Anemophilous Pollen Research Articles

Análise polínica de algumas amostras de própolis do Brasil meridional

Foi analisado o espectro polínico de treze amostras de própolis, oito provenientes do estado do Rio de Janeiro, duas de Minas Gerais, uma do Rio Grande do Sul e uma de São Paulo. A metodologia empregada para a extração de pólen de própolis, bem como a concentração em pólen visando a estudos morfológicos para a identificação de grupos taxonômicos, é proposta como padrão para análise polínica de própolis. Foram identificados, através da morfologia polínica, famílias e gêneros botânicos que caracterizam as regiões geográficas de coleta da própolis, e também o habitat de mata, capoeira, campo e culturas. Os táxons vegetais encontrados com maior freqüência foram: Eucalyptus, Compositae (principalmente o tipo polínico Eupatorium) e Cecropia. Este último gênero, juntamente com Ambrosia, Piper e Brosimum, constituíram o pólen anemófilo mais representativo nas amostras analisadas. Tendo uma estação de florada bem demarcada, o pólen de Mimosa caesalpiniaefolia e Citrus pode ser referencial para o período sazonal de coleta de própolis.

Pollen dispersal models in Quaternary plant ecology: Assumptions, parameters, and prescriptions

Models of atmospheric dispersal of anemophilous pollen are important tools in Quaternary plant ecology for determining pollen-source areas and for applying distance-weightings to vegetation data in formal pollen-vegetation calibrations. The most widely applied model is Prentice’s model, which uses a modified form of Sutton’s equation for atmospheric diffusion to predict pollen-source areas from size of the depositional basin and a set of depositional parameters (deposition velocity of the pollen grains and mean wind speed) and atmospheric parameters (turbulence parameter, vertical diffusion coefficient). We review the physical theory underlying Sutton’s equation and Prentice’s model, explore the effects of different values of the depositional and atmospheric parameters on model predictions, and provide prescriptions for model application, parameter specification, and further research on pollen dispersal. Most applications of the models to pollen dispersal have assumed neutral atmospheric conditions. We argue that most pollen dispersal takes place in unstable atmospheric conditions, and prescribe appropriate values for the atmospheric parameters for unstable conditions. Our simulations using these parameters indicate more widespread pollen dispersal from a source than under neutral conditions. We review available data sets for sedimentation velocity of pollen grains, and compare the measured estimates with sedimentation velocities predicted from Stokes’s Law to assess validity of the data. Substantial variability exists among data sets, but several are suitable for application to pollen-dispersal models. Finally, we discuss aspects of release, dispersal, and deposition of anemophilous pollen that are in need of further theoretical and empirical study. Such studies will contribute not only to Quaternary plant ecology but also to understanding of pollination biology, population genetics, and functional morphology of pollen grains and pollen-bearing organs.

Evaluation of indoor passive pollen sedimentation over 1 year: a possible source of contamination?

The study aimed to evaluate the possible contamination by passive indoor pollen sedimentation in a laboratory where routine pollen analyses were conducted, but where no particular laboratory policies were adopted to limit contamination. Gravimetric pollen deposition was observed on traps (petri dishes soaked with glycerol) set in the palynology laboratory, under an extractor hood and on the bench beside it over 1 year (1995–1996), and in an air filtered room in a flow cabinet and on its roof over 1 month for comparison. Under the extractor hood, three types of airborne particles were deposited: pollen grains, spores and algae, representing 32.35, 67.28 and 0.37%, respectively, of the total sedimented particles over 1 year. The number of pollen grains deposited on the surface trap ranged from 0 (27 November to 4 December 1995) to 707 (10–18 April 1995). The highest number of taxa during a weekly collection was 23 (9–15 May 1995). The pollen flora represented by anemophilous pollen (>90% of the trapped pollen) was related to the vegetation next to the laboratory:Acer, Carpinus, Castanea, Corylus, Cupressaceae, Pinus, Quercus, Salix, Taxus for trees and shrubs andArtemisia, Brassicaceae, Plantago, Poaceae, andUrticaceae for grasses and weeds. Indoor pollen deposition corresponded to the period of the outdoor pollination (macroscopic field observation) which lasted from March to the beginning of August. However, some pollen were almost always present in the collection (Poaceae, Salix, Castanea, Betula), reflecting the occurrence of pollen grains in the atmosphere out of the pollination period. Moreover, about five times more entomophilous pollen was found under the extractor hood compared to the other area of the laboratory; even in the flow cabinet of the air filtered room, 237 particles were captured (versus only 15 on the roof). These data suggest a possible human contamination during operations under the extractor hood or in the flow cabinet. Although few airborne pollen were found, possible contamination has to be considered in investigations where even low pollen quantities are of interest.

A preliminary survey of airborne pollen in Madras City

The atmospheric pollen of Madras city was surveyed during a 1-year period (January–December 1995) with a vertical cylinder trap. A total of 32 pollen types were identified, among which nine were present throughout the year. These belonged to Poaceae,Casuarina equisetifolia Foster and Foster f.,Prosopis juliflora (SW.) DC.,Acalypha indica L.,Parthenium hysterophorus L., Cyperaceae,Cocos nucifera L., Amaranthaceae, andTypha angustata Borry and Chaub. Among the identified pollen, 61.05% belonged to trees, 21.01% to grasses, 11.65% to herbs and 6.27% to shrubs. Anemophilous pollen contributed about 52.87% to the total while entomophilous and amphiphilous pollen contributed 38.89 and 8.22%, respectively. Pollen belonging to Poaceae were found to be most predominant in the air of Madras city followed byCasuarina equisetifolia andProsopis juliflora.

Plant Resources Foraged byPolybia Scutellaris(Hym. Vespidae) in the Argentine Pampas

Abstract The plants foraged by Polybia scutellaris were studied by analysing the pollen of honey collected from six nests. 34 morphological types were identified. These honeys showed a predominance of Poaceae and Cyperaceae pollen. The main access to anemophilous pollen is through the honeydew produced by Claviceps in Paspalum dilatatum. The principal sources of nectar were the native “Astereae” (Aster squamatus, Baccharis sp. and Solidago chilensis) and Eucalyptus sp. When collecting honeydew and nectar, wasps foraged plants close to their nest. Most of the plants visited belonged to a dense population. The successive flowering reflected in these honeys, shows that wasps also consume honey in summer and that it is not all stored for the winter season.

Pollen feeding by adults of the hoverflyMelanostoma fasciatum(Diptera: Syrphidae)

Abstract Pollen feeding by adult hoverflies of Melanostoma fasciatum, collected from organic paddocks at Flock House, Bulls, North Island, New Zealand, were studied by dissection. Up to six different pollen types were found in one hoverfly. On average, they fed only on 2.71 pollen species. 71% of gravid females but only 13% of males reached the maximum score (scale 0–5) for pollen content in the gut. Very few hoverflies had no pollen. Of the 15 identified pollen groups, plantain, phacelia, coriander, and graminaceous pollen were consumed in large quantities by gravid females. Differences in feeding spectra between sexes probably reflected the need for energy in males and for the protein required for egg maturation in females. Earlier views of strict preference for anemophilous pollen by M. fasciatum cannot be upheld.

Anemophilous pollen in the diet of Syrphid flies with special reference to the leaf feeding strategy occurring in Xylotini. (Diptera, Syrphidae)

Anemophilous pollen in the diet of Syrphid flies with special reference to the leaf feeding strategy occurring in Xylotini. (Diptera, Syrphidae)

Australian cretaceous terrestrial faunas and floras: biostratigraphic and biogeographic implications

Nonmarine Cretaceous sediments representing fluvial/lacustrine deposits occur in 22 of Australia's 23 Mesozoic depositional basins. They are associated with open to marginal marine sediments whose enclosed planktic faunas and floras provide tie points to the Tethyan and European stages. Integration of marine and nonmarine sequences has been effected through spore-pollen biostratigraphies which in turn are linked to macroplant zones, vertebrate ranges and radiometric dates. This evidence is reviewed and it is concluded that the C. hughesii-P. pannosus spore-pollen Zones define Aptian to Albian ages and that their zonal boundaries are isochronous across Australia; the P. mawsonii-F. longus spore-pollen Zones in south-eastern Australia are datable as Turonian-Maastrichtian. However, evidence for a Cenomanian age for the intervening A. distocarinatus Zone is not indubitable. Also, the position of the Jurassic-Cretaceous boundary and the temporal significance of several index taxa of the ?latest Jurassic-Barremian C. australiensis-F. wonthaggiensis Zones in eastern Australia and the B. eneabbaensis-lower B. limbatus Zones in Western Australia is not certain. Isochronous incomings of individual spore-pollen taxa on a regional scale relate to the mode of dispersal of the source plant, and to the distribution of environments suitable for dispersal. For the Aptian-Albian, when Australia was inundated by shallow seas and lake/river systems that fed into them, several index taxa sourced from aquatic and strandline plants appear to have temporal significance. By contrast, anemophilous pollen are stratigraphically useful and temporally significant in the Turonian-Maastrichtian of south-eastern Australia. Throughout the Cretaceous, Australia supported a succession of coniferous forests. Early Cretaceous podocarp/araucarian/ Ginkgo canopy associations were modified in the Late Cretaceous by the loss of Ginkgo and the introduction of rainforest Proteaceae and Nothofagus. Regional variations in the vegetation reflect topographic, edaphic and climatic variations between the disparate sedimentary basins. Floral migration within Australia and between associated land masses occurred in a step-wise fashion, and was mostly west to east. Two dinosaur faunas are recognized: one, in the Aptian-early Albian of Victoria, consists of small ornithopods and theropods; and the other, in the middle Albian-Cenomanian of Queensland, comprises ankylosaurs, sauropods and theropods. The Victorian herbivorous dinosaurs were low feeders and probably shared a single mode of feeding, whereas those from Queensland may have had several feeding modes and fed up to 6 m from the ground. The small ornithopods, mostly from Victoria, were hypsilophodontians with grinding dentitions; their food source may have been lycopods or diaspores of podocarps and Ginkgo. Ankylosaurs seem to have preferred soft vegetation, some possibly aquatic. The Queensland sauropods may have fed on living and dead vegetation, perhaps including fleshy seeds of podocarps/taxads and gleicheniaceous ferns that apparently proliferated in the region. The lungfish had grinding toothplates and were probably omnivorous like extant Neoceratodus forsteri. Victorian faunas contain several relicts including the youngest known temnospondyl, the theropod Allosaurus, the lungfish Ceratodus avus, and the freshwater mussel Mesohydridella ipsviciensis. Australian earliest Cretaceous climates were temperate with cool temperatures (0–12°C) and high precipitation levels (750–1150 mm/year) in southern regions where winter freezing may have occurred during the Aptian. A warming trend during the Albian is indicated by land vegetation and verified by isotope palaeotemperatures (12–16°C) from the marine realm. Cool to warm temperate climates prevailed in the south-east during Turonian-Maastrichtian times; sea water temperatures were 16–28°C, and the vegetation is indicative of high humidities.

Floraisons et contenu pollinique atmosphérique en région parisienne (1987–1988)

The folowing of the vegetation and of the pollen contents of the air were studied during two years in three stations of area of Paris. In a first time (beginning of the spring) it is the anemophilous pollen of the great trees which is dominant. More later, these pollens are reinforced, and replaced (but then the total amount of the atmospheric pollens is furthermore little) by the grasses pollens. The pollinic emission of the herbs is not important in comparison with these of the trees. The other results show the irregularity of the atmospheric pollen abundance between the different years. The climatic and meteorological influences are very important to explain these facts. The differences between the stations of forest, contry and suburban are noticeable, but on the whole the rythm and the typical of the evolution of the flowering and of the air contents in pollen are the same always.

Pollen analysis of some spring honeys from the western Himalayan region of Uttar Pradesh, India

In the apiaries of the western Himalayan region (Kumaon and Garhwal hills) of Uttar Pradesh, the honey is harvested twice in a year i.e. in autumn and spring. Out of 12 spring samples of honey analysed, there are 10 unifloral and 2 multifloral samples. The dominant entomophilous pollen types in unifloral samples areBrassica, and Rosaceae-Prunus type. It has been suggested that the anemophilous pollen types namely,Alnus andRumex may be used as markers of honey samples originated from the Himalayan region. The data presented in the paper are useful in standardization of honey samples.

OPTIMUM POLLEN AND FEMALE RECEPTOR SIZE FOR ANEMOPHILY

A set of mathematical models is developed to describe the relationship between the sizes of pollen grains and female receptors which result in maximum anemophilous pollen transfer. The models predict anemophilous plants should have Stokes numbers in the range of 1.0 to 2.72. The Stokes number is a function of both pollen size and effective receptive surface size. The models were tested with data gathered for 28 assumed anemophilous species and 20 known zoophilous species. The models identify anemophily with an accuracy of approximately 75%. If pollen size alone is used to determine anemophily, then accuracy drops to only 50%. The Stokes number criterion reported here could help in the determination of anemophily of extant and fossil plant taxa.

Diurnal activity patterns in hoverflies (Diptera, Syrphidae)

Abstract. 1. Time‐budgets are constructed from censuses of hoverflies. Larger species spend less time in flight.2. Most species are active under similar conditions of light intensity, but a shade‐tolerant (Melanostoma scalare Fabr.) and a sun‐loving species (Metasyrphus corollae Fabr.) were identified.3. Large species become active (i.e. move, by flying or feeding) at lower temperatures than small ones, except M.scalare, which is tolerant to cool temperatures. This means that, M.scalare apart, the order of species appearing during the day is size‐dependent, largest first.4. Previous claims about the diel periodicity of syrphids can be reconciled by considering the importance of individual thermal balance.5. Tolerance to low temperatures in small hoverflies is associated with feeding on anemophilous pollen; this may indicate a proline‐fuelled flight.

La palynologie : un outil de caractérisation des faciès marins et continentaux à la limite Muschelkalk supérieur - Lettenkohle. Palynology : a means of characterising marine and continental facies at the Upper Muschelkalk - Lettenkohle boundary

A paly nological study of 94 samples from the Upper Muschelkalk -Lettenkohle boundary aimed to follow in detail the evolution of the microflora during the transition from a marine to a continental environment. Two reference sections about 400 km apart were studied, one at Laudenbach in Lower Saxony (West Germany), the other at Wasseionne (France). The rich palynoflora recovered (about 120 species) include algae, Acritarcha, spores and pollen grains. Sedimentological (tidal channels, mud cracks) and faunal (estheriae, lingulae in life position, stromatolites) criteria enabled the precise determination of the boundary between the marine and continental environments. The palynoflora studied on each side of this limit was divided into three categories : spores, anemophilous pollen grains and acritarcha-tasmanacea. For each level studied, the relative proportions of each of the categories were estimated and transfered to the three vertices of an equilateral triangle. This representation of the palynoflora enables a very precise characterization of the sedimentary environments through the points on the diagram ; the spore vertex indicates a coast, the anemophilous vertex, a more distant shore and the acritarcha-tasmanacea vertex, a marine environment.

Studies on the Aerobiology of a Himalayan Alpine Zone, Rudranath, India

The aerobiology of a Himalayan alpine zone in Rudranath at 3600 m above sea level was investigated. The atmospheric particulates were analyzed by exposing adhesive-coated slides, at intervals of 24 h, on a gravity sampling device. The aerobiological composition was found to be 65.5 7o fungal spores, 23.9go pollen grains, and 10.401o miscellaneous biotic objects. The majority of the flowering plants growing in the alpine environment are entomophilous (insect pollinated); their pollen was trapped in lower numbers, while many anemophilous (windborne) pollen grains traveled from the adjacent temperate and subtropical localities of lower altitudes. However, these species from alpine altitudes act as suitable hosts for several of the fungal elements indicating comparatively higher numbers of sporomorphs. Although a number of these microbes are of ubiquitous nature, the presence of liverworts, mosses, Arthrinium plus hyaline rods, and characteristic unidentified structures, grouped as miscellaneous, are characteristic of this locality.

The fine structure of the exine in relation to the stickiness of angiosperm pollen

The variable stickiness of entomophilous (mostly sticky) and anemophilous (always powdery) pollen always depends on the particular distribution and consistency of the pollenkitt on the pollen surface and is related to the fine structure of the exine. Two different “strategies” in exine evolution following the trend from entomophily towards anemophily are significant: 1. (1) Pollen grains without a tectum: the sticky pollen results mainly from the deposition of a great amount of homogeneous, mostly electron-dense pollenkitt between the columellae — so the sporoderm becomes incrusted with pollenkitt. In contrast powdery pollen results mainly from the deposition of a tiny amount of mostly heterogeneous, usually electron-transparent pollenkitt between the columellae, while a considerable amount of pollenkitt remains on the loculus wall. 2. (2) Pollen grains with a tectum: the sticky pollen results mainly from the attachment of a moderate amount of usually electron-dense, homogeneous pollenkitt on the tectum surface, while pollenkitt also enters into the exine cavities. In contrast powdery pollen results mainly from the deposition of an always heterogeneous, usually electron-transparent pollenkitt as a thin film covering parts of the tectum surface, while a great deal of an inhomogeneous, but mostly electron-dense pollenkitt fills up the exine cavities. In both cases the characters of “amphiphilous” pollen hold the balance between the extremes with respect to pollen stickiness, to the homogeneity and electron-density of pollenkitt and the mode of its distribution on the pollen surface.

Interstades würmiens : Laugerie et Lascaux

Several pollen analysis, dating from about 20 000 B P (18 000 B C), concern the period coming immediatly after the coldest Würmian maximum. The most complete sequence comes from Abri Fristch (a rock shelter in south-western France). The lowest part of the diagram indicates a cold period : arboreal species are poorly represented (4 %)-, the Liguliflorae are dominant. In the next phase, the percentage of the Cichonae falls from 82 % to 46 % , whilst the trees reach 22 % . Thermophilous species such as Quercus, Ulmus, Tilia, Carpinus and Hedera appear. That particular temperate phase is defined as « Interstade de Laugene », with a 14 C age of 19 200 B.P.. Then another cold phase, probably short, is recorded, with 3 % of trees and 72 % of Cichonae. It is dated by 14 C as 1 8 260 B.P. at Laugene rock shelter, another famous site, in Dordogne (France). The upper part of the pollen diagram from Abri Fritsch indicates a new warmer interlude (17 980 to 16 630 B P ), the « Interstade de Lascaux » already referred to. If these two warm phases appear to be very similar when considering the percentages of the trees, they differ in the composition of the herbaceous layer. During the « Interstade de Laugene », the vegetation has a steppe character . Compositae are dominant, with Rubiaceae, Helianthemum and Ephedra. In contrast, during the « Interstade de Lascaux », the Gramineae are dominant, and wetness is indicated by the rise of ferns, and Salix, Alnus, Tilia. This domination by graminaceous is recorded in a few other sites in France, in connection with that interlude : in Lascaux cave (17 190 B P ), Laugene (17 040 B P ), and Pegoune cave (17 410 B P ) In Spain, the pollen diagram from Chufin (Astunas) shows an increase in the ferns and a rise in the Gramineae at 17 470 B.P. In the La Riera cave, the same phenomenon appears : it may be linked to this interstadial. These alternations between the Cichoneae and Gramineae can be appreciated in pollen diagrams from archaeological or other terrestrial sites but not in those from peat-bogs, which show chiefly anemophilous pollen, in addition to aquatic or water-side pollen grains.

Absolute jährliche Pollenniederschlagsmengen an verschiedenen Beobachtungsorten in der Bundesrepublik Deutschland

Pollen deposition at nine localities was investigated from 1969 to 1971. The annual pollen catches, made in Tauber pollen collectors (and, too, in some Bergerhoff dust collectors), were analysed with respect to their composition by absolute countings using the method of Jørgensen 1967. The data obtained were compared in different respects, the more general results being as follows: 1. Collectors of the same type, exposed at one locality at distances of only a few meters from each other yielded very different pollen quantities and still more different numbers of the single pollen types. The reason for these “accidental” differences must be a very uneven distribution of the pollen in the air, caused by very different pollen concentrations in the single turbulence elements. 2. The comparision of collectors of different types (Tauber and Bergerhoff vessels) yielded no constant relation between each other; if such a relation existed generally, it would always be concealed by the much greater differences just mentioned between one collector and the other. 3. Much greater than the differences of short time and very local character are those from year to year at one sampling site, caused by different flowering intensity, different frost damages and different meteorological conditions of pollen transport. 4. For some plant species the years of maximum pollen deposition were the same over the whole area under investigation, for other species the maximum pollen years coincided only over a more limited area. 5. The average annual pollen deposition rate, covering all anemophilous pollen types, was very similar for most of the sampling sites (2200 to 3600 pollen grains/cm 2 ). Much lower values were obtained only for an island site (Sylt), higher values, up to more than 11.000 pollen graim/cm 2 , were correlated with urban sampling sites. 6. It was shown that pollen deposition contributes only to low extent (ca. 1–2 %, in all cases less than 5 %) to the whole dust deposition. Some further results concerning the correlations between the actual vegetation of the sampling sites and their average pollen spectra, the amount of local pollen deposition, the differences in pollen deposition between landscapcs poorer and richer in forests etc. will be reported in the following text and tables.

Absolute pollen diagram of Redrock Lake, Boulder County, Colorado

Redrock Lake is situated at 3,095 m in the subalpine zone on the east flank of the Front Range, Boulder County, Colorado. The lake lies on Pinedale moraine, and it contains 170 cm of organic sediments that overlie 10 cm of silty clay. The oldest of seven 14C dates from the organic sediment is 9,490 ± 150 yr B.P., a minimum estimate of the time since Middle Pinedale ice receded from the lake basin. A percentage pollen diagram and an absolute pollen diagram providing pollen deposition rates in grains/cm 2/ 14C yr are compared and contrasted. Possible measurement errors are considered in detail, and for the first time confidence limits are assigned to all pollen data. A means of converting 14C years to calendar years is presented, and its effect on the diagram's deposition rates is discussed. The silty clay contains a peculiar Artemisia-dominated pollen assemblage with very low pollen influx rates, which suggests the lake was receiving large volumes of glacial meltwater during its early history. The overlying organic sediments are characterized by pollen deposition rates of 4,000–6,000 grains/cm 2/yr. With fluctuations, deposition rates of Pinus and total anemophilous pollen increase upward in the core; this evidence for a general upward shift in the region's vegetation zones during Postglacial time is supported by pollen trends from modern surface samples.

British Bees and Wind-borne Pollen

IT is well known that the perianth in wind-pollinated plants is lacking or greatly reduced and inconspicuous, that nectar-secreting glands are absent and that immense quantities of pollen are produced compared with entomophilous flowers. Furthermore, the individual pollen grains are more suited to carriage by wind, with their thinner walls and simpler form lacking spines or surface sculpture. They have a markedly lower specific gravity and do not cohere en masse like those of insect-fertilized flowers. It is therefore rather surprising to find that solitary bees of the genus Andrena sometimes collect large quantities of anemophilous pollen, for example, Quercus, Fagus, Castanea, as the analyses per cent of individual pollen loads taken off the species named below demonstrate: In addition, pollen loads containing high proportions of Quercus pollen have been taken off A. jacobi Perk., and of Castanea pollen off A. dorsata (Kirby) and A. thoracica (Fab.).