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Euphrasia stricta D. Wolff ex J. F. Lehm. (Orobanchaceae) is a representative of plants that are widely used in folk medicine, phytomedicine, and homeopathy. The medicinal raw material derived from the drug eyebright is applied primarily in treatment of ophthalmic diseases. The investigations of trichomes in drug eyebright (Euphrasia stricta D. Wolff ex J. F. Lehm) were conducted in 2010-2011. Using light microscopy and scanning electron microscopy, their location and morphological and anatomical features were identified. Three types of non-glandular trichomes were found: short unicellular, long 1-2 celled, and long 2-celled with wall ornamentation. Additionally, 7 types of glandular trichomes were found; these included: unicellular clavate, 2-3-celled clavate, capitate with a unicellular head and a 3-celled stalk, capitate with a unicellular head and a 2-celled stalk, capitate with a 2-celled head, conical papillae, and ribbon-like trichomes with wall thickening. [ABSTRACT FROM AUTHOR]

Aesculus hippocastanum L. is an ornamental tree appreciated for its beautiful flowers and leaves. The flowers of this species contain secondary metabolites exhibiting pharmacological activity. They also produce essential oils and coloured "nectar guides", which enable insects to reach nectar and pollen. The aim of the study was to investigate the types and characteristics of chestnut flower trichomes, which may contain biologically active substances. The analyses were performed using light, fluorescence, and scanning electron microscopy. Three types of trichomes were found on the sepals and the surface of the ovary, whereas the corolla petals exhibited two types of hairs and papillae. The hairs differ in terms of their length and number of cells. The perianth and pistil had no capitate hairs, whereas the ovary exhibited the presence of colleters. Histochemical assays revealed that all the types of trichomes and papillae contained lipids or essential oils; hence, they can be classified as glandular structures. The "nectar guides" were characterised by higher density of secretory hairs than that on the rest of the petal surface, which implies that these petal fragments may emit stronger fragrance. [ABSTRACT FROM AUTHOR]

Many plants develop in the petal epidermis papillae emitting essential oils. In species of the genus Allium, papillae occur in the ovary epidermis. The aim of this study was to determine the structure of papillae in Allium karataviense Regel and to perform histochemical tests that would allow the components of their secretion to be investigated, mainly the presence of essential oils. Examination was performed using light and scanning electron microscopy. It was found that in conical papillae, with a height of about 83 μm, there were large cell nuclei, a thick outer wall with a layer of striated cuticle, and a varying degree of cell vacuolation, depending on the age of the ovary. Using histochemical reactions, we demonstrated neutral lipids, acid lipids and pectins to occur in the papillae. Neutral lipids are characteristic of essential oils. [ABSTRACT FROM AUTHOR]

The present study is a continuation of our research on the structure of healthy leaves of Aesculus hippocastanum and leaves damaged by larvae of Cameraria ohridella. In this study, the epidermal micromorphology of both leaf surfaces in A. hippocastanum was investigated by scanning electron microscopy (SEM). Light microscopy was used to examine on which side of the leaf blades eggs of Cameraria ohridella were laid. The characteristic features of the adaxial and abaxial epidermis were shown. In the hypostomatic leaves of the studied species, the stomata occurred at a density of 173 x mm-2 and they represented the cyclocytic type. A striated layer of the cuticle was observed only in the adaxial epidermis in which glandular hairs were also present along the midribs. Non-glandular trichomes grew only on the surface of the midribs or in their axils in the abaxial epidermis. We found eggs of C. ohridella only on the adaxial surface of the epidermis. Using SEM, we also observed in the mines leaf tissues damaged by C. ohridella. We found palisade parenchyma to be absent, whereas in the spongy parenchyma there could be seen large intercellular spaces and at places a dense mass of organic matter, formed from damaged cells and larval excrement. The vascular bundles and calcium oxalate crystals remained in the feeding places. We found numerous bacteria, fungal spores and hyphae as well as cleistothecia of Erysiphales in the mines on the surface of the damaged mesophyll. The glandular trichomes occurring only locally on the leaves, the relatively thin cell walls of the epidermis and a not well-developed cuticle layer on their surface do not protect sufficiently these leaves against the invasion of C. ohridella. On the other hand, damaged tissue areas are a convenient place for the growth of bacteria and fungi. [ABSTRACT FROM AUTHOR]

The article focuses on a research conducted to examine the ultrastructure and anatomical characteristics of nectary and odour-producing tissues presents on petals of the plant Myosotis scorpioides' flowers with scanning and transmission electron microscopy technique. It mentions presence of multiple plastids, large cell nuclei, and rough endoplasmic reticulum (ER) in nectary cells' ultrastructure and secretion of essential oils from papillae present in the petal's adaxial epidermis.

The article focuses on research conducted to examine the micromorphology and topography of Aesculus x carnea's (A. xcarnea) nectaries using scanning electron microscopy. Topics discussed include abundant secretion of nectar by nectary glands of flower, formation of incomplete ring around staminal filaments' base, covering only four stamens out of seven in the flower, by nectary gland, as per the study, and classification of stomata as cyclocytic type as its is surrounded by 6 to 7 guard cells.

The aim of this study was to verify which parameters of the atmospheric pollen season can distinguish between pollen types, the ranges of parameter values that delineate classes of taxa, and finally which taxa are similar to others within the domain of these parameter ranges. Decision tree algorithms were applied and the best tree was chosen to describe the rules of pollen classification. The study material consisted of airborne pollen grains of the following eight taxa: Alnus, Betula, Carpinus, Corylus, Cupressaceae, Fraxinus, Populus and Ulmus. Research was conducted in Lublin in eastern Poland during 2001-2013. The following six atmospheric pollen season parameters were analyzed: season start and end, duration, maximum daily pollen concentration, date of maximum pollen concentration, and the Seasonal Pollen Index (SPI). Four algorithms were used in data analysis and the J4.8 algorithm was chosen as the best for taxa classification, date of the end of season and the SPI value belonging to characteristics that served most to discriminate between pollen types. Based on the classification tree, the following four groups of taxa were identified: (i) Ulmus; (ii) Corylus, Alnus, Populus; (iii) Betula; and (iv) Carpinus, Fraxinus, Cupressaceae. [ABSTRACT FROM AUTHOR]

Flos Lamii albi has a high biological activity and is widely used in herbal medicine. The aim of the study was to characterize the secretory structures present in Lamium album subsp. album corolla and the location of phenolic compounds. Additionally, we carried out qualitative phytochemical analyses of flavonoids and phenolic acids. Light, fluorescence, and scanning electron microscopy were used to analyze the structure of the floral organs. The main classes of phenolic compounds and their localization were determined histochemically. Phytochemical analyses were performed with high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). Six types of glandular trichomes were found which contained flavonoids, phenolic acids, and tannins. The phytochemical studies demonstrated the presence of caffeic, chlorogenic, ferulic, gallic, p-coumaric, protocatechuic, syringic, gentisic, and vanillic phenolic acids as well as rutoside, isoquercetin, and quercetin flavonoids. The corolla in L. album subsp. album has antioxidant properties due to the presence of various polyphenols, as shown by the histo- and phytochemical analyses. The distribution and morphology of trichomes and the content of phenolic compounds in the corolla have taxonomic, pharmacognostic, and practical importance, facilitating the identification of the raw material. [ABSTRACT FROM AUTHOR]

The small flowers of Myosotis scorpioides are pollinated by various groups of insects feeding on their nectar accumulating at the base of the corolla tube. To date, only few studies have focused on the anatomy and ultrastructure of nectaries in plants from the family Boraginaceae. The aim of this study was to analyse the structure of the M. scorpioides nectary at different levels of organisation, with special emphasis on its ultrastructure, which has not been investigated so far. The studies were carried out with the use of light, fluorescence, scanning electron, and transmission electron microscopes. Undulated discoidal nectaries with a diameter of up to 0.9 mm and a height of about 0.2 mm were localised at the ovary base. There were numerous nectarostomata on the top and abaxial surfaces of the nectary. Phenolic compounds present in the nectary exhibited autofluorescence. The ultrastructural studies of nectary epidermis and secretory parenchyma cells revealed the presence of thin cell walls, different-sized vacuoles, medium-sized nuclei, plasmodesmata in the cell walls, and various types of chromoplasts. Numerous mitochondria were visible in close proximity to the plastids. Additionally, clusters of dictyosomes, well-developed rough ER profiles, and numerous ribosomes and different-sized vesicles often located near the cell walls were observed. Our study conducted at the subcellular level indicated high metabolic activity of the M. scorpioides nectary. The presence of phenolic compounds in the nectary may both serve as a protection of this part of the flower against biological factors and contribute to the intensification of the floral scent acting as a pollinator attractant., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The dataset presents a 43 year-long reanalysis of pollen seasons for three major allergenic genera of trees in Europe: alder (Alnus), birch (Betula), and olive (Olea). Driven by the meteorological reanalysis ERA5, the atmospheric composition model SILAM predicted the flowering period and calculated the Europe-wide dispersion pattern of pollen for the years 1980-2022. The model applied an extended 4-dimensional variational data assimilation of in-situ observations of aerobiological networks in 34 European countries to reproduce the inter-annual variability and trends of pollen production and distribution. The control variable of the assimilation procedure was the total pollen release during each flowering season, implemented as an annual correction factor to the mean pollen production. The dataset was designed as an input to studies on climate-induced and anthropogenically driven changes in the European vegetation, biodiversity monitoring, bioaerosol modelling and assessment, as well as, in combination with intra-seasonal observations, for health-related applications., (© 2024. The Author(s).)

Introduction and Objective: Species of the genus Artemisia (Asteraceae) are weeds and ruderal plants growing in northern temperate regions of the world. Many of them are used in medicine and the cosmetic industry and for culinary purposes. Pollen grains of plants of this genus contain the most important aeroallergens., Material and Methods: An aerobiological study conducted with the volumetric method in Lublin in 2001-2022. Trend lines for the season parameters were established. Spearman's correlation and stepwise regression analyses were carried out to determine relationships between various parameters of the pollen season and meteorological factors. PCA analysis was also carried out to visually compare the pollen seasons., Results: In Lublin, central-eastern Poland, the Artemisia pollen season lasted on average from the second ten days of July to the end of August, with its beginning depending on the temperature in April and May. The highest pollen concentrations were mainly recorded in the first half of August and were largely dependent on the mean temperature in June and July. The second peak in the pollen season recorded in September was associated with the presence of Artemisia annua pollen. Intense sunshine in June and the higher temperatures in June and July resulted in significant reduction in the Artemisia annual pollen sum (by 65%) over 22 years. Artemisia vulgaris is abundant in the Lublin region and contributes substantially to the amount of Artemisia pollen in the aeroplankton., Conclusions: The downward trend in the amount of Artemisia pollen was a result of the increase in temperatures observed in the summer months, and the declining rainfall rates. The global warming effect is extremely unfavourable for plants of Artemisia vulgaris, as they require moist soil substrates for growth.

Achillea millefolium L. herb and flowers have high biological activity; hence, they are used in medicine and cosmetics. The aim of this study was to perform morpho-anatomical analyses of the raw material, including secretory tissues, histochemical assays of the location of lipophilic compounds, and quantitative and qualitative analysis of essential oil (EO). Light and scanning electron microscopy techniques were used to analyse plant structures. The qualitative analyses of EO were carried out using gas chromatography-mass spectrometry (GC/MS). The results of this study showed the presence of exogenous secretory structures in the raw material, i.e., conical cells (papillae) on the adaxial surface of petal teeth and biseriate glandular trichomes on the surface flowers, bracts, stems, and leaves. Canal-shaped endogenous secretory tissue was observed in the stems and leaves. The histochemical assays revealed the presence of total, acidic, and neutral lipids as well as EO in the glandular trichome cells. Additionally, papillae located at the petal teeth contained neutral lipids. Sesquiterpenes were detected in the glandular trichomes and petal epidermis cells. The secretory canals in the stems were found to contain total and neutral lipids. The phytochemical assays demonstrated that the A. millefolium subsp. millefolium flowers contained over 2.5-fold higher amounts of EO (6.1 mL/kg) than the herb (2.4 mL/kg). The EO extracted from the flowers and herb had a similar dominant compounds: β-pinene, bornyl acetate, (E)-nerolidol, 1,8-cineole, borneol, sabinene, camphor, and α-pinene. Both EO samples had greater amounts of monoterpenes than sesquiterpenes. Higher amounts of oxygenated monoterpenes and oxygenated sesquiterpenoids were detected in the EO from the herb than from the flowers.

Lamium album is a native common plant growing in Eurasia. It is used in medicine and cosmetics and is highly valued in apiculture. The aim of the study was to investigate the structure of the floral nectary in three stages of flower development. Additionally, histochemical studies of the nectary and nectar guides present on the lower corolla lobe were carried out. No detailed analyses of nectary tissues in this species have been conducted to date. The present analyses were performed with the use of light, fluorescence, and scanning electron microscopy. The nectary gland in the flowers of Lamium album subsp. album formed an incomplete ring at the ovary base. The nectarostomata were arranged in clusters only in the adaxial epidermis of the anterior part of the nectary. During the secretory activity of the nectary (1st day of flowering), numerous small vacuoles and cells with large lobulate nuclei with surrounding plastid clusters were observed in the epidermis and glandular parenchyma cells. The vascular bundles contained xylem and phloem elements. Corolla wilting (3rd day of flowering) was accompanied by destructive changes in the nectary parenchyma, leading to the formation of empty spaces and appearance of cell remnants on the nectary surface. The histochemical analyses revealed the presence of starch and phenolic compounds as well as acidic and neutral lipids, which are characteristic of essential oils, in the nectary tissues. The nectar guides were composed of large yellow papillae containing phenolic compounds and acidic and neutral lipids, which were also present in glandular trichomes and abaxial parenchyma cells. The present study has demonstrated that the scent of Lamium album subsp. album flowers is produced with the involvement of essential oils contained in adaxial and abaxial epidermis cells, glandular trichomes, and nectary tissues., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Although lime trees have numerous benefits, they can pose a threat to allergy sufferers during the flowering period, as their pollen exhibits allergenic properties. This paper presents the results of 3 years of aerobiological research (2020-2022) carried out with the volumetric method in Lublin and Szczecin. A comparison of the pollen seasons in both cities revealed substantially higher concentrations of lime pollen in the air of Lublin than of Szczecin. In the individual years of the study, the maximum pollen concentrations were approximately 3-fold higher, and the annual pollen sum was about 2-3 times higher in Lublin than in Szczecin. Considerably higher lime pollen concentrations were recorded in both cities in 2020 than in the other years, which was probably associated with the 1.7-2.5 °C increase in the average temperature in April compared to the other two years. The maximum lime pollen concentrations were recorded during the last ten days of June or at the beginning of July in both Lublin and Szczecin. This period was associated with the greatest risk of pollen allergy development in sensitive subjects. The increased production of lime pollen in 2020 and in 2018-2019 with the increase in the mean temperature in April, reported in our previous study, may indicate a response of lime trees to the global warming phenomenon. Cumulative temperatures calculated for Tilia may serve as a basis for forecasting the beginning of the pollen season.

Dracocephalum moldavica is an aromatic plant with a lemon scent and versatile use. Its flowers produce large amounts of nectar, which is collected by bees and bumblebees. The aim of the study was to investigate the structure of the floral nectary in this melliferous plant, which has not been analysed to date. The analyses were carried out with the use of light, fluorescence, scanning electron, and transmission electron microscopy, as well as histochemical techniques. The four-lobed nectary with a diameter of 0.9-1.2 mm and a maximum height of 1.2 mm is located at the ovary base; one of its lobes is larger than the others and bears 20-30 nectarostomata and 8-9 glandular trichomes. The histochemical assays revealed the presence of essential oil and phenolic compounds in the nectary tissues and in glandular trichomes. The nectary tissues are supplied by xylem- and phloem-containing vascular bundles. The nectariferous parenchyma cells have numerous mitochondria, plastids, ribosomes, dictyosomes, ER profiles, vesicles, thin cell walls, and plasmodesmata. Starch grains are present only in the tissues of nectaries in floral buds. The study showed high metabolic activity of D. moldavica nectary glands, i.e., production of not only nectar but also essential oil, which may increase the attractiveness of the flowers to pollinators, inhibit the growth of fungal and bacterial pathogens, and limit pest foraging.

Chaenomeles japonica is an attractive ornamental shrub flowering in spring. It is also a valuable source of nectar and pollen for entomofauna. The study was carried out to investigate the structure of hypanthial nectaries present in the flowers of this species with the use of light and scanning electron microscopy. Nectary tissues were examined in three stages of flowering, with special focus placed on changes occurring in the epidermis and nectariferous parnechyma. Long-styled flowers, which produce nectar abundantly, were selected for the study. The nectary parenchyma was shown to consist of multiple cell layers (up to 20). The epidermis was initially single-layered, but the number of layers gradually increased to 2-3 during the following days of flowering. The outer walls of epidermis cells were covered by a strongly undulating cuticle with massive striae. Cracks and perforations, which are probably nectar release sites, were visible between the striae. The presence of the secretion in the intercellular spaces between the parenchyma layer and the epidermis may indicate apoplastic nectar transport. The presence of stomata, as well as pores in the cuticle layer of the nectary epidermis, suggests that C. japonica nectar is secreted in two ways: (i) through the nectarostomata and (ii) ordinary epidermis cells with the involvement of the cuticle., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Trollius europeus L. flowers produce nectar available to various groups of insects. No anatomical studies of these floral nectaries have been conducted to date. This study presents the structure of nectaries at different levels of organisation and the characteristics of petaloids, nectary leaves (petals), and stamens, including their micromorphology. The analyses of the nectaries were carried out with the use of light, fluorescence, scanning electron, and transmission electron microscopy techniques. The nectary located in a small cavity on the nectary leaf consists of the epidermis, nectar-producing parenchyma, and subnectary parenchyma, which has three large vascular bundles containing phloem and xylem. Amyloplasts with starch granules are present only in the parenchyma surrounding the vascular bundles. The other cells of the nectary parenchyma contain only chromoplasts with large plastoglobules. Since there are no chloroplasts, sugars required for nectar production are assumed to originate from phloem sap. The numerous plasmodesmata in the cell walls indicate a symplastic route of pre-nectar. Nectar is secreted onto the nectary surface in the holocrine mode. After disorganisation of the cytoplasmic structure, the epidermal cell wall is disrupted and the cell contents along with the nectar are released into the depression on the nectary leaf. The secretion of nectar from cells is non-synchronous and lasts 4-5 days. The content of nectar proteins and lipids derived from the cytoplasm of epidermal cells increases the nutritional value of the secretion, which may be important for pollinators., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Natural defensive substances synthesized by plants that could replace synthetic pesticides in the protection of plants against insect invasions are constantly being sought. The study assessed changes in the qualitative and quantitative composition of secondary metabolites in horse chestnut leaves collected in different locations and differing in the sensitivity of the plant to the invasion by the horse-chestnut leaf miner. An attempt was made to identify compounds that are most responsible for the increased plant resistance to this threat. Additionally, changes in the anatomy of chestnut leaves affected by the pest were presented. It was noticed that the trees differed in the composition of secondary metabolites already in the initial growing season, which should be related to the influence of habitat conditions. The analysis of the profile of the compounds in non-infested and infested horse chestnut leaves revealed a clear response of the plant to the stress factor, i.e., the foraging of the horse-chestnut leaf miner. Catechins seem to be compounds involved in plant resistance. The leaf anatomy showed enhanced accumulation of phenolic compounds at the pest foraging sites. Hypertrophy and thickened and cracked cell walls of the spongy parenchyma were visible in the vicinity of the mines.

(1) Background: Centaurea cyanus L. is a medicinal plant whose flowers are widely used in herbal medicine. The aim of the study was to localise flower tissues that are responsible for the production of secretory products in petals and to analyse the volatile compounds. The volatile compounds of the flowers of this species have not been investigated to date. (2) Methods: Light, fluorescence, scanning and transmission electron microscopy techniques were used in the study. Lipophilic compounds were localised in the tissues using histochemical assays. Volatile compounds were determined with the use of solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). (3) Results: The study showed production of secretion in the petal parenchyma, whose ultrastructure has features of a secretory tissue. The lipophilic secretion was localised in the cells and intercellular spaces of the parenchyma and in the walls and surface of epidermal cells, where it accumulated after release through cuticle microchannels. Sesquiterpenes were found to constitute the main group of volatile compounds, with the highest content of β-caryophyllene (26.17%) and α-humulene (9.77%). (4) Conclusions: Given the presence of some volatile components that are often found in resins (caryophyllene, delta-cadinene) and the abundant secretion residues on the epidermal surface, we suppose that the C. cyanus secretion released by the flowers is a resinaceous mixture (oleoresin), which is frequently found in plants, as shown by literature data. This secretion may play an important role in the therapeutic effects of C. cyanus flowers.

Birch belongs to the most important allergenic taxa in Europe, therefore information on the start dates of the pollen season is very important for allergists and their patients as well as for climatologists. The study examined changes in the start of the birch pollen season as well as determined the trend of these changes. Pollen monitoring was performed in Lublin (eastern Poland) in the period 2001-2019 using the volumetric method. The Makra-test was used to detect periods with significantly higher or lower average of the onset than the average for the whole dataset. Two significant falls in the average of the pollen season start were found in 2007 and 2014. Besides, taking into account the 2-3-year rhythm of high and low concentrations of birch pollen in the atmospheric air, linear trends were fitted for the subsets of high and low abundance seasons. Significant changes in Betula pollen season start dates were only determined for the highly abundance seasons, while the results for seasons with a low concentration did not allow rejecting the hypothesis about the lack of a linear trend in the changes in the studied parameter. Moreover, a significant polynomial relationship was found between the beginning of a pollen season and the average values of monthly temperatures preceded a season. These analyses show that the start dates of the Betula pollen season are getting significantly earlier. The dynamics of changes differ between seasons with high and low concentrations of pollen., Competing Interests: The authors have declared that no competing interests exist.

The aim of this study was to conduct a histochemical analysis to localize lipids, terpenes, essential oil, and iridoids in the trichomes of the L. album subsp. album corolla. Morphometric examinations of individual trichome types were performed. Light and scanning electron microscopy techniques were used to show the micromorphology and localization of lipophilic compounds and iridoids in secretory trichomes with the use of histochemical tests. Additionally, the content of essential oil and its components were determined using gas chromatography-mass spectrometry (GC-MS). Qualitative analyses of triterpenes carried out using high-performance thin-layer chromatography (HPTLC) coupled with densitometric detection, and the iridoid content expressed as aucubin was examined with spectrophotometric techniques. We showed the presence of iridoids and different lipophilic compounds in papillae and glandular and non-glandular trichomes. On average, the flowers of L. album subsp. album yielded 0.04 mL/kg of essential oil, which was dominated by aldehydes, sesquiterpenes, and alkanes. The extract of the L. album subsp. album corolla contained 1.5 × 10 -3 ± 4.3 × 10 -4 mg/mL of iridoid aucubin and three triterpenes: oleanolic acid, β-amyrin, and β-amyrin acetate. Aucubin and β-amyrin acetate were detected for the first time. We suggest the use of L. album subsp. album flowers as supplements in human nutrition.

In recent years, allergies due to airborne pollen allergens have shown an increasing trend, along with the severity of allergic symptoms in most industrialized countries, while synergism with other common atmospheric pollutants has also been identified as affecting the overall quality of citizenly life. In this study, we propose the state-of-the-art WRF-Chem model, which is a complex Eulerian meteorological model integrated on-line with atmospheric chemistry. We used a combination of the WRF-Chem extended towards birch pollen, and the emission module based on heating degree days, which has not been tested before. The simulations were run for the moderate season in terms of birch pollen concentrations (year 2015) and high season (year 2016) over Central Europe, which were validated against 11 observational stations located in Poland. The results show that there is a big difference in the model's performance for the two modelled years. In general, the model overestimates birch pollen concentrations for the moderate season and highly underestimates birch pollen concentrations for the year 2016. The model was able to predict birch pollen concentrations for first allergy symptoms (above 20 pollen m -3 ) as well as for severe symptoms (above 90 pollen m -3 ) with probability of detection at 0.78 and 0.68 and success ratio at 0.75 and 0.57, respectively for the year 2015. However, the model failed to reproduce these parameters for the year 2016. The results indicate the potential role of correcting the total seasonal pollen emission in improving the model's performance, especially for specific years in terms of pollen productivity. The application of chemical transport models such as WRF-Chem for pollen modelling provides a great opportunity for simultaneous simulations of chemical air pollution and allergic pollen with one goal, which is a step forward for studying and understanding the co-exposure of these particles in the air.

Previous studies have demonstrated that plants are a very good indicator of global environmental variations. The responses of many plant species to climate change are confirmed by aerobiological research. This paper presents an analysis of many parameters of pollen seasons in the Amaranthaceae family based on measurements of pollen concentrations in atmospheric air. Pollen samples were collected with the volumetric method at a sampling site in Lublin (Poland) in 2001-2019. The obtained data were verified using statistical analyses. Moreover, the presence of pollenkitt on the pollen grain surface was examined in fresh anthers using scanning electron and light microscopes, since there are some difficulties in identification of Amaranthaceae pollen grains deposited on microscopic slides in aerobiological analysis. The pollen season in Amaranthaceae began on average on June 23 and ended on October 5, i.e. it lasted 105 days. The peak value and annual pollen sum were characterized by the highest variability in the study years in comparison with other season characteristics. The annual pollen sum was in the range from 183 to 725. Maximum concentrations were most often recorded in the second half of August, which is associated with the greatest risk of development of pollen allergy symptoms in sensitive subjects during this period. The results obtained in the 19-year study revealed that the pollen seasons began 14 days earlier. Similarly, the end of the season was accelerated by 24 days. The response of these plants to climate change also include the reduced pollen production by representatives of this family, which was manifested by a decrease in the annual sum of daily airborne pollen concentrations, on average by 35%, and a reduction in the maximum pollen concentration, on average by more than 60%. We found that temperature in May and June had an effect on pollen release, and relative air humidity in May influenced pollen concentrations. We noted significant similarities in the pollen release rate during the last 8 years of the study. The scanning electron microscopy examinations showed that the pollen grain surface in the representative of this family was covered completely or partially with pollenkitt. Hence, the apertures characteristic for pollen in this family were poorly visible. The presence of pollenkitt on the surface of these polyaperturate pollen grains may play an important role in preventing water loss during pollen migration in the air. Our research has demonstrated the response of plants flowering in summer to climate change. The results not only have practical importance for public health in the aspect of allergy risk but can also help to assess environmental changes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Centaurea cyanus L. is a valuable source of many different bioactive substances. It is used in herbal medicine, but the structure of its organs used as raw material and secretory tissues has been insufficiently examined. The aim of this paper was to investigate the microstructure of C. cyanus flowers, bracts, stems and leaves with particular emphasis on secretory structures. Moreover, the main classes of secondary metabolites present in the secretion were identified and the taxonomic value of some micromorphological and anatomical features was analysed. Histochemical, micromorphological and ultrastructural analyses of aboveground organs of C. cyanus were carried out using light, fluorescence, scanning and transmission electron microscopy. The analyses revealed the presence of petal papillae and a characteristic cuticular pattern on the petals, stamens and stylar hairs. There were four types of non-glandular trichomes on the bracts, leaves and stem surfaces. The epidermal cells of the bracts contained prismatic calcium oxalate crystals. Two kinds of secretory structures, i.e. glandular trichomes and ducts, were observed in the C. cyanus organs. The glandular trichomes were located on the bract and stem surfaces, and the ducts were detected in the leaves and stems. Ultrastructural analyses of the epithelium of the ducts showed the presence of strongly osmiophilic insoluble phenolic material in vacuoles as well as moderately osmiophilic insoluble lipidic material in elaioplasts and vesicles. The results of histochemical assays showed a heterogeneous nature of the duct secretion, which contained essential oil, lipids, flavonoids, tannins and terpenes containing steroids.

During the spring period, Betula pollen is the main cause of inhalant allergies in Poland and therefore it is important to monitor and forecast airborne pollen concentrations of this taxon. This study conducted a comparative analysis of the basic characteristics of Betula pollen seasons at the regional scale. The study was carried out from 2001 to 2016 in five cities in Poland: Lublin, Warsaw, Cracow, Sosnowiec, and Szczecin. To find the attributes of birch pollen seasons that mostly differentiated the individual cities, a general discriminant analysis (GDA) was performed, while a principal component analysis (PCA) allowed us to reduce the data space and present a scatterplot of PCA scores in order to compare pollen seasons in the individual cities. The contingency table was also analyzed to check whether there was a significant relationship between pollen counts in the studied years and cities. At most of the sites, biennial cycles of low and high pollen concentrations can be observed. Due to the high variation in seasons in each of these cities, two data groups were distinguished: Group 1 was composed of seasons with high pollen deposition (2001, 2003, 2006, 2008, 2010, 2012, 2014, 2016), and Group 2 comprising the other seasons. Multivariate analyses were performed on both these groups as well as in the entire dataset. End98, Peak Value, and Annual Total had the highest discriminant power. In Group 1, Warsaw and Sosnowiec differed the most in the investigated parameters, while Cracow and Szczecin differed the least. In both groups, most seasons with the highest pollen birch concentration were observed in Lublin, followed by Warsaw, while in Cracow, the number of such seasons was the smallest., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction and Objective: The timings of Fraxinus and Betula flowering and pollen release overlap, which may cause increased allergic reactions in sensitive people. The aim of the present study was to characterize Fraxinus pollen seasons in Lublin (central-eastern Poland) and to identify meteorological factors that most determine the occurrence of airborne pollen of this taxon, as well as obtain forecast models for the basic characteristics of the pollen season., Material and Methods: The study was conducted in Lublin during the period 2001-2016, employing the volumetric method. The seasons were compared by PCA (Principal Component Analysis). To determine relationships between meteorological conditions and the pattern of pollen seasons, regression analysis was used. Data for the period 2001-2015 were used to create forecast models by applying regression analysis, while the 2016 data served to verify these models., Results: Season end date and seasonal peak date were characterized by the lowest variation. The biggest differences were found for peak value and total annual pollen sum. The average dates of occurrence of ash pollen grains in the air of Lublin were between 13 April 13 - 3 May 3, whereas, on average, the pollen peak date occurred on 23 April. The factor loading values for the PC1 variable indicate that it is most strongly correlated with peak value and total pollen sum, while the PC2 variable correlated with the pollen season start date and season duration (a negative correlation). Regression models were developed for the following pollen season characteristics: season start, end and duration, seasonal peak date, and total annual pollen sum., Conclusions: The fit of the forecast models was at the level of 62-94%. Analysis of the data showed that weather conditions mainly in February were important factors controlling the Fraxinus pollen season.

Biological invasions are a major driver of global change, for which models can attribute causes, assess impacts and guide management. However, invasion models typically focus on spread from known introduction points or non-native distributions and ignore the transport processes by which species arrive. Here, we developed a simulation model to understand and describe plant invasion at a continental scale, integrating repeated transport through trade pathways, unintentional release events and the population dynamics and local anthropogenic dispersal that drive subsequent spread. We used the model to simulate the invasion of Europe by common ragweed (Ambrosia artemisiifolia), a globally invasive plant that causes serious harm as an aeroallergen and crop weed. Simulations starting in 1950 accurately reproduced ragweed's current distribution, including the presence of records in climatically unsuitable areas as a result of repeated introduction. Furthermore, the model outputs were strongly correlated with spatial and temporal patterns of ragweed pollen concentrations, which are fully independent of the calibration data. The model suggests that recent trends for warmer summers and increased volumes of international trade have accelerated the ragweed invasion. For the latter, long distance dispersal because of trade within the invaded continent is highlighted as a key invasion process, in addition to import from the native range. Biosecurity simulations, whereby transport through trade pathways is halted, showed that effective control is only achieved by early action targeting all relevant pathways. We conclude that invasion models would benefit from integrating introduction processes (transport and release) with spread dynamics, to better represent propagule pressure from native sources as well as mechanisms for long-distance dispersal within invaded continents. Ultimately, such integration may facilitate better prediction of spatial and temporal variation in invasion risk and provide useful guidance for management strategies to reduce the impacts of invasion., (© 2016 John Wiley & Sons Ltd.)

The aim of the study was to create and evaluate models for predicting high levels of daily pollen concentration of Corylus , Alnus , and Betula using a spatiotemporal correlation of pollen count. For each taxon, a high pollen count level was established according to the first allergy symptoms during exposure. The dataset was divided into a training set and a test set, using a stratified random split. For each taxon and city, the model was built using a random forest method. Corylus models performed poorly. However, the study revealed the possibility of predicting with substantial accuracy the occurrence of days with high pollen concentrations of Alnus and Betula using past pollen count data from monitoring sites. These results can be used for building (1) simpler models, which require data only from aerobiological monitoring sites, and (2) combined meteorological and aerobiological models for predicting high levels of pollen concentration.