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1.
Summary The herds and weeds pollen (NAP) and spores of Buenos Aires city were collected using a Tauber trap from July 1989 to June 1990. A high NAP pollen production period was found from October to March, reaching an annual peak in October. The NAP fraction is dominated by Compositae, Poaceae, Cyperaceae and Chenopodiaceae/Amaranthoideae. Spores are scarce along the year and they are mainly represented by Bryophytes. From the comparison of trees and shrubs pollen content (AP), NAP and Spores fractions, three aeropalynological seasons could be described: An AP Season with dominance of trees and shrubs, from July to October; a NAP Season with dominance of herbs and weeds, from November to April, and a Spore Season from May to June.  相似文献   

2.
A volumetric aeropalynological sampling was carried out for the first time in MontevideoUruguay, from October 2000 to September 2001, using a Rotorod sampler Model 40. During the year 76 pollen types were identified. Airborne pollen was recorded over the year but a maximum pollen period was observed from August to April. For the rest of the months, pollen concentration was below 1% of the total annual pollen (TP). The pollen spectrum was characterized by the dominance of herbaceous pollen (NAP), which represented 68% of the TP and dominates the spectrum from November to March. Poaceae was the most frequent and abundant pollen type accounting for 45% of TP. The pollen spectrum reflected the floristic diversity of the city and most of the sources of airborne pollen are present in local and regional flora. Fourteen pollen types reach more than 1% of the TP and most of them are cited as allergenic pollen in other regions. These results may prove important for future medical research.  相似文献   

3.
We sampled and analyzed surface sediments from 31 lakes along a latitudinal transect crossing the coniferous treeline on the Kola Peninsula, Russia. The major vegetation zones along the transect were tundra, birch-forest tundra, pine-forest tundra, and forest. The results indicate that the major vegetation types in our study area have distinct pollen spectra. Sum-of-squares cluster analysis and principal components analysis (PCA) groupings of pollen sites correspond to the major vegetation zones. PCA ordination of taxa indicates that the first axis separates taxa typical of the forest zone (Pinus, Picea) from taxa typical of tundra and forest-tundra zones (Polypodiaceae, Ericaceae, and Betula). The current position of the coniferous treeline, defined in our region by Pinus sylvestris, occurs roughly where Pinus pollen values reach 35% or greater. Arboreal pollen (AP)/non-arboreal pollen (NAP) ratios were calculated for each site and plotted against geographic distance along the transect. AP/NAP ratios of 7 or greater are found within pine-forest tundra and forest vegetation zones. Pinus stomates (dispersed stomatal guard cells) are absent from sites north of the coniferous treeline and all but two samples from the forested sites contain stomates. Stomate concentrations among the samples are highly variable and range from 10 to 458 per ml and positively correlate with the changing Pinus pollen values.  相似文献   

4.
This study reopens the discussion on the AP/NAP ratio that contrasts the total number of Arboreal Pollen grains (AP) to that of the Non-Arboreal Pollen grains (NAP), and its meaning in terms of vegetation land-cover. Based on a set of 52 present-day pollen assemblages (mostly moss polsters) from continental France and black- and-white aerial photographs of these localities, we perform statistical analyses to clarify the meaning of the AP/NAP ratio. Short- and long-distance transported pollen grains, possible over-representation of Pinus, and distortion of cultivated plants are among the biases explored here and for which answers are given. Grey level analysis of the aerial photographs provides direct estimates of the Tree Surface/Herb Surface (TS/HS) ratio for a radius of 1000 m around the sampling point. Statistical estimates of the AP/NAP and TS/HS cut-off values separating tree- and herb-prevalent landscapes are computed. Such results obtained from modern pollen records have been applied to a Late Pliocene small maar locality from southern France characterized by a very weak pollen transport and provide the basis to further distinguish tree- and herb-prevalent landscapes in past pollen records.  相似文献   

5.
A two-year aeropalynological study performed during January 14, 1993 to December 31, 1994 in Taipei City revealed 154 different pollen taxa, with the most frequent beingBroussonetia (31.3%),Trema (15%),Bischofia (6.9%),Mallotus (6.8%),Cyathea (3.8%),Morus (3.7%),Fraxinus (2.9%) and Gramineae (2.8%), respectively. Two quantitative peaks of pollen grains appeared in March and in September in 1993, but only one peak in 1994. The dominant pollen taxa during these two peaks wereBroussonetia andMallotus. The heavy rain in February 1994 seemed to have delayed the first pollen peak to April, butBroussonetia was still the most frequent taxon. After July 1994, six typhoons brought heavy precipitation to northern Taiwan. Different weather types might have an effect on the concentration of airborne pollen grains, so that the timing of quantitative peaks was different in the two studied years. Arboreal pollen (AP), non-arboreal pollen (NAP) and fern spores (FS) constituted 81.7%, 7.7% and 7.8% of the two-year sum, respectively. AP dominated from January to June, NAP in November and fern spores in July. Native species in the Taipei Basin and trees along urban roadsides were the common sources of airborne pollen. The pollen calendar of two years in Taipei City was submitted.  相似文献   

6.
For the first time, a volumetric study ofBuenos Aires city atmosphere was conductedusing a Lanzoni collector from March 1997through March 1998. Fifty-four pollen typeswere recorded of which 13 had a relativeconcentration of more than 1% of the yearlytotal. The lowest concentration of pollengrains was recorded in June, when Urticas,pp., Morus spp., and Myrtaceae were low.On the other hand, the highest concentration ofpollen grains was reached in September, with anincrease in Fraxinus spp. Theaeropalynological record may be divided intothree periods: *AP Dominant from July toOctober, *NAP Dominant from November toMarch, and *Residual Period from April toJune with low pollen concentrations.The greatest number of species was recorded inNovember, when 32 types were present, and thelowest number of species in June, when only 13pollen types were recorded. In June, the pollenconcentration was not dominated by any specieswhereas in September 85% of the pollen wasderived from one species of Fraxinus.Earlier studies on the aeropalynology of BuenosAires City were performed using Tauber andRotorod samplers. They were comparable to thisstudy, especially since the pollen peak wasreached in September, although the main pollenproducing species were different.  相似文献   

7.
Modern pollen samples from alpine vegetation on the Tibetan Plateau   总被引:6,自引:0,他引:6  
  • 1 A set of 316 modern surface pollen samples, sampling all the alpine vegetation types that occur on the Tibetan Plateau, has been compiled and analysed. Between 82 and 92% of the pollen present in these samples is derived from only 28 major taxa. These 28 taxa include examples of both tree (AP) and herb (NAP) pollen types.
  • 2 Most of the modern surface pollen samples accurately reflect the composition of the modern vegetation in the sampling region. However, airborne dust‐trap pollen samples do not provide a reliable assessment of the modern vegetation. Dust‐trap samples contain much higher percentages of tree pollen than non‐dust‐trap samples, and many of the taxa present are exotic. In the extremely windy environments of the Tibetan Plateau, contamination of dust‐trap samples by long‐distance transport of exotic pollen is a serious problem.
  • 3 The most characteristic vegetation types present on the Tibetan Plateau are alpine meadows, steppe and desert. Non‐arboreal pollen (NAP) therefore dominates the pollen samples in most regions. Percentages of arboreal pollen (AP) are high in samples from the southern and eastern Tibetan Plateau, where alpine forests are an important component of the vegetation. The relative importance of forest and non‐forest vegetation across the Plateau clearly follows climatic gradients: forests occur on the southern and eastern margins of the Plateau, supported by the penetration of moisture‐bearing airmasses associated with the Indian and Pacific summer monsoons; open, treeless vegetation is dominant in the interior and northern margins of the Plateau, far from these moisture sources.
  • 4 The different types of non‐forest vegetation are characterized by different modern pollen assemblages. Thus, alpine deserts are characterized by high percentages of Chenopodiaceae and Artemisia, with Ephedra and Nitraria. Alpine meadows are characterized by high percentages of Cyperaceae and Artemisia, with Ranunculaceae and Polygonaceae. Alpine steppe is characterized by high abundances of Artemisia, with Compositae, Cruciferae and Chenopodiaceae. Although Artemisia is a common component of all non‐forest vegetation types on the Tibetan Plateau, the presence of other taxa makes it possible to discriminate between the different vegetation types.
  • 5 The good agreement between modern vegetation and modern surface pollen samples across the Tibetan Plateau provides a measure of the reliability of using pollen data to reconstruct past vegetation patterns in non‐forested areas.
  相似文献   

8.
The northern slopes of central Tianshan Mountains in Xinjiang, northwestern China can provide an ideal database to research palaeoclimate as disturbance by human impact is relatively low and the vegetation zones reflect climatic gradients. In order to establish the correlation between modern climatic factors and surface pollen assemblages and to reconstruct palaeoclimate on the northern slope of central Tianshan Mountains, three Holocene sections in Daxigou, Huashuwozi and Sichanghu located at different elevations and vegetation zones were chosen for study. A total of 80 surface pollen samples in 86 vegetation quadrats were collected for pollen‐vegetation relationship analysis. The Warmth Index (WI) and Moisture Index (MI) were calculated based on averaged modern climate data during 1951 – 2000 at eight weather stations in the study area. Pollen percentages of Picea, Artemisia, Chenopodiaceae, Ephedra, and Tamarix, as well as A/C (Artemisia/Chenopodiaceae) and AP/NAP (arboreal/nonarboreal pollen) ratio were selected as pollen variables and WI and MI were chosen as climatic variables. The relationship between pollen percentages (Picea, Artemisia, Chenopodiaceae and Tamarix), A/C, AP/NAP ratio, WI and MI values were estimated (95% confidence interval) using stepwise multiple linear regression analysis. WI and MI values for the three sections were calculated using these regression equations, and palaeoclimate for the study area could be reconstructed. The results showed periods of both cool‐humid and warm‐dry conditions on the northern slopes of Tianshan Mountain during the late Holocene.  相似文献   

9.
The simplest and likeliest assumption concerning the cognitive bases of absolute pitch (AP) is that at its origin there is a particularly skilled function which matches the height of the perceived pitch to the verbal label of the musical tone. Since there is no difference in sound frequency resolution between AP and non-AP (NAP) musicians, the hypothesis of the present study is that the failure of NAP musicians in pitch identification relies mainly in an inability to retrieve the correct verbal label to be assigned to the perceived musical note. The primary hypothesis is that, when asked to identify tones, NAP musicians confuse the verbal labels to be attached to the stimulus on the basis of their phonetic content. Data from two AP tests are reported, in which subjects had to respond in the presence or in the absence of visually presented verbal note labels (fixed Do solmization). Results show that NAP musicians confuse more frequently notes having a similar vowel in the note label. They tend to confuse e.g. a 261 Hz tone (Do) more often with Sol than, e.g., with La. As a second goal, we wondered whether this effect is lateralized, i.e. whether one hemisphere is more responsible than the other in the confusion of notes with similar labels. This question was addressed by observing pitch identification during dichotic listening. Results showed that there is a right hemispheric disadvantage, in NAP but not AP musicians, in the retrieval of the verbal label to be assigned to the perceived pitch. The present results indicate that absolute pitch has strong verbal bases, at least from a cognitive point of view.  相似文献   

10.
Ontogeny of human neutrophil granulocyte alkaline phosphatase   总被引:1,自引:0,他引:1  
Human embryonic neutrophils (N) in the liver (from 8.5 mm crown-rump length) are alkaline phosphatase (AP) negative during the first trimester of pregnancy. Early bone marrow granulocytes (from eleventh to sixteenth weeks of gestation) behave similarly. Only a small percentage of slightly AP positive cells could be found. Occasional cells with strong NAP reaction appear in the second trimester. NAP positivity greatly increases in the third trimester and term-babies have a somewhat higher than normal NAP activity in circulating blood. Unlike NAP reaction, naphthol-AS-D-chloroacetate esterase and peroxidase reactions are positive even in the earliest (AP negative) neutrophils.  相似文献   

11.
In northwestern Tibet, an atmospheric pollen sampling was performed weekly during one year (August 1989 to August 1990). Moreover, 18 dust flux samples were obtained in the same region which covers three geographical units: the western margin of the Taklimakan desert, the northern Karakorum and the northwestern Kunlun mountains. The atmospheric pollen results show that the annual pollen frequency is dominated by regional components of montane and alpine desert and steppe, such as Artemisia, Chenopodiaceae, Cupressaceae and Poaceae. They also show that pollen taxa derived from much more distant sources such as warm temperate and subtropical humid forest zones are sometimes well represented. It is inferred that the majority of airborne pollen has been carried by wind during the flowering seasons of the plants, and this provides an evaluation of the influence of southerly and southwesterly summer monsoon air movements. The similarity of pollen spectra between dust flux samples and the atmospheric pollen trap from the Kunlun Mountains suggests that the pollen deposition evaluated by the dust flux method is representative of the pollen rain in the studied area. The dust samples from lower altitudes are characterized by high values of Chenopodiaceae and low ratios of Artemisia/Chenopodiaceae which vary clearly with altitude and possibly with moisture level. The Artemisia/Ephedra ratio shows similar variations to A/C. The percentage AP value is generally higher in mountains like Kunlun where the plant cover is extremely low in comparison with semiarid massifs such as Karakorum. Therefore, interpretation of AP pollen in the fossil record must take into account long distance wind transport.  相似文献   

12.
In the city of Santiago (33°27'S70°38'W), Chile, an atmospheric pollen was monitored for three years using a volumetric Hirst-type pollen trap. The aims of the study were: to assess the pollen types present in the atmosphere, their actual concentrations and dynamics (means and maxima); to establish the pollen calendar for Santiago; and to analyze the aerobiologic characteristics distinguishing introduced and native taxa. Results show that atmospheric pollen mainly originates from the following taxa: Platanus , Poaceae, Acer , Cupressus , Chenopodiaceae, Urticaceae, Morus , Plantago and Oleaceae. For the most frequent pollen types graphs of their atmospheric presence constructed and a table with relevant yearly data for the three studied (July-June) is presented. It is concluded, that the airborne pollen is originating mainly from introduced taxa, many of which are considered allergenic. Native taxa showed no high concentrations. The highest aiborne pollen concentrations where observed in September, however, atmospheric pollen thought to be capable of causing pollinosis, where present during the whole year. The highest pollen concentrations are mostly from trees.  相似文献   

13.
Aim To understand the scenarios of ‘anthropogenic biomes’ that integrate human and ecological systems, we need to explore the impacts of climate and human disturbance on vegetation in the past and present. Interactions among surface pollen, modern vegetation and human activities along climate and land‐use gradients are tested to evaluate the natural and anthropogenic forces shaping the modern vegetation, and hence to aid the reconstruction of vegetation and climate in the past. This in turn will help with future predictions. Location The North‐east China Transect (NECT) in north‐eastern China. Methods We analysed 33 surface pollen samples and 213 quadrats across four vegetation zones along the moisture/land‐use gradients of the NECT. Detrended correspondence analysis (DCA) and redundancy analysis (RDA) of 52 pollen taxa and three environmental variables were used to distinguish anthropogenic and climatic factors that affect surface pollen assemblages along the NECT. Results The 33 surface samples are divided into four pollen zones (forest, meadow steppe, typical steppe and desert steppe) corresponding to major vegetation types in the NECT. Variations in pollen ratios of fern/herb (F/H), Artemisia/Chenopodiaceae (A/C) and arboreal pollen/non‐arboreal pollen (AP/NAP) represent the vegetation and precipitation gradient along the NECT. DCA and RDA analyses suggest that surface pollen assemblages are significantly influenced by the precipitation gradient. Changes in the abundance of Chenopodiaceae pollen are related to both human activities and precipitation. Main conclusions Surface pollen assemblages, fossil pollen records, archaeological evidence and historical documents in northern China show that a large increase of Chenopodiaceae pollen indicates human‐caused vegetation degradation in sandy habitats. The A/C ratio is a good indicator of climatic aridity, but should be used in conjunction with multiple proxies of human activities and climate change in the pollen‐based reconstruction of anthropogenic biomes.  相似文献   

14.
This paper describes the pollen representation of vegetation patterns along an altitudinal transect in the South Caucasus region. Surface sediments from eight small- to medium-sized lakes and wetlands were analysed for modern pollen, and the results analysed numerically using detrended correspondence analysis (DCA) and dichotomised ordination (TWINSPAN). Pollen spectra from the semidesert region have a clear palynological signal characterised by an abundance of Chenopodiaceae. Differentiation of oak forest, upper tree-line and subalpine communities is more difficult: all are dominated by arboreal pollen (AP) types. The authors propose a number of indicator pollen types and pollen threshold values that may assist in detecting tree-line variations and deforestation events in Holocene pollen diagrams.  相似文献   

15.
16.
Pollen loads in the atmosphere of Darwin, a city located in the wet‐dry tropics of Australia, have been monitored for the period March 2004 to November 2005 as part of a large research program looking at atmospheric particles and human health. Seven pollen types dominate the pollen spectrum, the herbaceous families of Poaceae (grasses) and Cyperaceae (sedges), as well as several native tree and shrub taxa, Acacia, Callitris, Casuarina, Arecaceae and Myrtaceae. The pollen loads were found to have a strong seasonal component associated with the alternating wet (November to March) and dry (April to October) seasons of the region. Seventy percent of the yearly pollen load is captured during the dry season, with the peak pollen period occurring at the onset of the dry season (April–May) when most grasses are in flower. The daily pollen concentration decreases as the dry season progresses, accompanied by a change in composition; fewer herbaceous but increasing woody taxa. Preliminary health outcomes reveal a positive association between hay fever, Poaceae and Acacia pollen, as well as a significant association between total fungal spore concentrations and asthma. The Darwin record contrasts significantly with surveys conducted in the subtropical and temperate cities of Australia where temperature as opposed to rainfall and the prevalence of northern hemisphere exotic tree species have a greater influence over the seasonality and composition of the pollen loads.  相似文献   

17.
Patients diagnosed with a standard clinical method (subject to misclassification error) are often combined with patients diagnosed with a gold-standard method (with zero or very small misclassification error) in family-based studies of complex disease. For example, non-autopsied patients (NAP) are often included along with autopsy-proven (AP) patients in family-based studies of complex diseases, such as Alzheimer's disease (AD). Theoretical and simulation studies suggest that certain misclassification errors can result in severe reduction of power in genetic linkage and association analyses and that phenotype (or diagnostic) error can produce misleading results. Morton's test for heterogeneity can identify genomic regions where error may have led to loss in power. We applied this test to pedigree data from the NIMH Alzheimer's Disease Genetics Initiative Database separated into AP and NAP pedigrees. Morton's test identified one highly significant region of heterogeneity on chromosome 2. The source of the heterogeneity was due to significant indication of linkage in the AP pedigrees at position 109 cM (p value = 6.68 x 10(-5)) with no indication in the NAP pedigrees. Furthermore, Morton's test showed no evidence for heterogeneity on chromosome 19 in early-onset pedigrees that showed highly significant evidence for linkage in other published reports. These results suggest that supplementing linkage analysis with Morton's test can be usefully applied to genetic data sets that have AP and NAP samples, or other sample mixtures that include a 'gold standard' subgroup with reduced error rate, to increase power to detect linkage in the presence of diagnostic misclassification.  相似文献   

18.
Mites occurring on a number ofnatural and secondary (i.e., planted) hedgerowslocated in north-eastern Italy were monitoredwith particular attention being paid tophytoseiids (Acari: Phytoseiidae). Pollendiversity and abundance were analysed tohighlight potential relationships betweenpollen availability and phytoseiids. Secondaryhedgerows were structured in modules containinga single species (field maple, hornbeam,dogwood, hazel, and elderberry) andmodules containing a mixture of theabove-mentioned species. These hedgerows werelocated in an experimental farm where they werecontiguous to a vineyard. Natural hedgerowswere located in the same area. The pollen ofPoaceae was the most important component ofnon-arboreal pollen (NAP), and that ofelderberry of arboreal pollen (AP). Pollendiversity was higher on natural than onsecondary hedgerows. Generally, pollendensities reached relatively high levels fromlate April to late June and decreased insummer. Pollen was more abundant on naturalthan on secondary hedgerows and phytoseiidabundance showed a similar trend. On elderberryand hornbeam in natural hedgerows a potentialrelationship between pollen availability andthe abundance of phytoseiids, in particular ofEuseius finlandicus (Oudemans) was found.Experimental pollen applications increased thefecundity and the abundance of this species.  相似文献   

19.
A pollen calendar for Chittagong University Campus,Chittagong (Bangladesh)   总被引:2,自引:0,他引:2  
Summary This work presents a calendar of pollen types found in the atmosphere of Chittagong University Campus, Chittagong, Bangladesh, recorded over the period of March 1988–February 1990. A total of 9,225 pollen/cm2 was encountered and classified in 36 pollen types belonging to 26 families. The pollen concentration showed three peak periods, March, October and November and each period was dominated by a specific pollen type. Low frequency of pollen was probably due to heavy rainfall which washed down the pollen. January and February were also marked by lower abundance of pollen and was probably due to the low rate of flowering. This study clearly showed four airborne pollen seasons from October to November, December to February, March to April and June to September. The dominant pollen types were Poaceae, followed by Amaranthaceae, Arecaceae, Asteraceae and Cyperaceae. The pollen calendar was provided to show the range of flowering with the period of occurrence in air of the area studied.  相似文献   

20.
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