Abstract Insect pollination is critical for fruit production, particularly for pears, most of which have high self-incompatibility and are less preferred by pollinators than other fruit trees. Research has focused on fruit traits, and less is known about how floral traits may influence pollination and fruit production. Hypothesising that pollination-related traits differ between Asian and European pears, which exhibit large variation in pollination and distinct domestication processes, we conducted a systematic review of pear pollination studies published globally from 1922 to 2025. Research on pollination has increased rapidly over the last 25 years. Compared to European pears, we found that Asian pears are more pollinator-dependent and exhibit different floral traits: lower nectar sugar concentration and lower relative content of attractive floral scents, but higher pollen production and a higher relative content of N-containing floral scents. Although Asian pear flowers attract a similar number of insect pollinator taxa as European pears, current Asian pear production still relies mainly on artificial pollination. Moreover, various artificial pollination techniques and pollination management practices, including introducing indigenous Asian honey bees, which outperformed in collecting pear pollen, had uncertain effects on pollination and fruit production, as less attention was paid to understanding the nature of plant-pollinator interactions. Further studies are needed to investigate how the domestication process and the co-adaptations of Asian honey bees influence the pollination-related floral traits of pears. This may provide valuable insights into enhancing floral attractiveness, improving pollination efficiency, and increasing fruit production in monoculture Asian pears.

A 14 500-year multi-proxy reconstruction of climate and environmental change in Eastern Baltics

Intra-individual variation in pollen availability: An experimental analysis of its impact on plant-pollinator interactions.

The reproductive competence of banana (Musa spp.) is governed by genetic constitution, with its expression being modulated by environmental conditions prevailing during flowering, which is not well explored. The present investigation evaluated genotypic and environmental modulation of pollen count (PC), pollen viability (PV), pollen germination (PG), and stigma receptivity duration (SR) in fifteen banana genotypes across four flowering phases: FP1 (April-May, 2024), FP2 (July-August, 2024), FP3 (September-November, 2024), and FP4 (January-March, 2025). Substantial genotypic differences were evident, with the diploid genotype ‘Calcutta 4, AA’ consistently expressing maximal PC (24,051.4 ± 3349.66) and PV (71.73 ± 9.05%), whereas negligible to extremely poor pollen production was observed in ‘Banana-02/22, BB’ and ‘Alpan, AAB’. Reproductive performance peaked during FP1, characterized by elevated PC (8201.5 ± 1352.66), PV (56.24 ± 3.97%), and PG (45.9 ± 4.60%), and declined markedly under FP4, coinciding with reduced thermal accumulation. Diploid genotypes, notably ‘cv. Rose, AA’ and ‘Calcutta 4, AA’ exhibited consistently superior PG (≥ 60%), in contrast to triploids, which remained largely sterile. Correlation analysis indicated positive associations of PC, PV, and PG with biothermal indices, especially photothermal units, while SR exhibited a weak negative relationship, with maximum duration recorded during cooler flowering phases. These findings underscore the utility of integrating biometeorological cues with genotype-specific fertility attributes to optimize hybridization strategies under variable environmental regimes.

This study examined nectar and pollen production as well as pollinator visitation in Nigella damascena (Ranunculaceae), an annual ornamental and seed crop, over two flowering seasons. Flower anthesis lasted 6-7 days, with protandry: the male phase began on the first day, and pollen presentation continued until corolla senescence. Peak stigma receptivity occurred in 5-day-old flowers, resulting in a partial overlap of male and female functions between days 5 and 7. Nectar was secreted by petal-derived structures, with secretion beginning in 1-day-old flowers and steadily increasing, peaking on the day of maximum stigma receptivity. The nectar sugar composition differed between floral phases; it was sucrose-dominant in the male phase and sucrose-rich in the female phase. Significant year effects were observed for flowering abundance, nectar traits (volume, sugar production, concentration), and pollen output. Flowers were visited predominantly by honey bees, but bumblebees, solitary bees, and dipterans were also recorded. These results demonstrate that floral reward traits vary between years and contribute to differences in the temporal availability of nectar and pollen resources.

Irrigation and plant origin are key factors influencing plant growth, development, and reproductive strategies. These same factors may also affect the floral resource value of plants to pollinators, influencing the efficacy of pollinator plantings for conservation or enhancement. While these factors have been studied separately, few studies have examined how plant origin influences plant responses to irrigation for floral traits such as nectar and pollen. In this study, we evaluated 10 native and 10 non-native plants to Florida under two different irrigation treatments and measured floral density, floral display, floral resources (nectar and pollen), and pollinator visitation rates and diversity in an open field study. There was strong to very strong evidence that native plants produced higher floral densities and displays, along with greater amounts of pollen per plot, and attracted a higher number and diversity of pollinators as compared to non-native plants. Additionally, there was weak to moderate evidence that fully irrigated plants produced higher nectar volumes and pollen quantities per plot as well as pollen with higher protein content as compared to partially irrigated plants. However, there was no evidence that native and non-native plants responded differently to irrigation treatment. Additionally, individual pollinator guilds responded differently to origin and irrigation, highlighting the complexity of plant-pollinator interactions. We conclude that native plants consistently produce more flowers and attract a greater number and diversity of pollinators while irrigation affects the production and resource value of pollen and nectar. These findings emphasize the importance of considering both plant origin and irrigation on resource availability of flowers when selecting pollinator-friendly plants under varying climates and management regimes.

Transposons drive genetic diversity and evolution by altering the genomic landscape over time. Here, we describe DELAYED ABAXIAL TRICHOMES (DAB), a Helitron/RC transposable element in Arabidopsis thaliana that has a role in vegetative phase change and gametogenesis. A genome-wide association study (GWAS) for the timing of abaxial trichome development (an adult leaf trait) in A. thaliana revealed a conserved haplotype of polymorphisms within DAB that delays abaxial trichome production. CRISPR-Cas9-induced deletions of DAB are gametophytic pollen-lethal, indicating that this locus is also required for pollen production. DAB produces 24-nucleotide siRNAs with sequence complementarity to genes involved in embryogenesis, gametogenesis, and seed development. DAB also impacts the expression of ARGONAUTE genes, genes involved in RNA-directed DNA methylation (RdDM), as well as genes in several key genetic pathways. This global effect on gene expression suggests that DAB may have functions beyond those identified in this study.

Allergies are one of the major health challenges of our time, associated with a high individual burden of disease and high costs for the healthcare system. Given their prevalence, allergies are also highly relevant from a public health perspective. The development of allergic diseases is multifactorial. In addition to individual factors (e.g., genetic predisposition), environmental factors are particularly important. These include climate (including climate change), weather, and air pollution, which affect the biosphere and biodiversity. Pollen-associated allergic rhinitis is one of the most common allergies. Airborne pollen is strongly connected with climate (change) and air pollution. For example, interannual climate variability and climate change affect phenology, pollen production, and pollen transport, and air pollutants affect pollen allergenicity. Climate change also affects air quality as meteorological conditions influence relevant processes such as the emission, transport, chemistry, and deposition of air pollutants, which affect the occurrence, intensity, and duration of allergy symptoms. The aims of this position paper are: (a) to provide an overview of the current state of scientific knowledge on the effects of climate change and air quality on pollen allergies, (b) to discuss conflicting objectives in the fight against pollen allergies, and (c) to provide recommendations for policy makers, health professionals, public health measures, and future research.

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent systemic inflammation, which contributes to progressive multi-organ dysfunction, particularly in metabolically active tissues such as the liver and kidneys. Bee bread (Perga), a fermented bee pollen product rich in bioactive compounds, has been reported to exert anti-inflammatory and organ-protective effects; however, its tissue-specific influence on inflammatory responses under diabetic conditions remains incompletely defined. Thirty-two male Wistar Albino rats were randomly assigned to four groups: Control, DM, DM + Perga, and Perga. Diabetes was induced by streptozotocin (STZ; 55 mg/kg, i.p.). Perga was administered orally at a dose of 0.5 g/kg/day for 28 days. Pro-inflammatory cytokine levels (CRP, TNF-α, IL-1β, and IL-6) were quantified in liver and kidney tissues using ELISA. Histopathological alterations were evaluated by hematoxylin and eosin staining. DM significantly increased the IL-1β, IL-6, and CRP levels in hepatic tissue and elevated TNF-α, IL-1β, IL-6, and CRP levels in renal tissue. Perga administration attenuated these inflammatory responses, particularly reducing IL-1β and IL-6 levels in the liver and all measured cytokines in the kidney. Histopathological analyses revealed hepatocyte degeneration and necrosis, sinusoidal dilatation, tubular epithelial degeneration, and glomerular damage in diabetic rats, whereas Perga treatment partially improved hepatic alterations and improved renal structural integrity. These findings indicate that Perga exerts tissue-specific anti-inflammatory and protective effects in experimental diabetes, with a more pronounced impact on renal inflammation than on hepatic responses. Although its effects on hepatic TNF-α and CRP levels were limited, Perga may act as a natural modulator of cytokine-mediated inflammatory processes. Further studies are warranted to elucidate the underlying molecular mechanisms.

Bee pollen is a nutrient-dense food; however, its dense cell wall limits the bioavailability and digestive absorption of nutrients. This study established a co-fermentation process that combines Lactobacillus strains isolated from bee bread with commercial probiotics to improve the nutritional profile and functional properties of bee pollen. L. acidophilus (LBA1) and L. plantarum (LBP3) were isolated from bee bread and used for single-strain fermentation of bee pollen and its co-fermentation with commercial probiotics. The results indicated that fermentation increased the protein, free amino acid, vitamin C, and flavonoid contents. The co-fermentation product (FHL-99) of LBP3 and the commercial inoculant (99 strains) exhibited the highest cell wall disruption rate (67.57%) in artificial intestinal juice. Ex vivo activity analysis revealed enhanced DPPH, hydroxyl, and ABTS+ radical scavenging capacities of fermented bee pollen. Its inhibitory effects on hyaluronidase activity and protein thermal denaturation were also enhanced. FHL-99 demonstrated optimal performance across multiple indices, achieving a DPPH radical scavenging rate of 77.46% and hyaluronidase inhibition rate of 37.38%. In conclusion, synergistic co-fermentation can disrupt pollen cell walls and enrich bioactive constituents, providing an efficient biotechnological approach for the development of high-quality fermented bee pollen products.

Cupressales species are widely planted in urban landscapes, where their pollen represents a growing source of biological air pollution and contributes to seasonal allergies. Linking their flowering dynamics with atmospheric allergen loads is essential for understanding ecological flows of airborne particles in cities. We aimed to quantify interspecific differences in allergenic potential among common urban Cupressales taxa and to determine how flowering periods and pollen production shape airborne allergen levels. We specifically assessed variation in Cup a 1 homolog abundance to evaluate its relevance for landscape-scale allergy risk. The study was conducted in Poznań (Poland) during the 2023-2024 pollen seasons. Phenological observations, aerobiological monitoring, and immunoenzymatic assays were combined to relate flowering timing, atmospheric pollen concentrations, and allergen content across ten Cupressales species. Species differed substantially in flowering phenology, pollen output, and allergen levels. Taxus baccata, Thuja occidentalis, and Th. plicata released large amounts of pollen but contained low levels of Cup a 1 homologs. Conversely, Juniperus taxa and Callitropsis nootkatensis showed consistently high allergenicity, contributing disproportionately to peak atmospheric allergen loads despite moderate pollen release. These patterns indicate that allergen exposure risk is driven not only by pollen abundance but also by species-specific allergen potency. Urban planting dominated by high-allergenicity taxa may therefore intensify allergy symptoms at the neighbourhood scale. Our findings demonstrate that allergenicity metrics can inform urban vegetation planning. Selecting species with favourable phenological and allergenic profiles may help reduce airborne allergens and support healthier, more resilient urban landscapes.

Abstract A comprehensive understanding of seed plant reproduction requires extending molecular and hormonal research beyond angiosperm models to include gymnosperms. Cycads belongs to one of the ancientest lineages of spermatophytes, making it a critical system for understanding the evolution of plant reproduction. While phytohormones like auxin are known to be essential regulators of male reproductive development in angiosperms, their role in gymnosperms remains largely unknown. Here, we report the first spatiotemporal mapping of IAA (indol-3-acetic acid) distribution in the male cones of six Cycas species. Studying hormonal regulation in non-model organisms presents technical challenges. To overcome this, we employed a tailored approach combining high-resolution histology with IAA-immunolocalization assays to map the phytohormone distribution. Critically, we demonstrate the presence of IAA within the developing microsporangia, with a sharp concentration peak observed in the more advanced stage. Specifically, a strong IAA peak was observed in the sporophytic tissues of the microsporangial wall, notably the degenerating tapetum, and within the developing pollen grains. This spatial and temporal pattern strongly implicates IAA in regulating tapetum breakdown and pollen production in Cycas , reinforcing the hypothesis of auxin conserved critical role in male fertility across all seed plants. Additionally, our work highlights the efficacy of immunolocalization for dissecting hormonal mechanisms in non-model systems.

The rise in hay fever cases worldwide prompts the International Association of Aerobiology (IAA) to publish the International Aerobiology Newsletter twice a year, announcing international congresses and educational programs for professionals. The Pinaceae family, comprising 650 species, is known to have mildly allergenic pollen. This pollen is characterized by its large size, high volatility due to air sacs, unique palymorphology, and high pollen production. It is susceptible to climate change and environmental pollution, which is reflected in changing timing of plant phenology and pollen production, allergenic properties, and the emergence of teratomorphs. The purpose is to study the concentration of Pinaceae pollen in the air and their integrative contribution to the aerobiological spectrum of Karakol as potential pollen allergens. Airborne pollen belonging to the Pinaceae family was collected and identified during a 3-year (2015–2017) aerobiological monitoring program in Karakol, Kyrgyzstan, using a Lanzoni VPPS 2000 trap. During the study period, interannual variations in the total annual pollen index, as well as the dates of the beginning, peak, and end of the pollen season, were recorded. Season length, peak day dating, and maximum daily pollen concentrations varied significantly between years due to climate change and the peculiarities of pollen production in different years. Pinaceae pollen dominated the pollen spectrum of trees and shrubs, accounting for 68–75% of the annual total pollen count. It circulated in the air of Karakol throughout all study seasons, lasting from 108 to 130 days. Daily peaks in Pinus pollen concentration were recorded in May–June, reaching a maximum of 4,259 pollen grains/cm3. The average annual concentration over the 3-year study period was 10,555.3 pollen grains/cm3. The highest annual Pinus pollen level was reached in 2016 (16,002 pollen grains/cm3), and the lowest in the extremely hot year of 2015 (1,220 pollen grains/cm3). Thus, pine has a relatively short pollen season compared to pollen of leading aeroallergens (e.g., cereals – 171 days), but with a high pollen concentration. The high concentration of Pinus pollen in the air of Karakol and its cross-reactivity with other plant pollen allow Pinaceae pollen to be classified as potentially allergenic. The large pollen size and low protein content protected by a waxy coat are the main reasons for its low allergenicity. Under the influence of adverse anthropogenic factors and climate change, the waxy coat is destroyed, opening up allergenic proteins and allowing them to more easily penetrate mucous membranes, triggering allergic reactions.

Environmental context is vital when analysing archaeological sites and interpreting past human activity. Pollen, being widely dispersed and readily preserved in wetland sediments, is frequently used to investigate past land cover, especially in wetland-rich ‘blue-green’ lowland landscapes (landscapes formed in locations where hydrology is an important determinant of natural vegetation, geomorphology and land use, such as river valleys and estuaries; landscapes which are transitional between aquatic-dominated and terrestrial-dominated). Recent developments in quantitative landcover reconstruction from pollen diagrams, such as the Multiple Scenario Approach (MSA), improve interpretations by taking into account variations in pollen production, dispersal, and sedimentary basin properties. We apply the MSA to derive quantitative, spatially-informed land cover reconstructions for four prehistoric periods in a major UK blue-green lowland landscape, the Humberhead Levels. Reconstructed quantified land cover broadly confirms inferences from previous studies, showing the spread of wet woodland and development of raised mires in the middle Holocene, whilst highlighting the spatial complexity of this dynamic blue-green landscape. The reconstruction process highlights gaps in available data and shows, for example, that the complex interplay of freshwater and marine systems in the later Holocene is only partially understood; thus reconstructions can inform the development of future research agendas in this and other blue-green landscapes. The spatially referenced MSA outputs offer a powerful means of enhancing the integration of pollen analysis with other disciplines, including archaeology, and for developing clear hypotheses for future research.

Abstract Pollen records and models of pollen–vegetation relationships are required to reconstruct past plant abundances during the Holocene to answer specific questions on climate history, human impact, biodiversity, and their interactions. An important parameter for model applications is pollen productivity, estimated as relative pollen productivity (RPP) using a modern dataset of pollen assemblages and related plant cover using the extended R value (ERV) model. We present here the first study performed in India to obtain estimates of RPP for key plant taxa of the tropical dry evergreen forest (TDEF) formations in southeastern India. Pollen samples collected following standard protocols at 14 sites with a stratified random distribution provided 96 identified pollen morphotypes corresponding to 228 plant species in the field surveys. To facilitate comparison of these results with RPP values obtained in other tropical regions, the approach and programs of Sugita were used. Several combinations of 20 selected pollen morphotypes were deployed in the model runs that comprised different combinations of three Prentice–Sugita ERV submodels, with three pollen dispersion models for distance weighting of the vegetation data. The best RPP estimates were obtained for six major TDEF plant taxa including the reference taxon Poaceae with ERV submodel 3 and Prentice's dispersion model, as follows (±SD): Justicia ‐t. (herb) (19.02 ± 0.11) > Dodonaea viscosa (shrub) (17.70 ± 0.03) > Acacia ‐t. (tree) (13.48 ± 0.11) > Melastomataceae/Combretaceae (tree) (4.22 ± 0.01) > Randia (shrub) (1.97 ± 0.02) > Poaceae (herb) (1.00 ± 0.00). While several of these taxa occur elsewhere in Asia, the Caribbean and Africa, published RPP values for comparison are only available for Acacia ‐t. and Melastomataceae/Combretaceae in Africa. They differ greatly from the values in this study, implying a strong pollen underrepresentation of the two taxa compared to Poaceae in Africa, while there is a strong pollen overrepresentation for the same two taxa in southern India. This is tentatively explained by the different constituent species involved and differences in landscape structure and related field work strategies. These results highlight that large between‐continent differences in RPPs for the same taxa may occur.

Bioaccessibility of phenolics and anti-inflammatory effects during in vitro simulated digestion of enzymatically broken bee-collected pollen.

Relative pollen productivity estimates and quantitative land-cover reconstruction over the past millennium in cold-temperate coniferous forest in Northeast China

Flowers that present their anthers and stigma in close proximity can achieve precise animal-mediated pollen transfer, but risk self-pollination. One evolutionary solution is reciprocal herkogamy. Reciprocity of anther and style positions among different plants (i.e., a genetic dimorphism) is common in distylous plants, but very rare in enantiostylous plants. We investigated the pollination and reproductive system of the enantiostylous Caribbean plant Cubanicula xanthorrhizos (Haemodoraceae). We assessed stylar orientation of flowers and conducted controlled pollination experiments. We used videography of flower visitors and pollen load analysis to determine the pollination mechanism. We also measured floral morphology, pollen production, spectral reflectance, and volatile emissions. Cubanicula xanthorrhizos exhibits dimorphic enantiostyly with c. 50:50 left- to right-styled morphs. Plants are self-compatible, but pollinator dependent for seed production. Intra- and intermorph crosses are equally fertile. The nectarless flowers are pollinated by female carpenter bees (Xylocopa cubaecola) that collect pollen, often by sonication, from two centrally positioned yellow feeding anthers. An inconspicuous deflected pollinating anther deposits pollen on the side of the bee thorax, which contacts the stigma of the mirror-image morph. A yellow-orange "guide" on the white tepals appears to be a visual attractant. Flowers emit methoxy benzenoid volatiles that may also attract bees. Reciprocity of the style with a single pollinating stamen in C. xanthorrhizos appears to promote intermorph pollen export via "safe sites" on pollen-collecting bees. This novel case of dimorphic enantiostyly contributes to understanding of the evolution of floral polymorphisms.

Flower size is a key determinant of reproductive success in animal-pollinated plants. However, traditional interpretations of these costs have often overlooked critical aspects of floral investment, including the complex relationships between flower size and factors such as initial resource allocation, floral longevity, resource resorption efficiency and ultimate reproductive output. We studied two Yulania species (Y. liliiflora and Y. soulangeana) to compare large and small flowers in terms of floral traits, pollinator preference, seed set ratio and nutrient resorption. Large flowers exhibited significantly greater floral display area, dry weight and pollen production but shorter longevity than small flowers. Pollinators, particularly bumblebees and honeybees, preferentially visited large flowers first, enhancing cross-pollination. When only large flowers were retained on branches (small flowers bagged), pollinator visitation frequency and seed set ratio of large flowers did not differ significantly from the natural control. In contrast, branches with only small flowers (large flowers bagged) experienced a significant reduction in pollinator visits. Consequently, the seed set ratio of small flowers in the absence of large flowers decreased significantly compared to that of small flowers under natural conditions. This suggests large flowers enhance pollinator attraction, indirectly benefiting neighbouring small flowers. Additionally, large flowers demonstrated significantly higher nutrient resorption efficiency (N, P, chlorophyll, starch, sugars and proteins) from senescing petals than small flowers. These findings indicate that large floral displays are not wasteful but instead optimize nutrient recycling and reproductive success. Floral size variation thus represents an adaptive strategy balancing pollinator-mediated reproduction with efficient resource use. Our study provides new insights into the ecological and evolutionary significance of floral trait variation in perennial plants.

ABSTRACT Orchidaceae is one of the most diverse plant families among flowering plants. Orchid diversity is reflected in their varied morphophysiological adaptations. Orchids are notable for their variety of floral mechanisms, their pollen grains commonly released as units called pollinia, and their “dust-seeds” with undifferentiated embryos lacking endosperm. In addition, orchids usually show specialized pollination systems, as well as a wide variety of pre- and postzygotic barriers (morphological, temporal, geographical, and molecular), which preclude self-pollination, geitonogamy, and interspecific cross-pollination. This review addresses the specializations exhibited in the reproduction of orchids, from pollen production to seed formation, considering the role of the different pre- and postzygotic barriers in fruit and seed set. Furthermore, the relationship between reproductive systems and the final development of fruits and seeds in this vast plant family is discussed. The development of specialized reproductive mechanisms, through the evolutionary innovation of pollinia and hierarchical pre- and postzygotic reproductive barriers, strongly promotes outcrossing and ensures genetic compatibility. However, while these mechanisms enhance reproductive success, they simultaneously increase orchid vulnerability to environmental threats.