软质与硬质地表对树木花粉日飘散变化的影响

以油松(Pinus tabulaeformis)、白玉兰(Magnolia denudata)、白皮松(Pinus bungeana)、臭椿(Ailanthus altissima)为被试树种,对比研究了春季静风晴朗天气中软质与硬质两种地表条件下不同树种在距树10m高度1.5m处花粉浓度的日变化特征。研究结果表明:(1)4个树种在相同地表环境的花粉浓度日变化趋势基本一致,但同一树种花粉浓度的日变化特征在软、硬两种地表条件下的差异明显。软质地面一天内空气中花粉浓度最大值出现14:00时前后,04:00时花粉浓度最低,这与全天内空气温度的变化正好一致,而与空气相对湿度的变化恰好相反。硬质地表近地空间空气中的花粉浓度则呈现"双峰型"日变化特征,两次峰值分别出现在14:00时和20:00时,硬质地面花粉浓度20:00时晚高峰的出现时间与硬质地面温度日峰值一致。(2)分析硬质地表20:00时花粉浓度高峰出现的原因可能与硬质地面的散热特性有关,硬质地面夜间释放积蓄热量的过程会在一定程度上增强近地面空气的对流运动,并辅助空气中的花粉粒子不断飘散,形成花粉浓度晚高峰。(3)相对于软质地面来讲,硬质地表对空气中花粉飘散的影响作用持续时间更长,这也在一定程度上延长了致敏花粉的危害时间,加剧了致敏花粉的污染程度。研究还进一步在花粉致敏树种栽植、地表覆盖方式等方面进行了讨论;同时建议花粉症患者根据花粉污染发生规律合理规避花粉浓度聚集高峰期出行,从而有效缓解致敏花粉对易感人群的健康威胁。     

Annual,daily and diurnal variation of Urticaceae pollen in North-central London

Summary Annual differences in cumulative counts of Urticaceae pollen are found to relate primarily to the weather conditions during the pollen formative period (April and May) and secondarily to the weather prevailing during the season itself. Relative humidity, temperature, wind velocity and precipitation emerge as the most influential variables in the analysis of daily variations but their relative importance varies between years. Diurnal patterns in concentrations show general peaks occurring in the early evening but the severity and exact timing of these relates closely to wind direction. The implications of these results are considered in the context of forecasting.     

Follicle deviation and diurnal variation in circulating hormone concentrations in mares

The temporal relationships between follicle deviation and systemic hormone concentrations were studied in mares. Blood samples were obtained at 01:00, 07:00, 13:00, and 19:00 h from nine mares throughout an interovulatory interval. Diurnal variation in progesterone occurred on Days 4-12 and in LH on Days 4 and 5; the lowest concentration for both hormones was at 13:00 h. Ultrasonically observed deviation in the ovulatory follicular wave began on Day 15.7+/-0.5 (ovulation=Day 0). An increase (P<0.002) in LH began on Day 14 before the beginning of deviation, and an increase (P<0.05) in estradiol began at the beginning of deviation. Testosterone concentrations began to increase (P<0.05) 2 days after the beginning of deviation and reached maximum 1 day before the next ovulation. The beginning of deviation was encompassed by a decline (P<0.003) in cortisol concentrations, and the concentrations remained low during the preovulatory period.     

Multivariate statistical forecasting modeling to predict Poaceae pollen critical concentrations by meteoclimatic data

Forecasting pollen concentrations in the short term is a topic of major importance in aerobiology. Forecasting models proposed in the literature are numerous and increasingly complex, but they fail in at least 25 % of cases and are not available for all botanical species. This work makes it possible to build a forecast model from meteorological data for estimating pollen concentration over a certain threshold of Poaceae, an allergenic family. In Italy, about 25 % of the population suffer from allergies, these in 80 % of cases being caused by airborne allergens, including taxa of agricultural interest such as Poaceae. The pollen dispersion in air is determined by both the phenological stage of plants and the meteorological conditions; the pollen presence varies according to the year, month and even the time of the day. There is a correlation between environmental factors, pollen concentrations and pollinosis. A partial least squares discriminant analysis approach was used in order to predict the presence of Poaceae pollen in the atmosphere with a time lag of 3, 5, 7 days, on the basis of a data set of 14 meteorological and pollen variables over a period of 14 years (1997–2010). The results show a high accuracy in predicting pollen critical concentrations, with values ranging from 85.4 to 88.0 %. This study is hopefully a positive first step in the use of a statistical approach that in the next future could have clinical applications.     

Comparison of diurnal variation of airborne pollen in Mar del Plata (Argentina)

Intradiurnal variation of arboreal pollen (AP) in Mar del Plata city is compared during three non - consecutive years of survey and described in relation to the associated weather. The daily pattern of pollen abundance has a maximum between 10:00 and 12:00?h, while a minimum occurs at 18:00?h. The first two years of survey showed homogeneous daily trends, but in 1995 the maximum and minimum concentrations were delayed because of the change in position of the collecting station. Arboreal pollen spectrum presented qualitative and quantitative changes in the three years analysed. Results indicate optimal conditions for diurnal dispersion of arboreal pollen are high temperatures and low relative humidity. Also interaction between source position and wind direction has important effects on the timing of the peaks of some pollen types.     

Poaceae pollen concentrations in the atmosphere of three inland Croatian sites (2003-2004)

The aim of the study was to determine the length of Poaceae pollen season, intradiurnal, daily and monthly pollen variation, and the effect of some meteorological parameters on atmospheric pollen concentration, at three monitoring sites in inland Croatia during the 2003-2004 period. Seven-day Hirst volumetric pollen and spore traps were used for pollen sampling. At all three monitoring sites considerably higher precipitation and lower average temperature in 2004 led to a marked decrease in the grass pollen concentration in the air at all three monitoring sites. The highest grass pollen concentrations were recorded in Ivani? Grad (typical rural area), considerably lower in Samobor (effect of forest vegetation), and lowest in Zagreb (urban area). The highest atmospheric Poaceae pollen concentrations in inland Croatia were generally recorded in May and June. The highest intradiurnal concentrations were recorded between 8.00 and 12.00 a.m. Results of this aeropalynologic study are expected to help in preventing the symptoms of allergic reaction in individuals with Poaceae pollen hypersensitivity.     

城市复杂环境中碳通量日变化规律及其影响因素

城市是人类居住和活动最集中地区,其CO₂排放量占世界总排放量的71%,城市碳排放规律研究对全球碳减排工作具有重要意义。利用涡动相关技术观测了北京市某街区2015年至2016年的CO₂通量,重点研究了不同时间尺度和气象条件下的CO₂通量的日变化规律,分析了影响城市CO₂通量的社会及自然因素。结果表明,CO₂通量日变化特征具有（1）明显的早晚"双峰型"特征,早晚高峰分别出现在早上7：30-9：30和晚上17：30-20：30;（2）周末特征：周末早高峰时间延迟,晚于工作日约1.5h,且峰值低了约10.8%,但晚高峰时间提前,且峰值高于工作日约10.6%;（3）季节特征：冬季CO₂通量均值和早高峰值明显高于其他季节,夏季中午具有明显低峰区;（4）风向特征：在不同来风方向上,CO₂通量的日变化峰值差异很大;（5）天气特征：阴天双峰特征比晴天明显。研究表明CO₂通量日变化主要与交通流量动态变化关系最为密切,其次要受到植被的影响。因此,交通减排和植被增汇对于控制城市碳排放具有重要意义。     

The influence of ambient temperature on the abundance of Poaceae pollen

The sampling of pollen concentrations over six seasons in north London has revealed the importance of temperature in influencing the start, severity, daily and diurnal variation of Poaceae pollen seasons. Using accumulated degree days above 6°C and rainfall amount as predictors, models have been developed which account for 96% of the variation in the starting date and 91% of the variation in the severity of the Poaceae pollen season. Maximum daily temperature is an important influence on the daily pollen count although this relationship is not linear and maximum daily temperatures within the range 21.1–25°C are associated with the highest daily pollen concentrations. Likewise, when the two-hourly variation of pollen concentration is examined, temperatures within 2–4.9°C above the normal diurnal range, rather than in excess of 5.0°C, are found to be associated with the highest two-hourly concentrations. Occasional night-time maxima of pollen concentration have also been recorded and these are examined in relation to the possibility of temperature inversions, although few conclusive results have emerged.     

Effects of dietary D-psicose on diurnal variation in plasma glucose and insulin concentrations of rats

The effects of supplemental D-psicose in the diet on diurnal variation in plasma glucose and insulin concentrations were investigated in rats. Forty-eight male Wistar rats were divided into four groups. Each group except for the control group was fed a diet of 5% D-fructose, D-psicose, or psico-rare sugar (3:1 mixture of D-fructose and D-psicose) for 8 weeks. Plasma glucose levels were lower and plasma insulin levels were higher at all times of day in the psicose and psico-rare sugar groups than in the control and fructose groups. Weight gain was significantly lower in the psicose group than in the control and fructose groups. Liver glycogen content, both before and after meals was higher in the psicose group than in the control and fructose groups. These results suggest that supplemental D-psicose can lower plasma glucose levels and reduce body fat accumulation. Hence, D-psicose might be useful in preventing postprandial hyperglycemia in diabetic patients.     

Diurnal variation in airborne pollen concentrations of the selected taxa in Zagreb, Croatia

The number of individuals allergic to plant pollen has recently been on a constant increase. The knowledge of diurnal distribution and abundance of allergenic pollen types, their patterns and response to source position and weather is useful to correlate hay fever symptoms with the presence of allergenic pollen in the atmosphere. The aim of this study was to determine diurnal distribution of total airborne pollen, pollen of particular allergenic taxa, possible variation in diurnal pollen distribution at measuring sites placed at different heights, and effect of some meteorological parameters on airborne pollen concentrations. A 7-day Hirst-type volumetric pollen trap was used for pollen sampling. Qualitative and quantitative pollen analysis was performed under a light microscope (magnification x400). Total pollen of all plant taxa (Ambrosia sp., Betula sp., Cupressaceae, Urticaceae, Poaceae, Quercus sp., Fraxinus sp., Alnus sp., Corylus sp., Populus sp., Pinus sp., Picea sp.) observed showed a regular diurnal distribution at both sampling sites in both study years, with a rise in the pollen concentration recorded after 4.00 a.m. and 6.00 a.m., respectively. The peak pollen concentration occurred between 12.00 a.m. and 4.00 p.m., and the lowest diurnal pollen concentrations were recorded overnight. About 50% of the 24-h pollen concentration were released to the atmosphere between 10.00 a.m. and 4.00 p.m. The timing and size of diurnal peaks were closely related to high temperature, low humidity and south-west maximum wind direction.     

Parameterization of the birch pollen diurnal cycle

The purpose of this study was to investigate the patterns of birch pollen counts over a diurnal cycle and propose a parameterization that is useful for inclusion into operational and research short- and long-term modeling for birch pollen atmospheric transport and deposition at different spatial scales. The evaluation of patterns of diurnal cycles on monthly and interannual bases has been done based on analysis of a 26-year time series of birch pollen counts from the Danish pollen measurement site in Copenhagen. The suggested parameterization, based on a simple trigonometric function, includes dependencies on the time of birch pollen maximum and minimum occurrence on a diurnal cycle, averaged concentration at the end of the previous day, and time shift.     

云锦杜鹃叶片光合作用日变化特征

自然条件下, 对云锦杜鹃光合作用日进程和光响应进行了观测, 结果表明:夏季晴天云锦杜鹃阳叶净光合速率日进程曲线为"双峰"型, 光合效率午间明显降低。胞间CO₂ 浓度的日进程基本与净光合速率相反, 中午胞间CO₂ 浓度增高表明净光合速率午间降低主要受非气孔限制因素的影响。暗呼吸速率日进程呈单峰曲线, 中午最高。阴叶净光合速率在一天的大部分时间里变化不大。一天分时段光响应试验表明, 阳叶饱和光强和表观量子效率上午较高, 下午有所降低, 而光补偿点下午有所上升。阴叶的这些光合参数在上午和下午没有明显的变化。这些研究结果表明, 强光下光抑制的发生是引起云锦杜鹃阳叶光合效率午间降低的重要原因。逐步多元回归和通径分析表明, 光合有效辐射和空气温度是直接影响净光合速率日变化的主要因子。     

Air pollen dispersal in a tropical area

Volumetric data on airborne pollen have been gathered for two consecutive years at a neotropical location (Caracas). Among the 65 taxa which were identified, pollen from aCupressus species (introduced) and from aCecropia species (indigenous) were dominant. Less numerous but also abundant (daily averages ≥5 grains/m³ air) were pollen from Gramineae, Urticaceae,Alcalypha, Pinus, Piperaceae andMimosa. Pollen grains were recorded daily throughout the year. They increased in numbers during April–May and again during November–December. The first peak was contributed mainly by indigenous species, the second peak mainly by introduced species.     

Poaceae pollen in the air depending on the thermal conditions

The relationship between the meteorological elements, especially the thermal conditions and the Poaceae pollen appearance in the air, were analysed as a basis to construct a useful model predicting the grass season start. Poaceae pollen concentrations were monitored in 1991–2012 in Kraków using the volumetric method. Cumulative temperature and effective cumulative temperature significantly influenced the season start in this period. The strongest correlation was seen as the sum of mean daily temperature amplitudes from April 1 to April 14, with mean daily temperature >15 °C and effective cumulative temperature >3 °C during that period. The proposed model, based on multiple regression, explained 57 % of variation of the Poaceae season starts in 1991–2010. When cumulative mean daily temperature increased by 10 °C, the season start was accelerated by 1 day. The input of the interaction between these two independent variables into the factor regression model caused the increase in goodness of model fitting. In 2011 the season started 5 days earlier in comparison with the predicted value, while in 2012 the season start was observed 2 days later compared to the predicted day. Depending on the value of mean daily temperature from March 18th to the 31st and the sum of mean daily temperature amplitudes from April 1st to the 14th, the grass pollen seasons were divided into five groups referring to the time of season start occurrence, whereby the early and moderate season starts were the most frequent in the studied period and they were especially related to mean daily temperature in the second half of March.     

Pollinator visitation closely tracks diurnal patterns in pollen release

Premise

Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., “schedule” their pollen presentation) and attract pollinators in specific time frames.

Methods

We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees.

Results

The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability.

Conclusions

Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.     

Airborne Poaceae pollen in Porto (Portugal) and allergenic profiles of several grass pollen types

This work aims to investigate the presence of airborne grass pollen and to identify antigenic and allergenic profiles from eight different grass species collected in the Porto region (Portugal). Poaceae airborne pollen, sampled using a Hirst-type volumetric trap during 2003–2007, was the second most abundant type, and high concentrations were found from April to August. Pollen proteins extracted from the eight grass species collected were separated by SDS-PAGE, being the allergenic profile investigated by immunoblotting using sera from atopic patients and maize profilin polyclonal antibody (ZmPRO3). Pollen extract profiles showed several bands ranging from 10 to 97 kDa. In immunoblotting studies, a low molecular weight protein (12–13 kDa) was recognized by profilin antibody. Also, in all pollen extracts except Zea mays, the IgE binding proteins of 12–13 kDa were detected in sera from the 25 patients with different sensitization profiles presenting high IgE values (>80 kU/l). This protein can be considered as a potential causal agent of the allergic respiratory diseases.     

Comparative study of seasonal and intradiurnal variation of airborne herbaceous pollen in urban and rural areas

The content of herbaceous pollen in the atmosphere depends on the vegetal cover, climate and the weather and geographical conditions. The aim of the study reported here was to compare aerobiological data obtained from pollen monitoring stations located at sites differing with respect to their flora and microclimate – i.e. a town and a rural area. A volumetric method was used for sampling. In each microscopic preparation 12 vertical strips corresponding with 2-h intervals were analysed. A 90% method was used to determine the pollen season. The results were statistically verified using the u test and the Kolmogorov-Smirnov, Spearman and Wilcoxon tests. Higher values of the Seasonal Pollen Index (SPI), higher daily average concentrations and higher peak values were recorded in the rural area. An analysis of intradiurnal variations of airborne pollen showed that apart from the Poaceae the number of pollen grains in the air began to increase earlier in the day in the rural area; in the case of Rumex and Ambrosia, the maximum values also appeared a few hours earlier. For all the taxa investigated, the analysis of correlation showed a significant association between the daily average concentrations at both sites. The weakest association occurred for Plantago lanceolata; for all other taxa, the determination coefficients (R ²) were high. The results of the Wilcoxon test showed that, despite the strong positive association between daily concentrations of the pollen types investigated, there were differences in mean pollen concentrations in the overlapping pollen season. Mean concentrations of Poaceae and Rumex airborne pollen were significantly higher in the rural area in both years, and those of Urtica and P. lanceolata were significantly higher only in 2002.     

Modeling diurnal variation of marine populations

A number of marine populations exhibit diurnal variations in their behavioral pattern, and this phenomenon has been studied by several authors looking at a variety of species. But to our knowledge, fully adequate statistical tools have not been used in a comprehensive and systematic way. It is the goal of this article to bring forward relevant statistical techniques and to demonstrate how they can be used. Both parametric and nonparametric methods are employed, and we concentrate on such basic statistical issues as testing for the presence of diurnal variations using a nonparametric test and on estimating and testing the shape of diurnal oscillations. We indicate how this can be used to examine the effect of light on diurnal behavior. Our methods are illustrated using data from bottom trawl catches of cod (Gadus morhua) collected during winter surveys in the Barents Sea in the period 1985-1999.     

Annual variations in the concentrations of Betula pollen in the London area, 1961–1990

Annual variations in the ambient concentrations of Betula pollen monitored by volumetric sampling at sites in London and also at a site to the South of the city between the years 1961–1990 are analysed in relation to the main meteorological parameters. Attention is focussed on variations in the start and duration of the seasons and on the annual patterns of pollen abundance. Consideration is given also to the variation in the severity of seasons. The paper examines possible rhythms in the annual production of Betula pollen and develops empirical regression models from the analyses of the trends to predict the main characteristics of the seasons.     

Reliability of measures of spores of Alternaria and pollen concentrations in air over two towns in rural Australia

We examined the reliability of measurements from a single Burkard volumetric trap to represent the distribution of airborne concentrations of spores of Alternaria and pollen across two towns in rural Australia. Each town was sampled with three traps, sited 2.0 to 4.9 km apart, simultaneously. Substantial intra-class correlation coefficients (ICC) were observed between all three sites (ICC～0.52, 95% CI 0.30-0.71 to 0.76, 95% CI 0.61-0.87) when counts of pollen and Alternaria spores were relatively high. The correlation was poor when counts were low. Highly variable distributions of cypress pollen were found to be location dependent. We further compared two central lengthwise microscopic traverses of Burkard trap samples collected daily over one year. Correlation was strong for Alternaria spores (ICC～0.95, 95% CI 0.94-0.96), grass pollen (ICC～0.94, 95% CI 0.91-0.96) and total non-grass pollen (ICC～0.91, 95% CI 0.89-0.93). We conclude that a single central traverse of a Burkard trap sample collected at one location provides an acceptable measure of the concentrations of spores of Alternaria and grass pollen across the two rural towns when counts are relatively high. The measure is less reliable when counts are low.