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Pollen analysis, supplemented by 5 14C dates, was carried out on the lateglacial section (160 cm) of a core retrieved from the glacial Lake Trilistnika (2216 m) in the northwestern Rila Mountains (Bulgaria). The reconstruction of the lateglacial vegetation history is linked for the first time to a chronological framework for the time window 13000–10000 b.p. The delimitation of an interstadial/stadial cycle, analogous with the Bølling/Allerød-Younger Dryas from Western Europe, is based on important changes in the pollen stratigraphy. Mountain-steppe vegetation composed of Artemisia, Chenopodiaceae, Poaceae and other cold-resistant herbs, with isolated stands of Pinus and Juniperus-Ephedra shrubland, dominated the landscape after the ice-retreat. Interstadial conditions were established before 12815±130 b.p. The spread of tree vegetation at lower elevation as a response to the climate improvement was confined to the time interval 12110±95–11140±75 b.p. The Younger Dryas stadial is characterised by a re-advance of the mountain-steppe vegetation. The results are compared with other sites of lateglacial age from the high mountains (Rila, northern Pirin, western Rhodopes) in southern Bulgaria.  相似文献   

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Maria Lazarova 《Grana》2013,52(4):318-320
The occurrence of symptoms of pollen allergy is closely related to the presence of airborne pollen. In the region of southeastern Poland this kind of allergy appears usually from the middle of May till the end of July, when Gramineae and Cerealia pollens are discharging. This was confirmed by palynological studies here reported, performed in the years 1982–1987, and coupled with simultaneous assessment of 60 patients suffering from pollinosis. The results show that the total number of pollen types is variable in consecutive years. This indicates that both the exposition of patients to pollen allergens and the disease symptoms might vary.  相似文献   

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The fossil record of Peronosporomycetes (water moulds) is rather sparse, though their distinctive ornamentation means they are probably better reported than some true fungal groups. Here we describe a rare Palaeozoic occurrence of this group from a Guadalupian (Middle Permian) silicified peat deposit in the Bainmedart Coal Measures, Prince Charles Mountains, Antarctica. Specimens are numerous and comprise two morphologically distinct kinds of ornamented oogonia, of which some are attached to hyphae by a septum. Combresomyces caespitosus sp. nov. consists of spherical oogonia bearing densely spaced, long, hollow, slender, conical papillae with multiple sharply pointed, strongly divergent, apical branches that commonly form a pseudoreticulate pattern under optical microscopy. The oogonia are attached to a parental hypha by a short truncated stalk with a single septum. Combresomyces rarus sp. nov. consists of spherical oogonia bearing widely spaced, hollow, broad, conical papillae that terminate in a single bifurcation producing a pair of acutely divergent sharply pointed branches. The oogonium bears a short truncate extension where it attaches to the parental hypha. We propose that similarities in oogonium shape, size, spine morphology and hyphal attachment between the Permian forms from the Prince Charles Mountains and other reported Peronosporomycetes from Devonian to Triassic strata at widely separated localities elsewhere in the world delimit an extinct but once cosmopolitan Palaeozoic to early Mesozoic branch of the peronosporomycete clade. We name this order Combresomycetales and note that it played an important role in late Palaeozoic and early Mesozoic peatland ecosystems worldwide.  相似文献   

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The pancreatic amylase (AMY2, E.C. 3.2.1.1) polymorphism has been studied in 2346 individuals from south-central and south-eastern Bulgaria. The allele frequencies have been determined as AMY2*1 = 0.9520 and AMY2*2 = 0.0480. The neighbor joining tree of seven subpopulations revealed only small genetic distances. Compared with other populations, the Bulgarian sample clustered with samples from Romania, Hungary, Germany and Switzerland, with larger distances to Albania, Greece and Macedonia.  相似文献   

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For the prevention of hay fever (H.F.) we must know each year, which are our allergenic plants, and where and when they pollinate. For that purpose we combine: clinical history and skin tests, information collected by a team of skilled botanists (who go out in the field once in two weeks, and determine according to the flower's developmental stage, when its pollination is to be expected) and data (both clinical and aerobiological) collected in previous years. This way we are able to start the administration of preventive medication in time, before the relevant season has started, and till its end. With our preventive treatment schedule, we got the following results in a group of 221 children from the area served by our clinic: in order to be kept H.F. symptoms free, out of the 221: 36, needed only antihistamines, 108, needed in addition cromolyn, and 72, topical steroids, in the remaining 15, medication was not satisfactory, and immunotherapy was applied successfully. We conclude that each H.F. patient should get his own individual preventive treatment schedule, established on the grounds of his personal, and the aerobiological data.  相似文献   

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The seasonal variation of Aspergillus in the atmosphere of Mexico City was determined, using an Andersen air sampler, at different times of the day, over a period of one year. Aspergillus represented a low percentage of the total mould count, 5%, 4%, and 2% in the morning, noon, and night respectively. It was possible only in the morning to observe a seasonal trend for Aspergillus, with high colony numbers during the dry season. However, the highest CFUm-3 were detected in April for the three sampling times of the day.

Different percentages of negative growth plates were recorded during the sampling time, but a large percentage was recorded at noon.

Multiple regresional analyses indicate that significant correlations exist between Aspergillus CFUm-3 and vapor pressure and temperature inversion in the morning, and with temperature and daily range of temperature at night. Fourteen species of Aspergillus were identified, but A. niger, A. fumigatus, and A. flavus were the most abundant.  相似文献   

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Inhaled particle deposition sites must be identified to effectively treat human airway diseases. We have determined distribution patterns of a selected aeroallergen, ragweed pollen, among human extrathoracic (ET: i.e., oro-nasopharyngeal) regions and the lung. A predictive model validated by inhalation exposure data from human subjects was utilized. Deposition locations were primarily functions of 1. ragweed particle parameters (size: 14–20 μm, shape: spherical, and density: 1.14 g cm-3) and 2. mode of breathing. In the general population, two styles of inhalation are prevalent: normal augmentors (NAs), and mouth breathers (MBs), their clinical definitions are based on intra-ET airflow divisions. For a NA-mode breathing, sedentary (10 L min-1) adult, 88% of inhaled ragweed pollen was removed by the ET compartment and 7% collected within the lung. For a MB, the respective deposition efficiencies were 68% and 25%. To apply the model, we used a daily springtime ragweed pollen concentration of 300 grains m-3 and an exposure time of 0.5 hour to calculate actual doses for the respiratory system. Under the stipulated conditions, a MB would inhale 45 pollen grains per day and 8 would be deposited in the lung; the value is 3 grains for a NA. Frequently, individuals with impaired respiratory functions are MBs in whom such pollen deposits are likely contributors to airway disease.  相似文献   

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The present catalogue of the ants (Hymenoptera, Formicidae) of Bulgaria is made on a base of critical reconsideration of literature (covering the period from 1892 till 2009 and part of 2010) as well as on examination of the authors' and several museum's collections. A lot of data were omitted in the previous Bulgarian monograph on ants, lots of new data were recently added and many important additions and alterations were made due to taxonomic revisions of Eurasian Formicidae during the last three decades. Two new species are reported for the country [Temnothorax graecus (Forel, 1911) and Temnothorax cf. korbi (Emery, 1924)].This catalogue contains a list of 163 ant species belonging to 40 genera of 6 subfamilies now known from Bulgaria. Synonyms and information on the previously reported names in relevant publications are given. Known localities of the species are grouped by geographic regions. Maps with concrete localities or regions for each species were prepared. The conservation status of 13 ant species is given as they are included in IUCN Red List of Threatened Species and Bulgarian Biodiversity Act. In comparison with adjacent Balkan regions the ant fauna of Bulgaria is quite rich and its core is composed of South European elements.  相似文献   

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The core of Lake Kremensko-5, one of the cirque lakes in the northern Pirin Mountains of southwestern Bulgaria, contains sediments from more than 13,500 years b.p. and a pollen stratigraphy that can be correlated with the interstadial/stadial cycle of the Late-glacial period. Artemisia and Chenopodiaceae predominate in the basal part of the sequence, indicating the presence of mountain steppe type vegetation soon after the ice retreat. A sharp increase of Pinus diploxylon-type and Poaceae after 12,360 b.p. is followed by a return of Artemisia and Chenopodiaceae, marking the Younger Dryas. Its abrupt termination must result from an unconformity, for high values of Quercetum mixtum, dated at other sites in the Pirin Mountains as early Holocene, are missing here, perhaps because of erosion at a time of low lake level related to the high insolation maximum during the early Holocene.  相似文献   

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Elissaveta Bozilova 《Grana》2013,52(3):232-234
The length of the pollen deposition period covered by an individual moss sample is a matter of discussion. Here we evaluate (1) how many years of pollen deposition are contained in individual moss samples, (2) which factors (i.e. moss type, geographical location and thickness of sample) affect the pollen content, and (3) whether the time span of the pollen deposited in the moss is related to the pollen type. The pollen deposition period covered by 20 individual moss samples adjacent to pollen traps was estimated using the accumulation method. The investigated moss samples usually contain pollen from a period of two to five years. The length of the time period covered by the moss depends on the thickness of the moss cushion and, therefore, we recommend estimating the time period over which the moss has been growing by the increment method. Compared to pollen traps, mosses tend to accumulate more Poaceae and bisaccate grains (especially Picea) but less Cyperaceae pollen. Betula and pollen tetrads tend to be equally represented in mosses and traps. This study demonstrates that moss samples may contain sufficient pollen to be a reliable modern analogue for Quaternary peat and sediment samples but cannot be used to calculate pollen accumulation rates.  相似文献   

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During the last decades, various renaturation programmes have been initialized to recover nutrient sink and ecological functions of peatlands by rewetting. Rewetting, however, often results in the formation of hotspots for methane (CH4) emissions and in temporal dieback of local vegetation. The present study aimed at quantifying changes of CH4 and nitrous oxide (N2O) emissions in a peatland currently under continuous rewetting conditions. Emissions where studied at a permanently flooded site and a non-flooded peat site with fluctuating water tables by using common closed chamber method. The permanently flooded site revealed extremely high CH4 emissions (up to 1195 mg C m?2 d?1) which were positively correlated with temperature, nutrient content, dissolved organic carbon and nitrogen concentration of the peat soil water. In contrast, the non-flooded peat site, with lower and fluctuating water tables (WT), showed significantly lower CH4 emissions and an increasing trend of CH4 release associated with a generally increasing WT caused by the progressing rewetting process. Lower N2O emissions (<24 µg N m?2 d?1) were observed at the flooded site. By contrast, the non-flooded peat site with fluctuating WT showed significantly higher N2O emissions (up to 4178 µg N m?2 d?1), in particular at high temperatures during summer time. The present results indicate that permanently flooded conditions during rewetting processes might cause higher CH4 emissions compared to fluctuating WT which in contrast might enhance N2O emissions. In total, however, no decreasing trend for CH4 emissions throughout the five-year renaturation period could be found. At least for N2O we observed a decreasing trend during rewetting.  相似文献   

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Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts).The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species).Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country.  相似文献   

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Aeroallergens of the southeastern Missouri region were determined by skin test frequencies of 817 consecutive individuals and compared and contrasted with five years of air sampling using the Rotorod sampler. Household inhalants were found to induce the most frequently positive skin tests, especially house dust, feathers, house dust mite, wool, cat epithelium, tobacco, dog epithelium, and horse epithelium. Among the trees, pollen extracts of Acer saccharum (maple), Acer negundo (box-elder), Carya ovata/C. illinoensis (hickory/pecan), Juglans nigra (walnut), and Ulmus americana (elm) were the most commonly positive. A slightly higher level of skin reactivity was found to grass pollen extracts with Anlhoxanthum odoralum (sweet vernal), Phleum pratense (timothy), Cynodon dactylon (Bermuda), Agrostis alba (red top) and Festuca elatior (meadow fescue), all being quite similar in incidence, but Sorghum halepense (Johnson grass) was clearly less important. Ambrosia spp. (ragweed) and Xanthium commune (cocklebur) were the most frequent weed reactions with ragweed the most prominent allergen of outside environmental origin. Of the genera of fungi, skin tests to Epicoccum were most frequently positive. When reactivity level is considered, the other important fungi are Alternaria, Candida, Cladosporium, Curvularia, and Fusarium. Air sampling data generally correlates well with the positive skin tests frequencies i.e., the most numerous pollen, ragweed, has the highest skin test frequency and reactivity level. Similarly among the fungi the most numerous spores, Cladosporium, Alternaria, Fusarium, and Epicoccum have the highest frequencies and reactivity levels. Certain species appear to be able to sensitize patients in lower concentrations, such as box-elder and the grasses. Oak pollen and Cladosporium spores appear in large numbers, but seem less sensitizing.  相似文献   

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