at different sites along the alimentary tract in wild birds (crop x=24.2%±4.44 s.e., proventriculus x=34.0%±7.29 s.e., duodenum x=54.3%±5.42 s.e. and distal intestine x=64.2%±4.68 s.e.). The percentage of pollen grains emptied by captive L. discolor in the experimental trial (x=44.1%±2.77 s.e.) was not significantly different from that found in wild L. discolor (x=40.3%±4.25 s.e.). Both species of nectarivorous parrot were able to rapidly ingest large quantities of Eucalyptus pollen and appeared to empty the pollen grains efficiently. Eucalyptus pollen appears to be an important source of protein for these birds. [source] A fluorescence lifetime imaging scanning confocal endomicroscopeJOURNAL OF BIOPHOTONICS, Issue 1-2 2010Gordon T. Kennedy Abstract We describe a fluorescence lifetime imaging endomicroscope employing a fibre bundle probe and time correlated single photon counting. Preliminary images of stained pollen grains, eGFP-labelled cells exhibiting Förster resonant energy transfer and tissue autofluorescence are presented. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Pollen and sperm heteromorphism: convergence across kingdoms?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2005I. Till-Bottraud Abstract Sperm competition theory predicts that males should produce many, similar sperm. However, in some species of animals and plants, males exhibit a heteromorphism that results in the production of at least two different types of sperm or pollen grains. In animals, sperm heteromorphism typically corresponds to the production of one fertile morph and one (or more) sterile morph(s), whereas in plants two or more pollen morphs (one of which can be either sterile or fertile) are produced in all flowers but sometimes in different anthers. Heteromorphism has arisen independently several times across phyla and at different phylogenetic levels. Here, we compare and contrast sperm and pollen heteromorphism and discuss the evolutionary hypotheses suggested to explain heteromorphism in these taxa. These hypotheses include facilitation, nutritive contribution, blocking, cheap filler, sperm flushing or killing for animals; outcrossing and precise cross-pollen transfer or bet-hedging strategy for plants; cryptic female choice for both. We conclude that heteromorphism in the two phyla is most likely linked to a general evolutionary response to sexual selection, either to increase one male's sperm or pollen success in competition with other males, or mediate male/female interactions. Therefore, although sperm and pollen are not homologous, we suggest that heteromorphism represents an example of convergence across kingdoms. [source] Influences of Cross Pollination on Pollen Tube Growth and Fruit Set in Zuili Plums (Prunus salicina)JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2008Hui-Juan Jia Abstract Zuili plum (Prunus salicina L.) trees usually set fruit poorly, although they produce high quality fruit. To elucidate the causes of the poor fruit set, pollen tube growth into pistils and fruit set percentage were investigated after cross-, self- and open-pollination. Ovule development in Zuili pistils was also investigated. Pollen tube penetration into the ovules via the obturator and micropyle was best when Zuili pistils were pollinated by cv. Black Amber (P. domestica) pollen grains, although cross-pollinations with Hongxinli and Miili (P. salicina) pollen were more effective than self- and open-pollination. The fruit set percentage was also highest in pistils pollinated with Black Amber pollen grains. Morphological observation of Zuili pistils revealed that the trees produce "double pistils", developing two ovaries from a basal pistil, at a rate as high as 28%. In such abnormal pistils, most ovules were lacking an embryo sac or were entirely degenerated. The percentage of normally developed ovules was 24.3% and 8.9% in normal and double pistils, respectively. From these results, we conclude that the main causes of poor fruit set of Zuili plums are a lack of effective cross-pollination and the production of high percentages of double pistils in which normally developed ovules are scarcely formed. [source] Pollen Morphology of Tundra Shrubs and Submarginal Plants from Barrow, AlaskaJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 7 2006Ling-Yu Tang Abstract Investigation of plant morphological features, pollen, and habitat have been made for two shrub species from Barrow, Alaska, namely Dryas integrifolia M. Vahl and Salix rotundifolia Trautv., both of which are endemic to the Arctic floristic area. The former species has small lanceolate or plate leaves, whereas the latter has rounded leaves with distinct veins, rich in vitamin C. Both have dwarf and sprawling habits. Pollen studies showed that the pollen grains of the two species are spheroidal to sub-spheroidal or prolate. The type of aperture was tricolporate; pollen size 26.3,31.3 ,m; ornamentation finely reticulate under a light microscope (LM) and striate-reticulate under a scanning electron microscope (SEM) for D. integrafolia and finely reticulate under the LM and SEM for S. rotundifolia. Comparisons were made between the pollen from the same species from Arctic collections with those from China and Japan. Investigation of pollen morphology of tundra plants can provide significant data for comparative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in the Barrow area. (Managing editor: Ya-Qin Han) [source] Seasonality of modern pollen and sediment deposition in an estuarine context: the Severn Estuary Levels, southwest England,JOURNAL OF QUATERNARY SCIENCE, Issue 3 2008J. R. L. Allen Abstract Recent sedimentological and palynological research on subfossil Holocene banded sediments from the Severn Estuary Levels suggested seasonality of deposition, registered by variations in mineral grain-size and pollen assemblages between different parts of the bands. Here we provide data that strengthen this interpretation from sampling of modern sediments and pollen deposition on an active mudflat and saltmarsh on the margin of the Severn Estuary, and comparison with a vegetation survey and contemporary records of climate, river and tidal regimes. The results of grain-size analysis indicate deposition of comparatively coarse-grained silts during the relatively cool and windy conditions of winter and comparatively fine-grained sediments during relatively warm and calm summer months. Pollen analysis demonstrates the significance of long-term storage of pollen grains and fern spores in the estuarine waterbody, superimposed on which seasonal variations in pollen inputs from local and regional vegetation remain detectable. Copyright © 2007 John Wiley & Sons, Ltd. [source] Towards automation of palynology 2: the use of texture measures and neural network analysis for automated identification of optical images of pollen grains,JOURNAL OF QUATERNARY SCIENCE, Issue 8 2004P. LI Abstract The automation of palynology (the identification and counting of pollen grains and spores) will be a small step for image recognition, but a giant stride for palynology. Here we show the first successful automated identification, with 100% accuracy, of a realistic number of taxa. The technique used involves a neural network classifier applied to surface texture data from light microscope images. A further significance of the technique is that it could be adapted for the identification of a wide range of biological objects, both microscopic and macroscopic. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||