ARCTIC AEROPALYNOLOGY: SPORA OBSERVED ON STICKY SLIDES EXPOSED IN VARIOUS REGIONS IN 1950

1955 ◽  
Vol 33 (5) ◽  
pp. 401-415 ◽  
Author(s):  
Nicholas Polunin
Keyword(s):  
Pollen Grains ◽  
Ground Level ◽  
Growing Season ◽  
Baffin Island ◽  
Local Origin ◽  
Northern Areas ◽  
Main Period

Sticky slides were exposed more or less throughout the summer of 1950 in widely scattered arctic and other northern areas including Point Barrow, Alaska, northern-central Baffin Island, Jan Mayen Island, and Spitsbergen. Although the spora were generally sparse and conclusions must be regarded as tentative, it appeared that near ground level the incidence of pollen grains tended in general to coincide with the main period of flowering but that moss spores were in the air more or less throughout the growing season. Most (but by no means all) of the pollen observed could have been of local origin except in Spitsbergen, where there tended to be a preponderance of abietineous winged grains (mostly of Pinus) which were persistently caught practically throughout the brief summer although they had evidently been blown in from at least several hundred miles away.

scholarly journals Thunderstorm outflows preceding epidemics of asthma during spring and summer

Thorax ◽  
2001 ◽  
Vol 56 (6) ◽  
pp. 468-471
Author(s):  
G B Marks ◽  
J R Colquhoun ◽  
S T Girgis ◽  
M Hjelmroos Koski ◽  
A B A Treloar ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Ground Level ◽  
Fold Increase ◽  
Underlying Mechanism ◽  
Detailed Examination ◽  
Asthma Exacerbations ◽  
Eastern Australia ◽  
The Difference ◽  
High Concentrations ◽  
Thunderstorm Outflow

BACKGROUNDA study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism.METHODSA case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations.RESULTSThunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4–12 fold increase in the ambient concentration of grass pollen grains.CONCLUSIONSThese findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.

Temporal patterning of blooming phenology in Pedicularis on Mount Rainier

1983 ◽  
Vol 61 (3) ◽  
pp. 786-791 ◽  
Author(s):  
Virginia Dale Adams
Keyword(s):  
Pollen Grains ◽  
Growing Season ◽  
Sympatric Species ◽  
Temporal Patterning ◽  
Flowering Pattern ◽  
Subalpine Meadow ◽  
Evolutionary Force ◽  
Mount Rainier ◽  
Pollinator Sharing ◽  
Blooming Phenology

The temporal patterning of flowering of five sympatric species of Pedicularis in a subalpine meadow is documented. Two species bloom early in the growing season, one is intermediate, and two flower toward the later part of the season. The differences between species are related to the range of blooming periods (in days), the number of inflorescences at maximum bloom, and the time of peak bloom. No significant variation in flowering pattern occurred during the years of observation (1977, 1978, and 1979). More than 93% of the time individual bumblebees continued to forage on the same Pedicularis species as was previously visited; yet when switches in the diet of the bees occurred, they were more likely to be to another species of Pedicularis. Although individuals of other genera were in bloom, the bees switched to the Pedicularis species most synchronous in time and space to the previously preferred Pedicularis species. Counts were made of the number of pollen grains per flower, the reward for foraging bees. The last species to flower had the greatest reward but also had the largest ratio of the number of pollen grains to the number of ovules as compared with the previously flowering Pedicularis species. These results suggest that pollinator sharing is an important evolutionary force but that the quantity of the pollen reward may be more related to the number of ovules.

scholarly journals Photosynthesis of boreal ground vegetation after a forest clear-cut

2009 ◽  
Vol 6 (11) ◽  
pp. 2495-2507 ◽  
Author(s):  
L. Kulmala ◽  
J. Pumpanen ◽  
T. Vesala ◽  
P. Hari
Keyword(s):  
Photosynthetic Activity ◽  
Calluna Vulgaris ◽  
Ground Level ◽  
Growing Season ◽  
Plant Size ◽  
Rubus Idaeus ◽  
Temperature History ◽  
Ground Vegetation ◽  
Clear Cut ◽  
Species Specific

Abstract. Heather (Calluna vulgaris), rosebay willowherb (Epilobium angustifolium), wavy hair-grass (Deschampsia flexuosa) and raspberry (Rubus idaeus) are typical species at boreal clear-cut sites. In this study, we measured their photosynthesis separately in the growing season of 2005 using a manual chamber. All measured species showed clear and species-specific seasonal cycles of photosynthetic activity (Pmax). The maxima of C. vulgaris and E. angustifolium occurred around June and July, while that of R. idaeus occurred as late as August. A simple model of photosynthetic activity is presented, addressing the photosynthesis of C. vulgaris was mainly explained by temperature history when the soil moisture is high. The activity of deciduous D. flexuosa also followed the temperature history, unlike the activities of E. angustifolium and R. idaeus. During a short drought, some shoots decreased their Pmax levels but none of the species showed similar reactions between individuals. We also observed that the comparison of the whole-plant Pmax or respiration of different-sized individuals were less scattered than the results based on full-grown leaf mass, implying that species-specific rates of photosynthesis at ground level are rather similar regardless of the plant size. Using species composition and continuous temperature and light measurements, we upscaled the species-specific process rates and integrated fixed and respired CO2 of ground vegetation for the entire 2005 growing season. The photosynthetic production per surface area of soil was 760 g C m−2 y−1 at the fertile site and 300 g C m−2 y−1 at the infertile site. During the snow-free period (18 April–21 November), the above ground parts of measured species released 75 g C m−2 y−1 at the infertile site. At the fertile site, E. angustifolium and R. idaeus respired 22 and 12 g C m−2 y−1, respectively.

Distribution and dissemination of Mycosphaerella graminicola (Fuckel) Schroeter in relation to the epidemiology of speckled leaf blotch of wheat

1978 ◽  
Vol 29 (6) ◽  
pp. 1139 ◽  
Author(s):  
JS Brown ◽  
AW Kellock ◽  
RG Paddick
Keyword(s):  
Growing Season ◽  
Mycosphaerella Graminicola ◽  
Early Spring ◽  
Leaf Wetness ◽  
Direct Sunlight ◽  
Leaf Blotch ◽  
Late Autumn ◽  
Ascospore Discharge ◽  
Main Period ◽  
Wheat Stubble

The distribution of M. graminicola and the dissemination of ascospores in relation to the epidemiology of speckled leaf blotch of wheat in Victoria was studied. The fungus was present on wheat stubble throughout the Victorian wheat-belt and ascospores were discharged from stubble following periods of leaf wetness caused by rain or dew. Fertile perithecia were found on 1-year-old but not 2-year-old stubble. The viability of freshly ejected ascospores remained high throughout the growing season, and when shaded from direct sunlight ascospores remained viable for 1–2 weeks after release. The main period of ascospore discharge was late autumn to early spring, during which time the daily mean number of ascospores trapped 0.3 m above a commercial wheat stubble frequently exceeded 1000/m3 air.

Holocene and Last Interglacial cloudiness in eastern Baffin Island, Arctic CanadaThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.GEOTOP Publication 2008-0027.

2008 ◽  
Vol 45 (11) ◽  
pp. 1221-1234 ◽  
Author(s):  
Bianca Fréchette ◽  
Anne de Vernal ◽  
Pierre J.H. Richard
Keyword(s):  
Air Temperature ◽  
Growing Season ◽  
Dwarf Shrub ◽  
Interglacial Period ◽  
Vegetation Changes ◽  
Baffin Island ◽  
Last Interglacial ◽  
The Holocene ◽  
Growing Season Length ◽  
Shrub Tundra

This study presents Last Interglacial and Holocene vegetation and climate changes at Fog Lake (67°11′N, 63°15′W) on eastern Baffin Island, Arctic Canada. The vegetation cover is reported as vegetation structural types (or biomes). July air temperature and sunshine during the growing season (June–July–August–September) were reconstructed from pollen assemblages using the modern analogue technique. The vegetation of the Last Interglacial period evolved from a prostrate dwarf-shrub tundra to a low- and high-shrub tundra vegetation. The succession of four Arctic biomes was distinguished from the Last Interglacial sediments, whereas only one Arctic biome was recorded in the Holocene sediments. From ca. 8300 cal. years BP to present, hemiprostrate dwarf-shrub tundra occupied the soils around Fog Lake. During the Last Interglacial, growing season sunshine was higher than during the Holocene and July air temperature was 4 to 5 °C warmer than present. A principal component analysis helped in assessing relationship between floristic gradients and climate. The major vegetation changes through the Last Interglacial and Holocene were driven by July air temperature variations, whereas the minor, or subtle, vegetation changes seem rather correlated to September sunshine. This study demonstrates that growing season sunshine conditions can be reconstructed from Arctic pollen assemblages, thus providing information on feedbacks associated with cloud cover and summer temperatures, and therefore growing season length.

scholarly journals Pollen calendar of Lublin, 1995-2000

2012 ◽  
Vol 59 (1) ◽  
pp. 529-538 ◽  
Author(s):  
Krystyna Piotrowska
Keyword(s):  
Grass Pollen ◽  
Pollen Season ◽  
Gravimetric Method ◽  
Pollen Grains ◽  
Ground Level ◽  
Pollen Calendar ◽  
Herbaceous Plants ◽  
Above Ground Level ◽  
Grass Pollen Season ◽  
Trees And Shrubs

The measurements of pollen fall were carried out in Lublin in 1995 - 2000 years by the gravimetric method. The modified Durham sampler was applied, located at 9 m above ground level. On the base of results 6 year observations - the pollen calendar for Lublin was prepared. The following 15 plant taxa were taken under consideration: <i>Alnus</i>, <i>Corylus</i>, Cupressaceae, <i>Populus</i>, <i>Fraxinus</i>, <i>Betula</i>, <i>Quercus</i>, Pinaceae, Poaceae, <i>Rumex</i>, <i>Plantago</i>, <i>Urtica</i>, Chenopodiaceae, <i>Artemisia</i> and <i>Ambrosia</i>. The anemophilous plants' pollen season in Lublin began in half of February and lasted till half of September. First appeared pollen grains of decidous tress' and shrubs, then the coniferous. High values of pollen fall of these plants were noted till the end of May. Start of grass pollen season was recorded from the half of May, and at the latter part of this month, also other herbaceous plants. The highest concentrations of pollen were found in April and May when trees and shrubs pollinated. The highest annual totals were marked for plants of the following taxa: <i>Betula</i>, Poaceae, Pinaceae, <i>Alnus</i>, <i>Urtica</i>.

scholarly journals ISOLATE TWO SPECIES OF COMPOSITAE FAMILY E.armatus BOISS&HAUSSKN AND E.cephalotes DC. BY MORPHOLOGICAL AND VEGETATIVE SHOOT APEX FOR THE FIRST TIME IN IRAQ

2017 ◽  
Vol 48 (5) ◽  
Author(s):  
Al-Musawi & et al.
Keyword(s):  
Plant Species ◽  
Shoot Apex ◽  
Pollen Grains ◽  
Reproductive Organs ◽  
The Other ◽  
Vegetative Shoot ◽  
Northern Areas ◽  
Vegetative Shoot Apex ◽  
Perennial Herbs ◽  
First Time

Present study delts with morphological and vegetative shoot apex characteristics of two species  Echinops armatus and E.cephalotes (compositae) which collected during trips field to the northern areas of Iraq in the seasons of growth 2012-2014. As it presents the results and characters  had been shown for the first time in Iraq. plant species are perennial herbs spinous with woody, strong and solid stems that covered with many types of indumentums like spines and hairs, the study included characters of stems, leaves, involucres bracts and inflorescences as well as characters of growing points of the two species, and by examining buds in inflorescences found that the flowers are hermaphrodite, not sterile which containing all the reproductive organs like stamens, pollen grains, pistils and ovaries, an early dehesence as mature anthers and bloom before the maturation of pistils and disperse their pollen.The study also discussed variations within the characters and it became clear that the characters of leaves, stems and involucres especially inner cycle, including the importance of taxonomic great isolate the two species. Ranged prepare involucres braces  in the first species is (20-23) bracts while the number varied between (19-20) bracts in the other one. The study showed the importance of growing points  in isolating the two species where characterized by two meristematic area in longitudinal embryos species. The first spices recognized by two rows of cells, while the other one marked three rows or layers of components of Tunica cells area, and ensures find accurate measurements of parts phenotypic as well as illustrations of morphological and anatomical parts studied.                   

Cucumis anguria (West Indian gherkin).

2021 ◽  
Author(s):  
Julissa Rojas-Sandoval
Keyword(s):  
Pollen Grains ◽  
Growing Season ◽  
Low Fertility ◽  
Annual Rainfall ◽  
Editorial Committee ◽  
Male And Female ◽  
Tropical Plants ◽  
Wide Range ◽  
Male Flowers ◽  
Female Flowers

Abstract Genetics: The chromosome number reported for Cucumis anguria is 2n=24 (Ramachandran and Narayan, 1990; Flora of North America Editorial Committee, 2020). Reproductive Biology: Cucumis anguria is a monoecious species, with individual male and female flowers appearing on both plants, that depends of pollinators to transfer pollen grains in order to produce fruits. Although self-fertile, a degree of outcrossing results from insect pollination. Zagorcheva (1988) has suggested that C. anguria may also be a facultative apomict. The flowering season is of about 55-58 days. Male flowers appear before female flowers and both male and female flowers remain open for one day (from 7:30 am to 4:00 pm). The relationship between male and female flowers is on average 5.5 male flowers for each female flower. The greater number of male flowers compared to female flowers produces a greater flow of pollen in the crop and ensures pollination. Flowers are visited and pollinated by insects. In a study in Brazil, the most important visitor was Apis mellifera (72% of all visits) followed by native bees from the genera Plebeia sp. (16.7%), Exomalopsis sp. (8.3%) and Melissodes sp. (2.8%). Flowers are also visited by butterflies (Malerbo-Souza et al., 2020). Physiology and Phenology: Cucumis anguria is an annual species. Early growth is upright, followed by branching at the base to produce several trailing stems. Within its native distribution range, this species germinates in a few days during the summer rains when night temperatures are above 12°C and the soil is sufficiently wet. When plants are about 2-3 m length, they start to develop flowers. Fruits are often produced within 60 days after germination. Plants may produce up to 50 fruits per stem. Fruits remain attached to the withered annual stems long after these have died back at the end of the growing season (Wilkins-Ellert, 2004). Photoperiod is important and longer days coupled with higher temperatures confines plants to the production of male flowers. Shorter days and a drop in temperature stimulate the production of female flowers. Fruiting occurs within 60 days of planting and fruit are produced continuously, with as many as 50 fruits per plant produced during the growing season (Wilkins-Ellert, 2004). Environmental Requirements: Cucumis anguria prefers to grow in tropical and subtropical climates. It grows best in areas with mean annual temperatures ranging from 15°C to 28°C (tolerates 8°C-35°C) and mean annual rainfall between 800 mm-1000 mm (tolerates 300 mm-1700 mm). It is well adapted to soils with low fertility and is adapted to grow in a wide range of soil types, including Kalahari sands (regosols), red clays and black cotton soils (vertisols) with pH in the range 6-7.5 (tolerates 5.5 - 8.3), but it grows best on well drained sandy soils (Fernandes, 2011). This species is sensitive to cold and does not tolerate frost (Wilkins-Ellert, 2004; Useful Tropical Plants, 2020).

scholarly journals Land-Use and Height of Pollen Sampling Affect Pollen Exposure in Munich, Germany

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 145 ◽  
Author(s):  
Jesús Rojo ◽  
Jose Oteros ◽  
Antonio Picornell ◽  
Franziska Ruëff ◽  
Barbora Werchan ◽  
...  
Keyword(s):  
Airborne Pollen ◽  
Pollen Grains ◽  
Ground Level ◽  
Large Area ◽  
Dispersal Capacity ◽  
Pollen Types ◽  
Pollen Concentrations ◽  
Pollen Sources ◽  
Poaceae Pollen ◽  
The City

Airborne pollen concentrations vary depending on the location of the pollen trap with respect to the pollen sources. Two Hirst-type pollen traps were analyzed within the city of Munich (Germany): one trap was located 2 m above ground level (AGL) and the other one at rooftop (35 m AGL), 4.2 km apart. In general, 1.4 ± 0.5 times higher pollen amounts were measured by the trap located at ground level, but this effect was less than expected considering the height difference between the traps. Pollen from woody trees such as Alnus, Betula, Corylus, Fraxinus, Picea, Pinus and Quercus showed a good agreement between the traps in terms of timing and intensity. Similar amounts of pollen were recorded in the two traps when pollen sources were more abundant outside of the city. In contrast, pollen concentrations from Cupressaceae/Taxaceae, Carpinus and Tilia were influenced by nearby pollen sources. The representativeness of both traps for herbaceous pollen depended on the dispersal capacity of the pollen grains, and in the case of Poaceae pollen, nearby pollen sources may influence the pollen content in the air. The timing of the pollen season was similar for both sites; however, the season for some pollen types ended later at ground level probably due to resuspension processes that would favor recirculation of pollen closer to ground level. We believe measurements from the higher station provides a picture of background pollen levels representative of a large area, to which local sources add additional and more variable pollen amounts.

scholarly journals Ethylenediurea (EDU) effects on hybrid larch saplings exposed to ambient or elevated ozone over three growing seasons

2021 ◽  
Author(s):  
Evgenios Agathokleous ◽  
Mitsutoshi Kitao ◽  
Takayoshi Koike
Keyword(s):  
Photosynthetic Pigment ◽  
Ground Level ◽  
Growing Season ◽  
Growth Potential ◽  
Foliar Injury ◽  
Hybrid Larch ◽  
Ground Level Ozone ◽  
Growing Seasons ◽  
Elevated Ozone

AbstractGround-level ozone (O3) pollution is a persistent environmental issue that can lead to adverse effects on trees and wood production, thus indicating a need for forestry interventions to mediate O3 effects. We treated hybrid larch (Larix gmelinii var. japonica × L. kaempferi) saplings grown in nutrient-poor soils with 0 or 400 mg L−1 water solutions of the antiozonant ethylenediurea (EDU0, EDU400) and exposed them to ambient O3 (AOZ; 08:00 − 18:00 ≈ 30 nmol mol−1) or elevated O3 (EOZ; 08:00 − 18:00 ≈ 60 nmol mol−1) over three growing seasons. We found that EDU400 protected saplings against most effects of EOZ, which included extensive visible foliar injury, premature senescence, decreased photosynthetic pigment contents and altered balance between pigments, suppressed gas exchange and biomass production, and impaired leaf litter decay. While EOZ had limited effects on plant growth (suppressed stem diameter), it decreased the total number of buds per plant, an effect that was not observed in the first growing season. These results indicate that responses to EOZ might have implications to plant competitiveness, in the long term, as a result of decreased potential for vegetative growth. However, when buds were standardized per unit of branches biomass, EOZ significantly increased the number of buds per unit of biomass, suggesting a potentially increased investment to bud development, in an effort to enhance growth potential and competitiveness in the next growing season. EDU400 minimized most of these effects of EOZ, significantly enhancing plant health under O3-induced stress. The effect of EDU was attributed mainly to a biochemical mode of action. Therefore, hybrid larch, which is superior to its parents, can be significantly improved by EDU under long-term elevated O3 exposure, providing a perspective for enhancing afforestation practices.

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