Pollen concentrations inside private cars during the Poaceae and Artemisia spp. pollen season – a case study

A growing number of studies are researching indoor air concentrations of pollen in buildings, but to our knowledge no studies have dealt with the precise concentration of pollen inside private cars. The aim of this study was to assess the risk of exposure to pollen in private cars throughout the Poaceae and Artemisia spp. pollen season.

The study was conducted in the town of Lappeenranta and along Highway 6 in south‐east Finland between July 14 and August 17, 2003. The pollen concentrations were measured inside two moving and parked cars using rotorod‐type samplers. Surface and ambient Burkard samples were also collected.

Both Poaceae and Artemisia spp. pollen were recorded only on one day and in low concentrations (<10 pollen grains per cubic meter, pg/m³) inside moving and parked cars, whereas the concentrations of Betula spp. (0–15 vs. 0–12?pg/m³) and Pinus (0–41 vs. 0–80?pg/m³) ranged from low to moderate, respectively. The number of pollen grains on the inside surfaces of cars ranged from zero to 72?pg/cm² during the measurement periods.

The concentrations of Poaceae and Artemisia spp. pollen in the indoor air of the car during the flowering period were low, therefore, likely to cause reactions only in the most sensitive people. By contrast, even after the main flowering period the concentrations of Betula spp. pollen were on a level high enough to cause reactions in individuals with allergies.     

<Emphasis Type="BoldItalic">Betula</Emphasis> spp. pollen in the atmosphere of Novi Sad (2000–2002)

Pollen of Betula spp. is one of the main European aeroallergens. The aim of this study was to determine characteristics and occurrence of the Betula pollen in Novi Sad atmosphere, based on 3-year observations (2000–2002), and to compare pollen season start dates calculated by different methods. Pollen samples have been collected by Hirst volumetric method with a 7-day Burkard spore trap. Four methods (Sum 75, 2.5%, 30 and 1 pg/m ³) have been used for determination of the start dates of the Betula pollen season and the results have been compared. The total annual pollen sum increased during the observed period. In 2000, 2001 and 2002, the highest daily pollen concentrations were 97, 137 and 1034 pg/m ³, respectively. The earliest Betula pollen season start has been calculated by the 1 pg/m ³ method.     

Experimental results about Platanus pollen deposition

A comparison between the aerobiological and floristic data carried out for Platanus are reported. The source was constituted by 60 Platanus trees. When they were pollinating we calculated the total pollen prodution of the source, controlling the number of male inflorescences for each plant, the number of anthers for each inflorescence and the number of pollen for each anther. Aerobiological data were obtained with 16 Durham gravimetric samplers positioned over an area of approximately 25 km² at variable distances and in different directions to capture pollen transported by winds coming from any direction. In the first year of analysis, we carried out two kind of aerobiological monitoring positioning a Hirst volumetric trap near the closest gravimetric sampler. The two methods showed a similar trend in Platanus pollen profiles. In the following years, only Durham gravimetric samplers were used to study pollen dispersion. The data showed that there were high concentrations of pollen on the soil near the source while at distances higher than 800 m pollen concentration decreased dramatically. About 1/4 of all the pollen produced fell in an area within 400 m from the source and at a distance of 2750 m only 9 pollen grains/cm² fell throughout the entire season. This revised version was published online in June 2006 with corrections to the Cover Date.     

Mating System in a Low-density Natural Population of the Dioecious Wind-pollinated Patagonian Cypress

The mating system of a species is an essential factor that determines the genotypic frequencies of its populations in each generation. Thus, knowledge in this regard is important in the application of practical measures in conservation and forest tree breeding. Austrocedrus chilensis (D.DON) PIC. SER. ET BIZZARRI is a member of the Cupressaceae native to the Andean–Patagonian Forest of Argentina and Chile with regional economic importance. It is a dioecious tree with pollen and seeds distributed by wind. Isozyme markers were utilized to study the mating system of this species through the survey of individual effective pollen clouds in a natural low-density population. If random mating occurs, effective pollen clouds that pollinate single seed trees are expected to be genetically homogeneous. The classical HardyWeinberg test of panmixia was also performed. Although it failed to reject random mating, the analysis of the pollen clouds showed that this mating pattern does not occur. Evidence of locally distributed heterogeneous pollen clouds is presented. The two methods are critically compared.     

Division of the generative nucleus in cultured pollen tubes of the Bromeliaceae

Pollen germination, division of the generative nucleus and position of the generative nucleus in the pollen tube during in vitro germination were examined for six bromeliad cultivars. The influence of mixed amino acids (casein hydrolysate) and individual amino acids (Arg, Asn, Asp, Glu, Gly, Met, Phe, Orn, Tyr) were tested. Aechmea fasciata and A. chantinii pollen tubes showed more generative nuclear division in cultured pollen tubes than the other four cultivars tested. Casein hydrolysate did not stimulate generative nuclear division. In general arginine (1 mM) improved division of the Aechmea generative nucleus and to a lesser extent this of Vriesea `Christiane', Guzmania lingulata and Tillandsia cyanea. A concentration of 2 mM arginine reduced pollen tube growth of Aechmea. The vegetative nucleus was ahead of the generative nucleus in approximately 50% of the pollen tubes of all cultivars studied. In about 25% of the pollen tubes, the generative nucleus was ahead and in ±25% pollen tubes the vegetative and generative nuclei were joined together. The distance between the two generative nuclei and the distance from the generative nuclei to the pollen tube tip differed significantly for Aechmea fasciata and A. chantinii. The influence of different amino acids for Aechmea fasciata and A. chantinii varied with respect to pollen germination and generative nuclear division. Arg and Met improved nuclear division of both Aechmea cultivars. Pollen germination and sperm cell production were not linked. This information is important to ameliorate in vitro pollination methods used to overcome fertilization barriers in Bromeliaceae and other higher plants.     

鱼腥草花粉母细胞减数分裂特征及其育性研究

为深入了解鱼腥草花粉母细胞的减数分裂特征与花粉育性的关系,该研究采用卡宝品红染色法对2个鱼腥草居群花粉母细胞的减数分裂过程进行观察,并采用氯化三苯基四氮唑(TTC)染色法、I2-KI染色法、B-K培养基培养法及荧光显微镜观察法来检测鱼腥草花粉的活力及萌发率。结果发现:(1)鱼腥草减数分裂的进程与花序大小、花药颜色、花药长度均有密切的关系。(2)2个居群的鱼腥草中花粉母细胞减数分裂过程正常占88.2%,有11.8%的花粉母细胞减数分裂异常。(3)减数分裂异常表现在减数分裂过程中出现微核、落后染色体、染色体桥、不均等分离、多分体等现象,并发现在二分体阶段及单核花粉发育过程中存在细胞融合。(4)2个居群的鱼腥草花粉活力均不超过1.5%,花粉几乎不萌发。研究认为,鱼腥草花粉育性低的主要原因是单核花粉的发育过程异常,而非鱼腥草花粉母细胞减数分裂异常所致。     

An improved method for pollen release from anther: a case study with mangroves

The estimation of pollen production is widely used in pollination and reproductive ecology, aerobiology and pollen-vegetation relationship studies. Pollen release is the key step in estimating pollen production and therefore, the technique used to release pollen is critical. Three methods, the drying method (DM), mechanical method (MM) and chemical method (CM), are used to determine the amount of pollen released from anthers. Few studies have compared the results obtained from each method, making it difficult to determine which method is most appropriate in a given situation. In this study, we compared existing methods with a new method that increases the amount of pollen released from anthers. Eight species of mangrove trees from the Neilingding-Futian National Nature Reserve were selected for study. We combined the MM and CM to produce a new method (the ultrasonic method, UM). To determine the best ultrasonic treatment time using the UM, different durations were tested and the various responses were analysed. The relationships between pollen rupture and the ultrasonic treatment time, pollen size, exine thickness and aperture size were analysed. Finally, four methods for pollen release from anthers were compared. The results indicated that the UM could be an efficient method to release pollen from the anther. To avoid pollen rupture, ultrasonic treatment times in the UM should be less than 30 s. The pollen rupture rate was significantly correlated with the ultrasonic treatment time (r = 0.618, p < 0.001) and the aperture size (r = 0.248, p = 0.036). This comparative experiment indicated that the UM can generate a greater pollen yield than other methods while causing less pollen rupture than the MM. Therefore, the UM may be suitable for more plant species and more accurate for pollen production estimates than the existing three methods, particularly when estimating pollen production in all community plants.     

Influence of arginine,ornithine, DFMO and polyamines on division of the generative nucleus in cultured pollen tubes of <Emphasis Type="Italic">Aechmea fasciata</Emphasis> (Bromeliaceae)

During in vitro pollen tube growth of Aechmea fasciata the second pollen mitosis (PM II) that produces two sperm cells was influenced by exogenous amino acids. Arginine (Arg) as single amino acid was the limiting factor for the second mitosis of the generative nucleus and thus the formation of sperm cells in cultured pollen tubes of A. fasciata. The involvement of Arg was probably related to protein synthesis. The need for Arg was not related to polyamine (PA) biosynthesis, since PA added to the germination medium were unfavourable for sperm cell production. Both ornithine (Orn) and difluoromethylornithine (DFMO) inhibited the second mitosis in cultured pollen tubes of A. fasciata. The addition of Arg during the first 2 h of pollen germination was necessary to establish the division of the generative nucleus 6 h later.     

Pollination mechanisms in sixCampanula species (Campanulaceae)

Pollination mechanisms within the genusCampanula were studied. Tests were undertaken to examine whether in vitro culture of pollen grains can serve as a useful tool for understanding the self- and cross-pollination mechanisms among species. Characteristics of pollen germination were interpreted in relation to mating system and floral biology. Four annual species (Campanula kremeri, C. dichotoma, C. afra, C. lusitanica), and two perennial species (C. rotundifolia andC. persicifolia) were investigated. In the annual species pollen germinability is controlled by (1) the age of pollen and/or (2) in what position pollen is deposited around the style. Correlations were found between pollen germinability and mating system in three of the four annual species. No correlations were found either between germinability and age of pollen or position on the style in the perennial species. Pollen germinability reached its maximum in the middle of the male phase in all species, except forC. dichotoma, which had a decreasing germinability throughout anthesis. The germinability was lowest at the time of stigma receptivity for all species except forC. persicifolia, where the stigma did not develop as long as pollen remained on the style. The pollen collecting hairs and pollen removal have been found to play an important role controlling the stigma development, thus affecting self-pollination. This was especially pronounced inC. persicifolia. Further studies will be undertaken to elucidate factors influencing pollination within the genusCampanula.     

The Production of Transgenic Scots Pine (Pinus Sylvestris L.) via the Application of Transformed Pollen in Controlled Crossings

The study demonstrates the production of a transgenic Scots pine (Pinus sylvestris L.) seedling through the application of transformed pollen in controlled crossings. The pollen lots were transformed by particle bombardment, resulting in transient transformation frequencies varying from 15 to 49% of the germinated pollen grains, and bombarded pollen was used to pollinate megasporangiate strobili. Progeny was screened by histochemical, GUS assays, and selected seedlings were further analysed by PCR. PCR amplification revealed the presence of both the nptII and gusA genes in one seedling (23/237). Results were confirmed by Southern blot analysis. The morphology and growth of this transgenic seedling was normal. Although the transformation frequency of recovered plants was very low (1/14999), the present protocol suggests that production of transgenic Scots pine is possible without the use of any tissue culture methods or the involvement of marker genes, for selection of transformants.     

The interrelationship between the accumulation of lipids,protein and the level of acyl carrier protein during the development of Brassica napus L. pollen

Lipid accumulation during pollen and tapetal development was studied using cryostat sections of unfixed anthers from Brassica napus (rapeseed). Diamidino-2-henylindole (DAPI), a DNA fluorochrome, was used to stain the pollen nuclei in order to identify ten stages of pollen development in Brassica. Storage lipids (i.e. triacylglycerides) were stained using the fluorochrome Nile red. Pollen coat lipids are formed in tapetal plastids between the mid-vacuolate and early maturation pollen stages. The pollen coat components, including lipids and a proportion of the proteins, are derived from the remnants of the tapetum, after its rupture, during the second pollen mitosis. Quantitative microfluorometric analyses demonstrated four phases of lipid body accumulation or depletion in the developing pollen cytoplasm. The majority of storage lipids found in the cytoplasm of the mature pollen grain accumulated during the late vacuolate and early maturation stages when the pollen is bicellular. The level of acyl carrier protein, a protein integrally involved in lipid synthesis, was also found to be maximal in the developing pollen during the bicellular pollen stages of development. This coincided with the most active period of lipid accumulation. These data could indicate that the lipids of the pollen are synthesized in situ, by metabolic processes regulated by expression of genes in the haploid genome.To whom correspondence should be addressed     

Pollen morphology ofLactoridaceae

The pollen wall ultrastructure of the primitive AngiospermLactoris fernandeziana Phil. (Lactoridaceae) is described. The monosulcate aperture, granular wall structure and sacci (all primitive features) suggest placement of this family in theMagnoliales. Pollen ofLactoris is compared to fossil dispersed pollen from the Lower and lower-Upper Cretaceous. The fossil pollen shares characteristics which are restricted to theLactoridaceae suggesting that this family was present during the early Cretaceous.     

Airborne pollen sampling in a wildlife reserve in the south of Buenos Aires province,Argentina

The objective of this project was to study the pollen spectrum of the Marahué Wildlife Reserve (Central Argentina), the quantity and quality of airborne pollen grains, and to evaluate the contribution of outside sources, to protect a natural habitat with xerophytic shrub vegetation (“monte”) (the term “monte” is used for the dominant xerophytic shrub vegetation in the “partido” of Villarino) approximately 90 km south of Bahía Blanca. Sampling was performed weekly throughout a whole calendar year (January–December, 2003) using a volumetric impact sampler. Observations of flowering in the field were performed at the same time as the aerial sampling. Herbarium specimens were collected to make pollen collections of the species found in the study area, for reference purposes. The most abundant pollen types were Poaceae (31.3% total annual pollen), Amaranthus/Chenopodiaceae (25.3%), Eucalyptus (5%), Brassicaceae (3.9%), and Plantago (3.9%). This study showed the dispersion dynamics of pollen grains from characteristic species of the “partido” (the province of Buenos Aires is divided into partidos which are roughly equivalent to counties) of Villarino, the exotic flora of the surrounding area, and the pollen types from outside the region.

Aeropalynological study of <Emphasis Type="Italic">Vitis vinifera</Emphasis> in the Braga region (1999–2003)

This study shows the results of Vitis vinifera pollen season in the atmosphere of the Braga region (Portugal) for the last 5 years (1999–2003). The fluctuations in the airborne pollen concentration, the synchronic rhythms in the annual pollen trends and their relationship to the main meteorological parameters were investigated. The vineyard pollen season extends from late May to early July, presenting always a bimodal pattern. During the studied period several pollen types such as Poaceae, Castanea, Olea, Urticaceae, Quercus, Plantago, Rumex, Asteraceae, Pinaceae, Ericaceae and Eucalyptus were also observed. Airborne pollen concentration is highly influenced by mean temperature, rain, number of days with rain and wind direction.     

色季拉山10种报春花属植物花粉形态及其分类学意义

采用扫描电镜法,观察和比较了西藏色季拉山10种报春花的花粉形态特征,同时进行聚类分析,以期为该属植物分类提供孢粉学证据,并进一步为西藏报春花属植物杂交育种及种质资源的利用提供参考。结果表明：(1)供试10种报春花属植物的花粉形状为扁球形、近球形,其中,工布报春(Primula kongboensis)的花粉粒最小,暗紫脆蒴报春(P.calderiana)的花粉粒最大,西藏报春(P.tibetica)为多沟型花粉,其余报春花的花粉一般具3孔沟,大部分孔沟在极区汇合形成复合沟。(2)花粉外壁纹饰大多为穴状或网状,其中,中甸灯台报春(P.chungensis)和西藏报春为网状纹饰中的粗网状类型。(3)虽然基于花粉形态的聚类分析与植物学分类表现出一定的一致性,但粉报春组的西藏报春和工布报春则由于在孢粉学特征上具有明显差异,因此保持了相对较远的亲缘关系。该研究初步认为,色季拉山10种报春花粉形态存在种间差异,研究结果可为植物分类提供一定的参考依据。然而,在进行分类时,仍然需要结合形态学特征、分子生物学等方面综合考虑。     

Aeropalynological research in <Emphasis Type="Italic">Salitral de la Vidriera</Emphasis>, Buenos Aires province,Argentina

This paper reports results from monitoring atmospheric pollen in Salitral de la Vidriera, an area of natural vegetation near Bahía Blanca city (East Central Argentina). Sampling was carried out weekly during January to December 2003 and May 2005 to April 2006 using a volumetric impact sampler. Observations of flowering in the field were carried out at the same time as the aerial sampling. During this period, 43 pollen types were identified; most of these correspond to pollen grains from either herbaceous or shrubby vegetation typical of the study area, for example Amaranthus, Brassicaceae, Centaurea, Poaceae, Chenopodiaceae, Urticaceae, some Asteraceae, and Condalia microphylla. This study on the atmosphere of Salitral de la Vidriera allowed us to identify the components of the vegetation type dominant in the area, namely a shrubby halophytic steppe. A well represented family, for example Chenopodiaceae, could, under appropriate weather conditions, be an important contributor of pollen to Bahía Blanca.

Comparison of the Rotorod to other air samplers for the determination of Ambrosia artemisiifolia pollen concentrations conducted in the Environmental Exposure Unit

The Environmental Exposure Unit (EEU) is a 924 m³ facility (Kingston General Hospital, Ontario) in which uniform concentrations of various pollens in HEPA-filtered air at known rates of laminar airflow can be maintained. This facility provided a unique opportunity to compare several air samplers without the environmental variation inherent in outdoor comparisons. The purpose of this study was to conduct a quantitative comparison of pollen measurements using the Rotorod, Burkard™ Personal Volumetric Air Sampler, Air-O-Cell™ and a 37 mm open-faced filter cassette with a microporous filter in the EEU. Pollen samples were taken during clinical trials being conducted in the Unit. Raw pollen counts/m³ obtained using the different methods were corrected using published particle collection efficiencies for the particle size (∼ ∼20 μm) and airflow. Data were analyzed by ANOVA/Tukey HSD. No statistically significant differences were found between pollen concentrations determined by Rotorod, Air-O-Cell and filter cassette. Pollen levels determined by the Burkard were up to 2 times higher than the other sampling methods. Relative standard deviations were similar for the Rotorod, Burkard, and filter cassette and higher for the Air-O-Cell. This study demonstrated that, under our conditions, the Rotorod sampler provides consistent and reliable measurements of ragweed pollen concentrations.     

UK regional variations in Betula pollen (1993–1997)

Betula pollen is known to be an importantaeroallergen in Europe and the UK, with very largequantities of pollen released into the air at theheight of the season, making it the most abundant treepollen present in the UK spring air.There has been long term pollen monitoring in Cardiff,Derby and London but in recent years the number ofregional sites has increased.Seven sites throughout the UK have monitoredBetula pollen using Burkard samplers for the period1993–1997 and for this study regionaldifferences in Betula pollen and climate wereinvestigated.Detailed analysis revealed considerable variation inthe start dates, duration and quantityof Betula pollen for the seven UK sitesthroughout the five year period.These regional variations in Betula pollenduration and intensity of season, indicate theimportance of maintaining sites throughout the UK asan aid to clinicians, researchers and the generalpublic.     

Seasonal fluctuations of the airborne pollen spectrum in Murcia (SE Spain)

During six consecutive years (1993–1998), aBurkard volumetric pollen trap was continuouslyoperated to sample pollen from the air of thecity of Murcia. The aim of the study was toelucidate the spectra of airborne pollen andthe variations during the year, and toelaborate a pollen calendar. This time spanincludes the end of the period with severedrought from 1990–1995, which particularly affected the south-eastern region of Spain.The total sum of daily average pollenconcentrations amounted to 148,645 pollen grainsbelonging to 93 different taxa. A daily averageof 74 pollen grains/m³ and 11 taxa wererecorded, with maxima of 1157 and 27respectively. The total pollen amountregistered in a year correlated with yearlyrainfall, but there was no relation with meanannual temperature. As for annual fluctuations,there seemed to be no influence by totalrainfall or temperature. Spring and winter werethe seasons with the highest pollen counts andpollen diversity.From the 93 identified taxa, 36 are included inthe pollen calendar. Noteworthy findings are:(i) the presence of Thymelaeaceae,Robinia, Betula, Castanea,Zygophyllum, Caryophyllaceae andCannabis, (ii) a long pollen season ofChenopodiaceae/Amaranthaceae, Urticaceae,Poaceae, Arecaceae and Plantago, (iii)the occurrence of summer, autumn and winterflowering of Artemisia, (iv) the lateappearance of Corylus pollen, and (v) theminor presence of Casuarina pollen duringthe mid winter and late spring.     

后蕊苣苔属花粉形态的补充研究

首次对后蕊苣苔属(Opithandra)文采后蕊苣苔(O. wentsaii)、龙南后蕊苣苔(O. burttii)和裂檐苣苔(O. pumila)的花粉进行扫描电镜研究。结果表明:三者花粉形状与外壁纹饰差异显著。在前人研究基础上,综合花粉形状及外壁纹饰特征,将后蕊苣苔属花粉分为四大类群:第一大类群包括O. burttii、O. sinohenryi、O. primuloides和O. fargesii,该类群花粉近球形,网状纹饰,网脊较宽,宽度不均匀; 第二大类群包括 O. acaulis和O. pumila,该类群花粉近球形,网状纹饰不明显,刺密且显著; 第三大类群包括O. dalzielii、O. cinerea和O. dinghushanensis,该类群花粉近球形或扁球形,网状纹饰,网脊较窄,宽度均匀; 第四大类群包括O. wentsaii和O. obtusidentata,该类群花粉长椭圆球形,网状纹饰,网脊较窄,宽度均匀。结果与王文采对该属的分类系统不完全一致,对该属分类提出一些建议。