Pollen Particles Research Articles

Combining Mie–Raman and fluorescence observations: a step forward in aerosol classification with lidar technology

Abstract. The paper presents an approach to revealing the variability in aerosol type, at high spatiotemporal resolution, by combining fluorescence and Mie–Raman lidar observations. The multiwavelength Mie–Raman lidar system in operation at the ATOLL (ATmospheric Observation at liLLe) platform, Laboratoire d'Optique Atmosphérique, University of Lille, has included, since 2019, a wideband fluorescence channel allowing the derivation of the fluorescence backscattering coefficient βF. The fluorescence capacity GF, which is the ratio of βF to the aerosol backscattering coefficient, is an intensive particle property, strongly changing with aerosol type, thus providing a relevant basis for aerosol classification. In this first stage of research, only two intensive properties are used for classification, namely the particle depolarization ratio at 532 nm, δ532, and the fluorescence capacity, GF. These properties are considered because they can be derived at high spatiotemporal resolution and are quite specific to each aerosol type. In particular, in this study, we use a δ532–GF diagram to identify smoke, dust, pollen, and urban aerosol particles. We applied our new classification approach to lidar data obtained during the 2020–2021 period, which includes strong smoke, dust, and pollen episodes. The particle classification was performed with a height resolution of about 60 m and temporal resolution better than 8 min.

Plant‐Based Substrate Materials for Flexible Green Electronics

AbstractWith the increasing use of soft and flexible electronics, there is a growing need to develop substrate materials that mitigate potential environmental risks associated with non‐degradable electronics waste from synthetic substrate materials. To address this issue, the authors develop a novel, 2D plant‐based substrate termed “sporosubstrate”, which is made of non‐allergenic natural pollen. The pollen particle has a double‐layered architecture with an ultra‐tough sporopollenin exine, and a soft cellulose intine is engineered through an eco‐friendly process. In this manner, a readily available, economical, biodegradable, and biocompatible microgel can be prepared. This microgel can be used to create a variety of flexible shapes with customized mechanical, geometrical, electronic, and functional properties and performance characteristics such as thermal, chemical, and mechanical stability and optical transparency. Moreover, the authors demonstrate here different applications of the flexible natural substrate made of pollen microgel for use in electronic devices for health monitoring and wearable wireless heating. The results of this work point to opportunities for the development of a new class of flexible green electronics based on plant‐based materials in applications such as wearable sensors, implantable devices, and soft robotics.

The diurnal and seasonal variability of ice-nucleating particles at the High Altitude Station Jungfraujoch (3580 m a.s.l.), Switzerland

Abstract. Cloud radiative properties, cloud lifetime, and precipitation initiation are strongly influenced by the cloud phase. Between ∼ 235 and 273 K, ice-nucleating particles (INPs) are responsible for the initial phase transition from the liquid to the ice phase in cloud hydrometeors. This study analyzes immersion-mode INP concentrations measured at 243 K at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.) between February 2020 and January 2021, thereby presenting the longest continuous, high-resolution (20 min) data set of online INP measurements to date. The high time resolution and continuity allow us to study the seasonal and the diurnal variability of INPs. After exclusion of special events, like Saharan dust events (SDEs), we found a seasonal cycle of INPs, highest in April (median in spring 3.1 INP std L−1) followed by summer (median: 1.6 INP std L−1) and lowest in fall and winter (median: 0.5 and 0.7 INP std L−1, respectively). Pollen or subpollen particles were deemed unlikely to be responsible for elevated INP concentrations in spring and summer, as periods with high pollen loads from nearby measurement stations do not coincide with the periods of high INP concentrations. Furthermore, for days when the site was purely in the free troposphere (FT), no diurnal cycle in INP concentrations was observed, while days with boundary layer intrusions (BLIs) showed a diurnal cycle. The seasonal and diurnal variability of INPs during periods excluding SDEs is within a factor of 7 and 3.3, respectively, significantly lower than the overall variability observed in INP concentration including SDEs of more than 3 orders of magnitude, when peak values result from SDEs. The median INP concentration over the analyzed 12 months was 1.2 INP std L−1 for FT periods excluding SDEs and 1.4 INP std L−1 for both FT and BLI, and including SDEs, reflecting that despite SDEs showing strong but comparatively brief INP signals, they have a minor impact on the observed annual median INP concentration.

Simulation and experiment of tomato pollen particles release and motion characteristics based on optical flow target tracking method

Due to the reduction of the amount of natural pollinators, it is necessary to study the method and mechanism of greenhouse tomato mechanical vibration supplementary pollination. The release process and motion characteristics of pollen particles are very important for precision tomato supplementary pollination. In this paper, the pollen particles release and motion simulation model based on discrete element and hydrodynamics coupling method is established. The pollen particles position and trajectories detection algorithm based on optical flow target tracking method is designed. Compared with the detection results of high speed photography system, the relative error of pollen distribution range angle and pollen motion velocity of the simulation model is 7.94% and 8.87%, which shows the rationality and reliability of the established simulation model. Through the comprehensive analysis of the high speed photography observation results and simulation results, it can be concluded that the trend of pollen particles trajectories are vertical downward with random direction change, and greater vibration amplitude cause greater distribution range angle of pollen particles. There is no obvious trend of velocity change during the release process of each single pollen particle, and the relationship between vibration amplitude and average velocity of pollen particles is not obvious. The research results and the established model of this paper provide a mechanism basis for tomato mechanical vibration supplementary pollination and lay a foundation for the optimization of mechanical pollination method.

Mass concentration measurements of autumn bioaerosol using low-cost sensors in a mature temperate woodland free-air carbon dioxide enrichment (FACE) experiment: investigating the role of meteorology and carbon dioxide levels

Abstract. Forest environments contain a wide variety of airborne biological particles (bioaerosols), including pollen, fungal spores, bacteria, viruses, plant detritus, and soil particles. Forest bioaerosol plays a number of important roles related to plant and livestock health, human disease and allergenicity, and forest and wider ecology and are thought to influence biosphere–atmosphere interactions via warm and cold cloud formation. Despite the importance of bioaerosols, there are few measurements of forest aerosol, and there is a lack of understanding of how climate change will affect forest bioaerosol in the future. We installed low-cost optical particle counters (OPCs) to measure particles in the size range between 1 and 10 µm (PM10–PM1) for a period of 2 months in autumn 2018 at the Birmingham Institute of Forest Research (BIFoR) free-air carbon dioxide enrichment (FACE) facility. In the paper, we propose that the PM10–PM1 (particulate matter) metric is a good proxy for bioaerosols because of the bioaerosol representative size range, the location of the study site (a woodland in a rural location), the field measurement taking place during the season of peak fungal activity, and the low hygroscopicity of the particles measured. The BIFoR FACE facility fumigates three 700 m2 areas of the forest with an additional 150 ppm CO2 above ambient levels with minimal impacts on other potential environmental drivers such as temperature, humidity, and wind. This experimental set-up enabled us to investigate the effect of environmental variables, including elevated CO2 (eCO2), on bioaerosol proxy concentrations and to evaluate the performance of the low-cost OPCs in a forested environment. Operating the low-cost OPCs during autumn 2018, we aimed to capture predominantly the fungal bioaerosol season. Across the experimental duration, the OPCs captured both temporal and spatial variation in bioaerosol concentrations. Aerosol concentrations were affected by changing temperatures and wind speeds but, contrary to our initial hypothesis, not by relative humidity. We detected no effect of the eCO2 treatment on total bioaerosol concentrations, but a potential suppression of high-concentration bioaerosol events was detected under eCO2. In-canopy atmospheric dispersion modelling indicates that the median spore dispersion distance is sufficiently small that there is little mixing between treatment and control experiments. Our data demonstrate the suitability of low-cost OPCs, interpreted with due caution, for use in forests and so opens the possibility of forest bioaerosol monitoring in a wider range of habitats to a wider range of researchers at a modest cost.

One Year in the Extreme Isolation of Antarctica—Is This Enough to Modulate an “Allergic” Sensitization?

(1) Background: After spending a year wintering in Antarctica, individual expedition members have reported increased or even new allergic reactions to environmental allergens after their return. (2) Methods: Blood samples from five overwintering crews were analyzed using the chip based multiplex ALEX Allergy Explorer (MacroArray Diagnostics GmbH, Austria). (3) Results: About one third of the 39 participants displayed specific IgEs against pollen. In most individuals, kinetics showed a reduction in the specific IgE at the time about nine months after deployment to Antarctica. Five participants had the highest specific IgE levels after returning to the “normal” world. The examination of the specific IgE relative to house dust mites and storage mites showed different kinetics. Six out of 10 had the highest specific IgE concentrations at the inner Antarctic measurement time point. These data corresponded well to the general situation in the stations. At the stations themselves, there were almost no pollen particle load, especially at Concordia. (4) Conclusions: Antarctic long-term confinement can induce an altered immune function, which is in some individuals pronounced after return to the familiar allergen environment. Future prospective studies in larger cohorts are needed to further specify these first results.

Evaluation of Pollen Adhesion to Verofilcon-A Soft Contact Lenses

Purpose: A new 1-day disposable soft contact lens (SCL), verofilcon-A, constructed of silicone hydrogel material, has recently become available in Japan. This SCL has a very smooth surface produced by using the SMARTSURFACE ® Technology, and it was expected that pollen particles and protein components would not adhere easily to its surface. We examined the degree of pollen adhesion to the surface of the verofilcon-A material SCL and compared the results with those of other 1-day disposable SCLs (1DSCL). Methods: To determine the number of pollen grains attached to the surface of different types of SCLs, 0.01 mg/ml of cedar pollen solution was dropped onto the surface of 13 types of 1DSCL. After 24 h, each 1DSCL was rinsed in a shaker and washed five times with saline (n = 10 for each 1DSCL type). The number of pollen particles adhered to the 1DSCL and the percentage of surface area occupied by pollen was determined. Results: The number of pollen particles on the 1DSCLs ranged from 0 to 185 in the 200 × 200 µm area. The number of particles was lowest in the delefilcon-A and verofilcon-A SCLs with 0 particles, and the number was higher in the other 11 1DSCLs. The number of pollen particles was negatively correlated with the water content (r = −0.48), oxygen permeability (Dk; r = −0.43), oxygen transmissibility (r = −0.42), and center thickness (r = −0.33) of the 1DSCLs. The pollen adhesion area ranged from 0.0% to 3.1% and was lowest in the delefilcon-A and verofilcon-A 1DSCLs. There were significant differences in the pollen adhesion area between colored 1DSCLs (2.73 ± 1.97%) and clear 1DSCLs (1.03 ± 1.01%, P<0.001) and between hydroxyethyl methacrylate-based 1DSCLs (1.84 ± 1.45%) and silicone hydrogel-based 1DSCLs (0.05 ± 0.16%, P<0.001). Conclusion: These findings indicate that the verofilcon-A 1DSCL processed with SMARTSURFACE™ Technology is an excellent option for SCL users with allergic conjunctivitis during the high pollen season.

Introduction and simulation of a small electro cyclone for collecting indoor pollen particles

Since pollen is a major cause of allergies, collecting it from the environment seems to be beneficial. In this study, a new electro cyclone is proposed and simulated for collecting pollen from indoor environments. In this cyclone, an electrode is added to a traditional cyclone to apply additional force to particles that have already been pre-charged. The obtained results showed an increase of 14, 33 and 53 (%) in separation efficiency for pollen particle sizes of 10, 8 and 6 µm. Moreover, at lower inlet velocity, high electrostatic voltage enhances the efficiency, with the effect being more noticeable on finer particles. The validity of the simulation results was confirmed by comparing it with experimental and simulation findings of our previous study. It is also concluded that small electro cyclone systems are more efficient in removing fine particles from various gas streams.

Assessment of real-time bioaerosol particle counters using reference chamber experiments

Abstract. This study presents the first reference calibrations of three commercially available bioaerosol detectors. The Droplet Measurement Technologies WIBS-NEO (new version of the wideband integrated bioaerosol spectrometer), Plair Rapid-E, and Swisens Poleno were compared with a primary standard for particle number concentrations at the Federal Institute for Metrology (METAS). Polystyrene (PSL) spheres were used to assess absolute particle counts for diameters from 0.5 to 10 µm. For the three devices, counting efficiency was found to be strongly dependent on particle size. The results confirm the expected detection range for which the instruments were designed. While the WIBS-NEO achieves its highest efficiency with smaller particles, e.g. 90 % for 0.9 µm diameter, the Plair Rapid-E performs best for larger particles, with an efficiency of 58 % for particles with a diameter of 10 µm. The Swisens Poleno is also designed for larger particles but operates well from 2 µm. However, the exact counting efficiency of the Poleno could not be evaluated as the cut-off diameter range of the integrated concentrator unit was not completely covered. In further experiments, three different types of fluorescent particles were tested to investigate the fluorescent detection capabilities of the Plair Rapid-E and the Swisens Poleno. Both instruments showed good agreement with the reference data. While the challenge to produce known concentrations of larger particles above 10 µm or even fresh pollen particles remains, the approach presented in this paper provides a potential standardised validation method that can be used to assess counting efficiency and fluorescence measurements of automatic bioaerosol monitoring devices.

An integrated system for automated measurement of airborne pollen based on electrostatic enrichment and image analysis with machine vision

Here we describe an automated and compact pollen detection system that integrates enrichment, in-situ detection and self-cleaning modules. The system can achieve continuous capture and enrichment of pollen grains in air samples by electrostatic adsorption. The captured pollen grains are imaged with a digital camera, and an automated image analysis based on machine vision is performed, which enables a quantification of the number of pollen particles as well as a preliminary classification into two types of pollen grains. In order to optimize and evaluate the system performance, we developed a testing approach that utilizes an airflow containing a precisely metered amount of pollen particles surrounded by a sheath flow to achieve the generation and lossless transmission of standard gas samples. We studied various factors affecting the pollen capture efficiency, including the applied voltage, air flow rate and humidity. Under optimized conditions, the system was successfully used in the measurement of airborne pollen particles within a wide range of concentrations, spanning 3 orders of magnitude.

Identification of Pollens From Polymer Particles Levitating in an RF Plasma by the Polarization Imaging Method

Levitation of pollen particles has been demonstrated in a radio frequency (RF) plasma. Pollen particles from Japanese cypress are levitated to various heights from lower electrode, where they spontaneously form quasi ordered state. Levitating pollen particles are identified from divinylbenzene particles in real-time using the polarization imaging technique.

Inhalation and deposition of spherical and pollen particles after middle turbinate resection in a human nasal cavity

Middle turbinate resection significantly alters the anatomy and redistributes the inhaled air. The superior half of the main nasal cavity is opened up, increasing accessibility to the region. This is expected to increase inhalation dosimetry to the region during exposure to airborne particles. This study investigated the influence of middle turbinate resection on the deposition of inhaled pollutants that cover spherical and non-spherical particles (e.g. pollen). A computational model of the nasal cavity from CT scans, and its corresponding post-operative model with virtual surgery performed was created. Two constant flow rates of 5 L/min, and 15 L/min were simulated under a laminar flow field. Inhaled particles including pollen (non-spherical), and a spherical particle with reference density of 1000 kg/m3 were introduced in the surrounding atmosphere. The effect of surgery was most prominent in the less patent cavity side, since the change in anatomy was proportionally greater relative to the original airway space. The left cavity produced an increase in particle deposition at a flow rate of 15 L/min. The main particle deposition mechanisms were inertial impaction, and to a lesser degree gravitational sedimentation. The results are expected to provide insight into inhalation efficiency of different aerosol types, and the likelihood of deposition in different nasal cavity surfaces.

An Intrinsically Micro-/Nanostructured Pollen Substrate with Tunable Optical Properties for Optoelectronic Applications.

There is broad interest in developing photonically active substrates from naturally abundant, minimally processed materials that can help to overcome the environmental challenges of synthetic plastic substrates while also gaining inspiration from biological design principles. To date, most efforts have focused on rationally engineering the micro- and nanoscale structural properties of cellulose-based materials by tuning fibril and fiber dimensions and packing along with chemical modifications, while there is largely untapped potential to design photonically active substrates from other classes of natural materials with distinct morphological features. Herein, the fabrication of a flexible pollen-derived substrate is reported, which exhibits high transparency (>92%) and high haze (>84%) on account of the micro- and nanostructure properties of constituent pollen particles that are readily obtained from nature and require minimal extraction or processing to form the paper-like substrate based on colloidal self-assembly. Experiments and simulations confirm that the optical properties of the pollen substrate are tunable and arise from light-matter interactions with the spiky surface of pollen particles. In a proof-of-concept example, the pollen substrate is incorporated into a functional perovskite solar cell while the tunable optical properties of the intrinsically micro-/nanostructured pollen substrate can be useful for a wide range of optoelectronic applications.

CLUSTER COMPOSITION OF POLLEN PARTICLES OF ANEMOPHILIC PLANTS ENTERING ATMOSPHERE

A study is made on pollen emission into atmosphere of 21 species of anemophilous plants ( Betula divaricata Ledeb., Betula costata Trautv., Betula davurica Pall., Betula fruticosa Pall., Ulmus japonica (Rehd.)Sarg., Salix acutifolia Willd., Salix cinerea L., Salix purpurea L., Salix rosmarinifolia L., Alnus glutinosa (L.) Gaertn., Poa alpina L., Arrhenatherum elatius (L.) J. Presl & C. Presl, Briza maxima L., Deschampsia cespitosa (L.) P. Beauv., Urtica urens L., Carex altaica (Gorodkov) V.I. Krecz., Carex pallescens L., Carex flacca Schreb., Carex vesicaria L., Carex diluta M. Bieb., Plantago lanceolata L.), exposed by the Central Siberian Botanical Garden, SB RAS. These plants are widely spread over the territory of the Russian Federation and produce great amounts of allergenic pollen. The proportion of clusters of two or more pollen grains from the total number of pollen particles entering the atmosphere during the flowering periods of these plant species is estimated. It was shown that such clusters in significant quantities were formed in all series of experiments. At the same time, the proportion of pollen grains in their composition could reach 95% of the total number of pollen grains entering the atmosphere.

SEDIMENTATION VELOCITY OF POLLEN PARTICLES OF ANEMOPHILIC PLANTS GROWING ON TERRITORY OF THE CSBG SB RAS

The settling of pollen particles of four species of anemophilic plants ( Populus alba L., Salix hybrida , Miscanthus sinensis Andersson, Chosenia arbutifolia (Pall.) A. K. Skvortsov) growing in the exposition of the CSBS SB RAS was investigated. These species are widely used in landscaping cities of the Novosibirsk region and are producers of impressive amounts of allergenic pollen, which can be carried by the wind over significant distances. The presence of a significant proportion of clusters, which include two or more pollen grains, is shown. Settling rates were determined as individual pollen grains of these plant species and their clusters, which included from two to six pollen grains. Dependence of cluster sedimentation rate on number of pollen grains included in it is established.

Lidar depolarization ratio of atmospheric pollen at multiple wavelengths

Abstract. Lidar observations during the pollen season 2019 at the European Aerosol Research Lidar Network (EARLINET) station in Kuopio, Finland, were analyzed in order to optically characterize atmospheric pollen. Pollen concentration and type information were obtained by a Hirst-type volumetric air sampler. Previous studies showed the detectability of non-spherical pollen using depolarization ratio measurements. We present lidar depolarization ratio measurements at three wavelengths of atmospheric pollen in ambient conditions. In addition to the depolarization ratio detected with the multiwavelength Raman polarization lidar PollyXT at 355 and 532 nm, depolarization measurements of a co-located Halo Doppler lidar at 1565 nm were utilized. During a 4 d period of high birch (Betula) and spruce (Picea abies) pollen concentrations, unusually high depolarization ratios were observed within the boundary layer. Detected layers were investigated regarding the share of spruce pollen to the total pollen number concentration. Daily mean linear particle depolarization ratios of the pollen layers on the day with the highest spruce pollen share are 0.10 ± 0.02, 0.38 ± 0.23 and 0.29 ± 0.10 at 355, 532 and 1565 nm, respectively, whereas on days with lower spruce pollen share, depolarization ratios are lower with less wavelength dependence. This spectral dependence of the depolarization ratios could be indicative of big, non-spherical spruce pollen. The depolarization ratio of pollen particles was investigated by applying a newly developed method and assuming a backscatter-related Ångström exponent of zero. Depolarization ratios of 0.44 and 0.16 at 532 and 355 nm for the birch and spruce pollen mixture were determined.

Empirical formulation for multiple groups of primary biological ice nucleating particles from field observations over Amazonia

AbstractTo resolve the various types of biological ice nuclei (IN) with atmospheric models, an extension of the empirical parameterization (EP) (Phillips et al. 2008; 2013) is proposed to predict the active IN from multiple groups of primary biological aerosol particles (PBAPs). Our approach is to utilize coincident observations of PBAP sizes, concentrations, biological composition, and ice-nucleating ability. The parameterization organizes the PBAPs into five basic groups: fungal spores, bacteria, pollen, viral particles, plant/animal detritus, algae, and their respective fragments. This new biological component of the EP was constructed by fitting predicted concentrations of PBAP IN to those observed at the Amazon Tall Tower Observatory (ATTO) site located in the central Amazon. The fitting parameters for pollen and viral particles, plant/animal detritus, which are much less active as IN than fungal and bacterial groups, are constrained based on their ice nucleation activity from the literature. The parameterization has empirically derived dependencies on the surface area of each group (except algae), and the effects of variability in their mean sizes and number concentrations are represented via their influences on the surface area. The concentration of active algal IN is estimated from literature-based measurements.Predictions of this new biological component of the EP are consistent with previous laboratory and field observations not used in its construction. The EP scheme was implemented in a 0D parcel model. It confirms that biological IN account for most of the total IN activation at temperatures warmer than −20°C and at colder temperatures dust and soot become increasingly more important to ice nucleation.

Environmental implications of past socioeconomic events in Greater Poland during the last 1200 years. Synthesis of paleoecological and historical data

We explored the past environmental history inferred from a fen located in northwestern Poland, in a historically important location. Pollen, plant macrofossils, micro- and macrocharcoal particles, and non-pollen palynomorphs were analyzed continuously in a 1-cm resolution, supplemented with archeological data and historical written sources. The last 1200-year environmental history of the fen was supported with accelerator mass spectrometry (AMS) radiocarbon (14C) dating (19 dates per 172 cm of the profile) and validated by 59 210 Pb dates. Our research showed that primeval oak–hornbeam forests near the Kazanie mire disappeared gradually, starting from 1035 ± 20 cal. yr CE, due to the economic development of the newly formed Polish (Piast) statehood. The pollen data revealed no shortage of oak timber during the 11th century, as recorded by previous studies in the area between Poznań and Gniezno. The Czech invasion in 1039 CE, which was associated with mass depopulation and domestic crisis, seemed to be manifested by the increase of pioneer Betula taking advantage of weaker human impact. Substantial land-use changes started with the further development of Polish statehood between the 15th and the 16th century CE, as reflected by cultivated land, ruderal, and meadow and pasture pollen indicators, as well as the rise of microcharcoal influx. The economy of Poland was disrupted by a noticeable socioeconomic collapse in the 17th century CE, which caused depopulation (by approximately 67.5%) and a decline in arable land (by 35%). Paleoecological data reflect this socio-environmental crisis with a decrease in all anthropogenic indicators, rapid forest regeneration, and secondary succession of pine on the abandoned land. According to palynological data, rapid landscape transformation due to agricultural reforms and industrialization commenced in the 19th century CE and was associated with the expansion of pastures, meadows, and arable lands. The following rapid decrease of cultivated land pollen indicators in 1940 ± 10 cal. yr CE is linked with the economic collapse after World War II and/or the implementation of new crops which produce less pollen.

Pollen-Mimetic Metal-Organic Frameworks with Tunable Spike-Like Nanostructures That Promote Cell Interactions to Improve Antigen-Specific Humoral Immunity.

The exine capsules of pollen particles exhibit a variety of characteristic surface morphologies that promote their cell interactions; their use as antigen carriers for vaccination has been proposed. However, the allergy-causing substances in pollen particles may not all be removed, even by vigorous chemical treatments. To resolve this issue, this work develops systemic approaches for synthesizing pollen-mimetic metal-organic frameworks (MOFs), which comprise aluminum (Al) ions and an organic linker (2-aminoterephthalic acid), with tunable spike-like nanostructures on their surfaces. The as-synthesized MOFs act not only as a delivery vehicle that carries a model antigen (ovalbumin, OVA) but also as an adjuvant (Al). Scanning and transmission electron microscopies images reveal that the aspect ratio of the nanospikes that are grown on the MOFs can be controlled. A higher aspect ratio of the nanospikes on the MOFs is associated with greater cell attachment and faster and more efficient phagocytosis in cells, which results in greater expressions of pro-inflammatory cytokines. Consequently, a more robust immune response against the antigen of interest is elicited. These findings have broad implications for the rational design of the future antigen/adjuvant-presenting particles for vaccination.

Investigation of Fungal Strains Composition in Fruit Pollens for Artificial Pollination

Plants pollination are conducted through various pollinators such as wind, animals, and insects. Recently, the necessity for artificial pollination is drawing attention as the proportion of natural pollinators involved is decreasing over the years. Likewise, the trade in pollen for artificial pollination is also increasing worldwide. Through these imported pollens, many unknown microorganisms can flow from foreign countries. Among them, spores of various fungi present in the particles of pollen can be dispersed throughout the orchard. Therefore, in this study, the composition of fungal communities in imported pollen was revealed, and potential ecological characteristics of the fungi were investigated in four types of imported pollen. Top 10 operational taxonomic unit (OTU) of fungi were ranked among the following groups: Alternaria sp., Cladosporium sp., and Didymella glomerata which belong to many pathogenic species. Through FUNGuild analysis, the proportion of OTUs, which is assumed to be potentially plant pathogens, was higher than 50%, except for apple pollen in 2018. Based on this study of fungal structure, this information can suggest the direction of the pollen quarantine process and contribute to fungal biology in pollen