Atmospheric concentration of pollen grains at human height

An atmospheric survey at human height (1.5–1.8 ft) was carried out from February 1988 to January 1990, in four different ecozones of the Delhi metropolis. The samples were collected by using Burkard Personal Volumetric Sampler at weekly intervals. The sampler was operating for 15 min three times a day (07, 14, 20 hrs). Altogether, 84 pollen types were identified. Some of the dominant pollen types recorded were Poaceae (25.1%), Cheno/Amaranthaceae (14.5%) and Ricinus communis (12.3%) followed by Morus, Cannabis, Prosopis, Parthenium and Artemisia. Weekly variations were recorded for the total number of pollen of different types in different months. Two major pollen seasons 1. February — April and 2. August — October were observed, although pollen was recorded throughout the year. Significant variation in total and individual pollen concentration was recorded from different inhabited areas in the same urban locality. Any definite daily pattern in the occurrence of pollen was not recorded. The concentration at lower height was also poor.     

Late Pleistocene vegetation and environments near Lake Bullenmerri,Western Victoria

The stratigraphy and pollen analysis of the basal 5.73 m of an 11.73 m core from the centre of Victoria's deepest lake is described. The hypothesis is advanced that at 16 100 B.P. a cool semi-arid environment supporting a sparse or scattered Eucalyptus–Callitris woodland with an understorey of grasses, Asteraceae and Chenopodiaceae dominated the region. From this time the lake level fell and was at its lowest between 15 000 B.P. and 10 000 B.P. At about the same time Casuarina migrated into the region as Callitris, Asteraceae and Chenopodiaceae declined. There was a period from 9600 B.P. to 9200 B.P. when Acacia and Dodonaea were common around Lake Bullenmerri, but these declined and were replaced by the Eucalyptus-Casuarina woodland with a herbaceous understorey which persisted through the Holocene period in western Victoria until it was cleared by European settlers.     

The dispersion characteristics of airborne pollen in the Shijiazhuang (China) urban area and its relationship with meteorological factors

In this study, a Tauber pollen trap was used in the urban area of Shijiazhuang to monitor continuously the outdoor air pollen from 2007 to 2011. The trap was emptied at regular intervals (typically 15 days). The results show that airborne pollen assemblages are generally similar each year among 2007–2011 and are responsive to the flowering times of plants, being dominated by pollen from woody plants in the spring and by pollen from herbaceous plants in summer and autumn. Two peak pollen influx periods, especially for the main allergenic pollen taxa, are seen, one between early March to early June and a second between late August to early October. During the four seasons, the main pollen taxa are Juglans, Artemisia, Platanus, Populus, Chenopodiaceae, Urtica + Humulus, Rosaceae, Pinus, Poaceae, Cereals, Quercus, and Betula, and all taxa other than Rosaceae were confirmed by relevant studies to be allergenic pollen taxa. RDA analysis of pollen influx and meteorological factors shows that in spring, temperature and humidity have significant effects on the pollen influx of woody plants; in summer, humidity and precipitation have significant negative effects on pollen influx of herbaceous plants; in autumn, temperature, water vapor pressure, and precipitation have a significant positive influence on herbaceous pollen influx; in winter, there were no significant correlations between airborne pollen influx and meteorological factors. The results reveal the dispersion patterns of airborne pollen and provide an important reference to appropriate construction of urban green systems and the reliable reduction in regional pollinosis.     

Palynological studies of some roadside plants under exposure to traffic stress

The diverse pollutants emitted from automobiles can have adverse effects on the health and survival of plants, animals and human beings. Different plant species have been known to possess high potential of absorption, detoxification and tolerance of high levels of pollution. Considering this, the present study was carried out to assess the impact of automobile pollution on palynology of roadside plants. Three species, viz. Cannabis sativa, Cassia fistula and Thevetia peruviana growing along the roadsides of nine sites of Amritsar city under different levels of traffic stress were selected for the study. Pollen viability and pollen size were studied by staining pollen with 2,3,5-triphenyl tetrazolium chloride stain and observed under light microscope. Scanning electron microscope was used to study the changes in morphology of the pollen grains. It was observed that the percentage of pollen viability of three species was inversely proportional to the load of traffic at a particular site. Pollen viability was observed to be minimum (C. sativa—22.58 %; C. fistula—21.30 %; and T. peruviana—6.22 %) for the plants of the three species studied growing at traffic site I, site with heavy traffic load as compared to plants growing at sites with comparatively lesser traffic load. C. sativa growing at traffic site IV showed maximum pollen viability of 79.74 %, while C. fistula and T. peruviana growing at traffic site VIII exhibited maximum pollen viability of 83.32 and 68.78 %, respectively. Pollen size and morphology did not show any significant variation and remained unaffected with the increase in traffic stress.     

A 10-year survey of allergenic airborne pollen in the city of Porto (Portugal)

Airborne pollen calendars are useful to estimate the flowering season of the different plants as well as to indicate the allergenic potential present in the atmosphere at a given time. In this study, it is presented a 10-year survey of the atmospheric concentration of allergenic pollen types. Airborne pollen was performed, from 2003 to 2012, using a 7-day Hirst-type volumetric trap. The interannual variation of the daily mean concentration of the number of pollen grains and the main pollen season was determined as well as the hourly variations and correlation with meteorological parameters. During the study period, 18 different allergenic pollen types were considered based on its representativeness on the total annual airborne pollen concentration. The lowest annual concentrations were sampled in 2006 and the highest in 2007. The highest airborne pollen concentration was found during early spring and early summer. On the contrary, December was the month with the lowest pollen concentration. The major pollen sampled belongs to trees followed by weeds and grasses, being the most representative pollen types in the atmosphere: Urticaceae, Platanus, Poaceae, Pinaceae, Cupressaceae, Acer, Quercus, Castanea, Plantago, Alnus, Olea europaea, Betula, Myrtaceae and Populus. Intradiurnal distribution patterns of the pollen types studied presented differences with some taxa being predominantly sampled in the morning (9–11 a.m.) while others in first night hours (between 9 and 12 p.m.). Significantly correlations were found between the airborne pollen concentration and meteorological parameters.     

Aeropalynological study in Rohtak city, Haryana, India: a 2-year survey

An aeropalynological survey was conducted at two different sites in Rohtak city, Haryana, at a height of 1.8 m, three times a day, for two consecutive years (July 2007–June 2009). A total of 31 pollen types were identified to the lowest taxonomical level whenever possible. The major contributor to the pollen load was Cannabis sativa (28.9 %) followed by Poaceae (20.65 %), Chenopodiaceae/Amaranthaceae (10.56 %), Parthenium hysterophorus (6.80 %), Morus alba (6.15 %), Artemisia sp. (4.03 %), Cyperus sp. (3.20 %) and Eucalyptus sp. (3.07 %). Two major pollen seasons were recognized, that is, July–October and March–April, although pollen was recorded in varying concentrations all along the year. Spatial variations were also observed, with higher pollen loads at the site surrounded by dense vegetation. The study will provide preliminary but useful data to local allergologists for effective diagnosis and treatment of respiratory allergic ailments.     

Floral Preference of Melipona eburnea Friese (Hymenoptera: Apidae) in a Colombian Andean Region

Melipona eburnea Friese is a stingless bee kept in some regions of Colombia, where it is reported to be vulnerable to extinction due to habitat disturbance. To contribute to raising conservation strategies, the aim of this study was to identify the floral preferences of this species using melissopalynological analysis. A total of 31 pollen pot samples and 37 honey samples were taken from March 2009 through March 2010 from four colonies in Fusagasuga, Colombia. We found 92 pollen types: 17 from pollen pot samples, 39 from honey samples (indicating the sources of nectar), and 36 in both types of samples. The most frequent pollen types in the pollen pot samples were Myrcia type (100%), Eucalyptus globulus (96.9%), and Fraxinus uhdei (96.9%). The most frequent pollen types in honey samples were E. globulus (97.4%) and Myrcia type (94.9%). The pollen types corresponded mainly to native plants (68%), trees (44.5%), plants whose sexual system is hermaphroditic (56.5%), and plants with inflorescences (76.2%). The most frequent shapes of the flowers were brush-like (type Myrtaceae) and dish-like (type Asteraceae), and the preferred flower colors were white or cream (52.2%). In general, we found that M. eburnea showed a strong preference for trees of the family Myrtaceae to obtain nectar and pollen, including native and introduced species. Some other families are contributing significantly, such as Melastomataceae for pollen collection and Asteraceae for nectar. These results highlight the key plant species for the diet of M. eburnea.     

First aerobiological study in Mediterranean part of Croatia (Dalmatia): pollen spectrum and seasonal dynamics in the air of Split

The aim of this study was to investigate aerobiological dynamics of pollen in the Mediterranean part of Croatia in the air of the city of Split. Pollen monitoring during the period from 2005 to 2013 was performed using a Hirst volumetric trap. Among the identified pollen of 50 taxa, 21 were allergenic. The average annual pollen index was 33,513. Three pollination seasons were established: early winter season dominated by tree pollen, spring–summer season dominated by herbaceous plants and summer–autumn season with lower amounts of Parietaria and Cupressaceae pollen. According to the abundance, the main taxa were: Cupressaceae, Parietaria/Urtica, Pinus, Quercus, Olea, Carpinus/Ostrya, Poaceae, Platanus and Ambrosia. The annual pollen index together with the daily maximum concentrations showed an upward trend for selected taxa during the study period. The highest monthly pollen index and the highest biodiversity were recorded in April and the lowest during the late autumn and winter months. The pollen calendar created for the city of Split confirmed Mediterranean features of the pollen spectrum. The longest pollen seasons were recorded for Cupressaceae, Parietaria/Urtica and Poaceae pollen types. The correlations between pollen concentrations and meteorological parameters were analyzed. The correlations between pollen concentrations and temperature were positive, while the humidity and the precipitation mostly showed negative influence.     

Annual pollen spectrum in the air of Palma de Mallorca (Balearic Islands, Spain)

This aeropalynological study documented the pollen of 13 taxa with the highest concentration in the air of Palma de Mallorca during the years 2004–2010, using a Hirst-type volumetric spore trap. The taxa were Cupressaceae, Olea europaea, Platanus hispanica, Pinus spp., Parietaria judaica, Urtica membranacea, Quercus ilex, Poaceae, Chenopodiaceae/Amaranthaceae, Plantago spp., Castanea sativa, Pistacia lentiscus and Betula spp. These taxa accounted for 91.85 % of the total annual pollen recorded during the period. The mean annual pollen index was 20,027. The highest pollen counts occurred in February–June, representing 88.74 % of the annual total collected. Every year, there was a substantial increase in the concentration and types of pollen from March to May, followed by a decrease from July to January. The maximum annual total pollen count was recorded in 2005 with 25,870 and the minimum in 2009 with 14,726. The mean daily average pollen concentration count showed a declining trend over the study period. With respect to seasonal phases analysed, the later phase of the pollen season is more variable than the beginning. To observe the overall dynamics of the different pollen types better, a pollen calendar was established for Palma de Mallorca. The pollen calendar had typical Mediterranean features and is a useful tool for allergological and botanical awareness.     

A comparative study on the effects of altitude on daily and hourly airborne pollen counts

The concentration of pollen grains in the air was studied using two aerobiological volumetric Hirst-type spore traps, one at ground level and the other at a height of 16 m on a terrace. The study was carried out between 2009 and 2011, from March to June in Badajoz (SW Spain). Intradiurnal and daily pollen counts were compared with both, different meteorological parameters and the distribution of local pollen sources. Forty-six pollen types were identified and 89 % of the total grains corresponded to Quercus, Poaceae, Olea, Pinaceae and Plantago pollen types, in descending order. The mean height ratio of the daily pollen count was 1.02. Significant correlations were observed when comparing daily pollen counts for predominant pollen types at both levels. The comparisons have shown significant differences in the daily pollen count between the two samplers in the case of Olea and Pinaceae, but not for Quercus, Poaceae and Plantago. Similar results were obtained using the intradiurnal airborne pollen database. No significant correlation has been found between pollen count and the different meteorological parameters, showing no dependence on height. These differences of Olea and Pinaceae may be explained in part by the uneven distribution of the pollen sources and the disturbance by nearby buildings. The temporal variation patterns between the two sites were similar; however, taking into account the average of the data, the higher values were obtained first at the ground level and later at 16 m.     

Analysis of airborne allergenic pollen spectrum for 2009 in Timişoara, Romania

The objective of this investigation was to identify the overall pollen types and, more particularly, the allergenic pollen content in the investigated area and then to explore their seasonal variations. The measurement point was located in the Timi?oara city, Romania. A Lanzoni volumetric trap was used for sample collection. Duration of the pollen season of allergenic plants and respective variation in airborne pollen concentration are presented in the pollen calendar for the year 2009. Among the identified pollen of 23 types, 20 were allergenic: Taxaceae/Cupressaceae, Alnus sp., Fraxinus sp., Betula sp., Corylus sp., Carpinus sp., Salix sp., Populus sp., Ulmus sp., Juglans sp., Quercus sp., Pinaceae, Tilia, Poaceae, Urticaceae, Chenopodiaceae/Amaranthaceae, Rumex sp., Plantago sp., Artemisia sp., Ambrosia sp. These species prevail throughout almost the entire pollen season, from February–October, accounting for 87.03 % of the total pollen count. The greatest diversity of pollen types is detected in the months of spring. The summer months were characterized mostly by non-arboreal pollen types. In late summer and early autumn, Ambrosia airpollen was the most abundant in the atmosphere. The relationships between pollen concentrations and nine meteorological parameters are presented too. To analyze the correlation between pollen data and variables, the Spearman rank correlation coefficient was used. The correlation analysis of daily pollen counts and meteorological parameters showed that arboreal pollen and non-arboreal pollen counts were significantly correlated with temperature. The prevalence of pollen sensitization resulted to be very high in our patients with respiratory symptoms.     

Pollen of Apis honey from Maharashtra

Melissopalynological investigations are important in establishing an apiary industry. Pollen analyses of the nectar sources of Apis florea Fabr. from the Saoner region indicate the importance of this region for commercial bee keeping enterprises. Twenty seven samples were collected during winter season in the months of October 1997 to January 1998 and November 1998 to January 1999. In addition, 245 pollen loads were analyzed from 19 honey combs collected from the same region. Pollen grains were identified from reference slides. Of the 27 honey samples, 17 samples were unifloral and ten multifloral. A total of 39 pollen types were classified into 21 families. In the analyses of the 245 pollen loads Lagascea mollis Cav. was dominant in 57 pollen loads and Parthenium hysterophorus L. in 55 pollen loads. Weeds such as Parthenium hysterophorus, Sphaeranthus indicus L., Lagascea mollis, Bidens pilosa L. and Justicia procumbens L. were the common sources of nectar and pollen for Apis florea in the region. Agricultural tracts of the Saoner region in the Nagpur District have a good potential for sustaining beekeeping ventures because of the diversity of nectar and pollen taxa.     

The breakdown of macrophytes in a reservoir wetland

Weight losses from leaf laminae and petioles of Nelumbo lutea (Wild.) Pers., and from leaves of Ludwigia leptocarpa (Nutt.) Hara. and Typha angustifolia L., were measured by exposing air-dried leaf material in nylon mesh bags at upper (exposed 25 days, inundated 40 days) and lower (inundated 154 days) wetland sites in a Texas reservoir. No significant differences (P < 0.05) were found between sites, so data were combined to yield estimates of plant litter breakdown for the entire wetland. Breakdown rates (in percentage of ash free dry weight lost per day) for the 4 litter types were: Nelumbo leaves — 0.0108 ± 0.0016; Ludwigia — 0.0050 ± 0.0007; Typha — 0.0047 ± 0.0006; Nelumbo — petioles 0.003 ± 0.0010. Times required for a 95% loss of litter, based on an exponential model, are 278 days, 600 days, 638 days and 909 days for these 4 litter types, respectively. These rates are comparable to those reported for emergent aquatic macrophytes in other lakes and wetlands. Colonization of decaying wetland plants was dominated by the gatherers, Chironominii (54%) and Caenis sp. (26%).     

Secondary pollen types characteristic of Louisiana honeys

Nine secondary pollen types (those comprising 16–45% of the pollen sample) were recovered from 54 honey samples (10 g) collected from the major beekeeping areas of Louisiana. The pollen types in order of decreasing importance are:Berchemia scandens, rattan vine;Rubus spp., blackberry and dewberry;Salix spp., willow;Trifolium repens, white clover;Glycine max, soybean;Parthenocissus quinquefolia, Virginia creeper; Rosaceae, rose family;Cephalanthus occidentalis, buttonbush; andCornus spp., dogwood. The first four secondary types also appeared as dominant pollen (over 45%) in some of the Louisiana honey samples investigated and were previously reported. The remaining five pollen types and the “bee plants” associated with each pollen type are identified and described.     

Comparative study of the effect of distance on the daily and hourly pollen counts in a city in the south-western Iberian Peninsula

The airborne pollen concentration in the city of Badajoz was measured in two locations 2.9 km apart. The measurements were taken from January to June between 2009 and 2012 using Hirst-type volumetric aerobiological samplers. One sampler was placed at the Faculty of Science (FS) and the other at the Agricultural Engineering School (AES) of the University of Extremadura, Spain, on terraces located 16 and 6 m above ground, respectively. The two sets of hourly and daily pollen concentrations were compared regarding the meteorological parameters and the distribution of local pollen sources. A total of 46 pollen types were counted, with a mean total concentration of 43 pollen grains/m³ in the winter and 336 pollen grains/m³ in the spring. In the winter, pollen grains from (in decreasing order) Cupressaceae, Fraxinus–Phillyrea, Urticaceae spp., Alnus glutinosa and Urtica membranacea types represented 77 % of the total. In the spring, 89 % of the total was represented by pollen grains from (in decreasing order) Quercus, Poaceae, Olea, Pinaceae and Plantago. The FS/AES ratio was 0.57 in the winter and 1.31 in the spring. While a Wilcoxon test applied to the daily total concentration data showed statistically significant differences between the two sites, a correlation study based on the Spearman coefficient showed statistically significant correlations in both the winter and spring. The results were similar when comparing the separate pollen types, except for Urticaceae spp., which showed no statistically significant correlation. The meteorological data studied showed a statistically significant correlation with the daily concentrations. A comparison of the hourly concentration data showed no correspondence with the time of maximum concentration. The local distribution of pollen sources explained some of the differences found between the two sites. Overall, the results indicate that a single aerobiological sampler may be sufficiently representative to register the daily pollen grain data of an urban area of approximately 3 km or greater in diameter, although it underestimates the influence of heterogeneity in the distribution of the local flora.     

Aeropalynological spectrum of Hatay,Turkey, the eastern coast of the Mediterranean Sea

An aeropalynological study during the years 2014–2015 was performed in Hatay, which is a unique sociocultural and phytogeographical area located on the border of Turkey and Syria on the eastern coast of the Mediterranean. The sampling was performed by a Hirst-type volumetric sampler (Lanzoni VPPS 2000), and pollen grains of 54 taxa were identified, of which 83.21% of the annual sum belonged to woody taxa. The highest pollen concentration was recorded in February, of which a large amount came from the Cupressaceae/Taxaceae families. The diversity of the pollen reflected the vegetation of the area and plantations of the city center, but pollen grains from Euro-Siberian elements specific to Mount Amanos could not be recorded. Pollen types found at more than 3% of the annual pollen index and considered dominant pollen types were as follows: Cupressaceae/Taxaceae (50.86%), Olea europaea (12.67%), Moraceae (7.20%), Poaceae (5.99%), Quercus (5.35%), Urticaceae (3.79%) and Pinus (3.70%); almost all dominant pollen types in the city atmosphere were previously stated to be allergic. The main pollen season starting dates of common pollen types found were one or two weeks earlier than those of the surroundings. Many statistically significant correlations were found between daily pollen concentrations and daily meteorological parameters, e.g., Cupressaceae/Taxaceae Poaceae and Urticaceae pollen correlated negatively with mean temperature in both years, and in the hindermost two families daily pollen amounts significantly correlated with wind speed in the second year. Daily Olea europaea pollen concentration showed a significant negative correlation with the amount of total daily rainfall in the second year.     

Effective Long-Distance Pollen Dispersal in Centaurea jacea

Background

Agri-environment schemes play an increasingly important role for the conservation of rare plants in intensively managed agricultural landscapes. However, little is known about their effects on gene flow via pollen dispersal between populations of these species.

Methodology/Principal Findings

In a 2-year experiment, we observed effective pollen dispersal from source populations of Centaurea jacea in restored meadows, the most widespread Swiss agri-environment scheme, to potted plants in adjacent intensively managed meadows without other individuals of this species. Potted plants were put in replicated source populations at 25, 50, 100 m and where possible 200 m distance from these source populations. Pollen transfer among isolated plants was prevented by temporary bagging, such that only one isolated plant was accessible for flower visitors at any one time. Because C. jacea is self-incompatible, seed set in single-plant isolates indicated insect mediated effective pollen dispersal from the source population. Seed set was higher in source populations (35.7±4.4) than in isolates (4.8±1.0). Seed set declined from 18.9% of that in source populations at a distance of 25 m to 7.4% at 200 m. At a distance of 200 m seed set was still significantly higher in selfed plants, indicating long-distance effective pollen dispersal up to 200 m. Analyses of covariance suggested that bees contributed more than flies to this long-distance pollen dispersal. We found evidence that pollen dispersal to single-plant isolates was positively affected by the diversity and flower abundance of neighboring plant species in the intensively managed meadow. Furthermore, the decline of the dispersal was less steep when the source population of C. jacea was large.

Conclusions

We conclude that insect pollinators can effectively transfer pollen from source populations of C. jacea over at least 200 m, even when “recipient populations” consisted of single-plant isolates, suggesting that gene flow by pollen over this distance is very likely. Source population size and flowering environment surrounding recipient plants appear to be important factors affecting pollen dispersal in C. jacea. It is conceivable that most insect-pollinated plants in a network of restored sites within intensively managed grassland can form metapopulations, if distances between sites are of similar magnitude as tested here.     

Pollen deposition in a small closed drainage basin lake

A moss cushion and fifteen lake bottom samples from a small volcanic crater lake in southeastern South Australia were examined for pollen. The distribution of pollen types is analysed in relation to the distance from source areas of Eucalyptus woodland and Pinus radiata plantations, and in relation to water depth in the lake.Most taxa were only detectable in small quantities within a few metres of the source plants. The decline in these local pollen types led to a relative increase in regional pollen types in the centre of the lake. This is a problem which makes interpretation of the extent of the redeposition factor difficult for some taxa. The redeposition factor was small for extralocal taxa including Pinus radiata and Eucalyptus spp. as their relative frequencies declined noticeably toward the centre of the lake. Regional types included Casuarina stricta, Chenopodiaceae, Polygonaceae and Poaceae pollen. Aquatic pollen was derived within the lake and does not contribute to the regional pollen rain. The majority of these taxa have highest values near the source plants but were also deposited elsewhere in the lake. The exceptions to this were Triglochin and Typha angustifolin pollen; the former showed a distribution pattern which had little relation to the occurrence of the plant while the latter had highest relative frequencies away from the source plants. The implications in relation to water depth interpretation from fossil pollen profiles are discussed.     

Roman impact on the landscape near castellum Fectio,The Netherlands

Castellum Fectio was one of the largest fortifications along the Limes, the northern border of the Roman Empire. The castellum, situated 5 km southeast of Utrecht, the Netherlands, was occupied from around the start of our Era to ca. a.d. 260. It was situated along a river bend of the Rhine that was cut off from the main stream during the occupation of the Roman fort. A 6 m long sediment sequence was recovered from the infill of the residual channel and pieces of Roman wall plaster, glume bases of Triticum spelta and radiocarbon dates indicate that the sediments were deposited during the period of Roman occupation. The combined palaeoecological analyses—palynological, macrobotanical, entomological and geochemical—allow a detailed reconstruction of changing environmental conditions as a consequence of the Roman occupation. The pollen record reveals a dramatic decrease in arboreal pollen, suggesting that the Romans were involved in large-scale deforestation, transforming semi-open parkland to a landscape of meadows and agricultural fields. Non-pollen palynomorphs, botanical macrofossils and insect remains support this conclusion. The recorded mycoflora shows a shift from assemblages characterised by the tree pathogen Kretzschmaria deusta to assemblages dominated by spores of fungi associated with herbaceous plants, concurrent with the decrease in arboreal pollen. The presence of masticated bran fragments of cereals, clover remains, eggs of intestinal parasites and entomological and geochemical data in the upper part of the sequence indicates that these sediments largely consist of faeces that were dumped into the former channel. Surprisingly, seeds of salt tolerant species are encountered in the sediments of this inland site, which was situated outside the influence of the sea. Horses may have brought these seeds to Fectio in their intestinal tracts after grazing in coastal meadows.