首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Pollen concentrations in the atmosphere of Van city has been monitored for two consecutive years (2010–2011). This was the first detailed aeropalynological study for the elevated East Anatolia Region of Turkey. The sampling was performed by Hirst-type volumetric sampler, and pollen grains of 35 taxa were identified. The main pollen producers of the pollen flora were recorded as: Poaceae (20.94 %), Cupressaceae (10.53 %), Fraxinus (8.56 %), Chenopodiaceae/Amaranthaceae (7.77 %), Populus (7.75 %), Quercus (6.70 %), Platanus (6.68 %), Morus (5.57 %), Plantago (3.03 %). The pollen spectrum reflected the floristic diversity of the region, and the highest pollen concentration was recorded in April. There were a great percentage of allergenic taxa found in the city atmosphere, otherwise many of them scored under threshold values for risk of pollinosis. Statistical analyses were performed for correlating daily pollen concentrations of dominated pollen types concurrent with the data of meteorological parameters in MPS periods and number of significant correlations found. In addition, comparing 2-year data in terms of pollen concentrations and meteorological factors in MPS durations, many variables were found explanatory and concordant with the data. MPS starting dates of many plant taxa were found nearly a month later compared with western sites and lower altitudes of the country as well as Mediterranean countries; this case is mostly thought the ecological factors of the study area which directly affects the plant growth about the timing.  相似文献   

2.
Pollen ultrastructure has been studied in two relict and rare species of the genus Aristolochia, A. contorta Bunge and A. manshuriensis Kom. (Aristolochiaceae). Both species have inaperturate, spheroidal, sometimes distally monocolpate or distally bicolpate pollen grains. The equatorial and polar axes of pollen grain in A. manshuriensis are 48.5 and 44.0 μm, respectively. The percentage of defective pollen grains in A. manshuriensis is 3.4%. The fossulate, perforated exine is up to 2.3 μm in thickness; the sexine and the nexine are almost equal in thickness. In A. contorta, the equatorial axis of pollen grain is 36.6 μm: the defectiveness percentage, 24.5%. The exine is verrucate, up to 0.3 μm in thickness, while the sexine is two to three times thicker than the nexine. The pollen germination experiments have shown that pollen of A. manshuriensis, in contrast to A. contorta, can germinate in 10–20% sucrose at 22°С. These data and the high percentage of pollen defectiveness in A. contorta indicate that the androecium function in this species is reduced. The reduction of the androecium function is evidenced by a small amount of pollen grains in anthers or empty anthers and a high percentage of defective pollen grains.  相似文献   

3.
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.  相似文献   

4.
The present study has been carried out to assess the allergenicity of dominant pollen types from the atmosphere of nine districts of the state of Punjab, India. During the study period (2012–2014), 30 different kinds of pollens belonging to 17 families were recorded. Antigenic extract of thirteen pollen types were selected for skin prick tests (SPT). The allergenic pollens selected for the present study belong to families: Asteraceae, Amaranthaceae, Brassicaceae, Cannabaceae, Chenopodiaceae, Meliaceae, Moraceae, Myrtaceae and Xanthorrhoeaceae. Total 165 sensitized patients having diagnosed with bronchoprovocation test were selected for SPT. Diagnostic tests were performed in ENT department, Rajindra hospital Patiala, and SPT were done in the clinic of Dr. H.S. Bedi at Patiala. Antigenic reactivity (3+ to above) to various allergens varied from 2.4 to 9.09 %. Patients showed maximum allergenic sensitivity to Parthenium hystrophorus (9.09 %) followed by Morus alba (8.48 %), Amaranthus spinosus (7.87 %) and Ageratum sp. (6.06 %). Least reactivity was shown by Brassica compestris and Eucalyptus sp. (2.4 %).  相似文献   

5.
Pollen-related allergic diseases are a growing health problem. Thus, information on prevalence of airborne pollen may serve as guide for clinicians to accurately manage allergic diseases. In this study, an aeropalynological survey was conducted from November 2013 to October 2014 in Manila, Philippines, to determine the seasonal distribution of the most prevalent airborne pollen and correlate the influence of meteorological factors on their daily concentrations. A volumetric pollen trap was placed on a rooftop, 21 m above ground level. A total of 5677 pollen grains from 18 pollen types were identified, of which Urticaceae, Cannabaceae, Poaceae and Moraceae were the most prevalent. Other pollen types observed that represented 1 % of the total pollen concentration, in descending order, were Terminalia catappa, Myrtaceae, Muntingia calabura, Verbenaceae, Amaranthaceae, Cyperaceae, Caricaceae and Mimosa sp. Of the total airborne pollen, 87 % were obtained during the dry season (November–May). Pollen concentrations peaked (55 %) during the summer months (March–May), indicating a positive correlation (p < 0.01) between pollen concentration and temperature (maximum and mean). Alternatively, only 13 % of the pollen concentrations were obtained during the wet season (June–October). It was observed that pollen concentrations were negatively correlated (p < 0.01) with rainfall and humidity. As the pollen collection was done for one sampling year, only an approximation of the daily concentration of the pollen types was identified and correlated with meteorological factors. Further data collection is required to generate an accurate pollen calendar for use in allergy studies.  相似文献   

6.
The vegetation history of the Kargaly region has been reconstructed on the basis of pollen analysis of archaeological sediments and one peat bog, the only one found during some years of surveying this area. This latter, Novienky peat bog, located in the steppe transition zone, offers an interesting cultural and natural sequence. Palynological analysis reveals several palaeoecological phases from 4300 b.p. (Bronze Age) to the 18th–19th centuries a.d. (Russian period). Metallurgical activities in Kargaly caused deforestation from the Bronze Age onwards that mainly affected the distribution of birch forests in the region. The palaeoclimatic interpretation of the Novienki pollen diagram is based on the observed changes in the pollen curves of Picea (spruce), Pinus (pine), Abies (silver fir) and Betula (birch). These arboreal taxa are regarded as main climate indicators. The chronology is established on a 14C-dated pollen profile from the lowest peat layer as well as on the regional pollen sequences and archaeological stratigraphies.  相似文献   

7.
Identification of pollen grains of cultivated plants is essential in archaeobotanical studies. In this study, we investigated the pollen morphology of 30 species which are representatives of most of the crop plants in southern China, using a light microscope. Our results show that the pollen grains of these species or genera can generally be identified by their size, aperture(s) and exine sculpture. We found that: (1) some cultivated cereals can be distinguished from wild species of Poaceae according to their size frequency combined with their morphological features; (2) the lengths of the equatorial diameter (E), polar axis (P) and the greatest dimension of the lumina (the size of the network sculpturing) of the exine reticulum may be diagnostic features to distinguish some brassicaceous vegetables. There are significant differences between the E and P values among Brassica campestris (B. rapa, oilseed rape, Chinese cabbage), B. alboglabra (B. oleracea var. alboglabra, gai lan, Chinese kale), B. parachinensis (B. rapa var. parachinensis, choy sum, Chinese flowering cabbage) and B. chinensis (B. rapa ssp. chinensis, pak choi), but moderate differences in the longer axis length of the reticulum lumina, which provide potential for identifying species on the basis of pollen grains. We compared the P values and the longer axis length of the lumina of modern specimens of Brassicaceae pollen grains with those of fossil pollen extracted from the Ming-Qing cultural layer in the Fuqikou site at Chongqing, China, and found that the fossil pollen grains of Brassicaceae probably represent vegetable plants related to B. parachinensis. Moreover, we measured the diameters of rice pollen grains from modern paddy fields to assess the pollen size frequency and found that the size range from ~?34 to 38 µm is closely associated with rice pollen in southern China, which can be used to detect pollen signals of human activities in archaeobotanical investigations.  相似文献   

8.
Adem Bicakci 《Biologia》2006,61(4):457-461
In this study, pollen grains were identified using Durham sampler in the atmosphere of Sakarya in 2000 and 2001. During these two years, a total of 10 805 pollen grains were recorded. A total of 5 386 pollen grains per cm2 were recorded in 2000 and a total of 5 419 pollen grains per cm2 in 2001. Pollen fall in the years 2000–2001 comprised grains belonging to 40 taxa and some unidentified pollen grains. Of these taxa, 22 belonged to arboreal and 18 taxa to non arboreal plants. Total pollen grains consisted of 69.45% grains from arboreal plants, 28.11% grains from non-arboreal plants and 2.44% unidentified pollen grains. In the region investigated, Gramineae, Pinus sp., Quercus sp., Cupressaceae/Taxaceae, Salix sp., Platanus sp., Populus sp., Carpinus sp., Fagus sp., Chenopodiaceae/Amaranthaceae, Xanthium sp., Moraceae, Corylus sp., Fraxinus sp., and Urticaceae released the greatest amount of pollen. The season of maximum pollen fall was from March to May, with a prevalence of arboreal pollen in the first months, and of pollen from non-arboreal plants in the last months of the year.  相似文献   

9.
With a view to obtaining fuller information on airborne pollen content in the city of Havana, pollen sampling was carried out using a volumetric capture method, for the first time in Cuba. The study was conducted during 2 years (2011 and 2015). An annual pollen integral of 3414 grains was registered during the first year of study, whereas 5120 grains were observed along the 2015. Monthly maximum concentrations were recorded during April, June and July with total values close to 800 pollen grains. Of the 45 pollen types identified, Cecropia (38% of the total pollen identified in both years), Poaceae (18%), Urera type (9%) and Casuarina (6%) were particularly abundant. Although the main pollen types differed in terms of intradiurnal distribution, the highest concentrations were in all cases recorded between 0900 and 1300 hours. Maximum temperature was the variable most influencing airborne pollen counts in the air, with the exception of Casuarina. This paper sought to establish a methodological basis for the further development of aerobiological research in Cuba, thus helping to enhance the prevention and diagnosis of pollen allergies in the affected island population.  相似文献   

10.
The Early/Middle Miocene (European Land Mammal Zone MN5) localities of Sandelzhausen and Rothenstein 13 in southern Germany have yielded remains of about 13 ophidian taxa: Eoanilius sp. (Aniliidae), Bavarioboa ultima (Boidae), “Coluber” sp., ?Telescopus sp., Natrix sp., cf. Natrix sp., cf. “Neonatrix” sp., unidentified “colubrines” and “natricines” (Colubridae), Naja sp., an unidentified elapid (Elapidae), Vipera sp. (“Oriental viper”), Vipera sp. (“aspis complex”) (Viperidae). Both faunas document a transitional phase from those reported from several late Early and Middle Miocene sites of Central and Western Europe. The climates of Sandelzhausen and Rothenstein 13, as indicated by ophidian fossils, were warm, although not tropical or subtropical.  相似文献   

11.
Based on a five-year study of pollen production and release in two different natural populations of Mesua ferrea from Indo-Burma region of Northeast India, we determined that pollen output follows a spatio-temporal pattern. Pollen productivity determinations considered various sources of variability, including the number of flowers per branch, flowers per tree, anthers per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and population effects. Anthesis follows a forenoon pattern, whereas anther dehiscence pursues the diurnal pattern. The former was significantly correlated with the timing of floral visitation and pollen deposition on stigmas. The latter, however, had significant relationship with the deposition of pollen grains on microscopic slides. The Apis and Xylocopa bees are the efficient pollinators to achieve the reproductive success in M. ferrea. Annual production of pollen per tree varied from averages of 1.07 ± 0.10 × 1010 and 3.24 ± 0.16 × 1010 in years of low production, with alternate high years, producing 3.85 ± 0.34 × 1010 and 8.22 ± 0.76 × 1010 pollen grains per tree.  相似文献   

12.
This study has been focused on airborne pollen concentration in Northern Tunis. Pollen has been detected by a volumetric Hirst-type spore trap. This suction sampler was placed for two hydrologic years in the area of Mornag, northeastof Tunisia (36°40N; 10°17E). Fifty-two taxa were identified with heterogeneous daily pollen concentrations and a dominance of anemophilous plants. The main pollen types detected in the atmosphere were Olea europaea (38.7 and 20.75%), Cupressus (33.57 and 55.4%), Urticaceae (9.22 and 12.24%), Poaceae (3.55 and 3.32%), Mercurialis annua (2.96 and 1.6%) and Amaranthaceae (2.49 and 1.55%). The monthly pollen spectrum indicated a seasonal periodicity of airborne pollen with the main pollen season during spring. Two pollen seasons have been observed during these hydrologic years, due to both Cupressus and Amaranthaceae airborne pollen is represented during winter or spring, and also during autumn and late summer, respectively. Other pollen types represent a long pollen season, i.e., Urticaceae, starting in autumn and following until late spring. Daily pollen concentration showed a different behavior during the flowering season between both years, observing differences related to pollen index. Correlation between daily pollen concentrations of the dominant taxa showed a positive and significant correlation between airborne pollen concentrations of spring-pollinated taxa and mean temperature, but negative with maximum temperature, humidity and rainfall. In the case of minimum temperature, a different response, positive for trees and negative for herbaceous plants, has been observed.  相似文献   

13.
14.
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.  相似文献   

15.
Mycoceros antennatissimus gen. et sp. nov. is described and illustrated from pollen grains deposited on the bark of Elaeagnus angustifolia and Platanus?×?acerifolia in Hungary. This fungus is shown to capture pollen grains by its three-dimensional shape. It clearly shows seasonality and appears to be rare. The following factors determine its ecological niche: (1) the availability of fresh Pinaceae pollen grains deposited from the air on the bark of a nearby standing angiosperm tree with (2) water-retaining spongious bark, and (3) rainy weather. Conidia are mainly dispersed by stemflow rainwater, while they hardly become airborne. Direct polymerase chain reaction (PCR) from single conidia made it possible to perform molecular phylogenetic investigation in order to clarify its taxonomic relationship within the Ascomycota.  相似文献   

16.
Genebank conservation of pollen is valuable because it makes genetic resources immediately available for use in breeding programs. In the case of Citrus species, conserved anthers or pollen can be easily transported and used to develop new varieties with pathogen resistance and desirable quality and yield traits. The aim of this study was to develop and improve air-desiccation cryopreservation protocols for Citrus cavaleriei and Citrus maxima anthers in genebanks. In the current study, warming, rehydration, and in vitro germination conditions were optimized to achieve high levels of in vitro germination in Citrus pollen for ten cultivars after liquid nitrogen (LN) exposure. The optimal warming, rehydration, and in vitro germination medium formulations affected the germination levels after pollen cryopreservation, with species- and cultivar-dependent effects. The Citrus anthers were dehydrated to the moisture content of 5–14% before LN exposure and warmed at 25 (cryopreserved Citrus anthers with a moisture content of lower than 10%) or 37°C (a moisture content of 10% or higher), then rehydrated, and cultured on medium with 150-g L?1 sucrose, 0.1-g L?1 boric acid, 1.0-g L?1 calcium nitrate, 0.1-g L?1 potassium nitrate, 0.3-g L?1 magnesium sulfate, and 10-g L?1 agar. After 2 yr of storage, in vitro germination levels of Citrus pollen after cryopreservation were significantly higher (> 22% for all ten cultivars) than those of samples that were stored at 4°C (0%). In vitro germination levels of pollen from six of ten cultivars after cryopreservation remained relatively high after 2 yr of storage (38–93%). The highest viability of 93% was obtained for C. cavaleriei ‘2–3’. The methods identified in the current study could be used to cryopreserve C. cavaleriei and C. maxima anthers.  相似文献   

17.
Mucuna comprises 105 species with an overall pantropical distribution and is divided into three subgenera: M. subg. Mucuna, M. subg. Stizolobium and M. subg. Macrocarpa. Although phylogenetic studies have supported the occurrence of three main clades, evolutionary relationships among them are not fully resolved. The objective of this study was to examine pollen grain morphology from representatives of all three subgenera and map these onto the phylogenetic trees generated by analysis of other characters. Pollen grain surface, form, size, and aperture number were compared. A Bayesian inference tree using matK sequences was constructed. The results indicate that the representatives of M. subg. Macrocarpa have the smallest pollen grains in the genus (a synapomorphic character here identified for this subgenus) and that species of subgenus Mucuna (those with umbelliform inflorescences) have the largest pollen grains. Additional morphological diversity of the pollen grain surface was noted: reticulate and/or micro-reticulate (in all three subgenera), perforate, gemmate or verrucose (only in M. subg. Mucuna). For all studied taxa, the pollen grains are triaperturate, except for two species of M. subg. Mucuna, which have tetraperturate pollen. The phylogenetic tree obtained using the matK marker resolved M. subg. Stizolobium as the earliest diverging lineage in Mucuna. Based on this phylogeny, a reticulate ornamentation pattern of the pollen surface may represent the ancestral state for the genus, while the larger pollen size and the foraminate, gemmate, and verrucose ornamentations are derived characteristics within the genus. These putative derived ornamentations have been observed only in neotropical species.  相似文献   

18.
Two new unequivocal stagodontids, Fumodelphodon pulveris, gen. et. sp. nov., and Hoodootherium praeceps, gen. et. sp. nov., are described from the Turonian (~92 Ma) Smoky Hollow Member of the Straight Cliffs Formation, of southern Utah, USA. Mammals from this time period are poorly represented; the recovery of these two large stagodontids demonstrates the early emergence of faunal elements mostly associated with the later Cretaceous. These taxa represent the earliest stagodontids with crushing premolars (Fumodelphodon) and sectorial premolars (Hoodootherium), morphologically similar to the well-known stagodontids Didelphodon and Eodelphis, respectively. The similar morphologies suggest that these two new genera may be early members of later Cretaceous stagodontid clades, implying a ~ 7 Ma ghost lineage leading to Eodelphis and a ~ 15 Ma ghost lineage to Didelphodon. A reexamination of stagodontid characters suggests a basal placement of Pariadens within Stagodontidae, contrary to some recent studies. The discovery of two new stagodontids bearing lower molars morphologically similar to, but premolars distinct from, Eodelphis highlights the importance of the specialized premolar morphology for resolving the relationships between genera within Stagodontidae.  相似文献   

19.
The bacterial diversity of the outflows of Polichnitos (Lesvos, Greece) hot spring has been investigated. Cyanobacteria showing high sequence homologies with Phormidium sp. and Cyanobacterium aponinum were found. Members of the Alphaproteobacteria closely related to Rhodobium sp. Albidovulum sp., Rhodobacter sp., Microvigra sp., Nitratireductor sp. and Phaeobacter sp. Gammaproteobacteria, Betaproteobacteria and Firmicutes were represented by members of Idiomarina sp., Marinobacter sp., Shinella sp., Bacillus sp. and Clostridium sp. with sequence homologies ranging from 92% to 100%. Members of the Bacteroidetes and Planctomycetes were represented by sequences of novel phylogenetic linkages exhibiting 87–90% sequence homology with type strains. When the hot spring consortium was cultivated in bioreactor repeated batch culture under photo-autotrophic growth conditions at temperature < 30 °C, Cyanobacterium sp. dominated over Phormidium sp. Cyanobacterium sp. seems to have biotechnological potential since its extracellular broth exhibited a strong insecticidal activity against larvae of Aedes aegypti (a vector of important human diseases) and significant anti-cancer activity against the PC3 human prostate cancer cell line, while its toxicity against human endothelial cells was relatively low.  相似文献   

20.
A potential alternative strategy to chemical control of plant diseases could be the stimulation of plant defense by arbuscular mycorrhizal fungi (AMF). In the present study, the influence of three parameters (phosphorus supply, mycorrhizal inoculation, and wheat cultivar) on AMF protective efficiency against Blumeria graminis f. sp. tritici, responsible for powdery mildew, was investigated under controlled conditions. A 5-fold reduction (P/5) in the level of phosphorus supply commonly recommended for wheat in France improved Funneliformis mosseae colonization and promoted protection against B. graminis f. sp. tritici in a more susceptible wheat cultivar. However, a further decrease in P affected plant growth, even under mycorrhizal conditions. Two commercially available AMF inocula (F. mosseae, Solrize®) and one laboratory inoculum (Rhizophagus irregularis) were tested for mycorrhizal development and protection against B. graminis f. sp. tritici of two moderately susceptible and resistant wheat cultivars at P/5. Mycorrhizal levels were the highest with F. mosseae (38 %), followed by R. irregularis (19 %) and Solrize® (SZE, 8 %). On the other hand, the highest protection level against B. graminis f. sp. tritici was obtained with F. mosseae (74 %), followed by SZE (58 %) and R. irregularis (34 %), suggesting that inoculum type rather than mycorrhizal levels determines the protection level of wheat against B. graminis f. sp. tritici. The mycorrhizal protective effect was associated with a reduction in the number of conidia with haustorium and with an accumulation of polyphenolic compounds at B. graminis f. sp. tritici infection sites. Both the moderately susceptible and the most resistant wheat cultivar were protected against B. graminis f. sp. tritici infection by F. mosseae inoculation at P/5, although the underlying mechanisms appear rather different between the two cultivars. This study emphasizes the importance of taking into account the considered parameters when considering the use of AMF as biocontrol agents.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号