Environmental analysis of airborne pollen occurrence,pollen source distribution and phenology of <Emphasis Type="Italic">Fraxinus angustifolia</Emphasis>

Narrow-leafed ash (Fraxinus angustifolia) is a common polygamous tree growing on the banks of rivers in the western Mediterranean region. Pollination occurs during winter, and the tree’s pollen is among the most abundant during that season. This work aims to relate the phenology of pollen shedding, source tree distribution, meteorology and airborne pollen occurrence for the species. Aerobiological sampling was conducted in Badajoz (south-western Spain) using a Hirst volumetric sampler over 24 years (1993–2016). Trees were geo-localized in a circle 500 m in diameter surrounding the pollen sampler. During the last two periods, pollination phenology was studied in 10 specimens, five in the surroundings of the pollen station and five 3 km apart, at a frequency of 3–4 days on average. Moreover, a detailed analysis of pollen occurrence was conducted for these two periods. Daily data for the whole period and hourly data over the last 2 years were used, including pollen monitoring and meteorology. A comparison was made between pollen occurrence and source distribution. The main pollen season lasted on average 53 (28–75) days. Average values were less than 10 grains m^?3, except for two periods of 23–24 grains m^?3. Daily data and hourly data correlation with meteorology showed different signs in correlation analysis. Hourly analysis showed that the maximum concentration occurred just after noon. Most pollen was recorded at an average temperature of 9 °C. Analysis of pollen sources and pollen occurrence showed a close relationship between predominant wind directions and tree distribution. Peaks of phenology were not coincident with pollen peaks. No trends in pollination were found. Non-homogeneous distribution of pollen sources for Fraxinus angustifolia provided a suitable tool to demonstrate that wind direction plays a relevant role when aerobiological data are interpreted according to source distribution. A limitation in phenology analysis and aerobiological data was noted in the narrow-leafed ash species.     

Seasonal distribution of airborne pollen in Manila,Philippines, and the effect of meteorological factors to its daily concentrations

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.     

Late Holocene vegetation history and human activity shown by pollen analysis of Novienki peat bog (Kargaly region,Orenburg Oblast,Russia)

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.     

Pollen spectrum in Northern Tunis,Tunisia

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.     

Airborne pollen and fungal spores in Garki,Abuja (North-Central Nigeria)

The ambient atmosphere is dominated with pollen and spores, which trigger allergic reactions and diseases and impact negatively on human health. A survey of pollen and fungal spores constituents of the atmosphere of Garki, Abuja (North-Central Nigeria) was carried out for 1 year (June 1, 2011–May 31, 2012). The aim of the study was to determine the prevalence and abundance of pollen and fungal spores in the atmosphere and their relationship with meteorological parameters. Airborne samples were trapped using modified Tauber-like pollen trap, and the recipient solutions were subjected to acetolysis. Results revealed the abundance of fungal spores, pollen, fern spores, algal cysts and diatoms in decreasing order of dominance. The atmosphere was qualitatively and quantitatively dominated by pollen during the period of late rainy/harmattan season than the rainy season. Numerous fungal spores were trapped throughout the sampling periods among which Alternaria spp., Fusarium spp., Cladosporium spp. and Curvularia spp. dominated. These fungi have been implicated in allergic diseases and are dermatophytic, causing diverse skin diseases. Other pathogenic fungi found in the studied aeroflora were Dreschlera spp., Helminthosporium spp., Torula spp., Pithomyces spp., Tetraploa spp., Nigrospora ssp., Spadicoides spp., Puccinia spp. and Erysiphe graminis. Total pollen and fungal spores counts do not show significant correlation with meteorological parameters.     

An aeropalynological survey in the city of Van,a high altitudinal region,East Anatolia-Turkey

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.     

The Response of Physiological Characteristics,Expression of OSC Genes,and Accumulation of Triterpenoids in <Emphasis Type="Italic">Betula platyphylla</Emphasis> Sukto MeJA and SA Treatment

The pentacyclic triterpenoids from birch (Betula platyphylla suk) have broad pharmacological activities and can be potentially used for the development of anti-cancer and anti-AIDS drugs. In this study, we explored the effects of spraying 3-year-old white birch with different concentration of methyl jasmonate (MeJA) and salicylic acid (SA) on the expression of key genes in triterpenoid biosynthesis pathways and on the accumulation and physiological characteristics of triterpenoids in birch saplings. The results showed that spraying different concentration of MeJA and SA could obviously promote accumulation of total triterpenoids in 3-year-old white birch. The triterpenoid content in the stem bark was increased by 46.11 %, reaching 81.86 mg/g, after 1 day of treatment with 1 mmol·L^?1 MeJA (MJ2), and by 45.07 %, reaching 91.4 mg/g, after 14 days of treatment with 5 mmol·L^?1 SA (SA1). In addition, MeJA and SA treatment increased the contents of chlorophyll a and b, antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as photosynthetic performance, and affected the content of soluble sugar and soluble protein in birch leaf. Fluorescence quantitative polymerase chain reaction (qPCR) results showed that MeJA and SA treatment deferentially enhanced the key gene expression of cycloartenol synthase (BPX and BPX2), lupeol synthase (BPW) and beta-amyrin synthase (BPY) in triterpenoid synthesis pathway in birch bark and leaves. The results showed that MeJA and SA induced triterpenoid synthesis of birch plant is closely related with not only the expression of key genes of triterpenoid synthesis pathway but also photosynthesis, anti-stress response and physiological indexes, suggesting that regulation of triterpenoid synthesis of birch by MeJA and SA may involve in more complex mechanisms at physiological and molecular levels.     

Blood Feeding Status,Gonotrophic Cycle and Survivorship of <Emphasis Type="Italic">Aedes (Stegomyia) aegypti</Emphasis> (L.) (Diptera: Culicidae) Caught in Churches from Merida,Yucatan, Mexico

Blood-feeding status, gonotrophic cycle, and survival rates of Aedes (Stegmyia) aegypti (L.) was investigated in catholic churches from Merida, Yucatan. Female Ae. aegypti were caught using backpack aspirator during 25 consecutive days in rainy (2015) and dry season (2016). Blood-feeding status was determined by external examination of the abdomen and classified as unfed, fed, and gravid. Daily changes in the parous–nulliparous ratio were recorded, and the gonotrophic cycle length was estimated by a time series analysis. Also, was observed the vitellogenesis to monitoring egg maturity. In total, 408 females Ae. aegypti were caught, and there was a significant difference in the number of females collected per season (Z = ?6.729, P ≤ 0.05). A great number was caught in the rainy season (n = 329). In the dry season, 79 females were caught, which the fed females were twice greatest than the unfed. The length of gonotrophic cycle was estimated on the base of a high correlation coefficient value appearing every 4 days in rainy at 26.7 ± 1.22°C, and 3 days in dry season at 29.8 ± 1.47°C. The daily survival rate of the Ae. aegypti population was higher in both seasons, 0.94 and 0.93 for the rainy and dry season, respectively. The minimum time estimated for developing mature eggs after blood feeding was similar in both seasons (3.5 days in rainy versus 3.25 days in dry). The measurement of the vectorial capacity of Ae. aegypti in catholic churches could help to understand the dynamics of transmission of arboviruses in sites with high human aggregation.     

Do moss samples,pollen traps and modern lake sediments all collect pollen in the same way? A comparison from the forest limit area of northernmost Europe

Moss polsters, pollen traps and lake surface sediment samples are commonly used as climate calibration data or as modern analogues for reconstructing vegetation from fossil profiles, but the differences in pollen content between these media have received little attention. This study aims to analyse how the three media differ in reflecting individual vegetation types and spatial differences in vegetation. 119 modern samples (64 moss polsters, 37 lake surface sediment samples and 18 pollen traps from which a collection was made annually) were taken from northern Fennoscandia and the Kola Peninsula as a broad transect crossing the northernmost forest limits of Betula pubescens ssp. czerepanovii (mountain birch), Pinus sylvestris (Scots pine) and Picea abies (Norway spruce). The pollen assemblages from these samples were compared with the surrounding vegetation visually and via PCA (principle components analysis) and cluster analysis. Both comparisons allow a correct distinction between pollen assemblages of arctic/alpine heath, mountain birch dominated areas, and boreal coniferous forests. The differences between the vegetation zones are stronger than the differences between the sampling media. Nevertheless, lake sediment samples from the mountain birch woodland zone tend to overestimate pine and underestimate birch. Pollen traps are biased towards lower tree pollen percentages and higher values of shrubs, herbs and Cyperaceae. This bias is especially strong in traps that have missing years in the data. Irrespective of the vegetation zone, pollen traps tend to have lower Pinus pollen percentages than in the adjacent moss polsters.     

First-Rotation Performance of Five Short-Rotation Willow Cultivars on Different Soil Types and Along a Large Climate Gradient

The establishment of short-rotation willow coppice plantations for bioenergy production is proposed as a land management practice to reduce the use of fossil fuels. However, there is little information on the performance of different willow (Salix spp.) cultivars on various types of soils and over climate gradients. This study aimed to determine which set of soil, climatic conditions, and cultivars are conducive to greater growth in eastern Canada. The performance of five willow cultivars was followed over three growing seasons on eight sites representing a large hydroclimatic gradient. Both geographic location and cultivar had a significant effect on annual yields. Annual yields were on average greater in the southern part of the climatic gradient. Across all cultivars, annual yields were positively correlated to average annual temperature (r = 0.23), total annual precipitation (r = 0.77), average growing season temperature (r = 0.21), average growing season precipitation (r = 0.47), and degree days (r = 0.18), as well as soil pH (r = 0.37) and soil extractible P (r = 0.38), and negatively correlated to soil clay content (r = 0.33). Cultivars of the SX group (i.e., Salix miyabeana SX61, SX64, and SX67) showed greater yield than did cultivars of the SV group (i.e., Salix × dasyclados SV1 and Salix viminalis SV5027). These results indicate that at the landscape level, climate variables, especially climate-related variables, largely explain the yield of the selected willow cultivars. Nonetheless, soil pH, extractable P, and clay content likely play an important role in plantation yield.     

An analysis of long-term winter data on phytoplankton and zooplankton in Neusiedler See,a shallow temperate lake,Austria

In the last 40 years, the shallow steppe lake, Neusiedler See, was ice covered between 0 and 97 days. The North Atlantic Oscillation (NAO) as well as the Mediterranean Oscillation affected the lake and its conditions during winter. Both climate indices correlated negatively with the duration of ice cover and the timing of ice-out. Average winter phytoplankton biomass increased from less than 0.2 (0.05–0.84) mg FM l^?1 in the late 1960s/beginning of 1970s to 3.1 (1.72–5.61) mg FM l^?1 in the years 2001–2004. The increase in annual winter biomass of phytoplankton was associated with a significant shift in the composition of the algal assemblage. In the winter 1997/1998, diatoms contributed between 40 and 80% to the phytoplankton biomass while in 2006/2007 cyanoprokaryotes contributed 46%. Mean chlorophyll-a concentrations during winter were significantly correlated with those of total phosphorus (P_tot). Together with cold-water species (rotifer Rhinoglena fertöensis), perennial, eurythermal ones (copepod Arctodiaptomus spinosus) contributed to the zooplankton community. High zooplankton numbers were encountered when rotifers, particularly when densities of Rhinoglena fertöensis were high (r ² = 0.928). Zooplankton abundance and biomass varied from year to year but correlated positively with Chl-a (biomass ? r ² = 0.69; numbers ? r ² = 0.536). Winter zooplankton populations were primarily influenced by winter conditions, but in early winter also by survival of autumn populations, i.e., the more adults of Arctodiaptomus spinosus survived into winter, the higher was the zooplankton biomass in early winter. Phyto- and zooplankton dynamics in shallow lakes of the temperate region seem to critically depend on the biomass in autumn and on winter conditions, specifically on ice conditions and thus are related to climate signals such as the NAO.     

Enhancement of Nisin Production by <Emphasis Type="Italic">Lactococcus lactis</Emphasis> subsp. <Emphasis Type="Italic">lactis</Emphasis>

Lactococcus lactis subsp lactis BSA (L. lactis BSA) was isolated from a commercial fermented product (BSA Food Ingredients, Montreal, Canada) containing mixed bacteria that are used as starter for food fermentation. In order to increase the bacteriocin production by L. lactis BSA, different fermentation conditions were conducted. They included different volumetric combinations of two culture media (the Man, Rogosa and Sharpe (MRS) broth and skim milk), agitation level (0 and 100 rpm) and concentration of commercial nisin (0, 0.15, and 0.30 µg/ml) added into culture media as stimulant agent for nisin production. During fermentation, samples were collected and used for antibacterial evaluation against Lactobacillus sakei using agar diffusion assay. Results showed that medium containing 50 % MRS broth and 50 % skim milk gave better antibacterial activity as compared to other medium formulations. Agitation (100 rpm) did not improve nisin production by L. lactis BSA. Adding 0.15 µg/ml of nisin into the medium-containing 50 % MRS broth and 50 % skim milk caused the highest nisin activity of 18,820 AU/ml as compared to other medium formulations. This activity was 4 and ~3 times higher than medium containing 100 % MRS broth without added nisin (~4700 AU/ml) and 100 % MRS broth with 0.15 µg/ml of added nisin (~6650 AU/ml), respectively.     

Flowering phenology and potential pollen emission of three <Emphasis Type="Italic">Artemisia</Emphasis> species in relation to airborne pollen data in Poznań (Western Poland)

Artemisia pollen is an important allergen in Europe. In Poznań (Western Poland), three Artemisia species, A. vulgaris, A. campestris and A. absinthium, are widely distributed. However, the contributions of these species to the total airborne pollen are unknown. The aim of the study was to determine the flowering phenology and pollen production of the three abovementioned species and to construct a model of potential Artemisia pollen emission in the study area. Phenological observations were conducted in 2012 at six sites in Poznań using a BBCH phenological scale. Pollen production was estimated by counting the pollen grains per flower and recalculating the totals per inflorescence, plant and population in the study area. Airborne pollen concentrations were obtained using a Hirst-type volumetric trap located in the study area. Artemisia vulgaris began to flower the earliest, followed by A. absinthium and then A. campestris. The flowering of A. vulgaris corresponded to the first peak in the airborne pollen level, and the flowering of A. campestris coincided with the second pollen peak. The highest amounts of pollen per single plant were produced by A. vulgaris and A. absinthium. A. campestris produced considerably less pollen, however, due to its common occurrence, it contributed markedly (30 %) to the summation of total of recorded pollen. A. vulgaris is the most important pollen source in Poznań, but the roles of two other Artemisia species cannot be ignored. In particular, A. campestris should be considered as an important pollen contributor and likely might be one of the main causes of allergic reactions during late summer.     

CAT and MDH improve the germination and alleviate the oxidative stress of cryopreserved <Emphasis Type="Italic">Paeonia</Emphasis> and <Emphasis Type="Italic">Magnolia</Emphasis> pollen

Researches have reported that reactive oxygen species (ROS)-induced oxidative stress plays an important role in cell cryodamage during cryopreservation. In the current study, pollen from Magnolia denudata and Paeonia lactiflora ‘Zi Feng Chao Yang’ was cryopreserved and incubated with exogenous catalase (CAT) and malate dehydrogenase (MDH) immediately after thawing. The effect of CAT and MDH on the germination of cryopreserved pollen was measured. Based on that, the ROS level, lipid peroxidation and antioxidants activities in fresh pollen, cryopreserved pollen added with or without CAT or MDH were determined to investigate their relationship with oxidative stress. Pollen from Magnolia and Paeonia showed a significant loss of germination, but marked increase of ROS and malondialdehyde (MDA) production after cryostorage. Antioxidant profiles in them were also enhanced. CAT and MDH addition increased the post-LN pollen germination of Magnolia and Paeonia significantly. Their germination rate achieved the highest with 100 IU ml^?1 MDH and 400 IU ml^?1 CAT application, respectively. Compared to their untreated controls, ROS and MDA accumulation reduced significantly in cryopreserved Magnolia pollen treated with 100 IU ml^?1 MDH, while superoxide dismutase (SOD) activity improved markedly. In the case of Paeonia, significantly lower level of ROS and MDA, but higher activity of CAT and SOD were observed in cryopreserved pollen treated with 400 IU ml^?1 CAT. In conclusion, pollen deterioration after cryopreservation is associated with ROS-induced oxidative stress. Exogenous CAT and MDH can reduce the oxidative damage through the activity stimulation of antioxidant enzymes, and play a protective role in the pollen during cryopreservation.     

Identification of birch pollen species using FTIR spectroscopy

In this study, the morphology and chemical composition of pollen grains of six birch species (Betula utilis Doorenbos, B. dahurica, B. maximowicziana, B. pendula, B. pubescens and B. humilis) were examined to verify which of these features allow distinguishing them in a more unambiguous way. For this purpose, scanning electron microscopy and light microscopy, as well as Fourier transform infrared (FTIR) spectroscopy and curve-fitting analysis of amide I profile, were performed. The microscopy images show that the pollen grains of B. pubescens, B. pendula and B. humilis are similar in diameter and significantly smaller than those of others species, with the largest diameter observed for B. utilis Doorenbos. However, the results obtained from FTIR spectroscopy indicate that the chemical compositions of B. pubescens and B. pendula are similar, but B. humilis is outlaying. Summarizing, it is not possible to unambiguously state, which feature or which technique is the best for differentiating between the six chosen birch species. However, the study showed that both techniques have potential for identification of birch pollen species.     

Airborne pollen in the El-Hadjar town (Algeria NE)

The diversity of airborne pollen grains in El-Hadjar town (northeast Algeria) was measured for 1 year, from July 1, 2012 to June 30, 2013, by means of the gravimetric method using Durham apparatus. The total number of pollen grains/cm² was calculated from slides that were changed daily. This aerobiological study documented the air concentration of pollen from 50 taxa, where 28 belonged to arboreal and 22 to non-arboreal taxa. The percentage of pollen from arboreal and non-arboreal taxa was 56 and 44 %, respectively. From the list, the major collected taxa causing allergy in humans dominant in the Mediterranean area were Cupressaceae (14.86 %), Olea sp. (7.18 %), Casuarina sp. (6.44 %), and Fraxinus sp. (3.83 %) among arboreal plants, whereas for the non-arboreal plants Poaceae (23.20 %), Mercurialis sp. (12.58 %), Plantago sp. (1.69 %), Urticaceae (0.95 %), and Chenopodiaceae (0.85 %). The highest pollen counts occurred in the period from February to April. The pollen calendar for the region presented in this paper may be a useful tool for allergologists and botanical awareness.     

Cryopreservation of <Emphasis Type="Italic">Citrus</Emphasis> anthers in the National Crop Genebank of China

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.     

Rearing system for the predatory phytoseiid <Emphasis Type="Italic">Euseius concordis</Emphasis> (Acari: Phytoseiidae)

Several species of predatory mites, especially those of the family Phytoseiidae, are potentially useful for the control of pest mites and insects. Among the phytoseiids, Euseius concordis (Chant), a species commonly found in South America, has been studied for possible use as biological control agent of pest mites. Given that Euseius species are known to feed on plant leaves and on pollen, the objective of this study was to determine plant species and pollen sources suitable to establish a pilot method of production of that species, based on a set of comparisons in the laboratory. Out of four plant species evaluated in the study, higher survivorship of E. concordis females in the absence of supplementary food was observed on leaflets of Canavalia ensiformis L. Out of two pollen types, higher survivorship was obtained on pollen of Typha domingensis L. In a subsequent step, the population of E. concordis increased 19.3× within 21 days when that pollen of T. domingensis was offered to the predator on plantlets of C. ensiformis, at 25.0 ± 1 °C, 70.0 ± 10% RH and 12 h photophase. Future studies may confirm the economic viability of this setup for the mass production of E. concordis.     

Indoor and outdoor pollen concentrations in private and public spaces during the <Emphasis Type="Italic">Betula</Emphasis> pollen season

Although the number of studies of pollen concentrations inside and outside buildings is increasing, little is known about the efficiency of penetration of pollen from outdoor to indoor air, and further. We studied indoor and outdoor pollen concentrations in the town of Lappeenranta and in the municipality of Rautjärvi in SE Finland from May 3–23, 2004, i.e. throughout the Betula pollen season, and assessed the risk of exposure to pollen grains. Pollen concentrations were measured inside and outside a block of flats, a detached house, and the regional central hospital, using rotorod-type samplers; in the town of Joutseno data were compared with Burkard counts. Outdoor concentrations of Betula pollen grains ranged between low and abundant (0–855 grains m^?3). The corresponding indoor concentrations near the main front doors varied from low to moderate (0–17 grains m^?3) in the central hospital and were low (<10 grains m^?3) in both residential buildings. Indoor concentrations further from the main front door were low (<10 grains m^?3) at all study sites. The concentrations of Betula pollen decreased substantially from outdoors to indoors, and further toward the centre of the building, probably indicating relatively poor penetrating properties of the pollen grains and/or the short-lived presence of pollen grains in indoor air. The concentrations of Betula pollen inside the buildings during the peak flowering period were mostly at a level barely inducing reactions even in the most sensitive persons.     

Weathering the storm: how lodgepole pine trees survive mountain pine beetle outbreaks

Climate change leads to phenology shifts of many species. However, not all species shift in parallel, which can desynchronize interspecific interactions. Within trophic cascades, herbivores can be top–down controlled by predators or bottom–up controlled by host plant quality and host symbionts, such as plant-associated micro-organisms. Synchronization of trophic levels is required to prevent insect herbivore (pest) outbreaks. In a common garden experiment, we simulated an earlier arrival time (~2 weeks) of the aphid Rhopalosiphum padi on its host grass Lolium perenne by enhancing the aphid abundance during the colonization period. L. perenne was either uninfected or infected with the endophytic fungus Epichloë festucae var. lolii. The plant symbiotic fungus produces insect deterring alkaloids within the host grass. Throughout the season, we tested the effects of enhanced aphid abundance in spring on aphid predators (top–down) and grass–endophyte (bottom–up) responses. Higher aphid population sizes earlier in the season lead to overall higher aphid abundances, as predator occurrence was independent of aphid abundances on the pots. Nonetheless, after predator occurrence, aphids were controlled within 2 weeks on all pots. Possible bottom–up control of aphids by increased endophyte concentrations occurred time delayed after high herbivore abundances. Endophyte-derived alkaloid concentrations were not significantly affected by enhanced aphid abundance but increased throughout the season. We conclude that phenology shifts in an herbivorous species can desynchronize predator–prey and plant–microorganism interactions and might enhance the probability of pest outbreaks with climate change.